/*

Copyright (c) 2003-2014, Arvid Norberg
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in
      the documentation and/or other materials provided with the distribution.
    * Neither the name of the author nor the names of its
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.

*/

#include <ctime>
#include <algorithm>
#include <set>
#include <cctype>
#include <numeric>

#ifdef _MSC_VER
#pragma warning(push, 1)
#endif

#include <boost/bind.hpp>

#ifdef _MSC_VER
#pragma warning(pop)
#endif

#include "libtorrent/config.hpp"
#include "libtorrent/torrent_handle.hpp"
#include "libtorrent/session.hpp"
#include "libtorrent/torrent_info.hpp"
#include "libtorrent/tracker_manager.hpp"
#include "libtorrent/parse_url.hpp"
#include "libtorrent/bencode.hpp"
#include "libtorrent/hasher.hpp"
#include "libtorrent/entry.hpp"
#include "libtorrent/peer.hpp"
#include "libtorrent/peer_connection.hpp"
#include "libtorrent/bt_peer_connection.hpp"
#include "libtorrent/web_peer_connection.hpp"
#include "libtorrent/http_seed_connection.hpp"
#include "libtorrent/peer_id.hpp"
#include "libtorrent/alert.hpp"
#include "libtorrent/identify_client.hpp"
#include "libtorrent/alert_types.hpp"
#include "libtorrent/extensions.hpp"
#include "libtorrent/aux_/session_impl.hpp"
#include "libtorrent/instantiate_connection.hpp"
#include "libtorrent/assert.hpp"
#include "libtorrent/broadcast_socket.hpp"
#include "libtorrent/kademlia/dht_tracker.hpp"
#include "libtorrent/peer_info.hpp"
#include "libtorrent/enum_net.hpp"
#include "libtorrent/http_connection.hpp"
#include "libtorrent/gzip.hpp" // for inflate_gzip
#include "libtorrent/random.hpp"
#include "libtorrent/string_util.hpp" // for allocate_string_copy
#include "libtorrent/alloca.hpp"

#ifdef TORRENT_USE_OPENSSL
#include "libtorrent/ssl_stream.hpp"
#include <boost/asio/ssl/context.hpp>
#if BOOST_VERSION >= 104700
#include <boost/asio/ssl/verify_context.hpp>
#endif // BOOST_VERSION
#endif // TORRENT_USE_OPENSSL

using namespace libtorrent;
using boost::tuples::tuple;
using boost::tuples::get;
using boost::tuples::make_tuple;
using libtorrent::aux::session_impl;

namespace
{
	struct find_peer_by_ip
	{
		find_peer_by_ip(tcp::endpoint const& a, const torrent* t)
			: ip(a)
			, tor(t)
		{ TORRENT_ASSERT(t != 0); }
		
		bool operator()(session_impl::connection_map::value_type const& c) const
		{
			tcp::endpoint const& sender = c->remote();
			if (sender.address() != ip.address()) return false;
			if (tor != c->associated_torrent().lock().get()) return false;
			return true;
		}

		tcp::endpoint const& ip;
		torrent const* tor;
	};

	struct peer_by_id
	{
		peer_by_id(const peer_id& i): pid(i) {}
		
		bool operator()(session_impl::connection_map::value_type const& p) const
		{
			if (p->pid() != pid) return false;
			// have a special case for all zeros. We can have any number
			// of peers with that pid, since it's used to indicate no pid.
			if (pid.is_all_zeros()) return false;
			return true;
		}

		peer_id const& pid;
	};
}

namespace libtorrent
{
	int root2(int x)
	{
		int ret = 0;
		x >>= 1;
		while (x > 0)
		{
			// if this assert triggers, the block size
			// is not an even 2 exponent!
			TORRENT_ASSERT(x == 1 || (x & 1) == 0);
			++ret;
			x >>= 1;
		}
		return ret;
	}

#ifndef TORRENT_DISABLE_EXTENSIONS
	// defined in ut_pex.cpp
	bool was_introduced_by(peer_plugin const*, tcp::endpoint const&);
#endif

	torrent::torrent(
		session_impl& ses
		, tcp::endpoint const& net_interface
		, int block_size
		, int seq
		, add_torrent_params const& p
		, sha1_hash const& info_hash)
		: m_policy(this)
		, m_total_uploaded(0)
		, m_total_downloaded(0)
		, m_started(time_now())
		, m_storage(0)
		, m_num_connecting(0)
		, m_tracker_timer(ses.m_io_service)
		, m_ses(ses)
		, m_host_resolver(ses.m_io_service)
		, m_trackerid(p.trackerid)
		, m_save_path(complete(p.save_path))
		, m_url(p.url)
		, m_uuid(p.uuid)
		, m_source_feed_url(p.source_feed_url)
		, m_storage_constructor(p.storage)
		, m_added_time(time(0))
		, m_completed_time(0)
		, m_last_saved_resume(time(0))
		, m_last_seen_complete(0)
		, m_swarm_last_seen_complete(0)
		, m_num_verified(0)
		, m_average_piece_time(0)
		, m_piece_time_deviation(0)
		, m_total_failed_bytes(0)
		, m_total_redundant_bytes(0)
		, m_sequence_number(seq)
		, m_upload_mode_time(0)
		, m_state(torrent_status::checking_resume_data)
		, m_storage_mode(p.storage_mode)
		, m_announcing(false)
		, m_waiting_tracker(false)
		, m_seed_mode(false)
		, m_active_time(0)
		, m_last_working_tracker(-1)
		, m_finished_time(0)
		, m_sequential_download(false)
		, m_got_tracker_response(false)
		, m_connections_initialized(false)
		, m_super_seeding(false)
		, m_override_resume_data(p.flags & add_torrent_params::flag_override_resume_data)
#ifndef TORRENT_DISABLE_RESOLVE_COUNTRIES
		, m_resolving_country(false)
		, m_resolve_countries(false)
#endif
		, m_need_save_resume_data(true)
		, m_seeding_time(0)
		, m_time_scaler(0)
		, m_max_uploads((1<<24)-1)
		, m_save_resume_flags(0)
		, m_num_uploads(0)
		, m_block_size_shift(root2(block_size))
		, m_has_incoming(false)
		, m_files_checked(false)
		, m_queued_for_checking(false)
		, m_max_connections((1<<24)-1)
		, m_graceful_pause_mode(false)
		, m_need_connect_boost(true)
		, m_lsd_seq(0)
		, m_magnet_link(false)
		, m_apply_ip_filter(p.flags & add_torrent_params::flag_apply_ip_filter)
		, m_merge_resume_trackers(p.flags & add_torrent_params::flag_merge_resume_trackers)
		, m_padding(0)
		, m_priority(0)
		, m_complete(0xffffff)
		, m_state_subscription(p.flags & add_torrent_params::flag_update_subscribe)
		, m_in_state_updates(false)
		, m_is_active_download(false)
		, m_is_active_finished(false)
		, m_ssl_torrent(false)
		, m_deleted(false)
		, m_moving_storage(false)
		, m_inactive(false)
		, m_incomplete(0xffffff)
		, m_abort(false)
		, m_announce_to_dht((p.flags & add_torrent_params::flag_paused) == 0)
		, m_announce_to_trackers((p.flags & add_torrent_params::flag_paused) == 0)
		, m_announce_to_lsd((p.flags & add_torrent_params::flag_paused) == 0)
		, m_allow_peers((p.flags & add_torrent_params::flag_paused) == 0)
		, m_upload_mode(p.flags & add_torrent_params::flag_upload_mode)
		, m_auto_managed(p.flags & add_torrent_params::flag_auto_managed)
		, m_share_mode(p.flags & add_torrent_params::flag_share_mode)
		, m_last_download(0)
		, m_last_scrape(0)
		, m_last_upload(0)
		, m_downloaded(0xffffff)
		, m_interface_index(0)
		, m_progress_ppm(0)
		, m_inactive_counter(0)
		, m_use_resume_save_path(p.flags & add_torrent_params::flag_use_resume_save_path)
	{
		// if there is resume data already, we don't need to trigger the initial save
		// resume data
		if (!p.resume_data.empty() && (p.flags & add_torrent_params::flag_override_resume_data) == 0)
			m_need_save_resume_data = false;

#if TORRENT_USE_ASSERTS
		m_resume_data_loaded = false;
#endif
#if TORRENT_USE_UNC_PATHS
		m_save_path = canonicalize_path(m_save_path);
#endif

		if (!m_apply_ip_filter) ++m_ses.m_non_filtered_torrents;

		update_guage();

		if (!p.ti || !p.ti->is_valid())
		{
			// we don't have metadata for this torrent. We'll download
			// it either through the URL passed in, or through a metadata
			// extension. Make sure that when we save resume data for this
			// torrent, we also save the metadata
			m_magnet_link = true;
		}

		if (!m_torrent_file)
			m_torrent_file = (p.ti ? p.ti : new torrent_info(info_hash));

		// add web seeds from add_torrent_params
		for (std::vector<std::string>::const_iterator i = p.url_seeds.begin()
			, end(p.url_seeds.end()); i != end; ++i)
		{
			m_web_seeds.push_back(web_seed_entry(*i, web_seed_entry::url_seed));
		}

		m_trackers = m_torrent_file->trackers();
		if (m_torrent_file->is_valid())
		{
			m_seed_mode = p.flags & add_torrent_params::flag_seed_mode;
			m_connections_initialized = true;
			m_block_size_shift = root2((std::min)(block_size, m_torrent_file->piece_length()));
		}
		else
		{
			if (!p.name.empty()) m_name.reset(new std::string(p.name));
		}

		if (!m_url.empty() && m_uuid.empty()) m_uuid = m_url;

		TORRENT_ASSERT(m_ses.is_network_thread());
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
		debug_log("creating torrent: %s", torrent_file().name().c_str());
#endif
		m_net_interfaces.push_back(tcp::endpoint(net_interface.address(), 0));

		m_file_priority = p.file_priorities;

		if (m_seed_mode)
			m_verified.resize(m_torrent_file->num_pieces(), false);

		m_resume_data = p.resume_data;

#ifndef TORRENT_DISABLE_ENCRYPTION
		hasher h;
		h.update("req2", 4);
		h.update((char*)&m_torrent_file->info_hash()[0], 20);
		m_obfuscated_hash = h.final();
#endif

		INVARIANT_CHECK;

		if (p.flags & add_torrent_params::flag_sequential_download)
			m_sequential_download = true;

		if (p.flags & add_torrent_params::flag_super_seeding)
			m_super_seeding = true;

		set_max_uploads(p.max_uploads, false);
		set_max_connections(p.max_connections, false);
		set_upload_limit(p.upload_limit, false);
		set_download_limit(p.download_limit, false);

		if (!m_name && !m_url.empty()) m_name.reset(new std::string(m_url));

#ifndef TORRENT_NO_DEPRECATE
		if (p.tracker_url && std::strlen(p.tracker_url) > 0)
		{
			m_trackers.push_back(announce_entry(p.tracker_url));
			m_trackers.back().fail_limit = 0;
			m_trackers.back().source = announce_entry::source_magnet_link;
			m_torrent_file->add_tracker(p.tracker_url);
		}
#endif

		for (std::vector<std::string>::const_iterator i = p.trackers.begin()
			, end(p.trackers.end()); i != end; ++i)
		{
			m_trackers.push_back(announce_entry(*i));
			m_trackers.back().fail_limit = 0;
			m_trackers.back().source = announce_entry::source_magnet_link;
			m_torrent_file->add_tracker(*i);
		}

		if (settings().prefer_udp_trackers)
			prioritize_udp_trackers();
	}

#if 0
	
	// NON BOTTLED VERSION. SUPPORTS PROGRESS REPORTING

	// since this download is not bottled, this callback will
	// be called every time we receive another piece of the
	// .torrent file
	void torrent::on_torrent_download(error_code const& ec
		, http_parser const& parser
		, char const* data, int size)
	{
		if (m_abort) return;

		if (ec && ec != asio::error::eof)
		{
			set_error(ec, m_url);
			pause();
			return;
		}

		if (size > 0)
		{
			m_torrent_file_buf.insert(m_torrent_file_buf.end(), data, data + size);
			if (parser.content_length() > 0)
				set_progress_ppm(boost::int64_t(m_torrent_file_buf.size())
					* 1000000 / parser.content_length());
		}

		if (parser.header_finished() && parser.status_code() != 200)
		{
			set_error(error_code(parser.status_code(), get_http_category()), parser.message());
			pause();
			return;
		}

		if (!ec) return;

		// if this was received with chunked encoding, we need to strip out
		// the chunk headers
		size = parser.collapse_chunk_headers((char*)&m_torrent_file_buf[0], m_torrent_file_buf.size());
		m_torrent_file_buf.resize(size);

		std::string const& encoding = parser.header("content-encoding");
		if ((encoding == "gzip" || encoding == "x-gzip") && m_torrent_file_buf.size())
		{
			std::vector<char> buf;
			error_code ec;
			inflate_gzip(&m_torrent_file_buf[0], m_torrent_file_buf.size()
				, buf, 4 * 1024 * 1024, ex);
			if (ec)
			{
				set_error(ec, m_url);
				pause();
				std::vector<char>().swap(m_torrent_file_buf);
				return;
			}
			m_torrent_file_buf.swap(buf);
		}

		// we're done!
		error_code e;
		intrusive_ptr<torrent_info> tf(new torrent_info(
			&m_torrent_file_buf[0], m_torrent_file_buf.size(), e));
		if (e)
		{
			set_error(e, m_url);
			pause();
			std::vector<char>().swap(m_torrent_file_buf);
			return;
		}
		std::vector<char>().swap(m_torrent_file_buf);
		
		// update our torrent_info object and move the
		// torrent from the old info-hash to the new one
		// as we replace the torrent_info object
#if TORRENT_USE_ASSERTS
		int num_torrents = m_ses.m_torrents.size();
#endif
		// we're about to erase the session's reference to this
		// torrent, create another reference
		boost::shared_ptr<torrent> me(shared_from_this());

		m_ses.remove_torrent_impl(me, 0);

		m_torrent_file = tf;

		// now, we might already have this torrent in the session.
		session_impl::torrent_map::iterator i = m_ses.m_torrents.find(m_torrent_file->info_hash());
		if (i != m_ses.m_torrents.end())
		{
			if (!m_uuid.empty() && i->second->uuid().empty())
				i->second->set_uuid(m_uuid);
			if (!m_url.empty() && i->second->url().empty())
				i->second->set_url(m_url);
			if (!m_source_feed_url.empty() && i->second->source_feed_url().empty())
				i->second->set_source_feed_url(m_source_feed_url);

			// insert this torrent in the uuid index
			if (!m_uuid.empty() || !m_url.empty())
			{
				m_ses.m_uuids.insert(std::make_pair(m_uuid.empty()
					? m_url : m_uuid, i->second));
			}
			set_error(error_code(errors::duplicate_torrent, get_libtorrent_category()), "");
			abort();
			return;
		}

		m_ses.m_torrents.insert(std::make_pair(m_torrent_file->info_hash(), me));
		if (!m_uuid.empty()) m_ses.m_uuids.insert(std::make_pair(m_uuid, me));

		TORRENT_ASSERT(num_torrents == int(m_ses.m_torrents.size()));

		// if the user added any trackers while downloading the
		// .torrent file, serge them into the new tracker list
		std::vector<announce_entry> new_trackers = m_torrent_file->trackers();
		for (std::vector<announce_entry>::iterator i = m_trackers.begin()
			, end(m_trackers.end()); i != end; ++i)
		{
			// if we already have this tracker, ignore it
			if (std::find_if(new_trackers.begin(), new_trackers.end()
				, boost::bind(&announce_entry::url, _1) == i->url) != new_trackers.end())
				continue;

			// insert the tracker ordered by tier
			new_trackers.insert(std::find_if(new_trackers.begin(), new_trackers.end()
				, boost::bind(&announce_entry::tier, _1) >= i->tier), *i);
		}
		m_trackers.swap(new_trackers);

#ifndef TORRENT_DISABLE_ENCRYPTION
		hasher h;
		h.update("req2", 4);
		h.update((char*)&m_torrent_file->info_hash()[0], 20);
		m_obfuscated_hash = h.final();
#endif

		if (m_ses.m_alerts.should_post<metadata_received_alert>())
		{
			m_ses.m_alerts.post_alert(metadata_received_alert(
				get_handle()));
		}

		state_updated();

		set_state(torrent_status::downloading);

		m_override_resume_data = true;
		init();
	}
#else // if 0

	void torrent::on_torrent_download(error_code const& ec
		, http_parser const& parser, char const* data, int size)
	{
		if (m_abort) return;

		if (ec && ec != asio::error::eof)
		{
			set_error(ec, m_url);
			pause();
			return;
		}

		if (parser.status_code() != 200)
		{
			// #error there should really be an error code category for HTTP
			set_error(errors::http_error, parser.message());
			pause();
			return;
		}

		error_code e;
		intrusive_ptr<torrent_info> tf(new torrent_info(data, size, e));
		if (e)
		{
			set_error(e, m_url);
			pause();
			return;
		}
		
		// update our torrent_info object and move the
		// torrent from the old info-hash to the new one
		// as we replace the torrent_info object
#if TORRENT_USE_ASSERTS
		int num_torrents = m_ses.m_torrents.size();
#endif

		// we're about to erase the session's reference to this
		// torrent, create another reference
		boost::shared_ptr<torrent> me(shared_from_this());

		m_ses.remove_torrent_impl(me, 0);

		if (alerts().should_post<torrent_update_alert>())
			alerts().post_alert(torrent_update_alert(get_handle(), info_hash(), tf->info_hash()));

		m_torrent_file = tf;

		// now, we might already have this torrent in the session.
		session_impl::torrent_map::iterator i = m_ses.m_torrents.find(m_torrent_file->info_hash());
		if (i != m_ses.m_torrents.end())
		{
			if (!m_uuid.empty() && i->second->uuid().empty())
				i->second->set_uuid(m_uuid);
			if (!m_url.empty() && i->second->url().empty())
				i->second->set_url(m_url);
			if (!m_source_feed_url.empty() && i->second->source_feed_url().empty())
				i->second->set_source_feed_url(m_source_feed_url);

			// insert this torrent in the uuid index
			if (!m_uuid.empty() || !m_url.empty())
			{
				m_ses.m_uuids.insert(std::make_pair(m_uuid.empty()
					? m_url : m_uuid, i->second));
			}
			set_error(error_code(errors::duplicate_torrent, get_libtorrent_category()), "");
			abort();
			return;
		}

		m_ses.m_torrents.insert(std::make_pair(m_torrent_file->info_hash(), me));
		if (!m_uuid.empty()) m_ses.m_uuids.insert(std::make_pair(m_uuid, me));

		TORRENT_ASSERT(num_torrents == int(m_ses.m_torrents.size()));

		// if the user added any trackers while downloading the
		// .torrent file, serge them into the new tracker list
		std::vector<announce_entry> new_trackers = m_torrent_file->trackers();
		for (std::vector<announce_entry>::iterator i = m_trackers.begin()
			, end(m_trackers.end()); i != end; ++i)
		{
			// if we already have this tracker, ignore it
			if (std::find_if(new_trackers.begin(), new_trackers.end()
				, boost::bind(&announce_entry::url, _1) == i->url) != new_trackers.end())
				continue;

			// insert the tracker ordered by tier
			new_trackers.insert(std::find_if(new_trackers.begin(), new_trackers.end()
				, boost::bind(&announce_entry::tier, _1) >= i->tier), *i);
		}
		m_trackers.swap(new_trackers);

#ifndef TORRENT_DISABLE_ENCRYPTION
		hasher h;
		h.update("req2", 4);
		h.update((char*)&m_torrent_file->info_hash()[0], 20);
		m_obfuscated_hash = h.final();
#endif

		if (m_ses.m_alerts.should_post<metadata_received_alert>())
		{
			m_ses.m_alerts.post_alert(metadata_received_alert(
				get_handle()));
		}

		state_updated();

		set_state(torrent_status::downloading);

		m_override_resume_data = true;
		init();
	}

#endif // if 0

	void torrent::leave_seed_mode(bool seed)
	{
		if (!m_seed_mode) return;

		if (!seed)
		{
			// this means the user promised we had all the
			// files, but it turned out we didn't. This is
			// an error.

			// TODO: 2 post alert
		
#if defined TORRENT_ERROR_LOGGING
			debug_log("*** FAILED SEED MODE, rechecking");
#endif
		}

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("*** LEAVING SEED MODE (%s)", seed ? "as seed" : "as non-seed");
#endif
		m_seed_mode = false;
		// seed is false if we turned out not
		// to be a seed after all
		if (!seed)
		{
			set_state(torrent_status::downloading);
			force_recheck();
		}
		m_num_verified = 0;
		m_verified.clear();
	}

	void torrent::verified(int piece)
	{
		TORRENT_ASSERT(piece < int(m_verified.size()));
		TORRENT_ASSERT(piece >= 0);
		TORRENT_ASSERT(m_verified.get_bit(piece) == false);
		++m_num_verified;
		m_verified.set_bit(piece);
	}

	void torrent::start()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("starting torrent");
#endif
		TORRENT_ASSERT(!m_picker);

		if (!m_seed_mode)
		{
			m_picker.reset(new piece_picker());
			std::fill(m_file_progress.begin(), m_file_progress.end(), 0);

			if (!m_resume_data.empty())
			{
				int pos;
				error_code ec;
				if (lazy_bdecode(&m_resume_data[0], &m_resume_data[0]
					+ m_resume_data.size(), m_resume_entry, ec, &pos) != 0)
				{
					std::vector<char>().swap(m_resume_data);
					lazy_entry().swap(m_resume_entry);
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
					debug_log("resume data rejected: %s pos: %d", ec.message().c_str(), pos);
#endif
					if (m_ses.m_alerts.should_post<fastresume_rejected_alert>())
					{
						m_ses.m_alerts.post_alert(fastresume_rejected_alert(get_handle(), ec));
					}
				}
			}
		}

		if (!m_torrent_file->is_valid() && !m_url.empty())
		{
			// we need to download the .torrent file from m_url
			start_download_url();
		}
		else if (m_torrent_file->is_valid())
		{
			init();
		}
		else
		{
			// we need to start announcing since we don't have any
			// metadata. To receive peers to ask for it.
			set_state(torrent_status::downloading_metadata);
			start_announcing();
		}
	}

	bool torrent::is_active_download() const
	{
		return (m_state == torrent_status::downloading
			|| m_state == torrent_status::downloading_metadata)
			&& m_allow_peers
			&& !m_abort;
	}

	bool torrent::is_active_finished() const
	{
		return (m_state == torrent_status::finished
			|| m_state == torrent_status::seeding)
			&& m_allow_peers
			&& !m_abort;
	}

	void torrent::update_guage()
	{
		bool is_active_download = (m_state == torrent_status::downloading
			|| m_state == torrent_status::downloading_metadata)
			&& m_allow_peers
			&& !m_abort;

		bool is_active_finished = (m_state == torrent_status::finished
			|| m_state == torrent_status::seeding)
			&& m_allow_peers
			&& !m_abort;

		// update finished and downloading counters
		if (is_active_download != m_is_active_download)
		{
			if (is_active_download)
				m_ses.inc_active_downloading();
			else
				m_ses.dec_active_downloading();
			m_is_active_download = is_active_download;
		}

		if (is_active_finished != m_is_active_finished)
		{
			if (is_active_finished)
				m_ses.inc_active_finished();
			else
				m_ses.dec_active_finished();
			m_is_active_finished = is_active_finished;
		}
	}

	void torrent::start_download_url()
	{
		TORRENT_ASSERT(!m_url.empty());
		TORRENT_ASSERT(!m_torrent_file->is_valid());
		boost::shared_ptr<http_connection> conn(
			new http_connection(m_ses.m_io_service, m_ses.m_half_open			        
				, boost::bind(&torrent::on_torrent_download, shared_from_this()
					, _1, _2, _3, _4)
				, true // bottled
				, m_ses.settings().max_http_recv_buffer_size // bottled buffer size
				, http_connect_handler()
				, http_filter_handler()
#ifdef TORRENT_USE_OPENSSL
				, m_ssl_ctx.get()
#endif
				));

		conn->get(m_url, seconds(30), 0, &m_ses.proxy()
			, 5, m_ses.m_settings.user_agent);
		set_state(torrent_status::downloading_metadata);
	}

	void torrent::set_apply_ip_filter(bool b)
	{
		if (b == m_apply_ip_filter) return;
		if (b)
		{
			TORRENT_ASSERT(m_ses.m_non_filtered_torrents > 0);
			--m_ses.m_non_filtered_torrents;
		}
		else
		{
			++m_ses.m_non_filtered_torrents;
		}
		m_apply_ip_filter = b;
		m_policy.ip_filter_updated();
		state_updated();
	}

#ifndef TORRENT_DISABLE_DHT
	bool torrent::should_announce_dht() const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (m_ses.m_listen_sockets.empty()) return false;

		if (!m_ses.m_dht) return false;
		if (m_torrent_file->is_valid() && !m_files_checked) return false;
		if (!m_announce_to_dht) return false;
		if (!m_allow_peers) return false;

		// if we don't have the metadata, and we're waiting
		// for a web server to serve it to us, no need to announce
		// because the info-hash is just the URL hash
		if (!m_torrent_file->is_valid() && !m_url.empty()) return false;

		// don't announce private torrents
		if (m_torrent_file->is_valid() && m_torrent_file->priv()) return false;
		if (m_trackers.empty()) return true;
		if (!settings().use_dht_as_fallback) return true;

		int verified_trackers = 0;
		for (std::vector<announce_entry>::const_iterator i = m_trackers.begin()
			, end(m_trackers.end()); i != end; ++i)
			if (i->verified) ++verified_trackers;
			
		return verified_trackers == 0;
	}

#endif

	torrent::~torrent()
	{
		if (!m_apply_ip_filter)
		{
			TORRENT_ASSERT(m_ses.m_non_filtered_torrents > 0);
			--m_ses.m_non_filtered_torrents;
			m_apply_ip_filter = true;
		}

		TORRENT_ASSERT(m_ses.is_network_thread());
		// The invariant can't be maintained here, since the torrent
		// is being destructed, all weak references to it have been
		// reset, which means that all its peers already have an
		// invalidated torrent pointer (so it cannot be verified to be correct)
		
		// i.e. the invariant can only be maintained if all connections have
		// been closed by the time the torrent is destructed. And they are
		// supposed to be closed. So we can still do the invariant check.

		INVARIANT_CHECK;

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING || defined TORRENT_LOGGING
		log_to_all_peers("DESTRUCTING TORRENT");
#endif

		TORRENT_ASSERT(m_abort);
		TORRENT_ASSERT(m_connections.empty());
		if (!m_connections.empty())
			disconnect_all(errors::torrent_aborted);
	}

	void torrent::read_piece(int piece)
	{
		if (m_abort)
		{
			// failed
			m_ses.m_alerts.post_alert(read_piece_alert(
				get_handle(), piece, error_code(boost::system::errc::operation_canceled, get_system_category())));
			return;
		}

		TORRENT_ASSERT(piece >= 0 && piece < m_torrent_file->num_pieces());
		int piece_size = m_torrent_file->piece_size(piece);
		int blocks_in_piece = (piece_size + block_size() - 1) / block_size();

		// if blocks_in_piece is 0, rp will leak
		TORRENT_ASSERT(blocks_in_piece > 0);
		TORRENT_ASSERT(piece_size > 0);

		read_piece_struct* rp = new read_piece_struct;
		rp->piece_data.reset(new (std::nothrow) char[piece_size]);
		rp->blocks_left = 0;
		rp->fail = false;

		peer_request r;
		r.piece = piece;
		r.start = 0;
		for (int i = 0; i < blocks_in_piece; ++i, r.start += block_size())
		{
			r.length = (std::min)(piece_size - r.start, block_size());
			filesystem().async_read(r, boost::bind(&torrent::on_disk_read_complete
				, shared_from_this(), _1, _2, r, rp));
			++rp->blocks_left;
		}
	}

	void torrent::send_share_mode()
	{
#ifndef TORRENT_DISABLE_EXTENSIONS
		for (std::set<peer_connection*>::iterator i = m_connections.begin()
			, end(m_connections.end()); i != end; ++i)
		{
			if ((*i)->type() != peer_connection::bittorrent_connection) continue;
			bt_peer_connection* p = (bt_peer_connection*)*i;
			p->write_share_mode();
		}
#endif
	}

	void torrent::send_upload_only()
	{
#ifndef TORRENT_DISABLE_EXTENSIONS
		if (share_mode()) return;
		if (super_seeding()) return;

		for (std::set<peer_connection*>::iterator i = m_connections.begin();
			i != m_connections.end();)
		{
			// since the call to disconnect_if_redundant() may
			// delete the entry from this container, make sure
			// to increment the iterator early
			bt_peer_connection* p = (bt_peer_connection*)*i;
			++i;
			if (p->type() == peer_connection::bittorrent_connection)
				p->write_upload_only();
		}
#endif
	}

	void torrent::set_share_mode(bool s)
	{
		if (s == m_share_mode) return;

		m_share_mode = s;

		// in share mode, all pieces have their priorities initialized to 0
		std::fill(m_file_priority.begin(), m_file_priority.end(), !m_share_mode);

		update_piece_priorities();

		if (m_share_mode) recalc_share_mode();
	}

	void torrent::set_upload_mode(bool b)
	{
		if (b == m_upload_mode) return;

		m_upload_mode = b;

		state_updated();
		send_upload_only();

		if (m_upload_mode)
		{
			// clear request queues of all peers
			for (std::set<peer_connection*>::iterator i = m_connections.begin()
				, end(m_connections.end()); i != end; ++i)
			{
				peer_connection* p = (*i);
				p->cancel_all_requests();
			}
			// this is used to try leaving upload only mode periodically
			m_upload_mode_time = 0;
		}
		else
		{
			// reset last_connected, to force fast reconnect after leaving upload mode
			for (policy::iterator i = m_policy.begin_peer()
				, end(m_policy.end_peer()); i != end; ++i)
			{
				(*i)->last_connected = 0;
			}

			// send_block_requests on all peers
			for (std::set<peer_connection*>::iterator i = m_connections.begin()
				, end(m_connections.end()); i != end; ++i)
			{
				peer_connection* p = (*i);
				p->send_block_requests();
			}
		}
	}

	void torrent::handle_disk_error(disk_io_job const& j, peer_connection* c)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (!j.error) return;

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
		debug_log("disk error: (%d) %s in file: %s", j.error.value(), j.error.message().c_str()
			, j.error_file.c_str());
#endif

		TORRENT_ASSERT(j.piece >= 0);

		piece_block block_finished(j.piece, j.offset / block_size());

		if (j.action == disk_io_job::write)
		{
			// we failed to write j.piece to disk tell the piece picker
			if (has_picker() && j.piece >= 0) picker().write_failed(block_finished);
		}

		if (j.error == error_code(boost::system::errc::not_enough_memory, generic_category()))
		{
			if (alerts().should_post<file_error_alert>())
				alerts().post_alert(file_error_alert(j.error_file, get_handle(), j.error));
			if (c) c->disconnect(errors::no_memory);
			return;
		}

		// notify the user of the error
		if (alerts().should_post<file_error_alert>())
			alerts().post_alert(file_error_alert(j.error_file, get_handle(), j.error));

		// put the torrent in an error-state
		set_error(j.error, j.error_file);

		if (j.action == disk_io_job::write
			&& (j.error == boost::system::errc::read_only_file_system
			|| j.error == boost::system::errc::permission_denied
			|| j.error == boost::system::errc::operation_not_permitted
			|| j.error == boost::system::errc::no_space_on_device
			|| j.error == boost::system::errc::file_too_large))
		{
			// if we failed to write, stop downloading and just
			// keep seeding.
			// TODO: 1 make this depend on the error and on the filesystem the
			// files are being downloaded to. If the error is no_space_left_on_device
			// and the filesystem doesn't support sparse files, only zero the priorities
			// of the pieces that are at the tails of all files, leaving everything
			// up to the highest written piece in each file
			set_upload_mode(true);
			return;
		}

		// if the error appears to be more serious than a full disk, just pause the torrent
		pause();
	}

	void torrent::on_disk_read_complete(int ret, disk_io_job const& j
		, peer_request r, read_piece_struct* rp)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		disk_buffer_holder buffer(m_ses, j.buffer);

		--rp->blocks_left;
		if (ret != r.length)
		{
			rp->fail = true;
			rp->error = j.error;
			handle_disk_error(j);
		}
		else
		{
			std::memcpy(rp->piece_data.get() + r.start, j.buffer, r.length);
		}

		if (rp->blocks_left == 0)
		{
			int size = m_torrent_file->piece_size(r.piece);
			if (rp->fail)
			{
				m_ses.m_alerts.post_alert(read_piece_alert(
					get_handle(), r.piece, rp->error));
			}
			else
			{
				m_ses.m_alerts.post_alert(read_piece_alert(
					get_handle(), r.piece, rp->piece_data, size));
			}
			delete rp;
		}
	}

	void torrent::add_piece(int piece, char const* data, int flags)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(piece >= 0 && piece < m_torrent_file->num_pieces());
		int piece_size = m_torrent_file->piece_size(piece);
		int blocks_in_piece = (piece_size + block_size() - 1) / block_size();

		if (m_deleted) return;

		// avoid crash trying to access the picker when there is none
		if (!has_picker()) return;

		if (picker().have_piece(piece)
			&& (flags & torrent::overwrite_existing) == 0)
			return;

		peer_request p;
		p.piece = piece;
		p.start = 0;
		picker().inc_refcount(piece, 0);
		for (int i = 0; i < blocks_in_piece; ++i, p.start += block_size())
		{
			if (picker().is_finished(piece_block(piece, i))
				&& (flags & torrent::overwrite_existing) == 0)
				continue;

			p.length = (std::min)(piece_size - p.start, int(block_size()));
			char* buffer = m_ses.allocate_disk_buffer("add piece");
			// out of memory
			if (buffer == 0)
			{
				picker().dec_refcount(piece, 0);
				return;
			}
			disk_buffer_holder holder(m_ses, buffer);
			std::memcpy(buffer, data + p.start, p.length);
			filesystem().async_write(p, holder, boost::bind(&torrent::on_disk_write_complete
				, shared_from_this(), _1, _2, p));
			piece_block block(piece, i);
			picker().mark_as_downloading(block, 0, piece_picker::fast);
			picker().mark_as_writing(block, 0);
		}
		async_verify_piece(piece, boost::bind(&torrent::piece_finished
			, shared_from_this(), piece, _1));
		picker().dec_refcount(piece, 0);
	}

	void torrent::on_disk_write_complete(int ret, disk_io_job const& j
		, peer_request p)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		INVARIANT_CHECK;

		if (m_abort)
		{
			piece_block block_finished(p.piece, p.start / block_size());
			return;
		}

		piece_block block_finished(p.piece, p.start / block_size());

		if (ret == -1)
		{
			handle_disk_error(j);
			return;
		}

		if (!has_picker()) return;

		// if we already have this block, just ignore it.
		// this can happen if the same block is passed in through
		// add_piece() multiple times
		if (picker().is_finished(block_finished)) return;

		picker().mark_as_finished(block_finished, 0);
	}
	
	void torrent::on_disk_cache_complete(int ret, disk_io_job const& j)
	{
		// suggest this piece to all peers
		for (peer_iterator i = m_connections.begin();
			i != m_connections.end(); ++i)
			(*i)->send_suggest(j.piece);
	}

	bool torrent::add_merkle_nodes(std::map<int, sha1_hash> const& nodes, int piece)
	{
		return m_torrent_file->add_merkle_nodes(nodes, piece);
	}

	peer_request torrent::to_req(piece_block const& p) const
	{
		int block_offset = p.block_index * block_size();
		int block = (std::min)(torrent_file().piece_size(
			p.piece_index) - block_offset, int(block_size()));
		TORRENT_ASSERT(block > 0);
		TORRENT_ASSERT(block <= block_size());

		peer_request r;
		r.piece = p.piece_index;
		r.start = block_offset;
		r.length = block;
		return r;
	}

	std::string torrent::name() const
	{
		if (valid_metadata()) return m_torrent_file->name();
		if (m_name) return *m_name;
		return "";
	}

#ifndef TORRENT_DISABLE_EXTENSIONS

	void torrent::add_extension(boost::shared_ptr<torrent_plugin> ext)
	{
		m_extensions.push_back(ext);
	}

	void torrent::add_extension(boost::function<boost::shared_ptr<torrent_plugin>(torrent*, void*)> const& ext
		, void* userdata)
	{
		boost::shared_ptr<torrent_plugin> tp(ext(this, userdata));
		if (!tp) return;

		add_extension(tp);
		
		for (peer_iterator i = m_connections.begin();
			i != m_connections.end(); ++i)
		{
			peer_connection* p = *i;
			boost::shared_ptr<peer_plugin> pp(tp->new_connection(p));
			if (pp) p->add_extension(pp);
		}

		// if files are checked for this torrent, call the extension
		// to let it initialize itself
		if (m_connections_initialized)
			tp->on_files_checked();
	}

#endif

#ifdef TORRENT_USE_OPENSSL

#if BOOST_VERSION >= 104700
	bool torrent::verify_peer_cert(bool preverified, boost::asio::ssl::verify_context& ctx)
	{
		// if the cert wasn't signed by the correct CA, fail the verification
		if (!preverified) return false;

		// we're only interested in checking the certificate at the end of the chain.
		// TODO: is verify_peer_cert called once per certificate in the chain, and
		// this function just tells us which depth we're at right now? If so, the comment
		// makes sense.
		// any certificate that isn't the leaf (i.e. the one presented by the peer)
		// should be accepted automatically, given preverified is true. The leaf certificate
		// need to be verified to make sure its DN matches the info-hash
		int depth = X509_STORE_CTX_get_error_depth(ctx.native_handle());
		if (depth > 0) return true;

		X509* cert = X509_STORE_CTX_get_current_cert(ctx.native_handle());

		// Go through the alternate names in the certificate looking for matching DNS entries
		GENERAL_NAMES* gens = static_cast<GENERAL_NAMES*>(
			X509_get_ext_d2i(cert, NID_subject_alt_name, 0, 0));

#if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
		std::string names;
		bool match = false;
#endif
		for (int i = 0; i < sk_GENERAL_NAME_num(gens); ++i)
		{
			GENERAL_NAME* gen = sk_GENERAL_NAME_value(gens, i);
			if (gen->type != GEN_DNS) continue;
			ASN1_IA5STRING* domain = gen->d.dNSName;
			if (domain->type != V_ASN1_IA5STRING || !domain->data || !domain->length) continue;
			const char* torrent_name = reinterpret_cast<const char*>(domain->data);
			std::size_t name_length = domain->length;

#if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
			if (i > 1) names += " | n: ";
			names.append(torrent_name, name_length);
#endif
			if (strncmp(torrent_name, "*", name_length) == 0
				|| strncmp(torrent_name, m_torrent_file->name().c_str(), name_length) == 0)
			{
#if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
				match = true;
				// if we're logging, keep looping over all names,
				// for completeness of the log
				continue;
#endif
				return true;
			}
		}

		// no match in the alternate names, so try the common names. We should only
		// use the "most specific" common name, which is the last one in the list.
		X509_NAME* name = X509_get_subject_name(cert);
		int i = -1;
		ASN1_STRING* common_name = 0;
		while ((i = X509_NAME_get_index_by_NID(name, NID_commonName, i)) >= 0)
		{
			X509_NAME_ENTRY* name_entry = X509_NAME_get_entry(name, i);
			common_name = X509_NAME_ENTRY_get_data(name_entry);
		}
		if (common_name && common_name->data && common_name->length)
		{
			const char* torrent_name = reinterpret_cast<const char*>(common_name->data);
			std::size_t name_length = common_name->length;

#if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
			if (!names.empty()) names += " | n: ";
			names.append(torrent_name, name_length);
#endif

			if (strncmp(torrent_name, "*", name_length) == 0
				|| strncmp(torrent_name, m_torrent_file->name().c_str(), name_length) == 0)
			{
#if !defined(TORRENT_VERBOSE_LOGGING) && !defined(TORRENT_LOGGING)
				return true;
#else
				match = true;
#endif
			}
		}

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("<== incoming SSL CONNECTION [ n: %s | match: %s ]"
			, names.c_str(), match?"yes":"no");
		return match;
#endif

		return false;
	}
#endif // BOOST_VERSION

	void torrent::init_ssl(std::string const& cert)
	{
		using boost::asio::ssl::context;

		// this is needed for openssl < 1.0 to decrypt keys created by openssl 1.0+
		OpenSSL_add_all_algorithms();

		boost::uint64_t now = total_microseconds(time_now_hires() - min_time());
		// assume 9 bits of entropy (i.e. about 1 millisecond)
		RAND_add(&now, 8, 1.125);
		RAND_add(&info_hash()[0], 20, 3);
		// entropy is also added on incoming and completed connection attempts

		TORRENT_ASSERT(RAND_status() == 1);

#if BOOST_VERSION >= 104700
		// create the SSL context for this torrent. We need to
		// inject the root certificate, and no other, to
		// verify other peers against
		boost::shared_ptr<context> ctx(
			new (std::nothrow) context(m_ses.m_io_service, context::sslv23));

		if (!ctx)
		{
			error_code ec(::ERR_get_error(),
				asio::error::get_ssl_category());
			set_error(ec, "SSL context");
			pause();
			return;
		}

		ctx->set_options(context::default_workarounds
			| boost::asio::ssl::context::no_sslv2
			| boost::asio::ssl::context::single_dh_use);

		error_code ec;
		ctx->set_verify_mode(context::verify_peer
			| context::verify_fail_if_no_peer_cert
			| context::verify_client_once, ec);
		if (ec)
		{
			set_error(ec, "SSL verify mode");
			pause();
			return;
		}

		// the verification function verifies the distinguished name
		// of a peer certificate to make sure it matches the info-hash
		// of the torrent, or that it's a "star-cert"
		ctx->set_verify_callback(boost::bind(&torrent::verify_peer_cert, this, _1, _2), ec);
		if (ec)
		{
			set_error(ec, "SSL verify callback");
			pause();
			return;
		}

		SSL_CTX* ssl_ctx = ctx->impl();
		// create a new x.509 certificate store
		X509_STORE* cert_store = X509_STORE_new();
		if (!cert_store)
		{
			error_code ec(::ERR_get_error(),
				asio::error::get_ssl_category());
			set_error(ec, "x.509 certificate store");
			pause();
			return;
		}

		// wrap the PEM certificate in a BIO, for openssl to read
		BIO* bp = BIO_new_mem_buf((void*)cert.c_str(), cert.size());

		// parse the certificate into OpenSSL's internal
		// representation
		X509* certificate = PEM_read_bio_X509_AUX(bp, 0, 0, 0);

		BIO_free(bp);

		if (!certificate)
		{
			error_code ec(::ERR_get_error(),
				asio::error::get_ssl_category());
			X509_STORE_free(cert_store);
			set_error(ec, "x.509 certificate");
			pause();
			return;
		}

		// add cert to cert_store
		X509_STORE_add_cert(cert_store, certificate);

		X509_free(certificate);

		// and lastly, replace the default cert store with ours
		SSL_CTX_set_cert_store(ssl_ctx, cert_store);
#if 0
		char filename[100];
		snprintf(filename, sizeof(filename), "/tmp/%d.pem", rand());
		FILE* f = fopen(filename, "w+");
		fwrite(cert.c_str(), cert.size(), 1, f);
		fclose(f);
		ctx->load_verify_file(filename);
#endif
		// if all went well, set the torrent ssl context to this one
		m_ssl_ctx = ctx;
		// tell the client we need a cert for this torrent
		alerts().post_alert(torrent_need_cert_alert(get_handle()));
#else
		set_error(asio::error::operation_not_supported, "x.509 certificate");
		pause();
#endif
	}

#endif // TORRENT_OPENSSL

	peer_connection* torrent::find_lowest_ranking_peer() const
	{
		const_peer_iterator lowest_rank = end();
		for (const_peer_iterator i = begin(); i != end(); ++i)
		{
			// disconnecting peers don't count
			if ((*i)->is_disconnecting()) continue;
			if (lowest_rank == end() || (*lowest_rank)->peer_rank() > (*i)->peer_rank())
				lowest_rank = i;
		}

		if (lowest_rank == end()) return NULL;
		return *lowest_rank;
	}

	// this may not be called from a constructor because of the call to
	// shared_from_this()
	void torrent::init()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(m_torrent_file->is_valid());
		TORRENT_ASSERT(m_torrent_file->num_files() > 0);
		TORRENT_ASSERT(m_torrent_file->total_size() >= 0);

		if (int(m_file_priority.size()) > m_torrent_file->num_files())
			m_file_priority.resize(m_torrent_file->num_files());

		std::string cert = m_torrent_file->ssl_cert();
		if (!cert.empty())
		{
			m_ssl_torrent = true;
#ifdef TORRENT_USE_OPENSSL
			init_ssl(cert);
#endif
		}

		m_file_priority.resize(m_torrent_file->num_files(), 1);

		// initialize pad files to priority 0
		file_storage const& fs = m_torrent_file->files();
		for (int i = 0; i < fs.num_files(); ++i)
		{
			if (!fs.pad_file_at(i)) continue;
			m_file_priority[i] = 0;
		}
		m_file_progress.resize(m_torrent_file->num_files(), 0);

		m_block_size_shift = root2((std::min)(int(block_size()), m_torrent_file->piece_length()));

		if (m_torrent_file->num_pieces() > piece_picker::max_pieces)
		{
			set_error(errors::too_many_pieces_in_torrent, "");
			pause();
			return;
		}

		if (m_torrent_file->num_pieces() == 0)
		{
			set_error(errors::torrent_invalid_length, "");
			pause();
			return;
		}

		// Chicken-and-egg: need to load resume data to get last save_path
		// before constructing m_owning_storage, but need storage before
		// loading resume data. So peek ahead in this case.
		// only do this if the user is willing to have the resume data
		// settings override the settings set in add_torrent_params
		if (!m_use_resume_save_path && m_resume_entry.type() == lazy_entry::dict_t)
		{
			std::string p = m_resume_entry.dict_find_string_value("save_path");
			if (!p.empty()) m_save_path = p;
		}

		// the shared_from_this() will create an intentional
		// cycle of ownership, se the hpp file for description.
		m_owning_storage = new piece_manager(shared_from_this(), m_torrent_file
			, m_save_path, m_ses.m_files, m_ses.m_disk_thread, m_storage_constructor
			, (storage_mode_t)m_storage_mode, m_file_priority);
		m_storage = m_owning_storage.get();

		if (has_picker())
		{
			int blocks_per_piece = (m_torrent_file->piece_length() + block_size() - 1) / block_size();
			int blocks_in_last_piece = ((m_torrent_file->total_size() % m_torrent_file->piece_length())
				+ block_size() - 1) / block_size();
			m_picker->init(blocks_per_piece, blocks_in_last_piece, m_torrent_file->num_pieces());
		}

		if (m_share_mode)
		{
			// in share mode, all pieces have their priorities initialized to 0
			std::fill(m_file_priority.begin(), m_file_priority.end(), 0);
		}

		if (!m_connections_initialized)
		{
			m_connections_initialized = true;
			// all peer connections have to initialize themselves now that the metadata
			// is available
			for (torrent::peer_iterator i = m_connections.begin();
				i != m_connections.end();)
			{
				peer_connection* pc = *i;
				++i;
				if (pc->is_disconnecting()) continue;
				pc->on_metadata_impl();
				if (pc->is_disconnecting()) continue;
				pc->init();
			}
		}

		// in case file priorities were passed in via the add_torrent_params
		// and also in the case of share mode, we need to update the priorities
		update_piece_priorities();

		std::vector<web_seed_entry> const& web_seeds = m_torrent_file->web_seeds();
		m_web_seeds.insert(m_web_seeds.end(), web_seeds.begin(), web_seeds.end());

		if (m_seed_mode)
		{
			m_ses.m_io_service.post(boost::bind(&torrent::files_checked, shared_from_this()));
			std::vector<char>().swap(m_resume_data);
			lazy_entry().swap(m_resume_entry);
#if TORRENT_USE_ASSERTS
			m_resume_data_loaded = true;
#endif
			return;
		}

		set_state(torrent_status::checking_resume_data);

		if (m_resume_entry.type() == lazy_entry::dict_t)
		{
			int ev = 0;
			if (m_resume_entry.dict_find_string_value("file-format") != "libtorrent resume file")
				ev = errors::invalid_file_tag;
	
			std::string info_hash = m_resume_entry.dict_find_string_value("info-hash");
			if (!ev && info_hash.empty())
				ev = errors::missing_info_hash;

			if (!ev && sha1_hash(info_hash) != m_torrent_file->info_hash())
				ev = errors::mismatching_info_hash;

			if (ev && m_ses.m_alerts.should_post<fastresume_rejected_alert>())
			{
				m_ses.m_alerts.post_alert(fastresume_rejected_alert(get_handle()
					, error_code(ev, get_libtorrent_category())));
			}

			if (ev)
			{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
				debug_log("fastresume data rejected: %s"
					, error_code(ev, get_libtorrent_category()).message().c_str());
#endif
				std::vector<char>().swap(m_resume_data);
				lazy_entry().swap(m_resume_entry);
			}
			else
			{
				read_resume_data(m_resume_entry);
			}
		}
	
#if TORRENT_USE_ASSERTS
		m_resume_data_loaded = true;
#endif

		int num_pad_files = 0;
		TORRENT_ASSERT(block_size() > 0);
		for (int i = 0; i < fs.num_files(); ++i)
		{
			if (fs.pad_file_at(i)) ++num_pad_files;

			if (!fs.pad_file_at(i) || fs.file_size(i) == 0) continue;
			m_padding += boost::uint32_t(fs.file_size(i));
			
			peer_request pr = m_torrent_file->map_file(i, 0, fs.file_size(i));
			int off = pr.start & (block_size()-1);
			if (off != 0) { pr.length -= block_size() - off; pr.start += block_size() - off; }
			TORRENT_ASSERT((pr.start & (block_size()-1)) == 0);

			int block = block_size();
			int blocks_per_piece = m_torrent_file->piece_length() / block;
			piece_block pb(pr.piece, pr.start / block);
			for (; pr.length >= block; pr.length -= block, ++pb.block_index)
			{
				if (int(pb.block_index) == blocks_per_piece) { pb.block_index = 0; ++pb.piece_index; }
				m_picker->mark_as_finished(pb, 0);
			}
			// ugly edge case where padfiles are not used they way they're
			// supposed to be. i.e. added back-to back or at the end
			if (int(pb.block_index) == blocks_per_piece) { pb.block_index = 0; ++pb.piece_index; }
			if (pr.length > 0 && ((i+1 != fs.num_files() && fs.pad_file_at(i+1))
				|| i + 1 == fs.num_files()))
			{
				m_picker->mark_as_finished(pb, 0);
			}
		}

		if (m_padding > 0)
		{
			// if we marked an entire piece as finished, we actually
			// need to consider it finished

			std::vector<piece_picker::downloading_piece> const& dq
				= m_picker->get_download_queue();

			std::vector<int> have_pieces;

			for (std::vector<piece_picker::downloading_piece>::const_iterator i
				= dq.begin(); i != dq.end(); ++i)
			{
				int num_blocks = m_picker->blocks_in_piece(i->index);
				if (i->finished < num_blocks) continue;
				have_pieces.push_back(i->index);
			}

			for (std::vector<int>::iterator i = have_pieces.begin();
				i != have_pieces.end(); ++i)
			{
				we_have(*i);
			}
		}

		m_picker->set_num_pad_files(num_pad_files);

		m_storage->async_check_fastresume(&m_resume_entry
			, boost::bind(&torrent::on_resume_data_checked
			, shared_from_this(), _1, _2));
	}

	bt_peer_connection* torrent::find_introducer(tcp::endpoint const& ep) const
	{
#ifndef TORRENT_DISABLE_EXTENSIONS
		for (const_peer_iterator i = m_connections.begin(); i != m_connections.end(); ++i)
		{
			if ((*i)->type() != peer_connection::bittorrent_connection) continue;
			bt_peer_connection* p = (bt_peer_connection*)(*i);
			if (!p->supports_holepunch()) continue;
			peer_plugin const* pp = p->find_plugin("ut_pex");
			if (!pp) continue;
			if (was_introduced_by(pp, ep)) return (bt_peer_connection*)p;
		}
#endif
		return 0;
	}

	bt_peer_connection* torrent::find_peer(tcp::endpoint const& ep) const
	{
		for (const_peer_iterator i = m_connections.begin(); i != m_connections.end(); ++i)
		{
			peer_connection* p = *i;
			if (p->type() != peer_connection::bittorrent_connection) continue;
			if (p->remote() == ep) return (bt_peer_connection*)p;
		}
		return 0;
	}

	void torrent::on_resume_data_checked(int ret, disk_io_job const& j)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		if (ret == piece_manager::fatal_disk_error)
		{
			handle_disk_error(j);
			auto_managed(false);
			pause();
			set_state(torrent_status::queued_for_checking);
			std::vector<char>().swap(m_resume_data);
			lazy_entry().swap(m_resume_entry);
			return;
		}

		state_updated();

		if (m_resume_entry.type() == lazy_entry::dict_t)
		{
			using namespace libtorrent::detail; // for read_*_endpoint()
			peer_id id(0);

			if (lazy_entry const* peers_entry = m_resume_entry.dict_find_string("peers"))
			{
				int num_peers = peers_entry->string_length() / (sizeof(address_v4::bytes_type) + 2);
				char const* ptr = peers_entry->string_ptr();
				for (int i = 0; i < num_peers; ++i)
				{
					m_policy.add_peer(read_v4_endpoint<tcp::endpoint>(ptr)
						, id, peer_info::resume_data, 0);
				}
			}

			if (lazy_entry const* banned_peers_entry = m_resume_entry.dict_find_string("banned_peers"))
			{
				int num_peers = banned_peers_entry->string_length() / (sizeof(address_v4::bytes_type) + 2);
				char const* ptr = banned_peers_entry->string_ptr();
				for (int i = 0; i < num_peers; ++i)
				{
					policy::peer* p = m_policy.add_peer(read_v4_endpoint<tcp::endpoint>(ptr)
						, id, peer_info::resume_data, 0);
					if (p) m_policy.ban_peer(p);
				}
			}

#if TORRENT_USE_IPV6
			if (lazy_entry const* peers6_entry = m_resume_entry.dict_find_string("peers6"))
			{
				int num_peers = peers6_entry->string_length() / (sizeof(address_v6::bytes_type) + 2);
				char const* ptr = peers6_entry->string_ptr();
				for (int i = 0; i < num_peers; ++i)
				{
					m_policy.add_peer(read_v6_endpoint<tcp::endpoint>(ptr)
						, id, peer_info::resume_data, 0);
				}
			}

			if (lazy_entry const* banned_peers6_entry = m_resume_entry.dict_find_string("banned_peers6"))
			{
				int num_peers = banned_peers6_entry->string_length() / (sizeof(address_v6::bytes_type) + 2);
				char const* ptr = banned_peers6_entry->string_ptr();
				for (int i = 0; i < num_peers; ++i)
				{
					policy::peer* p = m_policy.add_peer(read_v6_endpoint<tcp::endpoint>(ptr)
						, id, peer_info::resume_data, 0);
					if (p) m_policy.ban_peer(p);
				}
			}
#endif

			// parse out "peers" from the resume data and add them to the peer list
			if (lazy_entry const* peers_entry = m_resume_entry.dict_find_list("peers"))
			{
				for (int i = 0; i < peers_entry->list_size(); ++i)
				{
					lazy_entry const* e = peers_entry->list_at(i);
					if (e->type() != lazy_entry::dict_t) continue;
					std::string ip = e->dict_find_string_value("ip");
					int port = e->dict_find_int_value("port");
					if (ip.empty() || port == 0) continue;
					error_code ec;
					tcp::endpoint a(address::from_string(ip, ec), (unsigned short)port);
					if (ec) continue;
					m_policy.add_peer(a, id, peer_info::resume_data, 0);
				}
			}

			// parse out "banned_peers" and add them as banned
			if (lazy_entry const* banned_peers_entry = m_resume_entry.dict_find_list("banned_peers"))
			{	
				for (int i = 0; i < banned_peers_entry->list_size(); ++i)
				{
					lazy_entry const* e = banned_peers_entry->list_at(i);
					if (e->type() != lazy_entry::dict_t) continue;
					std::string ip = e->dict_find_string_value("ip");
					int port = e->dict_find_int_value("port");
					if (ip.empty() || port == 0) continue;
					error_code ec;
					tcp::endpoint a(address::from_string(ip, ec), (unsigned short)port);
					if (ec) continue;
					policy::peer* p = m_policy.add_peer(a, id, peer_info::resume_data, 0);
					if (p) m_policy.ban_peer(p);
				}
			}
		}

		// only report this error if the user actually provided resume data
		if ((j.error || ret != 0) && !m_resume_data.empty()
			&& m_ses.m_alerts.should_post<fastresume_rejected_alert>())
		{
			m_ses.m_alerts.post_alert(fastresume_rejected_alert(get_handle(), j.error));
		}

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
		if (ret != 0)
		{
			debug_log("fastresume data rejected: ret: %d (%d) %s"
				, ret, j.error.value(), j.error.message().c_str());
		}
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		else
			debug_log("fastresume data accepted");
#endif
#endif

		// if ret != 0, it means we need a full check. We don't necessarily need
		// that when the resume data check fails. For instance, if the resume data
		// is incorrect, but we don't have any files, we skip the check and initialize
		// the storage to not have anything.
		if (ret == 0)
		{
			// there are either no files for this torrent
			// or the resume_data was accepted

			if (!j.error && m_resume_entry.type() == lazy_entry::dict_t)
			{
				// parse have bitmask
				lazy_entry const* pieces = m_resume_entry.dict_find("pieces");
				if (pieces && pieces->type() == lazy_entry::string_t
					&& int(pieces->string_length()) == m_torrent_file->num_pieces())
				{
					char const* pieces_str = pieces->string_ptr();
					for (int i = 0, end(pieces->string_length()); i < end; ++i)
					{
						if (pieces_str[i] & 1) we_have(i);
						if (m_seed_mode && (pieces_str[i] & 2)) m_verified.set_bit(i);
					}
				}
				else
				{
					lazy_entry const* slots = m_resume_entry.dict_find("slots");
					if (slots && slots->type() == lazy_entry::list_t)
					{
						for (int i = 0; i < slots->list_size(); ++i)
						{
							int piece = slots->list_int_value_at(i, -1);
							if (piece >= 0) we_have(piece);
						}
					}
				}

				// parse unfinished pieces
				int num_blocks_per_piece =
					static_cast<int>(torrent_file().piece_length()) / block_size();

				if (lazy_entry const* unfinished_ent = m_resume_entry.dict_find_list("unfinished"))
				{
					for (int i = 0; i < unfinished_ent->list_size(); ++i)
					{
						lazy_entry const* e = unfinished_ent->list_at(i);
						if (e->type() != lazy_entry::dict_t) continue;
						int piece = e->dict_find_int_value("piece", -1);
						if (piece < 0 || piece > torrent_file().num_pieces()) continue;

						if (m_picker->have_piece(piece))
							m_picker->we_dont_have(piece);

						std::string bitmask = e->dict_find_string_value("bitmask");
						if (bitmask.empty()) continue;

						const int num_bitmask_bytes = (std::max)(num_blocks_per_piece / 8, 1);
						if ((int)bitmask.size() != num_bitmask_bytes) continue;
						for (int k = 0; k < num_bitmask_bytes; ++k)
						{
							unsigned char bits = bitmask[k];
							int num_bits = (std::min)(num_blocks_per_piece - k*8, 8);
							for (int b = 0; b < num_bits; ++b)
							{
								const int block = k * 8 + b;
								if (bits & (1 << b))
								{
									m_picker->mark_as_finished(piece_block(piece, block), 0);
									if (m_picker->is_piece_finished(piece))
										async_verify_piece(piece, boost::bind(&torrent::piece_finished
											, shared_from_this(), piece, _1));
								}
							}
						}
					}
				}
			}

			files_checked();
		}
		else
		{
			// either the fastresume data was rejected or there are
			// some files
			set_state(torrent_status::queued_for_checking);
			if (should_check_files())
				queue_torrent_check();
		}

		std::vector<char>().swap(m_resume_data);
		lazy_entry().swap(m_resume_entry);
	}

	void torrent::queue_torrent_check()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (m_queued_for_checking) return;
		m_queued_for_checking = true;
		m_ses.queue_check_torrent(shared_from_this());
	}

	void torrent::dequeue_torrent_check()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (!m_queued_for_checking) return;
		m_queued_for_checking = false;
		m_ses.dequeue_check_torrent(shared_from_this());
	}

	void torrent::force_recheck()
	{
		if (!valid_metadata()) return;

		// if the torrent is already queued to check its files
		// don't do anything
		if (should_check_files()
			|| m_state == torrent_status::checking_resume_data)
			return;

		clear_error();

		disconnect_all(errors::stopping_torrent);
		stop_announcing();

		m_owning_storage->async_release_files();
		if (!m_picker) m_picker.reset(new piece_picker());
		std::fill(m_file_progress.begin(), m_file_progress.end(), 0);

		int blocks_per_piece = (m_torrent_file->piece_length() + block_size() - 1) / block_size();
		int blocks_in_last_piece = ((m_torrent_file->total_size() % m_torrent_file->piece_length())
			+ block_size() - 1) / block_size();
		m_picker->init(blocks_per_piece, blocks_in_last_piece, m_torrent_file->num_pieces());

		// assume that we don't have anything
		TORRENT_ASSERT(m_picker->num_have() == 0);
		m_files_checked = false;
		set_state(torrent_status::checking_resume_data);

		m_policy.recalculate_connect_candidates();

		if (m_auto_managed && !is_finished())
			set_queue_position((std::numeric_limits<int>::max)());

		std::vector<char>().swap(m_resume_data);
		lazy_entry().swap(m_resume_entry);
		m_storage->async_check_fastresume(&m_resume_entry
			, boost::bind(&torrent::on_force_recheck
			, shared_from_this(), _1, _2));
	}

	void torrent::on_force_recheck(int ret, disk_io_job const& j)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		state_updated();

		if (ret == piece_manager::fatal_disk_error)
		{
			handle_disk_error(j);
			return;
		}
		if (ret == 0)
		{
			// if there are no files, just start
			files_checked();
		}
		else
		{
			set_state(torrent_status::queued_for_checking);
			if (should_check_files())
				queue_torrent_check();
		}
	}

	void torrent::start_checking()
	{
		TORRENT_ASSERT(should_check_files());
		set_state(torrent_status::checking_files);

		m_storage->async_check_files(boost::bind(
			&torrent::on_piece_checked
			, shared_from_this(), _1, _2));
	}
	
	void torrent::on_piece_checked(int ret, disk_io_job const& j)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		state_updated();

		if (ret == piece_manager::disk_check_aborted)
		{
			dequeue_torrent_check();
			pause();
			return;
		}
		if (ret == piece_manager::fatal_disk_error)
		{
			if (m_ses.m_alerts.should_post<file_error_alert>())
			{
				m_ses.m_alerts.post_alert(file_error_alert(j.error_file, get_handle(), j.error));
			}
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
			debug_log("fatal disk error: (%d) %s", j.error.value(), j.error.message().c_str());
#endif
			auto_managed(false);
			pause();
			set_error(j.error, j.error_file);
			// recalculate auto-managed torrents sooner
			// in order to start checking the next torrent
			m_ses.trigger_auto_manage();
			return;
		}

		m_progress_ppm = size_type(j.piece) * 1000000 / torrent_file().num_pieces();

		TORRENT_ASSERT(m_picker);
		if (j.offset >= 0 && !m_picker->have_piece(j.offset))
		{
			we_have(j.offset);
			remove_time_critical_piece(j.offset);
		}

		// we're not done checking yet
		// this handler will be called repeatedly until
		// we're done, or encounter a failure
		if (ret == piece_manager::need_full_check) return;

		dequeue_torrent_check();
		files_checked();
	}

	void torrent::use_interface(std::string net_interfaces)
	{
		INVARIANT_CHECK;
		m_net_interfaces.clear();

		char* str = allocate_string_copy(net_interfaces.c_str());
		char* ptr = str;

		while (ptr)
		{
			char* space = strchr(ptr, ',');
			if (space) *space++ = 0;
			error_code ec;
			address a(address::from_string(ptr, ec));
			ptr = space;
			if (ec) continue;
			m_net_interfaces.push_back(tcp::endpoint(a, 0));
		}
		free(str);
	}

	tcp::endpoint torrent::get_interface() const
	{
		if (m_net_interfaces.empty()) return tcp::endpoint(address_v4(), 0);
		if (m_interface_index >= m_net_interfaces.size()) m_interface_index = 0;
		return m_net_interfaces[m_interface_index++];
	}

	void torrent::on_tracker_announce_disp(boost::weak_ptr<torrent> p
		, error_code const& e)
	{
#if defined TORRENT_ASIO_DEBUGGING
		complete_async("tracker::on_tracker_announce_disp");
#endif
		if (e) return;
		boost::shared_ptr<torrent> t = p.lock();
		if (!t) return;
		t->on_tracker_announce();
	}

	void torrent::on_tracker_announce()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		m_waiting_tracker = false;	
		if (m_abort) return;
		announce_with_tracker();
	}

	void torrent::lsd_announce()
	{
		if (m_abort) return;

		// if the files haven't been checked yet, we're
		// not ready for peers. Except, if we don't have metadata,
		// we need peers to download from
		if (!m_files_checked && valid_metadata()) return;

		if (!m_announce_to_lsd) return;

		if (m_torrent_file->is_valid()
			&& (m_torrent_file->priv()
				|| (torrent_file().is_i2p()
					&& !settings().allow_i2p_mixed)))
			return;

		if (is_paused()) return;

#ifdef TORRENT_USE_OPENSSL
		int port = is_ssl_torrent() ? m_ses.ssl_listen_port() : m_ses.listen_port();
#else
		int port = m_ses.listen_port();
#endif

		// announce with the local discovery service
		m_ses.announce_lsd(m_torrent_file->info_hash(), port
			, m_ses.settings().broadcast_lsd && m_lsd_seq == 0);
		++m_lsd_seq;
	}

#ifndef TORRENT_DISABLE_DHT

	void torrent::dht_announce()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (!m_ses.m_dht) return;
		if (!should_announce_dht()) return;

		TORRENT_ASSERT(m_allow_peers);

#ifdef TORRENT_USE_OPENSSL
		int port = is_ssl_torrent() ? m_ses.ssl_listen_port() : m_ses.listen_port();
#else
		int port = m_ses.listen_port();
#endif

		boost::weak_ptr<torrent> self(shared_from_this());

		// if we're a seed, we tell the DHT for better scrape stats
		int flags = is_seed() ? dht::dht_tracker::flag_seed : 0;
		// if we allow incoming uTP connections, set the implied_port
		// argument in the announce, this will make the DHT node use
		// our source port in the packet as our listen port, which is
		// likely more accurate when behind a NAT
		if (settings().enable_incoming_utp) flags |= dht::dht_tracker::flag_implied_port;

		m_ses.m_dht->announce(m_torrent_file->info_hash()
			, port, flags
			, boost::bind(&torrent::on_dht_announce_response_disp, self, _1));
	}

	void torrent::on_dht_announce_response_disp(boost::weak_ptr<libtorrent::torrent> t
		, std::vector<tcp::endpoint> const& peers)
	{
		boost::shared_ptr<libtorrent::torrent> tor = t.lock();
		if (!tor) return;
		tor->on_dht_announce_response(peers);
	}

	void torrent::on_dht_announce_response(std::vector<tcp::endpoint> const& peers)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (peers.empty()) return;

		if (m_ses.m_alerts.should_post<dht_reply_alert>())
		{
			m_ses.m_alerts.post_alert(dht_reply_alert(
				get_handle(), peers.size()));
		}

		if (torrent_file().priv() || (torrent_file().is_i2p()
			&& !settings().allow_i2p_mixed)) return;

		std::for_each(peers.begin(), peers.end(), boost::bind(
			&policy::add_peer, boost::ref(m_policy), _1, peer_id(0)
			, peer_info::dht, 0));

		do_connect_boost();
	}

#endif

	void torrent::announce_with_tracker(tracker_request::event_t e
		, address const& bind_interface)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		if (m_trackers.empty())
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("*** announce_with_tracker: no trackers");
#endif
			return;
		}

		if (m_abort) e = tracker_request::stopped;

		// if we're not announcing to trackers, only allow
		// stopping
		if (e != tracker_request::stopped && !m_announce_to_trackers)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("*** announce_with_tracker: event != stopped && !m_announce_to_trackers");
#endif
			return;
		}

		// if we're not allowing peers, there's no point in announcing
		if (e != tracker_request::stopped && !m_allow_peers)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("*** announce_with_tracker: event != stopped && !m_allow_peers");
#endif
			return;
		}

		TORRENT_ASSERT(m_allow_peers || e == tracker_request::stopped);

		if (e == tracker_request::none && is_finished() && !is_seed())
			e = tracker_request::paused;

		tracker_request req;
		req.apply_ip_filter = m_apply_ip_filter && m_ses.m_settings.apply_ip_filter_to_trackers;
		req.info_hash = m_torrent_file->info_hash();
		req.pid = m_ses.get_peer_id();
		req.downloaded = m_stat.total_payload_download() - m_total_failed_bytes;
		req.uploaded = m_stat.total_payload_upload();
		req.corrupt = m_total_failed_bytes;
		req.left = bytes_left();
		if (req.left == -1) req.left = 16*1024;
#ifdef TORRENT_USE_OPENSSL
		// if this torrent contains an SSL certificate, make sure
		// any SSL tracker presents a certificate signed by it
		req.ssl_ctx = m_ssl_ctx.get();
#endif

		// exclude redundant bytes if we should
		if (!settings().report_true_downloaded)
			req.downloaded -= m_total_redundant_bytes;
		if (req.downloaded < 0) req.downloaded = 0;

		req.event = e;
		error_code ec;

		// if we are aborting. we don't want any new peers
		req.num_want = (req.event == tracker_request::stopped)
			?0:settings().num_want;

		// SSL torrents use their own listen socket
#ifdef TORRENT_USE_OPENSSL
		if (is_ssl_torrent()) req.listen_port = m_ses.ssl_listen_port();
		else
#endif
		req.listen_port = m_ses.listen_port();
		if (m_ses.m_key)
			req.key = m_ses.m_key;
		else
			req.key = tracker_key();

		ptime now = time_now_hires();

		// the tier is kept as INT_MAX until we find the first
		// tracker that works, then it's set to that tracker's
		// tier.
		int tier = INT_MAX;

		// have we sent an announce in this tier yet?
		bool sent_announce = false;

		for (int i = 0; i < int(m_trackers.size()); ++i)
		{
			announce_entry& ae = m_trackers[i];
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
			debug_log("*** announce with tracker: considering \"%s\" "
				"[ announce_to_all_tiers: %d announce_to_all_trackers: %d"
				" i->tier: %d tier: %d "
				" is_working: %d fails: %d fail_limit: %d updating: %d"
				" can_announce: %d sent_announce: %d ]"
				, ae.url.c_str(), settings().announce_to_all_tiers
				, settings().announce_to_all_trackers
				, ae.tier, tier, ae.is_working(), ae.fails, ae.fail_limit
				, ae.updating, ae.can_announce(now, is_seed()), sent_announce);
#endif
			// if trackerid is not specified for tracker use default one, probably set explicitly
			req.trackerid = ae.trackerid.empty() ? m_trackerid : ae.trackerid;
			if (settings().announce_to_all_tiers
				&& !settings().announce_to_all_trackers
				&& sent_announce
				&& ae.tier <= tier
				&& tier != INT_MAX)
				continue;

			if (ae.tier > tier && sent_announce && !settings().announce_to_all_tiers) break;
			if (ae.is_working()) { tier = ae.tier; sent_announce = false; }
			if (!ae.can_announce(now, is_seed()))
			{
				// this counts
				if (ae.is_working()) sent_announce = true;
				continue;
			}
			
			req.url = ae.url;
			req.event = e;
			if (req.event == tracker_request::none)
			{
				if (!ae.start_sent) req.event = tracker_request::started;
				else if (!ae.complete_sent && is_seed()) req.event = tracker_request::completed;
			}

			if (!is_any(bind_interface)) req.bind_ip = bind_interface;
			else req.bind_ip = m_ses.m_listen_interface.address();

			if (settings().force_proxy)
			{
				// in force_proxy mode we don't talk directly to trackers
				// we only allow trackers if there is a proxy and issue
				// a warning if there isn't one
				std::string protocol = req.url.substr(0, req.url.find(':'));
				int proxy_type = m_ses.m_proxy.type;
	
				// http can run over any proxy, so as long as one is used
				// it's OK. If no proxy is configured, skip this tracker
				if ((protocol == "http" || protocol == "https")
					&& proxy_type == proxy_settings::none)
				{
					ae.next_announce = now + minutes(10);
					if (m_ses.m_alerts.should_post<anonymous_mode_alert>())
					{
						m_ses.m_alerts.post_alert(
							anonymous_mode_alert(get_handle()
								, anonymous_mode_alert::tracker_not_anonymous, req.url));
					}
					continue;
				}

				// for UDP, only socks5 and i2p proxies will work.
				// if we're not using one of those proxues with a UDP
				// tracker, skip it
				if (protocol == "udp"
					&& proxy_type != proxy_settings::socks5
					&& proxy_type != proxy_settings::socks5_pw
					&& proxy_type != proxy_settings::i2p_proxy)
				{
					ae.next_announce = now + minutes(10);
					if (m_ses.m_alerts.should_post<anonymous_mode_alert>())
					{
						m_ses.m_alerts.post_alert(
							anonymous_mode_alert(get_handle()
								, anonymous_mode_alert::tracker_not_anonymous, req.url));
					}
					continue;
				}
			}
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("==> TRACKER REQUEST \"%s\" event: %s abort: %d"
				, req.url.c_str()
				, (req.event==tracker_request::stopped?"stopped"
					:req.event==tracker_request::started?"started":"")
				, m_abort);

			if (m_abort)
			{
				boost::shared_ptr<aux::tracker_logger> tl(new aux::tracker_logger(m_ses));
				m_ses.m_tracker_manager.queue_request(m_ses.m_io_service, m_ses.m_half_open, req
					, tracker_login(), tl);
			}
			else
#endif
			{
				m_ses.m_tracker_manager.queue_request(m_ses.m_io_service, m_ses.m_half_open, req
					, tracker_login() , shared_from_this());
			}

			ae.updating = true;
			ae.next_announce = now + seconds(20);
			ae.min_announce = now + seconds(10);

			if (m_ses.m_alerts.should_post<tracker_announce_alert>())
			{
				m_ses.m_alerts.post_alert(
					tracker_announce_alert(get_handle(), req.url, req.event));
			}

			sent_announce = true;
			if (ae.is_working()
				&& !settings().announce_to_all_trackers
				&& !settings().announce_to_all_tiers)
				break;
		}
		update_tracker_timer(now);
	}

	void torrent::scrape_tracker()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		m_last_scrape = 0;

		if (m_trackers.empty()) return;

		int i = m_last_working_tracker;
		if (i == -1) i = 0;
		
		tracker_request req;
		req.apply_ip_filter = m_apply_ip_filter && m_ses.m_settings.apply_ip_filter_to_trackers;
		req.info_hash = m_torrent_file->info_hash();
		req.kind = tracker_request::scrape_request;
		req.url = m_trackers[i].url;
		req.bind_ip = m_ses.m_listen_interface.address();
		m_ses.m_tracker_manager.queue_request(m_ses.m_io_service, m_ses.m_half_open, req
			, tracker_login(), shared_from_this());
	}

	void torrent::tracker_warning(tracker_request const& req, std::string const& msg)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		INVARIANT_CHECK;

		if (m_ses.m_alerts.should_post<tracker_warning_alert>())
			m_ses.m_alerts.post_alert(tracker_warning_alert(get_handle(), req.url, msg));
	}
	
 	void torrent::tracker_scrape_response(tracker_request const& req
 		, int complete, int incomplete, int downloaded, int downloaders)
 	{
		TORRENT_ASSERT(m_ses.is_network_thread());
 
 		INVARIANT_CHECK;
		TORRENT_ASSERT(req.kind == tracker_request::scrape_request);
 
		announce_entry* ae = find_tracker(req);
		if (ae)
		{
			if (incomplete >= 0) ae->scrape_incomplete = incomplete;
			if (complete >= 0) ae->scrape_complete = complete;
			if (downloaded >= 0) ae->scrape_downloaded = downloaded;

			update_scrape_state();
		}

		if (m_ses.m_alerts.should_post<scrape_reply_alert>())
		{
			m_ses.m_alerts.post_alert(scrape_reply_alert(
				get_handle(), incomplete, complete, req.url));
		}
	}

	void torrent::update_scrape_state()
	{
		// loop over all trackers and find the largest numbers for each scrape field
		// then update the torrent-wide understanding of number of downloaders and seeds
		int complete = -1;
		int incomplete = -1;
		int downloaded = -1;
		for (std::vector<announce_entry>::iterator i = m_trackers.begin()
			, end(m_trackers.end()); i != end; ++i)
		{
			complete = (std::max)(i->scrape_complete, complete);
			incomplete = (std::max)(i->scrape_incomplete, incomplete);
			downloaded = (std::max)(i->scrape_downloaded, downloaded);
		}

		if ((complete >= 0 && m_complete != complete)
			|| (incomplete >= 0 && m_incomplete != incomplete)
			|| (downloaded >= 0 && m_downloaded != downloaded))
			state_updated();

		m_complete = complete;
		m_incomplete = incomplete;
		m_downloaded = downloaded;
	}
 
	void torrent::tracker_response(
		tracker_request const& r
		, address const& tracker_ip // this is the IP we connected to
		, std::list<address> const& tracker_ips // these are all the IPs it resolved to
		, std::vector<peer_entry>& peer_list
		, int interval
		, int min_interval
		, int complete
		, int incomplete
		, int downloaded 
		, address const& external_ip
		, const std::string& trackerid)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		INVARIANT_CHECK;
		TORRENT_ASSERT(r.kind == tracker_request::announce_request);

		if (external_ip != address() && !tracker_ips.empty())
			m_ses.set_external_address(external_ip, aux::session_impl::source_tracker
				, *tracker_ips.begin());

		ptime now = time_now();

		if (interval < settings().min_announce_interval)
			interval = settings().min_announce_interval;

		announce_entry* ae = find_tracker(r);
		if (ae)
		{
			if (incomplete >= 0) ae->scrape_incomplete = incomplete;
			if (complete >= 0) ae->scrape_complete = complete;
			if (downloaded >= 0) ae->scrape_downloaded = downloaded;
			if (!ae->start_sent && r.event == tracker_request::started)
				ae->start_sent = true;
			if (!ae->complete_sent && r.event == tracker_request::completed)
				ae->complete_sent = true;
			ae->verified = true;
			ae->updating = false;
			ae->fails = 0;
			ae->next_announce = now + seconds(interval);
			ae->min_announce = now + seconds(min_interval);
			int tracker_index = ae - &m_trackers[0];
			m_last_working_tracker = prioritize_tracker(tracker_index);

			if ((!trackerid.empty()) && (ae->trackerid != trackerid))
			{
				ae->trackerid = trackerid;
				if (m_ses.m_alerts.should_post<trackerid_alert>())
					m_ses.m_alerts.post_alert(trackerid_alert(get_handle(), r.url, trackerid));
			}

			update_scrape_state();
		}
		update_tracker_timer(now);

		if (complete >= 0 && incomplete >= 0)
			m_last_scrape = 0;

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("TRACKER RESPONSE\n"
				"interval: %d\n"
				"external ip: %s\n"
				"we connected to: %s\n"
				"peers:"
			, interval
			, print_address(external_ip).c_str()
			, print_address(tracker_ip).c_str());

		for (std::vector<peer_entry>::const_iterator i = peer_list.begin();
			i != peer_list.end(); ++i)
		{
			debug_log("  %16s %5d %s %s", i->ip.c_str(), i->port
				, i->pid.is_all_zeros()?"":to_hex(i->pid.to_string()).c_str()
				, identify_client(i->pid).c_str());
		}
#endif
		// for each of the peers we got from the tracker
		for (std::vector<peer_entry>::iterator i = peer_list.begin();
			i != peer_list.end(); ++i)
		{
			// don't make connections to ourself
			if (i->pid == m_ses.get_peer_id())
				continue;

			error_code ec;
			tcp::endpoint a(address::from_string(i->ip, ec), i->port);

			if (ec)
			{
				// assume this is because we got a hostname instead of
				// an ip address from the tracker

#if TORRENT_USE_I2P
				char const* top_domain = strrchr(i->ip.c_str(), '.');
				if (top_domain && strcmp(top_domain, ".i2p") == 0 && m_ses.m_i2p_conn.is_open())
				{
					// this is an i2p name, we need to use the sam connection
					// to do the name lookup
					/*
					m_ses.m_i2p_conn.async_name_lookup(i->ip.c_str()
						, boost::bind(&torrent::on_i2p_resolve
						, shared_from_this(), _1, _2));
					*/
					// it seems like you're not supposed to do a name lookup
					// on the peers returned from the tracker, but just strip
					// the .i2p and use it as a destination
					i->ip.resize(i->ip.size() - 4);
					m_policy.add_i2p_peer(i->ip.c_str(), peer_info::tracker, 0);
				}
				else
#endif
				{
#if defined TORRENT_ASIO_DEBUGGING
					add_outstanding_async("torrent::on_peer_name_lookup");
#endif
					tcp::resolver::query q(i->ip, to_string(i->port).elems);
					m_host_resolver.async_resolve(q,
						boost::bind(&torrent::on_peer_name_lookup, shared_from_this(), _1, _2, i->pid));
				}
			}
			else
			{
				// ignore local addresses from the tracker (unless the tracker is local too)
				// there are 2 reasons to allow this:
				// 1. retrackers are popular in russia, where an ISP runs a tracker within
				//    the AS (but not on the local network) giving out peers only from the
				//    local network
				// 2. it might make sense to have a tracker extension in the future where
				//    trackers records a peer's internal and external IP, and match up
				//    peers on the same local network
//				if (is_local(a.address()) && !is_local(tracker_ip)) continue;
				m_policy.add_peer(a, i->pid, peer_info::tracker, 0);
			}
		}

		if (m_ses.m_alerts.should_post<tracker_reply_alert>())
		{
			m_ses.m_alerts.post_alert(tracker_reply_alert(
				get_handle(), peer_list.size(), r.url));
		}
		m_got_tracker_response = true;

		// we're listening on an interface type that was not used
		// when talking to the tracker. If there is a matching interface
		// type in the tracker IP list, make another tracker request
		// using that interface
		// in order to avoid triggering this case over and over, don't
		// do it if the bind IP for the tracker request that just completed
		// matches one of the listen interfaces, since that means this
		// announce was the second one
		// don't connect twice just to tell it we're stopping

		if (((!is_any(m_ses.m_ipv6_interface.address()) && tracker_ip.is_v4())
			|| (!is_any(m_ses.m_ipv4_interface.address()) && tracker_ip.is_v6()))
			&& r.bind_ip != m_ses.m_ipv4_interface.address()
			&& r.bind_ip != m_ses.m_ipv6_interface.address()
			&& r.event != tracker_request::stopped)
		{
			std::list<address>::const_iterator i = std::find_if(tracker_ips.begin()
				, tracker_ips.end(), boost::bind(&address::is_v4, _1) != tracker_ip.is_v4());
			if (i != tracker_ips.end())
			{
				// the tracker did resolve to a different type of address, so announce
				// to that as well

				// tell the tracker to bind to the opposite protocol type
				address bind_interface = tracker_ip.is_v4()
					?m_ses.m_ipv6_interface.address()
					:m_ses.m_ipv4_interface.address();
				announce_with_tracker(r.event, bind_interface);
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
				debug_log("announce again using %s as the bind interface"
					, print_address(bind_interface).c_str());
#endif
			}
		}

		do_connect_boost();

		state_updated();
	}

	void torrent::do_connect_boost()
	{
		if (!m_need_connect_boost) return;

		m_need_connect_boost = false;
		// this is the first tracker response for this torrent
		// instead of waiting one second for session_impl::on_tick()
		// to be called, connect to a few peers immediately
		int conns = (std::min)((std::min)((std::min)(m_ses.m_settings.torrent_connect_boost
			, m_ses.m_settings.connections_limit - m_ses.num_connections())
			, m_ses.m_half_open.free_slots())
			, m_ses.m_boost_connections - m_ses.m_settings.connection_speed);

		while (want_more_peers() && conns > 0)
		{
			if (!m_policy.connect_one_peer(m_ses.session_time())) break;
			// increase m_ses.m_boost_connections for each connection
			// attempt. This will be deducted from the connect speed
			// the next time session_impl::on_tick() is triggered
			--conns;
			++m_ses.m_boost_connections;
		}

		if (want_more_peers()) m_ses.prioritize_connections(shared_from_this());
	}

	ptime torrent::next_announce() const
	{
		return m_waiting_tracker?m_tracker_timer.expires_at():min_time();
	}

	void torrent::force_tracker_request(ptime t, int tracker_idx)
	{
		if (is_paused()) return;
		if (tracker_idx == -1)
		{
			for (std::vector<announce_entry>::iterator i = m_trackers.begin()
				, end(m_trackers.end()); i != end; ++i)
				i->next_announce = (std::max)(t, i->min_announce) + seconds(1);
		}
		else
		{
			TORRENT_ASSERT(tracker_idx >= 0 && tracker_idx < int(m_trackers.size()));
			if (tracker_idx < 0 || tracker_idx >= int(m_trackers.size()))
				return;
			announce_entry& e = m_trackers[tracker_idx];
			e.next_announce = (std::max)(t, e.min_announce) + seconds(1);
		}
		update_tracker_timer(time_now_hires());
	}

	void torrent::set_tracker_login(
		std::string const& name
		, std::string const& pw)
	{
		m_username = name;
		m_password = pw;
	}

#if TORRENT_USE_I2P
	void torrent::on_i2p_resolve(error_code const& ec, char const* dest)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		INVARIANT_CHECK;

#if defined TORRENT_LOGGING
		if (ec)
			debug_log("i2p_resolve error: %s", ec.message().c_str());
#endif
		if (ec || m_ses.is_aborted()) return;

		m_policy.add_i2p_peer(dest, peer_info::tracker, 0);
	}
#endif

	void torrent::on_peer_name_lookup(error_code const& e, tcp::resolver::iterator host
		, peer_id pid)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		INVARIANT_CHECK;

#if defined TORRENT_ASIO_DEBUGGING
		complete_async("torrent::on_peer_name_lookup");
#endif

#if defined TORRENT_LOGGING
		if (e)
			debug_log("peer name lookup error: %s", e.message().c_str());
#endif
		if (e || host == tcp::resolver::iterator() ||
			m_ses.is_aborted()) return;

		if (m_apply_ip_filter
			&& m_ses.m_ip_filter.access(host->endpoint().address()) & ip_filter::blocked)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
			error_code ec;
			debug_log("blocked ip from tracker: %s", host->endpoint().address().to_string(ec).c_str());
#endif
			if (m_ses.m_alerts.should_post<peer_blocked_alert>())
				m_ses.m_alerts.post_alert(peer_blocked_alert(get_handle()
					, host->endpoint().address(), peer_blocked_alert::ip_filter));
			return;
		}
			
		m_policy.add_peer(*host, pid, peer_info::tracker, 0);
	}

	size_type torrent::bytes_left() const
	{
		// if we don't have the metadata yet, we
		// cannot tell how big the torrent is.
		if (!valid_metadata()) return -1;
		return m_torrent_file->total_size()
			- quantized_bytes_done();
	}

	size_type torrent::quantized_bytes_done() const
	{
//		INVARIANT_CHECK;

		if (!valid_metadata()) return 0;

		if (m_torrent_file->num_pieces() == 0)
			return 0;

		if (is_seed()) return m_torrent_file->total_size();

		// if any piece hash fails, we'll be taken out of seed mode
		// and m_seed_mode will be false
		if (m_seed_mode) return m_torrent_file->total_size();

		const int last_piece = m_torrent_file->num_pieces() - 1;

		size_type total_done
			= size_type(num_have()) * m_torrent_file->piece_length();

		// if we have the last piece, we have to correct
		// the amount we have, since the first calculation
		// assumed all pieces were of equal size
		if (m_picker->have_piece(last_piece))
		{
			int corr = m_torrent_file->piece_size(last_piece)
				- m_torrent_file->piece_length();
			total_done += corr;
		}
		return total_done;
	}

	// returns the number of bytes we are interested
	// in for the given block. This returns block_size()
	// for all blocks except the last one (if it's smaller
	// than block_size()) and blocks that overlap a padding
	// file
	int torrent::block_bytes_wanted(piece_block const& p) const
	{
		file_storage const& fs = m_torrent_file->files();
		int piece_size = m_torrent_file->piece_size(p.piece_index);
		int offset = p.block_index * block_size();
		if (m_padding == 0) return (std::min)(piece_size - offset, int(block_size()));

		std::vector<file_slice> files = fs.map_block(
			p.piece_index, offset, (std::min)(piece_size - offset, int(block_size())));
		int ret = 0;
		for (std::vector<file_slice>::iterator i = files.begin()
			, end(files.end()); i != end; ++i)
		{
			if (fs.pad_file_at(i->file_index)) continue;
			ret += i->size;
		}
		TORRENT_ASSERT(ret <= (std::min)(piece_size - offset, int(block_size())));
		return ret;
	}

	// fills in total_wanted, total_wanted_done and total_done
	void torrent::bytes_done(torrent_status& st, bool accurate) const
	{
		INVARIANT_CHECK;

		st.total_done = 0;
		st.total_wanted_done = 0;
		st.total_wanted = m_torrent_file->total_size();

		TORRENT_ASSERT(st.total_wanted >= m_padding);
		TORRENT_ASSERT(st.total_wanted >= 0);

		if (!valid_metadata() || m_torrent_file->num_pieces() == 0)
			return;

		TORRENT_ASSERT(st.total_wanted >= size_type(m_torrent_file->piece_length())
			* (m_torrent_file->num_pieces() - 1));

		const int last_piece = m_torrent_file->num_pieces() - 1;
		const int piece_size = m_torrent_file->piece_length();

		// if any piece hash fails, we'll be taken out of seed mode
		// and m_seed_mode will be false
		if (m_seed_mode || is_seed())
		{
			st.total_done = m_torrent_file->total_size() - m_padding;
			st.total_wanted_done = st.total_done;
			st.total_wanted = st.total_done;
			return;
		}

		TORRENT_ASSERT(num_have() >= m_picker->num_have_filtered());
		st.total_wanted_done = size_type(num_have() - m_picker->num_have_filtered())
			* piece_size;
		TORRENT_ASSERT(st.total_wanted_done >= 0);
		
		st.total_done = size_type(num_have()) * piece_size;
		TORRENT_ASSERT(num_have() < m_torrent_file->num_pieces());

		int num_filtered_pieces = m_picker->num_filtered()
			+ m_picker->num_have_filtered();
		int last_piece_index = m_torrent_file->num_pieces() - 1;
		if (m_picker->piece_priority(last_piece_index) == 0)
		{
			st.total_wanted -= m_torrent_file->piece_size(last_piece_index);
			--num_filtered_pieces;
		}
		st.total_wanted -= size_type(num_filtered_pieces) * piece_size;
	
		// if we have the last piece, we have to correct
		// the amount we have, since the first calculation
		// assumed all pieces were of equal size
		if (m_picker->have_piece(last_piece))
		{
			TORRENT_ASSERT(st.total_done >= piece_size);
			int corr = m_torrent_file->piece_size(last_piece)
				- piece_size;
			TORRENT_ASSERT(corr <= 0);
			TORRENT_ASSERT(corr > -piece_size);
			st.total_done += corr;
			if (m_picker->piece_priority(last_piece) != 0)
			{
				TORRENT_ASSERT(st.total_wanted_done >= piece_size);
				st.total_wanted_done += corr;
			}
		}
		TORRENT_ASSERT(st.total_wanted >= st.total_wanted_done);

		// this is expensive, we might not want to do it all the time
		if (!accurate) return;

		// subtract padding files
		if (m_padding > 0)
		{
			file_storage const& files = m_torrent_file->files();
			for (int i = 0; i < files.num_files(); ++i)
			{
				if (!files.pad_file_at(i)) continue;
				peer_request p = files.map_file(i, 0, files.file_size(i));
				for (int j = p.piece; p.length > 0; ++j)
				{
					int deduction = (std::min)(p.length, piece_size - p.start);
					bool done = m_picker->have_piece(j);
					bool wanted = m_picker->piece_priority(j) > 0;
					if (done) st.total_done -= deduction;
					if (wanted) st.total_wanted -= deduction;
					if (wanted && done) st.total_wanted_done -= deduction;
					TORRENT_ASSERT(st.total_done >= 0);
					TORRENT_ASSERT(st.total_wanted >= 0);
					TORRENT_ASSERT(st.total_wanted_done >= 0);
					p.length -= piece_size - p.start;
					p.start = 0;
					++p.piece;
				}
			}
		}

		TORRENT_ASSERT(st.total_done <= m_torrent_file->total_size() - m_padding);
		TORRENT_ASSERT(st.total_wanted_done <= m_torrent_file->total_size() - m_padding);
		TORRENT_ASSERT(st.total_wanted_done >= 0);
		TORRENT_ASSERT(st.total_done >= st.total_wanted_done);

		const std::vector<piece_picker::downloading_piece>& dl_queue
			= m_picker->get_download_queue();

		const int blocks_per_piece = (piece_size + block_size() - 1) / block_size();

		// look at all unfinished pieces and add the completed
		// blocks to our 'done' counter
		for (std::vector<piece_picker::downloading_piece>::const_iterator i =
			dl_queue.begin(); i != dl_queue.end(); ++i)
		{
			int corr = 0;
			int index = i->index;
			// completed pieces are already accounted for
			if (m_picker->have_piece(index)) continue;
			TORRENT_ASSERT(i->finished <= m_picker->blocks_in_piece(index));

#if TORRENT_USE_ASSERTS
			for (std::vector<piece_picker::downloading_piece>::const_iterator j = boost::next(i);
				j != dl_queue.end(); ++j)
			{
				TORRENT_ASSERT(j->index != index);
			}
#endif

			for (int j = 0; j < blocks_per_piece; ++j)
			{
#ifdef TORRENT_EXPENSIVE_INVARIANT_CHECKS
				TORRENT_ASSERT(m_picker->is_finished(piece_block(index, j))
					== (i->info[j].state == piece_picker::block_info::state_finished));
#endif
				if (i->info[j].state == piece_picker::block_info::state_finished)
				{
					corr += block_bytes_wanted(piece_block(index, j));
				}
				TORRENT_ASSERT(corr >= 0);
				TORRENT_ASSERT(index != last_piece || j < m_picker->blocks_in_last_piece()
					|| i->info[j].state != piece_picker::block_info::state_finished);
			}

			st.total_done += corr;
			if (m_picker->piece_priority(index) > 0)
				st.total_wanted_done += corr;
		}

		TORRENT_ASSERT(st.total_wanted <= m_torrent_file->total_size() - m_padding);
		TORRENT_ASSERT(st.total_done <= m_torrent_file->total_size() - m_padding);
		TORRENT_ASSERT(st.total_wanted_done <= m_torrent_file->total_size() - m_padding);
		TORRENT_ASSERT(st.total_wanted_done >= 0);
		TORRENT_ASSERT(st.total_done >= st.total_wanted_done);

		std::map<piece_block, int> downloading_piece;
		for (const_peer_iterator i = begin(); i != end(); ++i)
		{
			peer_connection* pc = *i;
			boost::optional<piece_block_progress> p
				= pc->downloading_piece_progress();
			if (!p) continue;

			if (m_picker->have_piece(p->piece_index))
				continue;

			piece_block block(p->piece_index, p->block_index);
			if (m_picker->is_finished(block))
				continue;

			std::map<piece_block, int>::iterator dp
				= downloading_piece.find(block);
			if (dp != downloading_piece.end())
			{
				if (dp->second < p->bytes_downloaded)
					dp->second = p->bytes_downloaded;
			}
			else
			{
				downloading_piece[block] = p->bytes_downloaded;
			}
#ifdef TORRENT_DEBUG
			TORRENT_ASSERT(p->bytes_downloaded <= p->full_block_bytes);
			TORRENT_ASSERT(p->full_block_bytes == to_req(piece_block(
				p->piece_index, p->block_index)).length);
#endif
		}
		for (std::map<piece_block, int>::iterator i = downloading_piece.begin();
			i != downloading_piece.end(); ++i)
		{
			int done = (std::min)(block_bytes_wanted(i->first), i->second);
			st.total_done += done;
			if (m_picker->piece_priority(i->first.piece_index) != 0)
				st.total_wanted_done += done;
		}

		TORRENT_ASSERT(st.total_done <= m_torrent_file->total_size() - m_padding);
		TORRENT_ASSERT(st.total_wanted_done <= m_torrent_file->total_size() - m_padding);

#ifdef TORRENT_DEBUG

		if (st.total_done >= m_torrent_file->total_size())
		{
			// Thist happens when a piece has been downloaded completely
			// but not yet verified against the hash
			fprintf(stderr, "num_have: %d\nunfinished:\n", num_have());
			for (std::vector<piece_picker::downloading_piece>::const_iterator i =
				dl_queue.begin(); i != dl_queue.end(); ++i)
			{
				fprintf(stderr, "  %d ", i->index);
				for (int j = 0; j < blocks_per_piece; ++j)
				{
					char const* state = i->info[j].state == piece_picker::block_info::state_finished ? "1" : "0";
					fputs(state, stderr);
				}
				fputs("\n", stderr);
			}
			
			fputs("downloading pieces:\n", stderr);

			for (std::map<piece_block, int>::iterator i = downloading_piece.begin();
				i != downloading_piece.end(); ++i)
			{
				fprintf(stderr, "   %d:%d  %d\n", int(i->first.piece_index), int(i->first.block_index), i->second);
			}

		}

		TORRENT_ASSERT(st.total_done <= m_torrent_file->total_size());
		TORRENT_ASSERT(st.total_wanted_done <= m_torrent_file->total_size());

#endif

		TORRENT_ASSERT(st.total_done >= st.total_wanted_done);
	}

	// passed_hash_check
	// 0: success, piece passed check
	// -1: disk failure
	// -2: piece failed check
	void torrent::piece_finished(int index, int passed_hash_check)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("*** PIECE_FINISHED [ p: %d | chk: %s | size: %d ]"
			, index, ((passed_hash_check == 0)
				?"passed":passed_hash_check == -1
				?"disk failed":"failed")
			, m_torrent_file->piece_size(index));
#endif

		TORRENT_ASSERT(valid_metadata());

		// it's possible to get here if the last piece was downloaded
		// from peers and inserted with add_piece at the same time.
		// if we're a seed, we won't have a piece picker, and can't continue
		if (is_seed()) return;

		TORRENT_ASSERT(!m_picker->have_piece(index));

		state_updated();

		// even though the piece passed the hash-check
		// it might still have failed being written to disk
		// if so, piece_picker::write_failed() has been
		// called, and the piece is no longer finished.
		// in this case, we have to ignore the fact that
		// it passed the check
		if (!m_picker->is_piece_finished(index)) return;

		if (passed_hash_check == 0)
		{
			// the following call may cause picker to become invalid
			// in case we just became a seed
			piece_passed(index);
			// if we're in seed mode, we just acquired this piece
			// mark it as verified
			if (m_seed_mode) verified(index);
		}
		else if (passed_hash_check == -2)
		{
			// piece_failed() will restore the piece
			piece_failed(index);
		}
		else
		{
			TORRENT_ASSERT(passed_hash_check == -1);
			m_picker->restore_piece(index);
			restore_piece_state(index);
		}
	}

	void torrent::update_sparse_piece_prio(int i, int start, int end)
	{
		TORRENT_ASSERT(m_picker);
		if (m_picker->have_piece(i) || m_picker->piece_priority(i) == 0)
			return;
		bool have_before = i == 0 || m_picker->have_piece(i - 1);
		bool have_after = i == end - 1 || m_picker->have_piece(i + 1);
		if (have_after && have_before)
			m_picker->set_piece_priority(i, 7);
		else if (have_after || have_before)
			m_picker->set_piece_priority(i, 6);
	}

	void torrent::we_have(int index)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		// update m_file_progress
		TORRENT_ASSERT(m_picker);
		TORRENT_ASSERT(!have_piece(index));
		TORRENT_ASSERT(!m_picker->have_piece(index));

		const int piece_size = m_torrent_file->piece_length();
		size_type off = size_type(index) * piece_size;
		int file_index = m_torrent_file->files().file_index_at_offset(off);
		int size = m_torrent_file->piece_size(index);
		file_storage const& fs = m_torrent_file->files();
		for (; size > 0; ++file_index)
		{
			size_type file_offset = off - fs.file_offset(file_index);
			TORRENT_ASSERT(file_index != fs.num_files());
			TORRENT_ASSERT(file_offset <= fs.file_size(file_index));
			int add = (std::min)(fs.file_size(file_index) - file_offset, size_type(size));
			m_file_progress[file_index] += add;

			TORRENT_ASSERT(m_file_progress[file_index]
				<= m_torrent_file->files().file_size(file_index));

			if (m_file_progress[file_index] >= m_torrent_file->files().file_size(file_index))
			{
				if (!m_torrent_file->files().pad_file_at(file_index))
				{
					if (m_ses.m_alerts.should_post<file_completed_alert>())
					{
						// this file just completed, post alert
						m_ses.m_alerts.post_alert(file_completed_alert(get_handle()
							, file_index));
					}
				}
			}
			size -= add;
			off += add;
			TORRENT_ASSERT(size >= 0);
		}

		remove_time_critical_piece(index, true);

		m_picker->we_have(index);
	}

	void torrent::piece_passed(int index)
	{
//		INVARIANT_CHECK;
		TORRENT_ASSERT(m_ses.is_network_thread());

		TORRENT_ASSERT(index >= 0);
		TORRENT_ASSERT(index < m_torrent_file->num_pieces());
#ifdef TORRENT_DEBUG
		// make sure all blocks were successfully written before we
		// declare the piece as "we have".
		piece_picker::downloading_piece dp;
		m_picker->piece_info(index, dp);
		int blocks_in_piece = m_picker->blocks_in_piece(index);
		TORRENT_ASSERT(dp.finished == blocks_in_piece);
		TORRENT_ASSERT(dp.writing == 0);
		TORRENT_ASSERT(dp.requested == 0);
		TORRENT_ASSERT(dp.index == index);
#endif

		if (m_ses.m_alerts.should_post<piece_finished_alert>())
		{
			m_ses.m_alerts.post_alert(piece_finished_alert(get_handle()
				, index));
		}

		m_need_save_resume_data = true;
		state_updated();

		remove_time_critical_piece(index, true);

		bool was_finished = m_picker->num_filtered() + num_have()
			== torrent_file().num_pieces();

		std::vector<void*> downloaders;
		m_picker->get_downloaders(downloaders, index);

		// increase the trust point of all peers that sent
		// parts of this piece.
		std::set<void*> peers;

		// these policy::peer pointers are owned by m_policy and they may be
		// invalidated if a peer disconnects. We cannot keep them across any
		// significant operations, but we should use them right away
		// ignore NULL pointers
		std::remove_copy(downloaders.begin(), downloaders.end()
			, std::inserter(peers, peers.begin()), (policy::peer*)0);

		for (std::set<void*>::iterator i = peers.begin()
			, end(peers.end()); i != end; ++i)
		{
			policy::peer* p = static_cast<policy::peer*>(*i);
			TORRENT_ASSERT(p != 0);
			if (p == 0) continue;
			TORRENT_ASSERT(p->in_use);
			p->on_parole = false;
			int trust_points = p->trust_points;
			++trust_points;
			if (trust_points > 8) trust_points = 8;
			p->trust_points = trust_points;
			if (p->connection)
			{
				TORRENT_ASSERT(p->connection->m_in_use == 1337);
				p->connection->received_valid_data(index);
			}
		}

		// announcing a piece may invalidate the policy::peer pointers
		// so we can't use them anymore

		downloaders.clear();
		peers.clear();

		we_have(index);

		for (peer_iterator i = m_connections.begin(); i != m_connections.end();)
		{
			intrusive_ptr<peer_connection> p = *i;
			++i;
			p->announce_piece(index);
		}

		if (settings().max_sparse_regions > 0
			&& m_picker->sparse_regions() > settings().max_sparse_regions)
		{
			// we have too many sparse regions. Prioritize pieces
			// that won't introduce new sparse regions
			// prioritize pieces that will reduce the number of sparse
			// regions even higher
			int start = m_picker->cursor();
			int end = m_picker->reverse_cursor();
			if (index > start) update_sparse_piece_prio(index - 1, start, end);
			if (index < end - 1) update_sparse_piece_prio(index + 1, start, end);
		}

#ifndef TORRENT_DISABLE_EXTENSIONS
		for (extension_list_t::iterator i = m_extensions.begin()
			, end(m_extensions.end()); i != end; ++i)
		{
			TORRENT_TRY {
				(*i)->on_piece_pass(index);
			} TORRENT_CATCH (std::exception&) {}
		}
#endif

		// since this piece just passed, we might have
		// become uninterested in some peers where this
		// was the last piece we were interested in
		for (peer_iterator i = m_connections.begin();
			i != m_connections.end();)
		{
			peer_connection* p = *i;
			// update_interest may disconnect the peer and
			// invalidate the iterator
			++i;
			// if we're not interested already, no need to check
			if (!p->is_interesting()) continue;
			// if the peer doesn't have the piece we just got, it
			// wouldn't affect our interest
			if (!p->has_piece(index)) continue;
			p->update_interest();
		}

		if (!was_finished && is_finished())
		{
			// torrent finished
			// i.e. all the pieces we're interested in have
			// been downloaded. Release the files (they will open
			// in read only mode if needed)
			finished();
			// if we just became a seed, picker is now invalid, since it
			// is deallocated by the torrent once it starts seeding
		}

		m_last_download = 0;

		if (m_share_mode)
			recalc_share_mode();
	}

	void torrent::piece_failed(int index)
	{
		// if the last piece fails the peer connection will still
		// think that it has received all of it until this function
		// resets the download queue. So, we cannot do the
		// invariant check here since it assumes:
		// (total_done == m_torrent_file->total_size()) => is_seed()
		INVARIANT_CHECK;
		TORRENT_ASSERT(m_ses.is_network_thread());

		TORRENT_ASSERT(m_storage);
		TORRENT_ASSERT(m_storage->refcount() > 0);
		TORRENT_ASSERT(m_picker.get());
		TORRENT_ASSERT(index >= 0);
	  	TORRENT_ASSERT(index < m_torrent_file->num_pieces());

		if (m_ses.m_alerts.should_post<hash_failed_alert>())
			m_ses.m_alerts.post_alert(hash_failed_alert(get_handle(), index));

		// increase the total amount of failed bytes
		add_failed_bytes(m_torrent_file->piece_size(index));

		std::vector<void*> downloaders;
		m_picker->get_downloaders(downloaders, index);

		// decrease the trust point of all peers that sent
		// parts of this piece.
		// first, build a set of all peers that participated
		std::set<void*> peers;
		std::copy(downloaders.begin(), downloaders.end(), std::inserter(peers, peers.begin()));

#ifdef TORRENT_DEBUG
		for (std::vector<void*>::iterator i = downloaders.begin()
			, end(downloaders.end()); i != end; ++i)
		{
			policy::peer* p = (policy::peer*)*i;
			if (p && p->connection)
			{
				p->connection->piece_failed = true;
			}
		}
#endif

#ifndef TORRENT_DISABLE_EXTENSIONS
		for (extension_list_t::iterator i = m_extensions.begin()
			, end(m_extensions.end()); i != end; ++i)
		{
			TORRENT_TRY {
				(*i)->on_piece_failed(index);
			} TORRENT_CATCH (std::exception&) {}
		}
#endif

		// did we receive this piece from a single peer?
		bool single_peer = peers.size() == 1;

		for (std::set<void*>::iterator i = peers.begin()
			, end(peers.end()); i != end; ++i)
		{
			policy::peer* p = static_cast<policy::peer*>(*i);
			if (p == 0) continue;
			TORRENT_ASSERT(p->in_use);
			bool allow_disconnect = true;
			if (p->connection)
			{
				TORRENT_ASSERT(p->connection->m_in_use == 1337);

				// the peer implementation can ask not to be disconnected.
				// this is used for web seeds for instance, to instead of
				// disconnecting, mark the file as not being haved.
				allow_disconnect = p->connection->received_invalid_data(index, single_peer);
			}

			if (m_ses.settings().use_parole_mode)
				p->on_parole = true;

			int hashfails = p->hashfails;
			int trust_points = p->trust_points;

			// we decrease more than we increase, to keep the
			// allowed failed/passed ratio low.
			trust_points -= 2;
			++hashfails;
			if (trust_points < -7) trust_points = -7;
			p->trust_points = trust_points;
			if (hashfails > 255) hashfails = 255;
			p->hashfails = hashfails;

			// either, we have received too many failed hashes
			// or this was the only peer that sent us this piece.
			// if we have failed more than 3 pieces from this peer,
			// don't trust it regardless.
			if (p->trust_points <= -7
				|| (single_peer && allow_disconnect))
			{
				// we don't trust this peer anymore
				// ban it.
				if (m_ses.m_alerts.should_post<peer_ban_alert>())
				{
					peer_id pid(0);
					if (p->connection) pid = p->connection->pid();
					m_ses.m_alerts.post_alert(peer_ban_alert(
						get_handle(), p->ip(), pid));
				}

				// mark the peer as banned
				m_policy.ban_peer(p);
#ifdef TORRENT_STATS
				++m_ses.m_banned_for_hash_failure;
#endif

				if (p->connection)
				{
#ifdef TORRENT_LOGGING
					debug_log("*** BANNING PEER: \"%s\" Too many corrupt pieces"
						, print_endpoint(p->ip()).c_str());
#endif
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
					p->connection->peer_log("*** BANNING PEER: Too many corrupt pieces");
#endif
					p->connection->disconnect(errors::too_many_corrupt_pieces);
				}
			}
		}

		// we have to let the piece_picker know that
		// this piece failed the check as it can restore it
		// and mark it as being interesting for download
		m_picker->restore_piece(index);

		// we might still have outstanding requests to this
		// piece that hasn't been received yet. If this is the
		// case, we need to re-open the piece and mark any
		// blocks we're still waiting for as requested
		restore_piece_state(index);

		TORRENT_ASSERT(m_storage);

		TORRENT_ASSERT(m_picker->have_piece(index) == false);

#ifdef TORRENT_DEBUG
		for (std::vector<void*>::iterator i = downloaders.begin()
			, end(downloaders.end()); i != end; ++i)
		{
			policy::peer* p = (policy::peer*)*i;
			if (p && p->connection)
			{
				p->connection->piece_failed = false;
			}
		}
#endif
	}

	void torrent::restore_piece_state(int index)
	{
		TORRENT_ASSERT(has_picker());
		for (peer_iterator i = m_connections.begin();
			i != m_connections.end(); ++i)
		{
			peer_connection* p = *i;
			std::vector<pending_block> const& dq = p->download_queue();
			std::vector<pending_block> const& rq = p->request_queue();
			for (std::vector<pending_block>::const_iterator k = dq.begin()
				, end(dq.end()); k != end; ++k)
			{
				if (k->timed_out || k->not_wanted) continue;
				if (int(k->block.piece_index) != index) continue;
				m_picker->mark_as_downloading(k->block, p->peer_info_struct()
					, (piece_picker::piece_state_t)p->peer_speed());
			}
			for (std::vector<pending_block>::const_iterator k = rq.begin()
				, end(rq.end()); k != end; ++k)
			{
				if (int(k->block.piece_index) != index) continue;
				m_picker->mark_as_downloading(k->block, p->peer_info_struct()
					, (piece_picker::piece_state_t)p->peer_speed());
			}
		}
	}

	void torrent::abort()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		if (m_abort) return;

		m_abort = true;

		update_guage();

		// if the torrent is paused, it doesn't need
		// to announce with even=stopped again.
		if (!is_paused())
		{
			stop_announcing();
		}

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING || defined TORRENT_LOGGING
		log_to_all_peers("ABORTING TORRENT");
#endif

		// disconnect all peers and close all
		// files belonging to the torrents
		disconnect_all(errors::torrent_aborted);

		// post a message to the main thread to destruct
		// the torrent object from there
		if (m_owning_storage.get())
		{
			m_storage->abort_disk_io();
			m_storage->async_release_files(
				boost::bind(&torrent::on_cache_flushed, shared_from_this(), _1, _2));
		}
		else
		{
			TORRENT_ASSERT(m_abort);
			if (alerts().should_post<cache_flushed_alert>())
				alerts().post_alert(cache_flushed_alert(get_handle()));
		}
		
		dequeue_torrent_check();

		if (m_state == torrent_status::checking_files)
			set_state(torrent_status::queued_for_checking);

		m_owning_storage = 0;
		m_host_resolver.cancel();
	}

	void torrent::super_seeding(bool on)
	{
		if (on == m_super_seeding) return;

		m_super_seeding = on;

		if (m_super_seeding) return;

		// disable super seeding for all peers
		for (peer_iterator i = begin(); i != end(); ++i)
		{
			(*i)->superseed_piece(-1, -1);
		}
	}

	int torrent::get_piece_to_super_seed(bitfield const& bits)
	{
		// return a piece with low availability that is not in
		// the bitfield and that is not currently being super
		// seeded by any peer
		TORRENT_ASSERT(m_super_seeding);
		
		// do a linear search from the first piece
		int min_availability = 9999;
		std::vector<int> avail_vec;
		for (int i = 0; i < m_torrent_file->num_pieces(); ++i)
		{
			if (bits[i]) continue;

			int availability = 0;
			for (const_peer_iterator j = begin(); j != end(); ++j)
			{
				if ((*j)->super_seeded_piece(i))
				{
					// avoid superseeding the same piece to more than one
					// peer if we can avoid it. Do this by artificially
					// increase the availability
					availability = 999;
					break;
				}
				if ((*j)->has_piece(i)) ++availability;
			}
			if (availability > min_availability) continue;
			if (availability == min_availability)
			{
				avail_vec.push_back(i);
				continue;
			}
			TORRENT_ASSERT(availability < min_availability);
			min_availability = availability;
			avail_vec.clear();
			avail_vec.push_back(i);
		}

		if (min_availability > 1)
		{
			// if the minimum availability is 2 or more,
			// we shouldn't be super seeding any more
			super_seeding(false);
			return -1;
		}

		return avail_vec[random() % avail_vec.size()];
	}

	void torrent::on_files_deleted(int ret, disk_io_job const& j)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		if (ret != 0)
		{
			alerts().post_alert(torrent_delete_failed_alert(get_handle(), j.error, m_torrent_file->info_hash()));
		}
		else
		{
			alerts().post_alert(torrent_deleted_alert(get_handle(), m_torrent_file->info_hash()));
		}
	}

	void torrent::on_files_released(int ret, disk_io_job const& j)
	{
/*
		TORRENT_ASSERT(m_ses.is_network_thread());

		if (alerts().should_post<torrent_paused_alert>())
		{
			alerts().post_alert(torrent_paused_alert(get_handle()));
		}
*/
	}

	void torrent::on_save_resume_data(int ret, disk_io_job const& j)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		if (!j.resume_data)
		{
			alerts().post_alert(save_resume_data_failed_alert(get_handle(), j.error));
		}
		else
		{
			m_need_save_resume_data = false;
			m_last_saved_resume = time(0);
			write_resume_data(*j.resume_data);
			alerts().post_alert(save_resume_data_alert(j.resume_data
				, get_handle()));
			state_updated();
		}
	}

	void torrent::on_file_renamed(int ret, disk_io_job const& j)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		
		if (ret == 0)
		{
			if (alerts().should_post<file_renamed_alert>())
				alerts().post_alert(file_renamed_alert(get_handle(), j.str, j.piece));
			m_torrent_file->rename_file(j.piece, j.str);
		}
		else
		{
			if (alerts().should_post<file_rename_failed_alert>())
				alerts().post_alert(file_rename_failed_alert(get_handle()
					, j.piece, j.error));
		}
	}

	void torrent::on_torrent_paused(int ret, disk_io_job const& j)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		if (alerts().should_post<torrent_paused_alert>())
			alerts().post_alert(torrent_paused_alert(get_handle()));
	}

	std::string torrent::tracker_login() const
	{
		if (m_username.empty() && m_password.empty()) return "";
		return m_username + ":" + m_password;
	}

	boost::uint32_t torrent::tracker_key() const
	{
		uintptr_t self = (uintptr_t)this;
		uintptr_t ses = (uintptr_t)&m_ses;
		sha1_hash h = hasher((char*)&self, sizeof(self))
			.update((char*)&m_storage, sizeof(m_storage))
			.update((char*)&ses, sizeof(ses))
			.final();
		unsigned char const* ptr = &h[0];
		return detail::read_uint32(ptr);
	}

	void torrent::cancel_non_critical()
	{
		std::set<int> time_critical;
		for (std::deque<time_critical_piece>::iterator i = m_time_critical_pieces.begin()
			, end(m_time_critical_pieces.end()); i != end; ++i)
		{
			time_critical.insert(i->piece);
		}

		for (std::set<peer_connection*>::iterator i
			= m_connections.begin(), end(m_connections.end()); i != end; ++i)
		{
			// for each peer, go through its download and request queue
			// and cancel everything, except pieces that are time critical
			peer_connection* p = *i;

			std::vector<pending_block> dq = p->download_queue();
			for (std::vector<pending_block>::iterator k = dq.begin()
				, end(dq.end()); k != end; ++k)
			{
				if (time_critical.count(k->block.piece_index)) continue;
				if (k->not_wanted || k->timed_out) continue;
				p->cancel_request(k->block, true);
			}

			std::vector<pending_block> rq = p->request_queue();
			for (std::vector<pending_block>::const_iterator k = rq.begin()
				, end(rq.end()); k != end; ++k)
			{
				if (time_critical.count(k->block.piece_index)) continue;
				p->cancel_request(k->block, true);
			}
		}
	}

	void torrent::set_piece_deadline(int piece, int t, int flags)
	{
		INVARIANT_CHECK;

		if (m_abort)
		{
			// failed
			if (flags & torrent_handle::alert_when_available)
			{
				m_ses.m_alerts.post_alert(read_piece_alert(
					get_handle(), piece, error_code(boost::system::errc::operation_canceled, get_system_category())));
			}
			return;
		}

		ptime deadline = time_now() + milliseconds(t);

		// if we already have the piece, no need to set the deadline.
		// however, if the user asked to get the piece data back, we still
		// need to read it and post it back to the user
		if (is_seed() || m_picker->have_piece(piece))
		{
			if (flags & torrent_handle::alert_when_available)
				read_piece(piece);
			return;
		}

		// if this is the first time critical piece we add. in order to make it
		// react quickly, cancel all the currently outstanding requests
		if (m_time_critical_pieces.empty())
		{
			// defer this by posting it to the end of the message queue.
			// this gives the client a chance to specify multiple time critical
			// pieces before libtorrent cancels requests
			m_ses.m_io_service.post(boost::bind(&torrent::cancel_non_critical, this));
		}

		for (std::deque<time_critical_piece>::iterator i = m_time_critical_pieces.begin()
			, end(m_time_critical_pieces.end()); i != end; ++i)
		{
			if (i->piece != piece) continue;
			i->deadline = deadline;
			i->flags = flags;

			// resort i since deadline might have changed
			while (boost::next(i) != m_time_critical_pieces.end() && i->deadline > boost::next(i)->deadline)
			{
				std::iter_swap(i, boost::next(i));
				++i;
			}
			while (i != m_time_critical_pieces.begin() && i->deadline < boost::prior(i)->deadline)
			{
				std::iter_swap(i, boost::prior(i));
				--i;
			}
			// just in case this piece had priority 0
			m_picker->set_piece_priority(piece, 7);
			return;
		}

		time_critical_piece p;
		p.first_requested = min_time();
		p.last_requested = min_time();
		p.flags = flags;
		p.deadline = deadline;
		p.peers = 0;
		p.piece = piece;
		std::deque<time_critical_piece>::iterator i = std::upper_bound(m_time_critical_pieces.begin()
			, m_time_critical_pieces.end(), p);
		m_time_critical_pieces.insert(i, p);

		// just in case this piece had priority 0
		m_picker->set_piece_priority(piece, 7);

		piece_picker::downloading_piece pi;
		m_picker->piece_info(piece, pi);
		if (pi.requested == 0) return;
		// this means we have outstanding requests (or queued
		// up requests that haven't been sent yet). Promote them
		// to deadline pieces immediately
		std::vector<void*> downloaders;
		m_picker->get_downloaders(downloaders, piece);

		int block = 0;
		for (std::vector<void*>::iterator i = downloaders.begin()
			, end(downloaders.end()); i != end; ++i, ++block)
		{
			policy::peer* p = (policy::peer*)*i;
			if (p == 0 || p->connection == 0) continue;
			p->connection->make_time_critical(piece_block(piece, block));
		}
	}

	void torrent::reset_piece_deadline(int piece)
	{
		remove_time_critical_piece(piece);
	}

	void torrent::remove_time_critical_piece(int piece, bool finished)
	{
		for (std::deque<time_critical_piece>::iterator i = m_time_critical_pieces.begin()
			, end(m_time_critical_pieces.end()); i != end; ++i)
		{
			if (i->piece != piece) continue;
			if (finished)
			{
				if (i->flags & torrent_handle::alert_when_available)
				{
					read_piece(i->piece);
				}

				// if first_requested is min_time(), it wasn't requested as a critical piece
				// and we shouldn't adjust any average download times
				if (i->first_requested != min_time())
				{
					// update the average download time and average
					// download time deviation
					int dl_time = total_milliseconds(time_now() - i->first_requested);
   
					if (m_average_piece_time == 0)
					{
						m_average_piece_time = dl_time;
					}
					else
					{
						int diff = abs(int(dl_time - m_average_piece_time));
						if (m_piece_time_deviation == 0) m_piece_time_deviation = diff;
						else m_piece_time_deviation = (m_piece_time_deviation * 9 + diff) / 10;
   
						m_average_piece_time = (m_average_piece_time * 9 + dl_time) / 10;
					}
				}
			}
			else if (i->flags & torrent_handle::alert_when_available)
			{
				// post an empty read_piece_alert to indicate it failed
				m_ses.m_alerts.post_alert(read_piece_alert(
					get_handle(), piece, error_code(boost::system::errc::operation_canceled, get_system_category())));
			}
			if (has_picker()) m_picker->set_piece_priority(piece, 1);
			m_time_critical_pieces.erase(i);
			return;
		}
	}

	void torrent::clear_time_critical()
	{
		for (std::deque<time_critical_piece>::iterator i = m_time_critical_pieces.begin();
			i != m_time_critical_pieces.end();)
		{
			if (i->flags & torrent_handle::alert_when_available)
			{
				// post an empty read_piece_alert to indicate it failed
				m_ses.m_alerts.post_alert(read_piece_alert(
					get_handle(), i->piece, error_code(boost::system::errc::operation_canceled, get_system_category())));
			}
			if (has_picker()) m_picker->set_piece_priority(i->piece, 1);
			i = m_time_critical_pieces.erase(i);
		}
	}

	// remove time critical pieces where priority is 0
	void torrent::remove_time_critical_pieces(std::vector<int> const& priority)
	{
		for (std::deque<time_critical_piece>::iterator i = m_time_critical_pieces.begin();
			i != m_time_critical_pieces.end();)
		{
			if (priority[i->piece] == 0)
			{
				if (i->flags & torrent_handle::alert_when_available)
				{
					// post an empty read_piece_alert to indicate it failed
					m_ses.m_alerts.post_alert(read_piece_alert(
						get_handle(), i->piece, error_code(boost::system::errc::operation_canceled, get_system_category())));
				}
				i = m_time_critical_pieces.erase(i);
				continue;
			}
			++i;
		}
	}

	void torrent::piece_availability(std::vector<int>& avail) const
	{
		INVARIANT_CHECK;

		TORRENT_ASSERT(valid_metadata());
		if (!has_picker())
		{
			avail.clear();
			return;
		}

		m_picker->get_availability(avail);
	}

	void torrent::set_piece_priority(int index, int priority)
	{
//		INVARIANT_CHECK;

		TORRENT_ASSERT(valid_metadata());
		if (is_seed()) return;

		// this call is only valid on torrents with metadata
		TORRENT_ASSERT(m_picker.get());
		TORRENT_ASSERT(index >= 0);
		TORRENT_ASSERT(index < m_torrent_file->num_pieces());
		if (index < 0 || index >= m_torrent_file->num_pieces()) return;

		bool was_finished = is_finished();
		bool filter_updated = m_picker->set_piece_priority(index, priority);
		TORRENT_ASSERT(num_have() >= m_picker->num_have_filtered());
		if (filter_updated)
		{
			update_peer_interest(was_finished);
			if (priority == 0) remove_time_critical_piece(index);
		}

	}

	int torrent::piece_priority(int index) const
	{
//		INVARIANT_CHECK;

		TORRENT_ASSERT(valid_metadata());
		if (is_seed()) return 1;

		// this call is only valid on torrents with metadata
		TORRENT_ASSERT(m_picker.get());
		TORRENT_ASSERT(index >= 0);
		TORRENT_ASSERT(index < m_torrent_file->num_pieces());
		if (index < 0 || index >= m_torrent_file->num_pieces()) return 0;

		return m_picker->piece_priority(index);
	}

	void torrent::prioritize_pieces(std::vector<int> const& pieces)
	{
		INVARIANT_CHECK;

		// this call is only valid on torrents with metadata
		TORRENT_ASSERT(valid_metadata());
		if (is_seed()) return;

		TORRENT_ASSERT(m_picker.get());

		int index = 0;
		bool filter_updated = false;
		bool was_finished = is_finished();
		for (std::vector<int>::const_iterator i = pieces.begin()
			, end(pieces.end()); i != end; ++i, ++index)
		{
			TORRENT_ASSERT(*i >= 0);
			TORRENT_ASSERT(*i <= 7);
			filter_updated |= m_picker->set_piece_priority(index, *i);
			TORRENT_ASSERT(num_have() >= m_picker->num_have_filtered());
		}
		if (filter_updated)
		{
			// we need to save this new state
			m_need_save_resume_data = true;

			update_peer_interest(was_finished);
			remove_time_critical_pieces(pieces);
		}

		state_updated();
	}

	void torrent::piece_priorities(std::vector<int>* pieces) const
	{
		INVARIANT_CHECK;

		// this call is only valid on torrents with metadata
		TORRENT_ASSERT(valid_metadata());
		if (is_seed())
		{
			pieces->clear();
			pieces->resize(m_torrent_file->num_pieces(), 1);
			return;
		}

		TORRENT_ASSERT(m_picker.get());
		m_picker->piece_priorities(*pieces);
	}

	namespace
	{
		void set_if_greater(int& piece_prio, int file_prio)
		{
			if (file_prio > piece_prio) piece_prio = file_prio;
		}
	}

	void nop() {}

	void torrent::prioritize_files(std::vector<int> const& files)
	{
		INVARIANT_CHECK;

		// this call is only valid on torrents with metadata
		if (!valid_metadata() || is_seed()) return;

		// the bitmask need to have exactly one bit for every file
		// in the torrent
		TORRENT_ASSERT(int(files.size()) == m_torrent_file->num_files());
		
		if (m_torrent_file->num_pieces() == 0) return;

		int limit = int(files.size());
		if (valid_metadata() && limit > m_torrent_file->num_files())
			limit = m_torrent_file->num_files();

		if (int(m_file_priority.size()) < limit)
			m_file_priority.resize(limit);

		std::copy(files.begin(), files.begin() + limit, m_file_priority.begin());

		if (valid_metadata() && m_torrent_file->num_files() > int(m_file_priority.size()))
			m_file_priority.resize(m_torrent_file->num_files(), 1);

		// storage may be NULL during shutdown
		if (m_torrent_file->num_pieces() > 0 && m_storage)
		{
			filesystem().async_set_file_priority(m_file_priority
				, boost::bind(&nop));
		}

		update_piece_priorities();
	}

	void torrent::set_file_priority(int index, int prio)
	{
		INVARIANT_CHECK;

		// this call is only valid on torrents with metadata
		if (!valid_metadata() || is_seed()) return;

		if (index < 0 || index >= m_torrent_file->num_files()) return;
		if (prio < 0) prio = 0;
		else if (prio > 7) prio = 7;
		if (int(m_file_priority.size()) <= index)
		{
			if (prio == 1) return;
			m_file_priority.resize(m_torrent_file->num_files(), 1);
		}
		if (m_file_priority[index] == prio) return;
		m_file_priority[index] = prio;
		// stoage may be NULL during shutdown
		if (m_storage)
		{
			filesystem().async_set_file_priority(m_file_priority
				, boost::bind(&nop));
		}
		update_piece_priorities();
	}
	
	int torrent::file_priority(int index) const
	{
		// this call is only valid on torrents with metadata
		if (!valid_metadata()) return 1;

		if (index < 0 || index >= m_torrent_file->num_files()) return 0;
		if (int(m_file_priority.size()) <= index) return 1;
		return m_file_priority[index];
	}

	void torrent::file_priorities(std::vector<int>* files) const
	{
		INVARIANT_CHECK;
		if (!valid_metadata())
		{
			files->resize(m_file_priority.size());
			std::copy(m_file_priority.begin(), m_file_priority.end(), files->begin());
			return;
		}

		files->resize(m_torrent_file->num_files(), 1);
		TORRENT_ASSERT(int(m_file_priority.size()) <= m_torrent_file->num_files());
		std::copy(m_file_priority.begin(), m_file_priority.end(), files->begin());
	}

	void torrent::update_piece_priorities()
	{
		INVARIANT_CHECK;

		if (m_torrent_file->num_pieces() == 0) return;

		size_type position = 0;
		int piece_length = m_torrent_file->piece_length();
		// initialize the piece priorities to 0, then only allow
		// setting higher priorities
		std::vector<int> pieces(m_torrent_file->num_pieces(), 0);
		file_storage const& fs = m_torrent_file->files();
		for (int i = 0; i < fs.num_files(); ++i)
		{
			if (i >= m_torrent_file->num_files()) break;
			size_type start = position;
			size_type size = m_torrent_file->files().file_size(i);
			if (size == 0) continue;
			position += size;
			if (m_file_priority[i] == 0) continue;

			// mark all pieces of the file with this file's priority
			// but only if the priority is higher than the pieces
			// already set (to avoid problems with overlapping pieces)
			int start_piece = int(start / piece_length);
			int last_piece = int((position - 1) / piece_length);
			TORRENT_ASSERT(last_piece < int(pieces.size()));
			// if one piece spans several files, we might
			// come here several times with the same start_piece, end_piece
			std::for_each(pieces.begin() + start_piece
				, pieces.begin() + last_piece + 1
				, boost::bind(&set_if_greater, _1, m_file_priority[i]));
		}
		prioritize_pieces(pieces);
	}

	// this is called when piece priorities have been updated
	// updates the interested flag in peers
	void torrent::update_peer_interest(bool was_finished)
	{
		for (peer_iterator i = begin(); i != end();)
		{
			peer_connection* p = *i;
			// update_interest may disconnect the peer and
			// invalidate the iterator
			++i;
			p->update_interest();
		}

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("*** UPDATE_PEER_INTEREST [ finished: %d was_finished %d ]"
			, is_finished(), was_finished);
#endif

		// the torrent just became finished
		if (is_finished() && !was_finished)
		{
			finished();
		}
		else if (!is_finished() && was_finished)
		{
			// if we used to be finished, but we aren't anymore
			// we may need to connect to peers again
			resume_download();
		}
	}

	void torrent::filter_piece(int index, bool filter)
	{
		INVARIANT_CHECK;

		TORRENT_ASSERT(valid_metadata());
		if (is_seed()) return;

		// this call is only valid on torrents with metadata
		TORRENT_ASSERT(m_picker.get());
		TORRENT_ASSERT(index >= 0);
		TORRENT_ASSERT(index < m_torrent_file->num_pieces());

		if (index < 0 || index >= m_torrent_file->num_pieces()) return;

		bool was_finished = is_finished();
		m_picker->set_piece_priority(index, filter ? 1 : 0);
		update_peer_interest(was_finished);
	}

	void torrent::filter_pieces(std::vector<bool> const& bitmask)
	{
		INVARIANT_CHECK;

		// this call is only valid on torrents with metadata
		TORRENT_ASSERT(valid_metadata());
		if (is_seed()) return;

		TORRENT_ASSERT(m_picker.get());

		bool was_finished = is_finished();
		int index = 0;
		for (std::vector<bool>::const_iterator i = bitmask.begin()
			, end(bitmask.end()); i != end; ++i, ++index)
		{
			if ((m_picker->piece_priority(index) == 0) == *i) continue;
			if (*i)
				m_picker->set_piece_priority(index, 0);
			else
				m_picker->set_piece_priority(index, 1);
		}
		update_peer_interest(was_finished);
	}

	bool torrent::is_piece_filtered(int index) const
	{
		// this call is only valid on torrents with metadata
		TORRENT_ASSERT(valid_metadata());
		if (is_seed()) return false;
		
		TORRENT_ASSERT(m_picker.get());
		TORRENT_ASSERT(index >= 0);
		TORRENT_ASSERT(index < m_torrent_file->num_pieces());

		if (index < 0 || index >= m_torrent_file->num_pieces()) return true;

		return m_picker->piece_priority(index) == 0;
	}

	void torrent::filtered_pieces(std::vector<bool>& bitmask) const
	{
		INVARIANT_CHECK;

		// this call is only valid on torrents with metadata
		TORRENT_ASSERT(valid_metadata());
		if (is_seed())
		{
			bitmask.clear();
			bitmask.resize(m_torrent_file->num_pieces(), false);
			return;
		}

		TORRENT_ASSERT(m_picker.get());
		m_picker->filtered_pieces(bitmask);
	}

	void torrent::filter_files(std::vector<bool> const& bitmask)
	{
		INVARIANT_CHECK;

		// this call is only valid on torrents with metadata
		if (!valid_metadata() || is_seed()) return;

		// the bitmask need to have exactly one bit for every file
		// in the torrent
		TORRENT_ASSERT((int)bitmask.size() == m_torrent_file->num_files());

		if (int(bitmask.size()) != m_torrent_file->num_files()) return;
		
		size_type position = 0;

		if (m_torrent_file->num_pieces())
		{
			int piece_length = m_torrent_file->piece_length();
			// mark all pieces as filtered, then clear the bits for files
			// that should be downloaded
			std::vector<bool> piece_filter(m_torrent_file->num_pieces(), true);
			for (int i = 0; i < (int)bitmask.size(); ++i)
			{
				size_type start = position;
				position += m_torrent_file->files().file_size(i);
				// is the file selected for download?
				if (!bitmask[i])
				{           
					// mark all pieces of the file as downloadable
					int start_piece = int(start / piece_length);
					int last_piece = int(position / piece_length);
					// if one piece spans several files, we might
					// come here several times with the same start_piece, end_piece
					std::fill(piece_filter.begin() + start_piece, piece_filter.begin()
						+ last_piece + 1, false);
				}
			}
			filter_pieces(piece_filter);
		}
	}

	bool has_empty_url(announce_entry const& e) { return e.url.empty(); }

	void torrent::replace_trackers(std::vector<announce_entry> const& urls)
	{
		m_trackers.clear();
		std::remove_copy_if(urls.begin(), urls.end(), back_inserter(m_trackers)
			, &has_empty_url);

		m_last_working_tracker = -1;
		for (std::vector<announce_entry>::iterator i = m_trackers.begin()
			, end(m_trackers.end()); i != end; ++i)
		{
			if (i->source == 0) i->source = announce_entry::source_client;
			i->complete_sent = is_seed();
		}

		if (settings().prefer_udp_trackers)
			prioritize_udp_trackers();

		if (!m_trackers.empty()) announce_with_tracker();

		m_need_save_resume_data = true;
	}

	void torrent::prioritize_udp_trackers()
	{
		// look for udp-trackers
		for (std::vector<announce_entry>::iterator i = m_trackers.begin()
			, end(m_trackers.end()); i != end; ++i)
		{
			if (i->url.substr(0, 6) != "udp://") continue;
			// now, look for trackers with the same hostname
			// that is has higher priority than this one
			// if we find one, swap with the udp-tracker
			error_code ec;
			std::string udp_hostname;
			using boost::tuples::ignore;
			boost::tie(ignore, ignore, udp_hostname, ignore, ignore)
				= parse_url_components(i->url, ec);
			for (std::vector<announce_entry>::iterator j = m_trackers.begin();
				j != i; ++j)
			{
				std::string hostname;
				boost::tie(ignore, ignore, hostname, ignore, ignore)
					= parse_url_components(j->url, ec);
				if (hostname != udp_hostname) continue;
				if (j->url.substr(0, 6) == "udp://") continue;
				using std::swap;
				using std::iter_swap;
				swap(i->tier, j->tier);
				iter_swap(i, j);
				break;
			}
		}
	}

	bool torrent::add_tracker(announce_entry const& url)
	{
		std::vector<announce_entry>::iterator k = std::find_if(m_trackers.begin()
			, m_trackers.end(), boost::bind(&announce_entry::url, _1) == url.url);
		if (k != m_trackers.end()) 
		{
			k->source |= url.source;
			return false;
		}
		k = std::upper_bound(m_trackers.begin(), m_trackers.end(), url
			, boost::bind(&announce_entry::tier, _1) < boost::bind(&announce_entry::tier, _2));
		if (k - m_trackers.begin() < m_last_working_tracker) ++m_last_working_tracker;
		k = m_trackers.insert(k, url);
		if (k->source == 0) k->source = announce_entry::source_client;
		if (!m_trackers.empty()) announce_with_tracker();
		return true;
	}

	bool torrent::choke_peer(peer_connection& c)
	{
		INVARIANT_CHECK;

		TORRENT_ASSERT(!c.is_choked());
		TORRENT_ASSERT(!c.ignore_unchoke_slots());
		TORRENT_ASSERT(m_num_uploads > 0);
		if (!c.send_choke()) return false;
		--m_num_uploads;
		state_updated();
		return true;
	}
	
	bool torrent::unchoke_peer(peer_connection& c, bool optimistic)
	{
		INVARIANT_CHECK;

		TORRENT_ASSERT(!m_graceful_pause_mode);
		TORRENT_ASSERT(c.is_choked());
		TORRENT_ASSERT(!c.ignore_unchoke_slots());
		// when we're unchoking the optimistic slots, we might
		// exceed the limit temporarily while we're iterating
		// over the peers
		if (m_num_uploads >= m_max_uploads && !optimistic) return false;
		if (!c.send_unchoke()) return false;
		++m_num_uploads;
		state_updated();
		return true;
	}

	void torrent::cancel_block(piece_block block)
	{
		INVARIANT_CHECK;

		for (peer_iterator i = m_connections.begin()
			, end(m_connections.end()); i != end; ++i)
		{
			(*i)->cancel_request(block);
		}
	}

#ifdef TORRENT_USE_OPENSSL
	std::string password_callback(int length, boost::asio::ssl::context::password_purpose p
		, std::string pw)
	{
		if (p != boost::asio::ssl::context::for_reading) return "";
		return pw;
	}

	// certificate is a filename to a .pem file which is our
	// certificate. The certificate must be signed by the root
	// cert of the torrent file. any peer we connect to or that
	// connect to use must present a valid certificate signed
	// by the torrent root cert as well
	void torrent::set_ssl_cert(std::string const& certificate
		, std::string const& private_key
		, std::string const& dh_params
		, std::string const& passphrase)
	{
		if (!m_ssl_ctx)
		{
			if (alerts().should_post<torrent_error_alert>())
				alerts().post_alert(torrent_error_alert(get_handle()
					, error_code(errors::not_an_ssl_torrent)));
			return;
		}

		using boost::asio::ssl::context;
		error_code ec;
		m_ssl_ctx->set_password_callback(boost::bind(&password_callback, _1, _2, passphrase), ec);
		if (ec)
		{
			if (alerts().should_post<torrent_error_alert>())
				alerts().post_alert(torrent_error_alert(get_handle(), ec));
		}
		m_ssl_ctx->use_certificate_file(certificate, context::pem, ec);
		if (ec)
		{
			if (alerts().should_post<torrent_error_alert>())
				alerts().post_alert(torrent_error_alert(get_handle(), ec));
		}
		m_ssl_ctx->use_private_key_file(private_key, context::pem, ec);
		if (ec)
		{
			if (alerts().should_post<torrent_error_alert>())
				alerts().post_alert(torrent_error_alert(get_handle(), ec));
		}
		m_ssl_ctx->use_tmp_dh_file(dh_params, ec);
		if (ec)
		{
			if (alerts().should_post<torrent_error_alert>())
				alerts().post_alert(torrent_error_alert(get_handle(), ec));
		}
	}

	void torrent::set_ssl_cert_buffer(std::string const& certificate
		, std::string const& private_key
		, std::string const& dh_params)
	{
		if (!m_ssl_ctx) return;

#if BOOST_VERSION < 105400
		if (alerts().should_post<torrent_error_alert>())
			alerts().post_alert(torrent_error_alert(get_handle()
				, error_code(boost::system::errc::not_supported, get_system_category())));
#else
		boost::asio::const_buffer certificate_buf(certificate.c_str(), certificate.size());

		using boost::asio::ssl::context;
		error_code ec;
		m_ssl_ctx->use_certificate(certificate_buf, context::pem, ec);
		if (ec)
		{
			if (alerts().should_post<torrent_error_alert>())
				alerts().post_alert(torrent_error_alert(get_handle(), ec));
		}

		boost::asio::const_buffer private_key_buf(private_key.c_str(), private_key.size());
		m_ssl_ctx->use_private_key(private_key_buf, context::pem, ec);
		if (ec)
		{
			if (alerts().should_post<torrent_error_alert>())
				alerts().post_alert(torrent_error_alert(get_handle(), ec));
		}

		boost::asio::const_buffer dh_params_buf(dh_params.c_str(), dh_params.size());
		m_ssl_ctx->use_tmp_dh(dh_params_buf, ec);
		if (ec)
		{
			if (alerts().should_post<torrent_error_alert>())
				alerts().post_alert(torrent_error_alert(get_handle(), ec));
		}
#endif // BOOST_VERSION
	}

#endif

	void torrent::remove_peer(peer_connection* p)
	{
//		INVARIANT_CHECK;

		TORRENT_ASSERT(p != 0);
		TORRENT_ASSERT(m_ses.is_network_thread());

		peer_iterator i = m_connections.find(p);
		if (i == m_connections.end())
		{
			TORRENT_ASSERT(false);
			return;
		}

		if (ready_for_connections())
		{
			TORRENT_ASSERT(p->associated_torrent().lock().get() == NULL
				|| p->associated_torrent().lock().get() == this);

			if (p->is_seed())
			{
				if (m_picker.get())
				{
					m_picker->dec_refcount_all(p);
				}
			}
			else
			{
				if (m_picker.get())
				{
					bitfield const& pieces = p->get_bitfield();
					TORRENT_ASSERT(pieces.count() <= int(pieces.size()));
					m_picker->dec_refcount(pieces, p);
				}
			}
		}

		if (!p->is_choked() && !p->ignore_unchoke_slots())
		{
			--m_num_uploads;
			m_ses.m_unchoke_time_scaler = 0;
		}

		policy::peer* pp = p->peer_info_struct();
		if (pp)
		{
			if (pp->optimistically_unchoked)
				m_ses.m_optimistic_unchoke_time_scaler = 0;

			TORRENT_ASSERT(pp->prev_amount_upload == 0);
			TORRENT_ASSERT(pp->prev_amount_download == 0);
			pp->prev_amount_download += p->statistics().total_payload_download() >> 10;
			pp->prev_amount_upload += p->statistics().total_payload_upload() >> 10;
		}

		m_policy.connection_closed(*p, m_ses.session_time());
		p->set_peer_info(0);
		TORRENT_ASSERT(i != m_connections.end());
		m_connections.erase(i);
	}

	void torrent::remove_web_seed(std::list<web_seed_entry>::iterator web)
	{
		if (web->resolving)
		{
			web->removed = true;
			return;
		}
		peer_connection * peer = web->peer_info.connection;
		if (peer) {
			TORRENT_ASSERT(peer->m_in_use == 1337);
			peer->set_peer_info(0);
		}
		if (has_picker()) picker().clear_peer(&web->peer_info);
					

		m_web_seeds.erase(web);
	}

	void torrent::connect_to_url_seed(std::list<web_seed_entry>::iterator web)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		TORRENT_ASSERT(!web->resolving);
		if (web->resolving) return;

		if (int(m_connections.size()) >= m_max_connections
			|| m_ses.num_connections() >= m_ses.settings().connections_limit)
			return;

		std::string protocol;
		std::string auth;
		std::string hostname;
		int port;
		std::string path;
		error_code ec;
		boost::tie(protocol, auth, hostname, port, path)
			= parse_url_components(web->url, ec);
		if (port == -1)
		{
			port = protocol == "http" ? 80 : 443;
		}

		if (ec)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
			debug_log("failed to parse web seed url: %s", ec.message().c_str());
#endif
			if (m_ses.m_alerts.should_post<url_seed_alert>())
			{
				m_ses.m_alerts.post_alert(
					url_seed_alert(get_handle(), web->url, ec));
			}
			// never try it again
			remove_web_seed(web);
			return;
		}

		if (web->peer_info.banned)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("banned web seed: %s", web->url.c_str());
#endif
			if (m_ses.m_alerts.should_post<url_seed_alert>())
			{
				m_ses.m_alerts.post_alert(
					url_seed_alert(get_handle(), web->url
						, error_code(libtorrent::errors::peer_banned, get_libtorrent_category())));
			}
			// never try it again
			remove_web_seed(web);
			return;
		}
		
#ifdef TORRENT_USE_OPENSSL
		if (protocol != "http" && protocol != "https")
#else
		if (protocol != "http")
#endif
		{
			if (m_ses.m_alerts.should_post<url_seed_alert>())
			{
				m_ses.m_alerts.post_alert(
					url_seed_alert(get_handle(), web->url, errors::unsupported_url_protocol));
			}
			// never try it again
			remove_web_seed(web);
			return;
		}

		if (hostname.empty())
		{
			if (m_ses.m_alerts.should_post<url_seed_alert>())
			{
				m_ses.m_alerts.post_alert(
					url_seed_alert(get_handle(), web->url, errors::invalid_hostname));
			}
			// never try it again
			remove_web_seed(web);
			return;
		}

		if (port == 0)
		{
			if (m_ses.m_alerts.should_post<url_seed_alert>())
			{
				m_ses.m_alerts.post_alert(
					url_seed_alert(get_handle(), web->url, errors::invalid_port));
			}
			// never try it again
			remove_web_seed(web);
			return;
		}

		if (m_ses.m_port_filter.access(port) & port_filter::blocked)
		{
			if (m_ses.m_alerts.should_post<url_seed_alert>())
			{
				m_ses.m_alerts.post_alert(
				url_seed_alert(get_handle(), web->url, errors::port_blocked));
			}
			// never try it again
			remove_web_seed(web);
			return;
		}

		if (web->endpoint.port() != 0)
		{
			connect_web_seed(web, web->endpoint);
			return;
		}

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("resolving web seed: %s", web->url.c_str());
#endif

		proxy_settings const& ps = m_ses.proxy();
		if (ps.type == proxy_settings::http
			|| ps.type == proxy_settings::http_pw)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("resolving proxy for web seed: %s", web->url.c_str());
#endif

			// use proxy
			web->resolving = true;
			tcp::resolver::query q(ps.hostname, to_string(ps.port).elems);
			m_host_resolver.async_resolve(q,
				boost::bind(&torrent::on_proxy_name_lookup, shared_from_this(), _1, _2, web));
		}
		else if (ps.proxy_hostnames
			&& (ps.type == proxy_settings::socks5
				|| ps.type == proxy_settings::socks5_pw))
		{
			connect_web_seed(web, tcp::endpoint(address(), port));
		}
		else
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("resolving web seed: %s", web->url.c_str());
#endif

			web->resolving = true;
			tcp::resolver::query q(hostname, to_string(port).elems);
			m_host_resolver.async_resolve(q,
				boost::bind(&torrent::on_name_lookup, shared_from_this(), _1, _2, web
					, tcp::endpoint()));
		}
	}

	void torrent::on_proxy_name_lookup(error_code const& e, tcp::resolver::iterator host
		, std::list<web_seed_entry>::iterator web)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		INVARIANT_CHECK;

		TORRENT_ASSERT(web->resolving == true);
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("completed resolve proxy hostname for: %s", web->url.c_str());
#endif
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
		if (e)
			debug_log("proxy name lookup error: %s", e.message().c_str());
#endif
		web->resolving = false;

		if (web->removed)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("removed web seed");
#endif
			remove_web_seed(web);
			return;
		}

		if (m_abort) return;

		if (e || host == tcp::resolver::iterator())
		{
			if (m_ses.m_alerts.should_post<url_seed_alert>())
			{
				m_ses.m_alerts.post_alert(
					url_seed_alert(get_handle(), web->url, e));
			}

			// the name lookup failed for the http host. Don't try
			// this host again
			remove_web_seed(web);
			return;
		}

		if (m_ses.is_aborted()) return;

#ifndef TORRENT_DISABLE_GEO_IP
		int as = m_ses.as_for_ip(host->endpoint().address());
#ifdef TORRENT_DEBUG
		web->peer_info.inet_as_num = as;
#endif
		web->peer_info.inet_as = m_ses.lookup_as(as);
#endif

		if (int(m_connections.size()) >= m_max_connections
			|| m_ses.num_connections() >= m_ses.settings().connections_limit)
			return;

		tcp::endpoint a(host->endpoint());

		using boost::tuples::ignore;
		std::string hostname;
		int port;
		error_code ec;
		std::string protocol;
		boost::tie(protocol, ignore, hostname, port, ignore)
			= parse_url_components(web->url, ec);
		if (port == -1) port = protocol == "http" ? 80 : 443;

		if (ec)
		{
			if (m_ses.m_alerts.should_post<url_seed_alert>())
			{
				m_ses.m_alerts.post_alert(
					url_seed_alert(get_handle(), web->url, ec));
			}
			remove_web_seed(web);
			return;
		}

		if (m_apply_ip_filter
			&& m_ses.m_ip_filter.access(a.address()) & ip_filter::blocked)
		{
			if (m_ses.m_alerts.should_post<peer_blocked_alert>())
				m_ses.m_alerts.post_alert(peer_blocked_alert(get_handle()
					, a.address(), peer_blocked_alert::ip_filter));
			return;
		}

		web->resolving = true;
		tcp::resolver::query q(hostname, to_string(port).elems);
		m_host_resolver.async_resolve(q,
			boost::bind(&torrent::on_name_lookup, shared_from_this(), _1, _2, web, a));
	}

	void torrent::on_name_lookup(error_code const& e, tcp::resolver::iterator host
		, std::list<web_seed_entry>::iterator web, tcp::endpoint proxy)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		INVARIANT_CHECK;

		TORRENT_ASSERT(web->resolving == true);
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("completed resolve: %s", web->url.c_str());
#endif
		web->resolving = false;
		if (web->removed)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("removed web seed");
#endif
			remove_web_seed(web);
			return;
		}

		if (m_abort) return;

		if (e || host == tcp::resolver::iterator())
		{
			if (m_ses.m_alerts.should_post<url_seed_alert>())
				m_ses.m_alerts.post_alert(url_seed_alert(get_handle(), web->url, e));
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
			debug_log("*** HOSTNAME LOOKUP FAILED: %s: (%d) %s"
				, web->url.c_str(), e.value(), e.message().c_str());
#endif

			// unavailable, retry in 30 minutes
			web->retry = time_now() + minutes(30);
			return;
		}

		tcp::endpoint a(host->endpoint());

		// fill in the peer struct's address field
		web->endpoint = a;

		if (int(m_connections.size()) >= m_max_connections
			|| m_ses.num_connections() >= m_ses.settings().connections_limit)
			return;

		connect_web_seed(web, a);
	}

	void torrent::connect_web_seed(std::list<web_seed_entry>::iterator web, tcp::endpoint a)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (m_apply_ip_filter
			&& m_ses.m_ip_filter.access(a.address()) & ip_filter::blocked)
		{
			if (m_ses.m_alerts.should_post<peer_blocked_alert>())
				m_ses.m_alerts.post_alert(peer_blocked_alert(get_handle()
					, a.address(), peer_blocked_alert::ip_filter));
			return;
		}
		
		TORRENT_ASSERT(web->resolving == false);
		TORRENT_ASSERT(web->peer_info.connection == 0);

		web->endpoint = a;
		if (a.address().is_v4())
		{
			web->peer_info.addr = a.address().to_v4();
			web->peer_info.port = a.port();
		}

		if (is_paused()) return;
		if (m_ses.is_aborted()) return;

		boost::shared_ptr<socket_type> s(new (std::nothrow) socket_type(m_ses.m_io_service));
		if (!s) return;
	
		void* userdata = 0;
#ifdef TORRENT_USE_OPENSSL
		bool ssl = string_begins_no_case("https://", web->url.c_str());
		if (ssl)
		{
			userdata = m_ssl_ctx.get();
			if (!userdata) userdata = &m_ses.m_ssl_ctx;
		}
#endif
		bool ret = instantiate_connection(m_ses.m_io_service, m_ses.proxy(), *s, userdata, 0, true);
		(void)ret;
		TORRENT_ASSERT(ret);

		proxy_settings const& ps = m_ses.proxy();
		if (s->get<http_stream>())
		{
			// the web seed connection will talk immediately to
			// the proxy, without requiring CONNECT support
			s->get<http_stream>()->set_no_connect(true);
		}

		using boost::tuples::ignore;
		std::string hostname;
		error_code ec;
		boost::tie(ignore, ignore, hostname, ignore, ignore)
			= parse_url_components(web->url, ec);
		if (ec)
		{
			if (m_ses.m_alerts.should_post<url_seed_alert>())
				m_ses.m_alerts.post_alert(url_seed_alert(get_handle(), web->url, ec));
			return;
		}

		if (ps.proxy_hostnames
			&& (ps.type == proxy_settings::socks5
				|| ps.type == proxy_settings::socks5_pw))
		{
			// we're using a socks proxy and we're resolving
			// hostnames through it
			socks5_stream* str =
#ifdef TORRENT_USE_OPENSSL
				ssl ? &s->get<ssl_stream<socks5_stream> >()->next_layer() :
#endif
				s->get<socks5_stream>();
			TORRENT_ASSERT(str);

			str->set_dst_name(hostname);
		}

		setup_ssl_hostname(*s, hostname, ec);
		if (ec)
		{
			if (m_ses.m_alerts.should_post<url_seed_alert>())
				m_ses.m_alerts.post_alert(url_seed_alert(get_handle(), web->url, ec));
			return;
		}

		boost::intrusive_ptr<peer_connection> c;
		if (web->type == web_seed_entry::url_seed)
		{
			c = new (std::nothrow) web_peer_connection(
				m_ses, shared_from_this(), s, a, *web);
		}
		else if (web->type == web_seed_entry::http_seed)
		{
			c = new (std::nothrow) http_seed_connection(
				m_ses, shared_from_this(), s, a, *web);
		}
		if (!c) return;

#if TORRENT_USE_ASSERTS
		c->m_in_constructor = false;
#endif

#ifndef TORRENT_DISABLE_EXTENSIONS
		for (extension_list_t::iterator i = m_extensions.begin()
			, end(m_extensions.end()); i != end; ++i)
		{
			boost::shared_ptr<peer_plugin>
				pp((*i)->new_connection(c.get()));
			if (pp) c->add_extension(pp);
		}
#endif

		TORRENT_TRY
		{
			TORRENT_ASSERT(!c->m_in_constructor);
			// add the newly connected peer to this torrent's peer list
			m_connections.insert(boost::get_pointer(c));
			m_ses.m_connections.insert(c);

			TORRENT_ASSERT(!web->peer_info.connection);
			web->peer_info.connection = c.get();
#if TORRENT_USE_ASSERTS
			web->peer_info.in_use = true;
#endif

			c->add_stat(size_type(web->peer_info.prev_amount_download) << 10
				, size_type(web->peer_info.prev_amount_upload) << 10);
			web->peer_info.prev_amount_download = 0;
			web->peer_info.prev_amount_upload = 0;
#if defined TORRENT_VERBOSE_LOGGING 
			debug_log("web seed connection started: %s", web->url.c_str());
#endif

			c->start();

			if (c->is_disconnecting()) return;

			m_ses.m_half_open.enqueue(
				boost::bind(&peer_connection::on_connect, c, _1)
				, boost::bind(&peer_connection::on_timeout, c)
				, seconds(settings().peer_connect_timeout));
		}
		TORRENT_CATCH (std::exception& e)
		{
			TORRENT_DECLARE_DUMMY(std::exception, e);
			(void)e;
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
			debug_log("*** HOST NAME LOOKUP FAILED: %s", e.what());
#endif
			c->disconnect(errors::no_error, 1);
		}
	}

#ifndef TORRENT_DISABLE_RESOLVE_COUNTRIES
	namespace
	{
		unsigned long swap_bytes(unsigned long a)
		{
			return (a >> 24) | ((a & 0xff0000) >> 8) | ((a & 0xff00) << 8) | ((a & 0xff) << 24);
		}
	}
	
	void torrent::resolve_peer_country(boost::intrusive_ptr<peer_connection> const& p) const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (m_resolving_country
			|| is_local(p->remote().address())
			|| p->has_country()
			|| p->is_connecting()
			|| p->is_queued()
			|| p->in_handshake()
			|| p->remote().address().is_v6()) return;

		asio::ip::address_v4 reversed(swap_bytes(p->remote().address().to_v4().to_ulong()));
		error_code ec;
		tcp::resolver::query q(reversed.to_string(ec) + ".zz.countries.nerd.dk", "0");
		if (ec)
		{
			p->set_country("!!");
			return;
		}
		m_resolving_country = true;
		m_host_resolver.async_resolve(q,
			boost::bind(&torrent::on_country_lookup, shared_from_this(), _1, _2, p));
	}

	namespace
	{
		struct country_entry
		{
			int code;
			char const* name;
		};
	}

	void torrent::on_country_lookup(error_code const& error, tcp::resolver::iterator i
		, intrusive_ptr<peer_connection> p) const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		INVARIANT_CHECK;
		
		m_resolving_country = false;

		if (m_abort) return;

		// must be ordered in increasing order
		static const country_entry country_map[] =
		{
			  {  4,  "AF"}, {  8,  "AL"}, { 10,  "AQ"}, { 12,  "DZ"}, { 16,  "AS"}
			, { 20,  "AD"}, { 24,  "AO"}, { 28,  "AG"}, { 31,  "AZ"}, { 32,  "AR"}
			, { 36,  "AU"}, { 40,  "AT"}, { 44,  "BS"}, { 48,  "BH"}, { 50,  "BD"}
			, { 51,  "AM"}, { 52,  "BB"}, { 56,  "BE"}, { 60,  "BM"}, { 64,  "BT"}
			, { 68,  "BO"}, { 70,  "BA"}, { 72,  "BW"}, { 74,  "BV"}, { 76,  "BR"}
			, { 84,  "BZ"}, { 86,  "IO"}, { 90,  "SB"}, { 92,  "VG"}, { 96,  "BN"}
			, {100,  "BG"}, {104,  "MM"}, {108,  "BI"}, {112,  "BY"}, {116,  "KH"}
			, {120,  "CM"}, {124,  "CA"}, {132,  "CV"}, {136,  "KY"}, {140,  "CF"}
			, {144,  "LK"}, {148,  "TD"}, {152,  "CL"}, {156,  "CN"}, {158,  "TW"}
			, {162,  "CX"}, {166,  "CC"}, {170,  "CO"}, {174,  "KM"}, {175,  "YT"}
			, {178,  "CG"}, {180,  "CD"}, {184,  "CK"}, {188,  "CR"}, {191,  "HR"}
			, {192,  "CU"}, {203,  "CZ"}, {204,  "BJ"}, {208,  "DK"}, {212,  "DM"}
			, {214,  "DO"}, {218,  "EC"}, {222,  "SV"}, {226,  "GQ"}, {231,  "ET"}
			, {232,  "ER"}, {233,  "EE"}, {234,  "FO"}, {238,  "FK"}, {239,  "GS"}
			, {242,  "FJ"}, {246,  "FI"}, {248,  "AX"}, {250,  "FR"}, {254,  "GF"}
			, {258,  "PF"}, {260,  "TF"}, {262,  "DJ"}, {266,  "GA"}, {268,  "GE"}
			, {270,  "GM"}, {275,  "PS"}, {276,  "DE"}, {288,  "GH"}, {292,  "GI"}
			, {296,  "KI"}, {300,  "GR"}, {304,  "GL"}, {308,  "GD"}, {312,  "GP"}
			, {316,  "GU"}, {320,  "GT"}, {324,  "GN"}, {328,  "GY"}, {332,  "HT"}
			, {334,  "HM"}, {336,  "VA"}, {340,  "HN"}, {344,  "HK"}, {348,  "HU"}
			, {352,  "IS"}, {356,  "IN"}, {360,  "ID"}, {364,  "IR"}, {368,  "IQ"}
			, {372,  "IE"}, {376,  "IL"}, {380,  "IT"}, {384,  "CI"}, {388,  "JM"}
			, {392,  "JP"}, {398,  "KZ"}, {400,  "JO"}, {404,  "KE"}, {408,  "KP"}
			, {410,  "KR"}, {414,  "KW"}, {417,  "KG"}, {418,  "LA"}, {422,  "LB"}
			, {426,  "LS"}, {428,  "LV"}, {430,  "LR"}, {434,  "LY"}, {438,  "LI"}
			, {440,  "LT"}, {442,  "LU"}, {446,  "MO"}, {450,  "MG"}, {454,  "MW"}
			, {458,  "MY"}, {462,  "MV"}, {466,  "ML"}, {470,  "MT"}, {474,  "MQ"}
			, {478,  "MR"}, {480,  "MU"}, {484,  "MX"}, {492,  "MC"}, {496,  "MN"}
			, {498,  "MD"}, {500,  "MS"}, {504,  "MA"}, {508,  "MZ"}, {512,  "OM"}
			, {516,  "NA"}, {520,  "NR"}, {524,  "NP"}, {528,  "NL"}, {530,  "AN"}
			, {533,  "AW"}, {540,  "NC"}, {548,  "VU"}, {554,  "NZ"}, {558,  "NI"}
			, {562,  "NE"}, {566,  "NG"}, {570,  "NU"}, {574,  "NF"}, {578,  "NO"}
			, {580,  "MP"}, {581,  "UM"}, {583,  "FM"}, {584,  "MH"}, {585,  "PW"}
			, {586,  "PK"}, {591,  "PA"}, {598,  "PG"}, {600,  "PY"}, {604,  "PE"}
			, {608,  "PH"}, {612,  "PN"}, {616,  "PL"}, {620,  "PT"}, {624,  "GW"}
			, {626,  "TL"}, {630,  "PR"}, {634,  "QA"}, {634,  "QA"}, {638,  "RE"}
			, {642,  "RO"}, {643,  "RU"}, {646,  "RW"}, {654,  "SH"}, {659,  "KN"}
			, {660,  "AI"}, {662,  "LC"}, {666,  "PM"}, {670,  "VC"}, {674,  "SM"}
			, {678,  "ST"}, {682,  "SA"}, {686,  "SN"}, {690,  "SC"}, {694,  "SL"}
			, {702,  "SG"}, {703,  "SK"}, {704,  "VN"}, {705,  "SI"}, {706,  "SO"}
			, {710,  "ZA"}, {716,  "ZW"}, {724,  "ES"}, {732,  "EH"}, {736,  "SD"}
			, {740,  "SR"}, {744,  "SJ"}, {748,  "SZ"}, {752,  "SE"}, {756,  "CH"}
			, {760,  "SY"}, {762,  "TJ"}, {764,  "TH"}, {768,  "TG"}, {772,  "TK"}
			, {776,  "TO"}, {780,  "TT"}, {784,  "AE"}, {788,  "TN"}, {792,  "TR"}
			, {795,  "TM"}, {796,  "TC"}, {798,  "TV"}, {800,  "UG"}, {804,  "UA"}
			, {807,  "MK"}, {818,  "EG"}, {826,  "GB"}, {834,  "TZ"}, {840,  "US"}
			, {850,  "VI"}, {854,  "BF"}, {858,  "UY"}, {860,  "UZ"}, {862,  "VE"}
			, {876,  "WF"}, {882,  "WS"}, {887,  "YE"}, {891,  "CS"}, {894,  "ZM"}
		};

		if (error || i == tcp::resolver::iterator())
		{
			// this is used to indicate that we shouldn't
			// try to resolve it again
			p->set_country("--");
			return;
		}

		while (i != tcp::resolver::iterator()
			&& !i->endpoint().address().is_v4()) ++i;
		if (i != tcp::resolver::iterator())
		{
			// country is an ISO 3166 country code
			int country = i->endpoint().address().to_v4().to_ulong() & 0xffff;
			
			// look up the country code in the map
			const int size = sizeof(country_map)/sizeof(country_map[0]);
			country_entry tmp = {country, ""};
			country_entry const* j =
				std::lower_bound(country_map, country_map + size, tmp
					, boost::bind(&country_entry::code, _1) < boost::bind(&country_entry::code, _2));
			if (j == country_map + size
				|| j->code != country)
			{
				// unknown country!
				p->set_country("!!");
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
				debug_log("IP \"%s\" was mapped to unknown country: %d"
					, print_address(p->remote().address()).c_str(), country);
#endif
				return;
			}
			
			p->set_country(j->name);
		}
	}
#endif

	void torrent::read_resume_data(lazy_entry const& rd)
	{
		m_total_uploaded = rd.dict_find_int_value("total_uploaded");
		m_total_downloaded = rd.dict_find_int_value("total_downloaded");
		m_active_time = rd.dict_find_int_value("active_time");
		m_finished_time = rd.dict_find_int_value("finished_time");
		m_seeding_time = rd.dict_find_int_value("seeding_time");
		m_last_seen_complete = rd.dict_find_int_value("last_seen_complete");
		m_complete = rd.dict_find_int_value("num_complete", 0xffffff);
		m_incomplete = rd.dict_find_int_value("num_incomplete", 0xffffff);
		m_downloaded = rd.dict_find_int_value("num_downloaded", 0xffffff);
		set_upload_limit(rd.dict_find_int_value("upload_rate_limit", -1));
		set_download_limit(rd.dict_find_int_value("download_rate_limit", -1));
		set_max_connections(rd.dict_find_int_value("max_connections", -1));
		set_max_uploads(rd.dict_find_int_value("max_uploads", -1));
		m_seed_mode = rd.dict_find_int_value("seed_mode", 0) && m_torrent_file->is_valid();
		if (m_seed_mode) m_verified.resize(m_torrent_file->num_pieces(), false);
		super_seeding(rd.dict_find_int_value("super_seeding", 0));

		m_last_scrape = rd.dict_find_int_value("last_scrape", 0);
		m_last_download = rd.dict_find_int_value("last_download", 0);
		m_last_upload = rd.dict_find_int_value("last_upload", 0);

		if (!m_use_resume_save_path)
		{
			std::string p = rd.dict_find_string_value("save_path");
			if (!p.empty()) m_save_path = p;
		}

		m_url = rd.dict_find_string_value("url");
		m_uuid = rd.dict_find_string_value("uuid");
		m_source_feed_url = rd.dict_find_string_value("feed");

		if (!m_uuid.empty() || !m_url.empty())
		{
			boost::shared_ptr<torrent> me(shared_from_this());

			// insert this torrent in the uuid index
			m_ses.m_uuids.insert(std::make_pair(m_uuid.empty()
				? m_url : m_uuid, me));
		}

		// TODO: make this more generic to not just work if files have been
		// renamed, but also if they have been merged into a single file for instance
		// maybe use the same format as .torrent files and reuse some code from torrent_info
		// The mapped_files needs to be read both in the network thread
		// and in the disk thread, since they both have their own mapped files structures
		// which are kept in sync
		lazy_entry const* mapped_files = rd.dict_find_list("mapped_files");
		if (mapped_files && mapped_files->list_size() == m_torrent_file->num_files())
		{
			for (int i = 0; i < m_torrent_file->num_files(); ++i)
			{
				std::string new_filename = mapped_files->list_string_value_at(i);
				if (new_filename.empty()) continue;
				m_torrent_file->rename_file(i, new_filename);
			}
		}
		
		m_added_time = rd.dict_find_int_value("added_time", m_added_time);
		m_completed_time = rd.dict_find_int_value("completed_time", m_completed_time);
		if (m_completed_time != 0 && m_completed_time < m_added_time)
			m_completed_time = m_added_time;

		lazy_entry const* file_priority = rd.dict_find_list("file_priority");
		if (file_priority && file_priority->list_size()
			== m_torrent_file->num_files())
		{
			for (int i = 0; i < file_priority->list_size(); ++i)
				m_file_priority[i] = file_priority->list_int_value_at(i, 1);
			update_piece_priorities();
		}

		lazy_entry const* piece_priority = rd.dict_find_string("piece_priority");
		if (piece_priority && piece_priority->string_length()
			== m_torrent_file->num_pieces())
		{
			char const* p = piece_priority->string_ptr();
			for (int i = 0; i < piece_priority->string_length(); ++i)
				m_picker->set_piece_priority(i, p[i]);
			m_policy.recalculate_connect_candidates();
		}

		if (!m_override_resume_data)
		{
			int auto_managed_ = rd.dict_find_int_value("auto_managed", -1);
			if (auto_managed_ != -1) m_auto_managed = auto_managed_;
		}

		int sequential_ = rd.dict_find_int_value("sequential_download", -1);
		if (sequential_ != -1) set_sequential_download(sequential_);

		if (!m_override_resume_data)
		{
			int paused_ = rd.dict_find_int_value("paused", -1);
			if (paused_ != -1)
			{
				set_allow_peers(!paused_);
				m_announce_to_dht = !paused_;
				m_announce_to_trackers = !paused_;
				m_announce_to_lsd = !paused_;
			}
			int dht_ = rd.dict_find_int_value("announce_to_dht", -1);
			if (dht_ != -1) m_announce_to_dht = dht_;
			int lsd_ = rd.dict_find_int_value("announce_to_lsd", -1);
			if (lsd_ != -1) m_announce_to_lsd = lsd_;
			int track_ = rd.dict_find_int_value("announce_to_trackers", -1);
			if (track_ != -1) m_announce_to_trackers = track_;
		}

		lazy_entry const* trackers = rd.dict_find_list("trackers");
		if (trackers)
		{
			if (!m_merge_resume_trackers) m_trackers.clear();
			int tier = 0;
			for (int i = 0; i < trackers->list_size(); ++i)
			{
				lazy_entry const* tier_list = trackers->list_at(i);
				if (tier_list == 0 || tier_list->type() != lazy_entry::list_t)
					continue;
				for (int j = 0; j < tier_list->list_size(); ++j)
				{
					announce_entry e(tier_list->list_string_value_at(j));
					if (std::find_if(m_trackers.begin(), m_trackers.end()
						, boost::bind(&announce_entry::url, _1) == e.url) != m_trackers.end())
						continue;
					e.tier = tier;
					e.fail_limit = 0;
					m_trackers.push_back(e);
				}
				++tier;
			}
			std::sort(m_trackers.begin(), m_trackers.end(), boost::bind(&announce_entry::tier, _1)
				< boost::bind(&announce_entry::tier, _2));

			if (settings().prefer_udp_trackers)
				prioritize_udp_trackers();
		}

		lazy_entry const* url_list = rd.dict_find_list("url-list");
		if (url_list)
		{
			for (int i = 0; i < url_list->list_size(); ++i)
			{
				std::string url = url_list->list_string_value_at(i);
				if (url.empty()) continue;
				if (m_torrent_file->num_files() > 1 && url[url.size()-1] != '/') url += '/';
				add_web_seed(url, web_seed_entry::url_seed);
			}
		}

		lazy_entry const* httpseeds = rd.dict_find_list("httpseeds");
		if (httpseeds)
		{
			for (int i = 0; i < httpseeds->list_size(); ++i)
			{
				std::string url = httpseeds->list_string_value_at(i);
				if (url.empty()) continue;
				add_web_seed(url, web_seed_entry::http_seed);
			}
		}

		if (m_torrent_file->is_merkle_torrent())
		{
			lazy_entry const* mt = rd.dict_find_string("merkle tree");
			if (mt)
			{
				std::vector<sha1_hash> tree;
				tree.resize(m_torrent_file->merkle_tree().size());
				std::memcpy(&tree[0], mt->string_ptr()
					, (std::min)(mt->string_length(), int(tree.size()) * 20));
				if (mt->string_length() < int(tree.size()) * 20)
					std::memset(&tree[0] + mt->string_length() / 20, 0
						, tree.size() - mt->string_length() / 20);
				m_torrent_file->set_merkle_tree(tree);
			}
			else
			{
				// TODO: 0 if this is a merkle torrent and we can't
				// restore the tree, we need to wipe all the
				// bits in the have array, but not necessarily
				// we might want to do a full check to see if we have
				// all the pieces. This is low priority since almost
				// no one uses merkle torrents
				TORRENT_ASSERT(false);
			}
		}
	}

	boost::intrusive_ptr<torrent_info const> torrent::get_torrent_copy()
	{
		if (!m_torrent_file->is_valid()) return boost::intrusive_ptr<torrent_info>();

		// copy the torrent_info object
		return boost::intrusive_ptr<torrent_info>(new torrent_info(*m_torrent_file));
	}
	
	void torrent::write_resume_data(entry& ret) const
	{
		using namespace libtorrent::detail; // for write_*_endpoint()
		ret["file-format"] = "libtorrent resume file";
		ret["file-version"] = 1;
		ret["libtorrent-version"] = LIBTORRENT_VERSION;

		ret["total_uploaded"] = m_total_uploaded;
		ret["total_downloaded"] = m_total_downloaded;

		ret["active_time"] = m_active_time;
		ret["finished_time"] = m_finished_time;
		ret["seeding_time"] = m_seeding_time;
		ret["last_seen_complete"] = m_last_seen_complete;

		ret["num_complete"] = m_complete;
		ret["num_incomplete"] = m_incomplete;
		ret["num_downloaded"] = m_downloaded;

		ret["sequential_download"] = m_sequential_download;

		ret["seed_mode"] = m_seed_mode;
		ret["super_seeding"] = m_super_seeding;

		ret["added_time"] = m_added_time;
		ret["completed_time"] = m_completed_time;

		ret["last_scrape"] = m_last_scrape;
		ret["last_download"] = m_last_download;
		ret["last_upload"] = m_last_upload;

		ret["save_path"] = m_save_path;

		if (!m_url.empty()) ret["url"] = m_url;
		if (!m_uuid.empty()) ret["uuid"] = m_uuid;
		if (!m_source_feed_url.empty()) ret["feed"] = m_source_feed_url;
		
		const sha1_hash& info_hash = torrent_file().info_hash();
		ret["info-hash"] = std::string((char*)info_hash.begin(), (char*)info_hash.end());

		if (valid_metadata())
		{
			if (m_magnet_link || (m_save_resume_flags & torrent_handle::save_info_dict))
				ret["info"] = bdecode(&torrent_file().metadata()[0]
					, &torrent_file().metadata()[0] + torrent_file().metadata_size());
		}

		// blocks per piece
		int num_blocks_per_piece =
			static_cast<int>(torrent_file().piece_length()) / block_size();
		ret["blocks per piece"] = num_blocks_per_piece;

		if (m_torrent_file->is_merkle_torrent())
		{
			// we need to save the whole merkle hash tree
			// in order to resume
			std::string& tree_str = ret["merkle tree"].string();
			std::vector<sha1_hash> const& tree = m_torrent_file->merkle_tree();
			tree_str.resize(tree.size() * 20);
			std::memcpy(&tree_str[0], &tree[0], tree.size() * 20);
		}

		// if this torrent is a seed, we won't have a piece picker
		// and there will be no half-finished pieces.
		if (has_picker())
		{
			const std::vector<piece_picker::downloading_piece>& q
				= m_picker->get_download_queue();

			// unfinished pieces
			ret["unfinished"] = entry::list_type();
			entry::list_type& up = ret["unfinished"].list();

			// info for each unfinished piece
			for (std::vector<piece_picker::downloading_piece>::const_iterator i
				= q.begin(); i != q.end(); ++i)
			{
				if (i->finished == 0) continue;

				entry piece_struct(entry::dictionary_t);

				// the unfinished piece's index
				piece_struct["piece"] = i->index;

				std::string bitmask;
				const int num_bitmask_bytes
					= (std::max)(num_blocks_per_piece / 8, 1);

				for (int j = 0; j < num_bitmask_bytes; ++j)
				{
					unsigned char v = 0;
					int bits = (std::min)(num_blocks_per_piece - j*8, 8);
					for (int k = 0; k < bits; ++k)
						v |= (i->info[j*8+k].state == piece_picker::block_info::state_finished)
						? (1 << k) : 0;
					bitmask.append(1, v);
					TORRENT_ASSERT(bits == 8 || j == num_bitmask_bytes - 1);
				}
				piece_struct["bitmask"] = bitmask;
				// push the struct onto the unfinished-piece list
				up.push_back(piece_struct);
			}
		}

		// save trackers
		entry::list_type& tr_list = ret["trackers"].list();
		tr_list.push_back(entry::list_type());
		int tier = 0;
		for (std::vector<announce_entry>::const_iterator i = m_trackers.begin()
			, end(m_trackers.end()); i != end; ++i)
		{
			// don't save trackers we can't trust
			// TODO: 1 save the send_stats state instead of throwing them away
			// it may pose an issue when downgrading though
			if (i->send_stats == false) continue;
			if (i->tier == tier)
			{
				tr_list.back().list().push_back(i->url);
			}
			else
			{
				tr_list.push_back(entry::list_t);
				tr_list.back().list().push_back(i->url);
				tier = i->tier;
			}
		}

		// save web seeds
		if (!m_web_seeds.empty())
		{
			entry::list_type& url_list = ret["url-list"].list();
			entry::list_type& httpseed_list = ret["httpseeds"].list();
			for (std::list<web_seed_entry>::const_iterator i = m_web_seeds.begin()
				, end(m_web_seeds.end()); i != end; ++i)
			{
				if (i->type == web_seed_entry::url_seed)
					url_list.push_back(i->url);
				else if (i->type == web_seed_entry::http_seed)
					httpseed_list.push_back(i->url);
			}
		}

		// write have bitmask
		// the pieces string has one byte per piece. Each
		// byte is a bitmask representing different properties
		// for the piece
		// bit 0: set if we have the piece
		// bit 1: set if we have verified the piece (in seed mode)
		entry::string_type& pieces = ret["pieces"].string();
		pieces.resize(m_torrent_file->num_pieces());
		if (is_seed())
		{
			std::memset(&pieces[0], 1, pieces.size());
		}
		else
		{
			for (int i = 0, end(pieces.size()); i < end; ++i)
				pieces[i] = m_picker->have_piece(i) ? 1 : 0;
		}

		if (m_seed_mode)
		{
			TORRENT_ASSERT(m_verified.size() == pieces.size());
			for (int i = 0, end(pieces.size()); i < end; ++i)
				pieces[i] |= m_verified[i] ? 2 : 0;
		}

		// write renamed files
		// TODO: 0 make this more generic to not just work if files have been
		// renamed, but also if they have been merged into a single file for instance.
		// using file_base
		if (&m_torrent_file->files() != &m_torrent_file->orig_files()
			&& m_torrent_file->files().num_files() == m_torrent_file->orig_files().num_files())
		{
			entry::list_type& fl = ret["mapped_files"].list();
			file_storage const& fs = m_torrent_file->files();
			for (int i = 0; i < fs.num_files(); ++i)
			{
				fl.push_back(fs.file_path(i));
			}
		}

		// write local peers

		std::back_insert_iterator<entry::string_type> peers(ret["peers"].string());
		std::back_insert_iterator<entry::string_type> banned_peers(ret["banned_peers"].string());
#if TORRENT_USE_IPV6
		std::back_insert_iterator<entry::string_type> peers6(ret["peers6"].string());
		std::back_insert_iterator<entry::string_type> banned_peers6(ret["banned_peers6"].string());
#endif

		// failcount is a 5 bit value
		int max_failcount = (std::min)(settings().max_failcount, 31);

		int num_saved_peers = 0;

		for (policy::const_iterator i = m_policy.begin_peer()
			, end(m_policy.end_peer()); i != end; ++i)
		{
			error_code ec;
			policy::peer const* p = *i;
			address addr = p->address();
			if (p->banned)
			{
#if TORRENT_USE_IPV6
				if (addr.is_v6())
				{
					write_address(addr, banned_peers6);
					write_uint16(p->port, banned_peers6);
				}
				else
#endif
				{
					write_address(addr, banned_peers);
					write_uint16(p->port, banned_peers);
				}
				continue;
			}

			// we cannot save remote connection
			// since we don't know their listen port
			// unless they gave us their listen port
			// through the extension handshake
			// so, if the peer is not connectable (i.e. we
			// don't know its listen port) or if it has
			// been banned, don't save it.
			if (!p->connectable) continue;

			// don't save peers that don't work
			if (int(p->failcount) >= max_failcount) continue;

			// the more peers we've saved, the more picky we get
			// about which ones are worth saving
			if (num_saved_peers > 10
				&& int (p->failcount) > 0
				&& int(p->failcount) > (40 - (num_saved_peers - 10)) * max_failcount / 40)
				continue;

			// if we have 40 peers, don't save any peers whom
			// we've only heard from through the resume data
			if (num_saved_peers > 40 && p->source == peer_info::resume_data)
				continue;

#if TORRENT_USE_IPV6
			if (addr.is_v6())
			{
				write_address(addr, peers6);
				write_uint16(p->port, peers6);
			}
			else
#endif
			{
				write_address(addr, peers);
				write_uint16(p->port, peers);
			}
			++num_saved_peers;
		}

		ret["upload_rate_limit"] = upload_limit();
		ret["download_rate_limit"] = download_limit();
		ret["max_connections"] = max_connections();
		ret["max_uploads"] = max_uploads();
		ret["paused"] = is_torrent_paused();
		ret["announce_to_dht"] = m_announce_to_dht;
		ret["announce_to_trackers"] = m_announce_to_trackers;
		ret["announce_to_lsd"] = m_announce_to_lsd;
		ret["auto_managed"] = m_auto_managed;

		// write piece priorities
		entry::string_type& piece_priority = ret["piece_priority"].string();
		piece_priority.resize(m_torrent_file->num_pieces());
		if (is_seed())
		{
			std::memset(&piece_priority[0], 1, pieces.size());
		}
		else
		{
			for (int i = 0, end(piece_priority.size()); i < end; ++i)
				piece_priority[i] = m_picker->piece_priority(i);
		}

		// write file priorities
		entry::list_type& file_priority = ret["file_priority"].list();
		file_priority.clear();
		for (int i = 0, end(m_file_priority.size()); i < end; ++i)
			file_priority.push_back(m_file_priority[i]);
	}

	void torrent::get_full_peer_list(std::vector<peer_list_entry>& v) const
	{
		v.clear();
		v.reserve(m_policy.num_peers());
		for (policy::const_iterator i = m_policy.begin_peer();
			i != m_policy.end_peer(); ++i)
		{
			peer_list_entry e;
			e.ip = (*i)->ip();
			e.flags = (*i)->banned ? peer_list_entry::banned : 0;
			e.failcount = (*i)->failcount;
			e.source = (*i)->source;
			v.push_back(e);
		}
	}

	void torrent::get_peer_info(std::vector<peer_info>& v)
	{
		v.clear();
		for (peer_iterator i = begin();
			i != end(); ++i)
		{
			peer_connection* peer = *i;
			TORRENT_ASSERT(peer->m_in_use == 1337);

			// incoming peers that haven't finished the handshake should
			// not be included in this list
			if (peer->associated_torrent().expired()) continue;

			v.push_back(peer_info());
			peer_info& p = v.back();
			
			peer->get_peer_info(p);
#ifndef TORRENT_DISABLE_RESOLVE_COUNTRIES
			if (resolving_countries())
				resolve_peer_country(intrusive_ptr<peer_connection>(peer));
#endif
		}
	}

	void torrent::get_download_queue(std::vector<partial_piece_info>* queue)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		queue->clear();
		std::vector<block_info>& blk = m_ses.m_block_info_storage;
		blk.clear();

		if (!valid_metadata() || !has_picker()) return;
		piece_picker const& p = picker();
		std::vector<piece_picker::downloading_piece> const& q
			= p.get_download_queue();

		const int blocks_per_piece = m_picker->blocks_in_piece(0);
		blk.resize(q.size() * blocks_per_piece);
		// for some weird reason valgrind claims these are uninitialized
		// unless it's zeroed out here (block_info has a construct that's
		// supposed to initialize it)
		if (!blk.empty())
			memset(&blk[0], 0, sizeof(blk[0]) * blk.size());

		int counter = 0;
		for (std::vector<piece_picker::downloading_piece>::const_iterator i
			= q.begin(); i != q.end(); ++i, ++counter)
		{
			partial_piece_info pi;
			pi.piece_state = (partial_piece_info::state_t)i->state;
			pi.blocks_in_piece = p.blocks_in_piece(i->index);
			pi.finished = (int)i->finished;
			pi.writing = (int)i->writing;
			pi.requested = (int)i->requested;
			TORRENT_ASSERT(counter * blocks_per_piece + pi.blocks_in_piece <= int(blk.size()));
			pi.blocks = &blk[counter * blocks_per_piece];
			int piece_size = int(torrent_file().piece_size(i->index));
			for (int j = 0; j < pi.blocks_in_piece; ++j)
			{
				block_info& bi = pi.blocks[j];
				bi.state = i->info[j].state;
				bi.block_size = j < pi.blocks_in_piece - 1 ? block_size()
					: piece_size - (j * block_size());
				bool complete = bi.state == block_info::writing
					|| bi.state == block_info::finished;
				if (i->info[j].peer == 0)
				{
					bi.set_peer(tcp::endpoint());
					bi.bytes_progress = complete ? bi.block_size : 0;
				}
				else
				{
					policy::peer* p = static_cast<policy::peer*>(i->info[j].peer);
					if (p->connection)
					{
						bi.set_peer(p->connection->remote());
						if (bi.state == block_info::requested)
						{
							boost::optional<piece_block_progress> pbp
								= p->connection->downloading_piece_progress();
							if (pbp && pbp->piece_index == i->index && pbp->block_index == j)
							{
								bi.bytes_progress = pbp->bytes_downloaded;
								TORRENT_ASSERT(bi.bytes_progress <= bi.block_size);
							}
							else
							{
								bi.bytes_progress = 0;
							}
						}
						else
						{
							bi.bytes_progress = complete ? bi.block_size : 0;
						}
					}
					else
					{
						bi.set_peer(p->ip());
						bi.bytes_progress = complete ? bi.block_size : 0;
					}
				}

				pi.blocks[j].num_peers = i->info[j].num_peers;
			}
			pi.piece_index = i->index;
			queue->push_back(pi);
		}
	
	}
	
	bool torrent::connect_to_peer(policy::peer* peerinfo, bool ignore_limit)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		TORRENT_ASSERT(peerinfo);
		TORRENT_ASSERT(peerinfo->connection == 0);

		peerinfo->last_connected = m_ses.session_time();
#ifdef TORRENT_DEBUG
		if (!settings().allow_multiple_connections_per_ip)
		{
			// this asserts that we don't have duplicates in the policy's peer list
			peer_iterator i_ = std::find_if(m_connections.begin(), m_connections.end()
				, boost::bind(&peer_connection::remote, _1) == peerinfo->ip());
#if TORRENT_USE_I2P
			TORRENT_ASSERT(i_ == m_connections.end()
				|| (*i_)->type() != peer_connection::bittorrent_connection
				|| peerinfo->is_i2p_addr);
#else
			TORRENT_ASSERT(i_ == m_connections.end()
				|| (*i_)->type() != peer_connection::bittorrent_connection);
#endif
		}
#endif

		// extend connect timeout by this many seconds
		int timeout_extend = 0;

		TORRENT_ASSERT(want_more_peers() || ignore_limit);
		TORRENT_ASSERT(m_ses.num_connections() < m_ses.settings().connections_limit || ignore_limit);

		tcp::endpoint a(peerinfo->ip());
		TORRENT_ASSERT(!m_apply_ip_filter
			|| (m_ses.m_ip_filter.access(peerinfo->address()) & ip_filter::blocked) == 0);

		boost::shared_ptr<socket_type> s(new socket_type(m_ses.m_io_service));

#if TORRENT_USE_I2P
		bool i2p = peerinfo->is_i2p_addr;
		if (i2p)
		{
			if (m_ses.i2p_proxy().hostname.empty())
			{
				// we have an i2p torrent, but we're not connected to an i2p
				// SAM proxy.
				if (alerts().should_post<i2p_alert>())
					alerts().post_alert(i2p_alert(error_code(errors::no_i2p_router
						, get_libtorrent_category())));
				return false;
			}

			bool ret = instantiate_connection(m_ses.m_io_service, m_ses.i2p_proxy(), *s);
			(void)ret;
			TORRENT_ASSERT(ret);
			s->get<i2p_stream>()->set_destination(static_cast<policy::i2p_peer*>(peerinfo)->destination);
			s->get<i2p_stream>()->set_command(i2p_stream::cmd_connect);
			s->get<i2p_stream>()->set_session_id(m_ses.m_i2p_conn.session_id());
			// i2p setups are slow
			timeout_extend = 20;
		}
		else
#endif
		{
			// this is where we determine if we open a regular TCP connection
			// or a uTP connection. If the m_utp_socket_manager pointer is not passed in
			// we'll instantiate a TCP connection
			utp_socket_manager* sm = 0;

			if (m_ses.m_settings.enable_outgoing_utp
				&& (!m_ses.m_settings.enable_outgoing_tcp
					|| peerinfo->supports_utp
					|| peerinfo->confirmed_supports_utp))
				sm = &m_ses.m_utp_socket_manager;

			// don't make a TCP connection if it's disabled
			if (sm == 0 && !m_ses.m_settings.enable_outgoing_tcp) return false;

			void* userdata = 0;
#ifdef TORRENT_USE_OPENSSL
			if (is_ssl_torrent() && m_ses.settings().ssl_listen != 0)
			{
				userdata = m_ssl_ctx.get();
				// SSL handshakes are slow
				timeout_extend = 10;
			}
#endif

			bool ret = instantiate_connection(m_ses.m_io_service, m_ses.proxy(), *s, userdata, sm, true);
			(void)ret;
			TORRENT_ASSERT(ret);

#if defined TORRENT_USE_OPENSSL && BOOST_VERSION >= 104700
			if (is_ssl_torrent())
			{
				// for ssl sockets, set the hostname
				std::string host_name = to_hex(m_torrent_file->info_hash().to_string());

#define CASE(t) case socket_type_int_impl<ssl_stream<t> >::value: \
	s->get<ssl_stream<t> >()->set_host_name(host_name); break;

				switch (s->type())
				{
					CASE(stream_socket)
					CASE(socks5_stream)
					CASE(http_stream)
					CASE(utp_stream)
					default: break;
				};
			}
#undef CASE
#endif
		}

		m_ses.setup_socket_buffers(*s);

		boost::intrusive_ptr<peer_connection> c(new bt_peer_connection(
			m_ses, s, a, peerinfo, m_ses.get_peer_id(), shared_from_this(), true));

#if TORRENT_USE_ASSERTS
		c->m_in_constructor = false;
#endif

 		c->add_stat(size_type(peerinfo->prev_amount_download) << 10
			, size_type(peerinfo->prev_amount_upload) << 10);
 		peerinfo->prev_amount_download = 0;
 		peerinfo->prev_amount_upload = 0;

#ifndef TORRENT_DISABLE_EXTENSIONS
		for (extension_list_t::iterator i = m_extensions.begin()
			, end(m_extensions.end()); i != end; ++i)
		{
			TORRENT_TRY {
				boost::shared_ptr<peer_plugin> pp((*i)->new_connection(c.get()));
				if (pp) c->add_extension(pp);
			} TORRENT_CATCH (std::exception&) {}
		}
#endif

		// add the newly connected peer to this torrent's peer list
		m_connections.insert(boost::get_pointer(c));
		m_ses.m_connections.insert(c);
		m_policy.set_connection(peerinfo, c.get());
		c->start();

		int timeout = settings().peer_connect_timeout;
		if (peerinfo) timeout += 3 * peerinfo->failcount;
		timeout += timeout_extend;

		TORRENT_TRY
		{
			m_ses.m_half_open.enqueue(
				boost::bind(&peer_connection::on_connect, c, _1)
				, boost::bind(&peer_connection::on_timeout, c)
				, seconds(timeout));
		}
		TORRENT_CATCH (std::exception&)
		{
			std::set<peer_connection*>::iterator i
				= m_connections.find(boost::get_pointer(c));
			if (i != m_connections.end()) m_connections.erase(i);
			c->disconnect(errors::no_error, 1);
			return false;
		}

		if (m_share_mode)
			recalc_share_mode();

		return peerinfo->connection;
	}

	bool torrent::set_metadata(char const* metadata_buf, int metadata_size)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		if (m_torrent_file->is_valid()) return false;

		hasher h;
		h.update(metadata_buf, metadata_size);
		sha1_hash info_hash = h.final();

		if (info_hash != m_torrent_file->info_hash())
		{
			if (alerts().should_post<metadata_failed_alert>())
			{
				alerts().post_alert(metadata_failed_alert(get_handle()
					, error_code(errors::mismatching_info_hash, get_libtorrent_category())));
			}
			return false;
		}

		lazy_entry metadata;
		error_code ec;
		int ret = lazy_bdecode(metadata_buf, metadata_buf + metadata_size, metadata, ec);
		if (ret != 0 || !m_torrent_file->parse_info_section(metadata, ec, 0))
		{
			// this means the metadata is correct, since we
			// verified it against the info-hash, but we
			// failed to parse it. Pause the torrent
			if (alerts().should_post<metadata_failed_alert>())
			{
				alerts().post_alert(metadata_failed_alert(get_handle(), ec));
			}
			set_error(errors::invalid_swarm_metadata, "");
			pause();
			return false;
		}

		if (m_ses.m_alerts.should_post<metadata_received_alert>())
		{
			m_ses.m_alerts.post_alert(metadata_received_alert(
				get_handle()));
		}

		// this makes the resume data "paused" and
		// "auto_managed" fields be ignored. If the paused
		// field is not ignored, the invariant check will fail
		// since we will be paused but without having disconnected
		// any of the peers.
		m_override_resume_data = true;

		// we have to initialize the torrent before we start
		// disconnecting redundant peers, otherwise we'll think
		// we're a seed, because we have all 0 pieces
		init();

		// disconnect redundant peers
		for (std::set<peer_connection*>::iterator i = m_connections.begin()
			, end(m_connections.end()); i != end;)
		{
			std::set<peer_connection*>::iterator p = i++;
			(*p)->disconnect_if_redundant();
		}

		m_need_save_resume_data = true;

		return true;
	}

	bool connecting_time_compare(peer_connection const* lhs, peer_connection const* rhs)
	{
		bool lhs_connecting = lhs->is_connecting() && !lhs->is_disconnecting();
		bool rhs_connecting = rhs->is_connecting() && !rhs->is_disconnecting();
		if (lhs_connecting > rhs_connecting) return false;
		if (lhs_connecting < rhs_connecting) return true;

		// a lower value of connected_time means it's been waiting
		// longer. This is a less-than comparison, so if lhs has
		// waited longer than rhs, we should return false.
		return lhs->connected_time() > rhs->connected_time();
	}

	bool torrent::attach_peer(peer_connection* p)
	{
//		INVARIANT_CHECK;

#ifdef TORRENT_USE_OPENSSL
#if BOOST_VERSION >= 104700
		if (is_ssl_torrent())
		{
			// if this is an SSL torrent, don't allow non SSL peers on it
			boost::shared_ptr<socket_type> s = p->get_socket();

			//
#define SSL(t) socket_type_int_impl<ssl_stream<t> >::value: \
			ssl_conn = s->get<ssl_stream<t> >()->native_handle(); \
			break;

			SSL* ssl_conn = 0;

			switch (s->type())
			{
				case SSL(stream_socket)
				case SSL(socks5_stream)
				case SSL(http_stream)
				case SSL(utp_stream)
			};

#undef SSL

			if (ssl_conn == 0)
			{
				// don't allow non SSL peers on SSL torrents
				p->disconnect(errors::requires_ssl_connection);
				return false;
			}

			if (!m_ssl_ctx)
			{
				// we don't have a valid cert, don't accept any connection!
				p->disconnect(errors::invalid_ssl_cert);
				return false;
			}

			if (SSL_get_SSL_CTX(ssl_conn) != m_ssl_ctx->native_handle())
			{
				// if the SSL_CTX associated with this connection is
				// not the one belonging to this torrent, the SSL handshake
				// connected to one torrent, and the BitTorrent protocol
				// to a different one. This is probably an attempt to circumvent
				// access control. Don't allow it.
				p->disconnect(errors::invalid_ssl_cert);
				return false;
			}
		}
#else // BOOST_VERSION
		if (is_ssl_torrent())
		{
			p->disconnect(asio::error::operation_not_supported);
			return false;
		}
#endif
#else // TORRENT_USE_OPENSSL
		if (is_ssl_torrent())
		{
			// Don't accidentally allow seeding of SSL torrents, just
			// because libtorrent wasn't built with SSL support
			p->disconnect(errors::requires_ssl_connection);
			return false;
		}
#endif // TORRENT_USE_OPENSSL

		TORRENT_ASSERT(p != 0);
		TORRENT_ASSERT(!p->is_outgoing());

		m_has_incoming = true;

		if (m_apply_ip_filter
			&& m_ses.m_ip_filter.access(p->remote().address()) & ip_filter::blocked)
		{
			if (m_ses.m_alerts.should_post<peer_blocked_alert>())
				m_ses.m_alerts.post_alert(peer_blocked_alert(get_handle()
					, p->remote().address(), peer_blocked_alert::ip_filter));
			p->disconnect(errors::banned_by_ip_filter);
			return false;
		}

		if ((m_state == torrent_status::queued_for_checking
			|| m_state == torrent_status::checking_files
			|| m_state == torrent_status::checking_resume_data)
			&& valid_metadata())
		{
			p->disconnect(errors::torrent_not_ready);
			return false;
		}
		
		if (m_ses.m_connections.find(p) == m_ses.m_connections.end())
		{
			p->disconnect(errors::peer_not_constructed);
			return false;
		}

		if (m_ses.is_aborted())
		{
			p->disconnect(errors::session_closing);
			return false;
		}

		bool maybe_replace_peer = false;

		if (m_connections.size() >= m_max_connections)
		{
			// if more than 10% of the connections are outgoing
			// connection attempts that haven't completed yet,
			// disconnect one of them and let this incoming
			// connection through.
			if (m_num_connecting > m_max_connections / 10)
			{
				// find one of the connecting peers and disconnect it
				// find any peer that's connecting (i.e. a half-open TCP connection)
				// that's also not disconnecting

				// disconnect the peer that's been wating to establish a connection
				// the longest
				std::set<peer_connection*>::iterator i = std::max_element(begin(), end()
					, &connecting_time_compare);

				if (i == end() || !(*i)->is_connecting() || (*i)->is_disconnecting())
				{
					// this seems odd, but we might as well handle it
					p->disconnect(errors::too_many_connections);
					return false;
				}
				(*i)->disconnect(errors::too_many_connections);
            
				// if this peer was let in via connections slack,
				// it has done its duty of causing the disconnection
				// of another peer
				p->peer_disconnected_other();
			}
			else
			{
				maybe_replace_peer = true;
			}
		}

		TORRENT_TRY
		{
#ifndef TORRENT_DISABLE_EXTENSIONS
			for (extension_list_t::iterator i = m_extensions.begin()
				, end(m_extensions.end()); i != end; ++i)
			{
				boost::shared_ptr<peer_plugin> pp((*i)->new_connection(p));
				if (pp) p->add_extension(pp);
			}
#endif
			if (!m_policy.new_connection(*p, m_ses.session_time()))
			{
#if defined TORRENT_LOGGING
				debug_log("CLOSING CONNECTION \"%s\" peer list full"
					, print_endpoint(p->remote()).c_str());
#endif
				p->disconnect(errors::too_many_connections);
				return false;
			}
		}
		TORRENT_CATCH (std::exception& e)
		{
			TORRENT_DECLARE_DUMMY(std::exception, e);
			(void)e;
#if defined TORRENT_LOGGING
			debug_log("CLOSING CONNECTION \"%s\" caught exception: %s"
				, print_endpoint(p->remote()).c_str(), e.what());
#endif
			p->disconnect(errors::no_error);
			return false;
		}
		TORRENT_ASSERT(m_connections.find(p) == m_connections.end());
		m_connections.insert(p);
#ifdef TORRENT_DEBUG
		error_code ec;
		TORRENT_ASSERT(p->remote() == p->get_socket()->remote_endpoint(ec) || ec);
#endif

		TORRENT_ASSERT(p->peer_info_struct() != NULL);

		// we need to do this after we've added the peer to the policy
		// since that's when the peer is assigned its peer_info object,
		// which holds the rank
		if (maybe_replace_peer)
		{
			// now, find the lowest rank peer and disconnect that
			// if it's lower rank than the incoming connection
			peer_connection* peer = find_lowest_ranking_peer();

			// TODO: 3 if peer is a really good peer, maybe we shouldn't disconnect it
			if (peer && peer->peer_rank() < p->peer_rank())
			{
				peer->disconnect(errors::too_many_connections);
				p->peer_disconnected_other();
			}
			else
			{
				p->disconnect(errors::too_many_connections);
				// we have to do this here because from the peer's point of
				// it wasn't really attached to the torrent, but we do need
				// to let policy know we're removing it
				remove_peer(p);
				return false;
			}
		}

#if TORRENT_USE_INVARIANT_CHECKS
		m_policy.check_invariant();
#endif

		if (m_share_mode)
			recalc_share_mode();

		return true;
	}

	bool torrent::want_more_peers() const
	{
		return m_connections.size() < m_max_connections
			&& !is_paused()
			&& ((m_state != torrent_status::checking_files
			&& m_state != torrent_status::checking_resume_data
			&& m_state != torrent_status::queued_for_checking)
				|| !valid_metadata())
			&& m_policy.num_connect_candidates() > 0
			&& !m_abort
			&& (m_ses.settings().seeding_outgoing_connections
				|| (m_state != torrent_status::seeding
				&& m_state != torrent_status::finished));
	}

	void torrent::disconnect_all(error_code const& ec)
	{
// doesn't work with the !m_allow_peers -> m_num_peers == 0 condition
//		INVARIANT_CHECK;

		while (!m_connections.empty())
		{
			peer_connection* p = *m_connections.begin();
			TORRENT_ASSERT(p->associated_torrent().lock().get() == this);

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
			p->peer_log("*** CLOSING CONNECTION \"%s\"", ec.message().c_str());
#endif
#if TORRENT_USE_ASSERTS
			std::size_t size = m_connections.size();
#endif
			if (p->is_disconnecting())
				m_connections.erase(m_connections.begin());
			else
				p->disconnect(ec);
			TORRENT_ASSERT(m_connections.size() <= size);
		}
	}

	// this returns true if lhs is a better disconnect candidate than rhs
	bool compare_disconnect_peer(peer_connection const* lhs, peer_connection const* rhs)
	{
		// prefer to disconnect peers that are already disconnecting
		if (lhs->is_disconnecting() != rhs->is_disconnecting())
			return lhs->is_disconnecting();

		// prefer to disconnect peers we're not interested in
		if (lhs->is_interesting() != rhs->is_interesting())
			return rhs->is_interesting();

		// prefer to disconnect peers that are not seeds
		if (lhs->is_seed() != rhs->is_seed())
			return rhs->is_seed();

		// prefer to disconnect peers that are on parole
		if (lhs->on_parole() != rhs->on_parole())
			return lhs->on_parole();

		// prefer to disconnect peers that send data at a lower rate
		size_type lhs_transferred = lhs->statistics().total_payload_download();
		size_type rhs_transferred = rhs->statistics().total_payload_download();

		ptime now = time_now();
		size_type lhs_time_connected = total_seconds(now - lhs->connected_time());
		size_type rhs_time_connected = total_seconds(now - rhs->connected_time());

		lhs_transferred /= lhs_time_connected + 1;
		rhs_transferred /= (rhs_time_connected + 1);
		if (lhs_transferred != rhs_transferred)	
			return lhs_transferred < rhs_transferred;

		// prefer to disconnect peers that chokes us
		if (lhs->is_choked() != rhs->is_choked())
			return lhs->is_choked();

		return lhs->last_received() < rhs->last_received();
	}

	int torrent::disconnect_peers(int num, error_code const& ec)
	{
		INVARIANT_CHECK;

#ifdef TORRENT_DEBUG
		for (std::set<peer_connection*>::iterator i = m_connections.begin()
			, end(m_connections.end()); i != end; ++i)
		{
			// make sure this peer is not a dangling pointer
			TORRENT_ASSERT(m_ses.has_peer(*i));
		}
#endif
		int ret = 0;
		while (ret < num && !m_connections.empty())
		{
			std::set<peer_connection*>::iterator i = std::min_element(
				m_connections.begin(), m_connections.end(), compare_disconnect_peer);

			peer_connection* p = *i;
			++ret;
			TORRENT_ASSERT(p->associated_torrent().lock().get() == this);
#if TORRENT_USE_ASSERTS
			int num_conns = m_connections.size();
#endif
			p->disconnect(ec);
			TORRENT_ASSERT(int(m_connections.size()) == num_conns - 1);
		}

		return ret;
	}

	int torrent::bandwidth_throttle(int channel) const
	{
		return m_bandwidth_channel[channel].throttle();
	}

	// called when torrent is finished (all interesting
	// pieces have been downloaded)
	void torrent::finished()
	{
		INVARIANT_CHECK;

		TORRENT_ASSERT(is_finished());
		TORRENT_ASSERT(m_state != torrent_status::finished && m_state != torrent_status::seeding);

		set_state(torrent_status::finished);
		set_queue_position(-1);

		// we have to call completed() before we start
		// disconnecting peers, since there's an assert
		// to make sure we're cleared the piece picker
		if (is_seed()) completed();

		send_upload_only();

		state_updated();

		if (m_completed_time == 0)
			m_completed_time = time(0);

		// disconnect all seeds
		if (settings().close_redundant_connections)
		{
			// TODO: 1 should disconnect all peers that have the pieces we have
			// not just seeds. It would be pretty expensive to check all pieces
			// for all peers though
			std::vector<peer_connection*> seeds;
			for (peer_iterator i = m_connections.begin();
				i != m_connections.end(); ++i)
			{
				peer_connection* p = *i;
				TORRENT_ASSERT(p->associated_torrent().lock().get() == this);
				if (p->upload_only())
				{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
					p->peer_log("*** SEED, CLOSING CONNECTION");
#endif
					seeds.push_back(p);
				}
			}
			std::for_each(seeds.begin(), seeds.end()
				, boost::bind(&peer_connection::disconnect, _1, errors::torrent_finished, 0));
		}

		if (m_abort) return;

		m_policy.recalculate_connect_candidates();

		TORRENT_ASSERT(m_storage);
		// we need to keep the object alive during this operation
		m_storage->async_release_files(
			boost::bind(&torrent::on_files_released, shared_from_this(), _1, _2));
		
		// this torrent just completed downloads, which means it will fall
		// under a different limit with the auto-manager. Make sure we
		// update auto-manage torrents in that case
		if (m_auto_managed)
			m_ses.trigger_auto_manage();
	}

	// this is called when we were finished, but some files were
	// marked for downloading, and we are no longer finished	
	void torrent::resume_download()
	{
		INVARIANT_CHECK;
	
		if (m_state == torrent_status::checking_resume_data
			|| m_state == torrent_status::checking_files
			|| m_state == torrent_status::allocating)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("*** RESUME_DOWNLOAD [ skipping, state: %d ]"
			, int(m_state));
#endif
			return;
		}

		TORRENT_ASSERT(!is_finished());
		set_state(torrent_status::downloading);
		set_queue_position((std::numeric_limits<int>::max)());
		m_policy.recalculate_connect_candidates();

		m_completed_time = 0;

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("*** RESUME_DOWNLOAD");
#endif
		send_upload_only();
	}

	// called when torrent is complete (all pieces downloaded)
	void torrent::completed()
	{
		m_picker.reset();

		set_state(torrent_status::seeding);
		if (!m_announcing) return;

		ptime now = time_now();
		for (std::vector<announce_entry>::iterator i = m_trackers.begin()
			, end(m_trackers.end()); i != end; ++i)
		{
			if (i->complete_sent) continue;
			i->next_announce = now;
			i->min_announce = now;
		}
		announce_with_tracker();
	}

	// this will move the tracker with the given index
	// to a prioritized position in the list (move it towards
	// the begining) and return the new index to the tracker.
	int torrent::prioritize_tracker(int index)
	{
		INVARIANT_CHECK;

		TORRENT_ASSERT(index >= 0);
		TORRENT_ASSERT(index < int(m_trackers.size()));
		if (index >= (int)m_trackers.size()) return -1;

		while (index > 0 && m_trackers[index].tier == m_trackers[index-1].tier)
		{
			using std::swap;
			swap(m_trackers[index], m_trackers[index-1]);
			if (m_last_working_tracker == index) --m_last_working_tracker;
			else if (m_last_working_tracker == index - 1) ++m_last_working_tracker;
			--index;
		}
		return index;
	}

	int torrent::deprioritize_tracker(int index)
	{
		INVARIANT_CHECK;

		TORRENT_ASSERT(index >= 0);
		TORRENT_ASSERT(index < int(m_trackers.size()));
		if (index >= (int)m_trackers.size()) return -1;

		while (index < int(m_trackers.size()) - 1 && m_trackers[index].tier == m_trackers[index + 1].tier)
		{
			using std::swap;
			swap(m_trackers[index], m_trackers[index + 1]);
			if (m_last_working_tracker == index) ++m_last_working_tracker;
			else if (m_last_working_tracker == index + 1) --m_last_working_tracker;
			++index;
		}
		return index;
	}

	void torrent::files_checked()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(m_torrent_file->is_valid());

		if (m_abort)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("files_checked(), paused");
#endif
			return;
		}

		// we might be finished already, in which case we should
		// not switch to downloading mode. If all files are
		// filtered, we're finished when we start.
		if (m_state != torrent_status::finished
			&& m_state != torrent_status::seeding)
			set_state(torrent_status::downloading);

		INVARIANT_CHECK;

		if (m_ses.m_alerts.should_post<torrent_checked_alert>())
		{
			m_ses.m_alerts.post_alert(torrent_checked_alert(
				get_handle()));
		}
		
		// calling pause will also trigger the auto managed
		// recalculation
		// if we just got here by downloading the metadata,
		// just keep going, no need to disconnect all peers just
		// to restart the torrent in a second
		if (m_auto_managed)
		{
			// if this is an auto managed torrent, force a recalculation
			// of which torrents to have active
			m_ses.trigger_auto_manage();
		}

		if (!is_seed())
		{
			// turn off super seeding if we're not a seed
			if (m_super_seeding) m_super_seeding = false;

			// if we just finished checking and we're not a seed, we are
			// likely to be unpaused
			m_ses.trigger_auto_manage();

			if (is_finished() && m_state != torrent_status::finished)
				finished();
		}
		else
		{
			for (std::vector<announce_entry>::iterator i = m_trackers.begin()
				, end(m_trackers.end()); i != end; ++i)
				i->complete_sent = true;

			if (m_state != torrent_status::finished
				&& m_state != torrent_status::seeding)
				finished();
		}

#ifndef TORRENT_DISABLE_EXTENSIONS
		for (extension_list_t::iterator i = m_extensions.begin()
			, end(m_extensions.end()); i != end; ++i)
		{
			TORRENT_TRY {
				(*i)->on_files_checked();
			} TORRENT_CATCH (std::exception&) {}
		}
#endif

		m_connections_initialized = true;
		m_files_checked = true;

		for (torrent::peer_iterator i = m_connections.begin();
			i != m_connections.end();)
		{
			peer_connection* pc = *i;
			++i;

			// all peer connections have to initialize themselves now that the metadata
			// is available
			if (!m_connections_initialized)
			{
				if (pc->is_disconnecting()) continue;
				pc->on_metadata_impl();
				if (pc->is_disconnecting()) continue;
				pc->init();
			}

#ifdef TORRENT_VERBOSE_LOGGING
			pc->peer_log("*** ON_FILES_CHECKED");
#endif
			if (pc->is_interesting() && !pc->has_peer_choked())
			{
				request_a_block(*this, *pc);
				pc->send_block_requests();
			}
		}


		start_announcing();

		maybe_connect_web_seeds();
	}

	alert_manager& torrent::alerts() const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		return m_ses.m_alerts;
	}

	std::string torrent::save_path() const
	{
		return m_save_path;
	}

	bool torrent::rename_file(int index, std::string const& name)
	{
		INVARIANT_CHECK;

		TORRENT_ASSERT(index >= 0);
		TORRENT_ASSERT(index < m_torrent_file->num_files());

		if (!m_owning_storage.get()) return false;

		m_owning_storage->async_rename_file(index, name
			, boost::bind(&torrent::on_file_renamed, shared_from_this(), _1, _2));
		return true;
	}

	void torrent::move_storage(std::string const& save_path, int flags)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		if (m_abort)
		{
			if (alerts().should_post<storage_moved_failed_alert>())
				alerts().post_alert(storage_moved_failed_alert(get_handle(), boost::asio::error::operation_aborted));
			return;
		}

		// storage may be NULL during shutdown
		if (m_owning_storage.get())
		{
#if TORRENT_USE_UNC_PATHS
			std::string path = canonicalize_path(save_path);
#else
			std::string const& path = save_path;
#endif
			m_owning_storage->async_move_storage(path, flags
				, boost::bind(&torrent::on_storage_moved, shared_from_this(), _1, _2));
			m_moving_storage = true;
		}
		else
		{
#if TORRENT_USE_UNC_PATHS
			m_save_path = canonicalize_path(save_path);
#else

			m_save_path = save_path;
#endif
			m_need_save_resume_data = true;

			if (alerts().should_post<storage_moved_alert>())
			{
				alerts().post_alert(storage_moved_alert(get_handle(), m_save_path));
			}
		}
	}

	void torrent::on_storage_moved(int ret, disk_io_job const& j)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		m_moving_storage = false;

		if (ret == piece_manager::no_error || ret == piece_manager::need_full_check)
		{
			if (alerts().should_post<storage_moved_alert>())
				alerts().post_alert(storage_moved_alert(get_handle(), j.str));
			m_save_path = j.str;
			m_need_save_resume_data = true;
			if (ret == piece_manager::need_full_check)
				force_recheck();
		}
		else
		{
			if (alerts().should_post<storage_moved_failed_alert>())
				alerts().post_alert(storage_moved_failed_alert(get_handle(), j.error));
		}
	}

	piece_manager& torrent::filesystem()
	{
		TORRENT_ASSERT(m_owning_storage.get());
		TORRENT_ASSERT(m_storage);
		return *m_storage;
	}


	torrent_handle torrent::get_handle()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		return torrent_handle(shared_from_this());
	}

	session_settings const& torrent::settings() const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		return m_ses.settings();
	}

#if TORRENT_USE_INVARIANT_CHECKS
	void torrent::check_invariant() const
	{
		for (std::deque<time_critical_piece>::const_iterator i = m_time_critical_pieces.begin()
			, end(m_time_critical_pieces.end()); i != end; ++i)
		{
			TORRENT_ASSERT(!is_seed());
			TORRENT_ASSERT(!has_picker() || !m_picker->have_piece(i->piece));
		}

		TORRENT_ASSERT(m_ses.is_network_thread());
		if (is_paused()) TORRENT_ASSERT(num_peers() == 0 || m_graceful_pause_mode);

		if (!should_check_files())
			TORRENT_ASSERT(m_state != torrent_status::checking_files);
		else
			TORRENT_ASSERT(m_queued_for_checking);

#ifdef TORRENT_EXPENSIVE_INVARIANT_CHECKS
		if (!m_ses.m_queued_for_checking.empty())
		{
			// if there are torrents waiting to be checked
			// assert that there's a torrent that is being
			// processed right now
			int found = 0;
			int found_active = 0;
			for (aux::session_impl::torrent_map::iterator i = m_ses.m_torrents.begin()
				, end(m_ses.m_torrents.end()); i != end; ++i)
				if (i->second->m_state == torrent_status::checking_files)
				{
					++found;
					if (i->second->should_check_files()) ++found_active;
				}

			// if the session is paused, there might still be some torrents
			// in the checking_files state that haven't been dequeued yet
			if (m_ses.is_paused())
			{
				TORRENT_ASSERT(found_active == 0);
			}
			else
			{
				// the case of 2 is in the special case where one switches over from
				// checking to complete.
				TORRENT_ASSERT(found_active >= 1);
				TORRENT_ASSERT(found_active <= 2);
				TORRENT_ASSERT(found >= 1);
			}
		}
#endif

		TORRENT_ASSERT(m_resume_entry.type() == lazy_entry::dict_t
			|| m_resume_entry.type() == lazy_entry::none_t);

		int num_uploads = 0;
		std::map<piece_block, int> num_requests;
		for (const_peer_iterator i = this->begin(); i != this->end(); ++i)
		{
#ifdef TORRENT_EXPENSIVE_INVARIANT_CHECKS
			// make sure this peer is not a dangling pointer
			TORRENT_ASSERT(m_ses.has_peer(*i));
#endif
			peer_connection const& p = *(*i);
			for (std::vector<pending_block>::const_iterator i = p.request_queue().begin()
				, end(p.request_queue().end()); i != end; ++i)
				++num_requests[i->block];
			for (std::vector<pending_block>::const_iterator i = p.download_queue().begin()
				, end(p.download_queue().end()); i != end; ++i)
				if (!i->not_wanted && !i->timed_out) ++num_requests[i->block];
			if (!p.is_choked() && !p.ignore_unchoke_slots()) ++num_uploads;
			torrent* associated_torrent = p.associated_torrent().lock().get();
			if (associated_torrent != this && associated_torrent != 0)
				TORRENT_ASSERT(false);
		}
		TORRENT_ASSERT(num_uploads == int(m_num_uploads));

		if (has_picker())
		{
			for (std::map<piece_block, int>::iterator i = num_requests.begin()
				, end(num_requests.end()); i != end; ++i)
			{
				piece_block b = i->first;
				int count = i->second;
				int picker_count = m_picker->num_peers(b);
				// if we're no longer downloading the piece
				// (for instance, it may be fully downloaded and waiting
				// for the hash check to return), the piece picker always
				// returns 0 requests, regardless of how many peers may still
				// have the block in their queue
				if (!m_picker->is_downloaded(b) && m_picker->is_downloading(b.piece_index))
					TORRENT_ASSERT(picker_count == count);
			}
			TORRENT_ASSERT(num_have() >= m_picker->num_have_filtered());
		}

		if (valid_metadata())
		{
			TORRENT_ASSERT(m_abort || m_error || !m_picker || m_picker->num_pieces() == m_torrent_file->num_pieces());
		}
		else
		{
			TORRENT_ASSERT(m_abort || m_error || !m_picker || m_picker->num_pieces() == 0);
		}

#ifdef TORRENT_EXPENSIVE_INVARIANT_CHECKS
		// make sure we haven't modified the peer object
		// in a way that breaks the sort order
		if (m_policy.begin_peer() != m_policy.end_peer())
		{
			policy::const_iterator i = m_policy.begin_peer();
			policy::const_iterator prev = i++;
			policy::const_iterator end(m_policy.end_peer());
			policy::peer_address_compare cmp;
			for (; i != end; ++i, ++prev)
			{
				TORRENT_ASSERT(!cmp(*i, *prev));
			}
		}
#endif

		size_type total_done = quantized_bytes_done();
		if (m_torrent_file->is_valid())
		{
			if (is_seed())
				TORRENT_ASSERT(total_done == m_torrent_file->total_size());
			else
				TORRENT_ASSERT(total_done != m_torrent_file->total_size() || !m_files_checked);

			TORRENT_ASSERT(block_size() <= m_torrent_file->piece_length());
		}
		else
		{
			TORRENT_ASSERT(total_done == 0);
		}
/*
		if (m_picker && !m_abort)
		{
			// make sure that pieces that have completed the download
			// of all their blocks are in the disk io thread's queue
			// to be checked.
			const std::vector<piece_picker::downloading_piece>& dl_queue
				= m_picker->get_download_queue();
			for (std::vector<piece_picker::downloading_piece>::const_iterator i =
				dl_queue.begin(); i != dl_queue.end(); ++i)
			{
				const int blocks_per_piece = m_picker->blocks_in_piece(i->index);

				bool complete = true;
				for (int j = 0; j < blocks_per_piece; ++j)
				{
					if (i->info[j].state == piece_picker::block_info::state_finished)
						continue;
					complete = false;
					break;
				}
				TORRENT_ASSERT(complete);
			}
		}
*/			
		if (m_files_checked && valid_metadata())
		{
			TORRENT_ASSERT(block_size() > 0);
		}


		for (std::vector<size_type>::const_iterator i = m_file_progress.begin()
			, end(m_file_progress.end()); i != end; ++i)
		{
			int index = i - m_file_progress.begin();
			TORRENT_ASSERT(*i <= m_torrent_file->files().file_size(index));
		}
	}
#endif

	void torrent::set_sequential_download(bool sd)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (m_sequential_download == sd) return;
		m_sequential_download = sd;

		m_need_save_resume_data = true;

		state_updated();
	}

	void torrent::queue_up()
	{
		set_queue_position(queue_position() == 0
			? queue_position() : queue_position() - 1);
	}

	void torrent::queue_down()
	{
		set_queue_position(queue_position() + 1);
	}

	void torrent::set_queue_position(int p)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT((p == -1) == is_finished()
			|| (!m_auto_managed && p == -1)
			|| (m_abort && p == -1));
		if (is_finished() && p != -1) return;
		if (p == m_sequence_number) return;

		state_updated();

		session_impl::torrent_map& torrents = m_ses.m_torrents;
		if (p >= 0 && m_sequence_number == -1)
		{
			int max_seq = -1;
			for (session_impl::torrent_map::iterator i = torrents.begin()
				, end(torrents.end()); i != end; ++i)
			{
				torrent* t = i->second.get();
				if (t->m_sequence_number > max_seq) max_seq = t->m_sequence_number;
				if (t->m_sequence_number >= p)
				{
					++t->m_sequence_number;
					t->state_updated();
				}
			}
			m_sequence_number = (std::min)(max_seq + 1, p);
		}
		else if (p < 0)
		{
			for (session_impl::torrent_map::iterator i = torrents.begin()
				, end(torrents.end()); i != end; ++i)
			{
				torrent* t = i->second.get();
				if (t == this) continue;
				if (t->m_sequence_number >= m_sequence_number
					&& t->m_sequence_number != -1)
				{
					--t->m_sequence_number;
					t->state_updated();
				}
			}
			m_sequence_number = p;
		}
		else if (p < m_sequence_number)
		{
			for (session_impl::torrent_map::iterator i = torrents.begin()
				, end(torrents.end()); i != end; ++i)
			{
				torrent* t = i->second.get();
				if (t == this) continue;
				if (t->m_sequence_number >= p 
					&& t->m_sequence_number < m_sequence_number
					&& t->m_sequence_number != -1)
				{
					++t->m_sequence_number;
					t->state_updated();
				}
			}
			m_sequence_number = p;
		}
		else if (p > m_sequence_number)
		{
			int max_seq = 0;
			for (session_impl::torrent_map::iterator i = torrents.begin()
				, end(torrents.end()); i != end; ++i)
			{
				torrent* t = i->second.get();
				int pos = t->m_sequence_number;
				if (pos > max_seq) max_seq = pos;
				if (t == this) continue;

				if (pos <= p
						&& pos > m_sequence_number
						&& pos != -1)
				{
					--t->m_sequence_number;
					t->state_updated();
				}

			}
			m_sequence_number = (std::min)(max_seq, p);
		}

		m_ses.m_auto_manage_time_scaler = 2;
	}

	void torrent::set_max_uploads(int limit, bool state_update)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(limit >= -1);
		if (limit <= 0) limit = (1<<24)-1;
		if (m_max_uploads != limit && state_update) state_updated();
		m_max_uploads = limit;

		m_need_save_resume_data = true;
	}

	void torrent::set_max_connections(int limit, bool state_update)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(limit >= -1);
		if (limit <= 0) limit = (1<<24)-1;
		if (m_max_connections != limit && state_update) state_updated();
		m_max_connections = limit;

		if (num_peers() > int(m_max_connections))
		{
			disconnect_peers(num_peers() - m_max_connections
				, error_code(errors::too_many_connections, get_libtorrent_category()));
		}

		m_need_save_resume_data = true;
	}

	int torrent::get_peer_upload_limit(tcp::endpoint ip) const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		const_peer_iterator i = std::find_if(m_connections.begin(), m_connections.end()
			, boost::bind(&peer_connection::remote, _1) == ip);
		if (i == m_connections.end()) return -1;
		return (*i)->get_upload_limit();
	}

	int torrent::get_peer_download_limit(tcp::endpoint ip) const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		const_peer_iterator i = std::find_if(m_connections.begin(), m_connections.end()
			, boost::bind(&peer_connection::remote, _1) == ip);
		if (i == m_connections.end()) return -1;
		return (*i)->get_download_limit();
	}

	void torrent::set_peer_upload_limit(tcp::endpoint ip, int limit)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(limit >= -1);
		peer_iterator i = std::find_if(m_connections.begin(), m_connections.end()
			, boost::bind(&peer_connection::remote, _1) == ip);
		if (i == m_connections.end()) return;
		(*i)->set_upload_limit(limit);
	}

	void torrent::set_peer_download_limit(tcp::endpoint ip, int limit)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(limit >= -1);
		peer_iterator i = std::find_if(m_connections.begin(), m_connections.end()
			, boost::bind(&peer_connection::remote, _1) == ip);
		if (i == m_connections.end()) return;
		(*i)->set_download_limit(limit);
	}

	void torrent::set_upload_limit(int limit, bool state_update)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(limit >= -1);
		if (limit <= 0) limit = 0;
		if (m_bandwidth_channel[peer_connection::upload_channel].throttle() != limit
			&& state_update)
			state_updated();
		m_bandwidth_channel[peer_connection::upload_channel].throttle(limit);

		m_need_save_resume_data = true;
	}

	int torrent::upload_limit() const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		int limit = m_bandwidth_channel[peer_connection::upload_channel].throttle();
		if (limit == (std::numeric_limits<int>::max)()) limit = -1;
		return limit;
	}

	void torrent::set_download_limit(int limit, bool state_update)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(limit >= -1);
		if (limit <= 0) limit = 0;
		if (m_bandwidth_channel[peer_connection::download_channel].throttle() != limit
			&& state_update)
			state_updated();
		m_bandwidth_channel[peer_connection::download_channel].throttle(limit);

		m_need_save_resume_data = true;
	}

	int torrent::download_limit() const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		int limit = m_bandwidth_channel[peer_connection::download_channel].throttle();
		if (limit == (std::numeric_limits<int>::max)()) limit = -1;
		return limit;
	}

	bool torrent::delete_files()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING || defined TORRENT_LOGGING
		log_to_all_peers("DELETING FILES IN TORRENT");
#endif

		disconnect_all(errors::torrent_removed);
		stop_announcing();

		// storage may be NULL during shutdown
		if (m_owning_storage.get())
		{
			TORRENT_ASSERT(m_storage);
			m_storage->async_delete_files(
				boost::bind(&torrent::on_files_deleted, shared_from_this(), _1, _2));
			m_deleted = true;
			return true;
		}
		return false;
	}

	void torrent::clear_error()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (!m_error) return;
		bool checking_files = should_check_files();
		m_ses.trigger_auto_manage();
		m_error = error_code();
		m_error_file.clear();

		state_updated();

		// if we haven't downloaded the metadata from m_url, try again
		if (!m_url.empty() && !m_torrent_file->is_valid())
		{
			start_download_url();
			return;
		}
		// if the error happened during initialization, try again now
		if (!m_storage) init();
		if (!checking_files && should_check_files())
			queue_torrent_check();
	}

	void torrent::set_error(error_code const& ec, std::string const& error_file)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		bool checking_files = should_check_files();
		m_error = ec;
		m_error_file = error_file;

		if (alerts().should_post<torrent_error_alert>())
			alerts().post_alert(torrent_error_alert(get_handle(), ec));

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING || defined TORRENT_LOGGING
		if (ec)
		{
			char buf[1024];
			snprintf(buf, sizeof(buf), "TORRENT ERROR: %s: %s", ec.message().c_str(), error_file.c_str());
			log_to_all_peers(buf);
		}
#endif

		if (checking_files && !should_check_files())
		{
			// stop checking
			m_storage->abort_disk_io();
			dequeue_torrent_check();
			set_state(torrent_status::queued_for_checking);
		}

		state_updated();
	}

	void torrent::auto_managed(bool a)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		if (m_auto_managed == a) return;
		bool checking_files = should_check_files();
		m_auto_managed = a;

		state_updated();

		// we need to save this new state as well
		m_need_save_resume_data = true;

		// recalculate which torrents should be
		// paused
		m_ses.trigger_auto_manage();

		if (!checking_files && should_check_files())
		{
			queue_torrent_check();
		}
		else if (checking_files && !should_check_files())
		{
			// stop checking
			m_storage->abort_disk_io();
			dequeue_torrent_check();
			set_state(torrent_status::queued_for_checking);
		}

		// if this torrent is running and just became auto-managed
		// we might want to pause it in favor of some other torrent
		if (m_auto_managed && !is_paused())
			m_ses.m_auto_manage_time_scaler = 2;
	}

	// the higher seed rank, the more important to seed
	int torrent::seed_rank(session_settings const& s) const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		enum flags
		{
			seed_ratio_not_met = 0x40000000,
			no_seeds = 0x20000000,
			recently_started = 0x10000000,
			prio_mask = 0x0fffffff
		};

		if (!is_finished()) return 0;

		int scale = 1000;
		if (!is_seed()) scale = 500;

		int ret = 0;

		ptime now = time_now();

		int finished_time = m_finished_time;
		int download_time = int(m_active_time) - finished_time;

		// if we haven't yet met the seed limits, set the seed_ratio_not_met
		// flag. That will make this seed prioritized
		// downloaded may be 0 if the torrent is 0-sized
		size_type downloaded = (std::max)(m_total_downloaded, m_torrent_file->total_size());
		if (finished_time < s.seed_time_limit
			&& (download_time > 1 && finished_time / download_time < s.seed_time_ratio_limit)
			&& downloaded > 0
			&& m_total_uploaded / downloaded < s.share_ratio_limit)
			ret |= seed_ratio_not_met;

		// if this torrent is running, and it was started less
		// than 30 minutes ago, give it priority, to avoid oscillation
		if (!is_paused() && now - m_started < minutes(30))
			ret |= recently_started;

		// if we have any scrape data, use it to calculate
		// seed rank
		int seeds = 0;
		int downloaders = 0;

		if (m_complete != 0xffffff) seeds = m_complete;
		else seeds = m_policy.num_seeds();

		if (m_incomplete != 0xffffff) downloaders = m_incomplete;
		else downloaders = m_policy.num_peers() - m_policy.num_seeds();

		if (seeds == 0)
		{
			ret |= no_seeds;
			ret |= downloaders & prio_mask;
		}
		else
		{
			ret |= ((1 + downloaders) * scale / seeds) & prio_mask;
		}

		return ret;
	}

	// this is an async operation triggered by the client	
	void torrent::save_resume_data(int flags)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;
	
		if (!valid_metadata())
		{
			alerts().post_alert(save_resume_data_failed_alert(get_handle()
				, errors::no_metadata));
			return;
		}

		if (!m_owning_storage.get())
		{
			alerts().post_alert(save_resume_data_failed_alert(get_handle()
				, errors::destructing_torrent));
			return;
		}

		m_need_save_resume_data = false;
		m_last_saved_resume = time(0);
		m_save_resume_flags = boost::uint8_t(flags);
		state_updated();

		TORRENT_ASSERT(m_storage);
		if (m_state == torrent_status::queued_for_checking
			|| m_state == torrent_status::checking_files
			|| m_state == torrent_status::checking_resume_data)
		{
			boost::shared_ptr<entry> rd(new entry);
			write_resume_data(*rd);
			alerts().post_alert(save_resume_data_alert(rd
				, get_handle()));
			return;
		}

		// storage may be NULL during shutdown
		if ((flags & torrent_handle::flush_disk_cache) && m_storage)
			m_storage->async_release_files();

		m_storage->async_save_resume_data(
			boost::bind(&torrent::on_save_resume_data, shared_from_this(), _1, _2));
	}
	
	bool torrent::should_check_files() const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		// #error should m_allow_peers really affect checking?
		return (m_state == torrent_status::checking_files
			|| m_state == torrent_status::queued_for_checking)
			&& (m_allow_peers || m_auto_managed)
			&& !has_error()
			&& !m_abort
			&& !m_graceful_pause_mode
			&& !m_ses.is_paused();
	}

	void torrent::flush_cache()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		// storage may be NULL during shutdown
		if (!m_owning_storage)
		{
			TORRENT_ASSERT(m_abort);
			return;
		}
		m_storage->async_release_files(
			boost::bind(&torrent::on_cache_flushed, shared_from_this(), _1, _2));
	}

	void torrent::on_cache_flushed(int /* ret */, disk_io_job const& j)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		if (m_ses.is_aborted()) return;

		if (alerts().should_post<cache_flushed_alert>())
			alerts().post_alert(cache_flushed_alert(get_handle()));
	}

	bool torrent::is_paused() const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		return !m_allow_peers || m_ses.is_paused() || m_graceful_pause_mode;
	}

	void torrent::pause(bool graceful)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		if (!m_allow_peers) return;
		if (!graceful) set_allow_peers(false);
		m_announce_to_dht = false;
		m_announce_to_trackers = false;
		m_announce_to_lsd = false;

		// we need to save this new state
		m_need_save_resume_data = true;
		state_updated();

		bool prev_graceful = m_graceful_pause_mode;
		m_graceful_pause_mode = graceful;

		if (!m_ses.is_paused() || (prev_graceful && !m_graceful_pause_mode))
		{
			do_pause();
			// if this torrent was just paused
			// we might have to resume some other auto-managed torrent
			m_ses.trigger_auto_manage();
		}
	}

	void torrent::do_pause()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (!is_paused()) return;

#ifndef TORRENT_DISABLE_EXTENSIONS
		for (extension_list_t::iterator i = m_extensions.begin()
			, end(m_extensions.end()); i != end; ++i)
		{
			TORRENT_TRY {
				if ((*i)->on_pause()) return;
			} TORRENT_CATCH (std::exception&) {}
		}
#endif

		m_inactive = false;

		state_updated();

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING || defined TORRENT_LOGGING
		log_to_all_peers("PAUSING TORRENT");
#endif

		// this will make the storage close all
		// files and flush all cached data
		if (m_owning_storage.get())
		{
			TORRENT_ASSERT(m_storage);
			m_storage->async_release_files(
				boost::bind(&torrent::on_torrent_paused, shared_from_this(), _1, _2));
			m_storage->async_clear_read_cache();
		}
		else
		{
			if (alerts().should_post<torrent_paused_alert>())
				alerts().post_alert(torrent_paused_alert(get_handle()));
		}

		if (!m_graceful_pause_mode)
		{
			disconnect_all(errors::torrent_paused);
		}
		else
		{
			// disconnect all peers with no outstanding data to receive
			// and choke all remaining peers to prevent responding to new
			// requests
			for (std::set<peer_connection*>::iterator i = m_connections.begin()
				, end(m_connections.end()); i != end;)
			{
				std::set<peer_connection*>::iterator j = i++;
				peer_connection* p = *j;
				TORRENT_ASSERT(p->associated_torrent().lock().get() == this);

				if (p->is_disconnecting())
				{
					m_connections.erase(j);
					continue;
				}

				if (p->outstanding_bytes() > 0)
				{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
					p->peer_log("*** CHOKING PEER: torrent graceful paused");
#endif
					// remove any un-sent requests from the queue
					p->clear_request_queue();
					// don't accept new requests from the peer
					if (!p->is_choked()) m_ses.choke_peer(*p);
					continue;
				}

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
				p->peer_log("*** CLOSING CONNECTION: torrent_paused");
#endif
				p->disconnect(errors::torrent_paused);
			}
		}

		stop_announcing();

		if (m_queued_for_checking && !should_check_files())
		{
			// stop checking
			m_storage->abort_disk_io();
			dequeue_torrent_check();
			set_state(torrent_status::queued_for_checking);
			TORRENT_ASSERT(!m_queued_for_checking);
		}
	}

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING || defined TORRENT_LOGGING
	void torrent::log_to_all_peers(char const* message)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
		for (peer_iterator i = m_connections.begin();
				i != m_connections.end(); ++i)
		{
			(*i)->peer_log("*** %s", message);
		}
#endif

		debug_log("%s", message);
	}
#endif

	// add or remove a url that will be attempted for
	// finding the file(s) in this torrent.
	void torrent::add_web_seed(std::string const& url, web_seed_entry::type_t type)
	{
		web_seed_entry ent(url, type);
		// don't add duplicates
		if (std::find(m_web_seeds.begin(), m_web_seeds.end(), ent) != m_web_seeds.end()) return;
		m_web_seeds.push_back(ent);
	}

	void torrent::add_web_seed(std::string const& url, web_seed_entry::type_t type
		, std::string const& auth, web_seed_entry::headers_t const& extra_headers)
	{
		web_seed_entry ent(url, type, auth, extra_headers);
		// don't add duplicates
		if (std::find(m_web_seeds.begin(), m_web_seeds.end(), ent) != m_web_seeds.end()) return;
		m_web_seeds.push_back(ent);
	}
	
	void torrent::set_allow_peers(bool b, bool graceful)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		if (m_allow_peers == b
			&& m_graceful_pause_mode == graceful) return;

		m_allow_peers = b;
		if (!m_ses.is_paused())
			m_graceful_pause_mode = graceful;

		if (!b)
		{
			m_announce_to_dht = false;
			m_announce_to_trackers = false;
			m_announce_to_lsd = false;
			do_pause();
		}
		else
		{
			do_resume();
		}

		update_guage();
	}

	void torrent::resume()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		if (m_allow_peers
			&& m_announce_to_dht
			&& m_announce_to_trackers
			&& m_announce_to_lsd) return;
		m_announce_to_dht = true;
		m_announce_to_trackers = true;
		m_announce_to_lsd = true;
		// this call will trigger a tracker announce, that's
		// why it's important to set announce_to_trackers to
		// true first
		set_allow_peers(true);
		if (!m_ses.is_paused()) m_graceful_pause_mode = false;

		// we need to save this new state
		m_need_save_resume_data = true;

		do_resume();
	}

	void torrent::do_resume()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (is_paused()) return;

#ifndef TORRENT_DISABLE_EXTENSIONS
		for (extension_list_t::iterator i = m_extensions.begin()
			, end(m_extensions.end()); i != end; ++i)
		{
			TORRENT_TRY {
				if ((*i)->on_resume()) return;
			} TORRENT_CATCH (std::exception&) {}
		}
#endif

		if (alerts().should_post<torrent_resumed_alert>())
			alerts().post_alert(torrent_resumed_alert(get_handle()));

		state_updated();

		m_started = time_now();
		clear_error();
		start_announcing();
		if (!m_queued_for_checking && should_check_files())
			queue_torrent_check();
	}

	void torrent::update_tracker_timer(ptime now)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (!m_announcing)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
			debug_log("*** update tracker timer: not announcing");
#endif
			return;
		}

		ptime next_announce = max_time();
		int tier = INT_MAX;

		bool found_working = false;

		for (std::vector<announce_entry>::iterator i = m_trackers.begin()
			, end(m_trackers.end()); i != end; ++i)
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			char msg[1000];
			snprintf(msg, sizeof(msg), "*** update tracker timer: considering \"%s\" "
				"[ announce_to_all_tiers: %d announce_to_all_trackers: %d"
				" found_working: %d i->tier: %d tier: %d "
				" is_working: %d fails: %d fail_limit: %d updating: %d ]"
				, i->url.c_str(), settings().announce_to_all_tiers
				, settings().announce_to_all_trackers, found_working
				, i->tier, tier, i->is_working(), i->fails, i->fail_limit
				, i->updating);
			debug_log(msg);
#endif
			if (settings().announce_to_all_tiers
				&& found_working
				&& i->tier <= tier
				&& tier != INT_MAX)
				continue;

			if (i->tier > tier && !settings().announce_to_all_tiers) break;
			if (i->is_working()) { tier = i->tier; found_working = false; }
			if (i->fails >= i->fail_limit && i->fail_limit != 0) continue;
			if (i->updating)
			{
				found_working = true;
			}
			else
			{
				ptime next_tracker_announce = (std::max)(i->next_announce, i->min_announce);
				if (next_tracker_announce < next_announce
					&& (!found_working || i->is_working()))
					next_announce = next_tracker_announce;
			}
			if (i->is_working()) found_working = true;
			if (found_working
				&& !settings().announce_to_all_trackers
				&& !settings().announce_to_all_tiers) break;
		}

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
		char msg[200];
		snprintf(msg, sizeof(msg), "*** update tracker timer: next_announce < now %d"
			" m_waiting_tracker: %d next_announce_in: %d"
			, next_announce <= now, m_waiting_tracker, total_seconds(now - next_announce));
		debug_log(msg);
#endif
		if (next_announce <= now) next_announce = now;

		// don't re-issue the timer if it's the same expiration time as last time
		// if m_waiting_tracker is false, expires_at() is undefined
		if (m_waiting_tracker && m_tracker_timer.expires_at() == next_announce) return;

		m_waiting_tracker = true;
		error_code ec;
		boost::weak_ptr<torrent> self(shared_from_this());

#if defined TORRENT_ASIO_DEBUGGING
		add_outstanding_async("tracker::on_tracker_announce_disp");
#endif
		m_tracker_timer.expires_at(next_announce, ec);
		m_tracker_timer.async_wait(boost::bind(&torrent::on_tracker_announce_disp, self, _1));
	}

	void torrent::start_announcing()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (is_paused())
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("start_announcing(), paused");
#endif
			return;
		}
		// if we don't have metadata, we need to announce
		// before checking files, to get peers to
		// request the metadata from
		if (!m_files_checked && valid_metadata())
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("start_announcing(), files not checked (with valid metadata)");
#endif
			return;
		}
		if (!m_torrent_file->is_valid() && !m_url.empty())
		{
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
			debug_log("start_announcing(), downloading URL");
#endif
			return;
		}
		if (m_announcing) return;

		m_announcing = true;

#ifndef TORRENT_DISABLE_DHT
		if (m_policy.num_peers() < 50 && m_ses.m_dht)
		{
			// we don't have any peers, prioritize
			// announcing this torrent with the DHT
			m_ses.prioritize_dht(shared_from_this());
		}
#endif

		if (!m_trackers.empty())
		{
			// tell the tracker that we're back
			std::for_each(m_trackers.begin(), m_trackers.end()
				, boost::bind(&announce_entry::reset, _1));
		}

		// reset the stats, since from the tracker's
		// point of view, this is a new session
		m_total_failed_bytes = 0;
		m_total_redundant_bytes = 0;
		m_stat.clear();

		announce_with_tracker();

		// private torrents are never announced on LSD
		// or on DHT, we don't need this timer.
		if (!m_torrent_file->is_valid()
			|| (!m_torrent_file->priv()
				&& (!m_torrent_file->is_i2p()
					|| settings().allow_i2p_mixed)))
		{
			if (m_ses.m_lsd) lsd_announce();
		}
	}

	void torrent::stop_announcing()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (!m_announcing) return;

		error_code ec;
		m_tracker_timer.cancel(ec);

		m_announcing = false;

		ptime now = time_now();
		for (std::vector<announce_entry>::iterator i = m_trackers.begin()
			, end(m_trackers.end()); i != end; ++i)
		{
			i->next_announce = now;
			i->min_announce = now;
		}
		announce_with_tracker(tracker_request::stopped);
	}

	void torrent::second_tick(stat& accumulator, int tick_interval_ms)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		boost::weak_ptr<torrent> self(shared_from_this());

#ifndef TORRENT_DISABLE_EXTENSIONS
		for (extension_list_t::iterator i = m_extensions.begin()
			, end(m_extensions.end()); i != end; ++i)
		{
			TORRENT_TRY {
				(*i)->tick();
			} TORRENT_CATCH (std::exception&) {}
		}

		if (m_abort) return;
#endif

		m_time_scaler--;
		if (m_time_scaler <= 0)
		{
			m_time_scaler = 10;

			if (settings().max_sparse_regions > 0
				&& m_picker
				&& m_picker->sparse_regions() > settings().max_sparse_regions)
			{
				// we have too many sparse regions. Prioritize pieces
				// that won't introduce new sparse regions
				// prioritize pieces that will reduce the number of sparse
				// regions even higher
				int start = m_picker->cursor();
				int end = m_picker->reverse_cursor();
				for (int i = start; i < end; ++i)
					update_sparse_piece_prio(i, start, end);
			}
		}

		// if we're in upload only mode and we're auto-managed
		// leave upload mode every 10 minutes hoping that the error
		// condition has been fixed
		if (m_upload_mode && m_auto_managed && int(m_upload_mode_time)
			>= settings().optimistic_disk_retry)
		{
			set_upload_mode(false);
		}

		if (is_paused() && !m_graceful_pause_mode)
		{
			// let the stats fade out to 0
			accumulator += m_stat;
 			m_stat.second_tick(tick_interval_ms);
			// if the rate is 0, there's no update because of network transfers
			if (m_stat.low_pass_upload_rate() > 0 || m_stat.low_pass_download_rate() > 0)
				state_updated();
			return;
		}

		if (settings().rate_limit_ip_overhead)
		{
			int up_limit = m_bandwidth_channel[peer_connection::upload_channel].throttle();
			int down_limit = m_bandwidth_channel[peer_connection::download_channel].throttle();

			if (down_limit > 0
				&& m_stat.download_ip_overhead() >= down_limit
				&& alerts().should_post<performance_alert>())
			{
				alerts().post_alert(performance_alert(get_handle()
					, performance_alert::download_limit_too_low));
			}

			if (up_limit > 0
				&& m_stat.upload_ip_overhead() >= up_limit
				&& alerts().should_post<performance_alert>())
			{
				alerts().post_alert(performance_alert(get_handle()
					, performance_alert::upload_limit_too_low));
			}
		}

		int seconds_since_last_tick = 1;
		if (m_ses.m_tick_residual >= 1000) ++seconds_since_last_tick;

		if (is_seed()) m_seeding_time += seconds_since_last_tick;
		if (is_finished()) m_finished_time += seconds_since_last_tick;
		if (m_upload_mode) m_upload_mode_time += seconds_since_last_tick;
		m_last_scrape += seconds_since_last_tick;
		m_active_time += seconds_since_last_tick;
		m_last_download += seconds_since_last_tick;
		m_last_upload += seconds_since_last_tick;

		// ---- TIME CRITICAL PIECES ----

#if TORRENT_DEBUG_STREAMING > 0
		std::vector<partial_piece_info> queue;
		get_download_queue(&queue);

		std::vector<peer_info> peer_list;
		get_peer_info(peer_list);

		std::sort(queue.begin(), queue.end(), boost::bind(&partial_piece_info::piece_index, _1)
			< boost::bind(&partial_piece_info::piece_index, _2));

		printf("average piece download time: %.2f s (+/- %.2f s)\n"
			, m_average_piece_time / 1000.f
			, m_piece_time_deviation / 1000.f);
		for (std::vector<partial_piece_info>::iterator i = queue.begin()
			, end(queue.end()); i != end; ++i)
		{
			extern void print_piece(libtorrent::partial_piece_info* pp
				, std::vector<libtorrent::peer_info> const& peers
				, std::vector<time_critical_piece> const& time_critical);

			print_piece(&*i, peer_list, m_time_critical_pieces);
		}
#endif // TORRENT_DEBUG_STREAMING

		if (!m_time_critical_pieces.empty() && !upload_mode())
		{
			request_time_critical_pieces();
		}

		// ---- WEB SEEDS ----

		maybe_connect_web_seeds();
		
		m_swarm_last_seen_complete = m_last_seen_complete;
		for (peer_iterator i = m_connections.begin();
			i != m_connections.end();)
		{
			peer_connection* p = *i;
			++i;

			// look for the peer that saw a seed most recently
			m_swarm_last_seen_complete = (std::max)(p->last_seen_complete(), m_swarm_last_seen_complete);

			if (!p->ignore_stats())
				m_stat += p->statistics();

			// updates the peer connection's ul/dl bandwidth
			// resource requests
			TORRENT_TRY {
				p->second_tick(tick_interval_ms);
			}
			TORRENT_CATCH (std::exception& e)
			{
				TORRENT_DECLARE_DUMMY(std::exception, e);
				(void)e;
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
				p->peer_log("*** ERROR %s", e.what());
#endif
				p->disconnect(errors::no_error, 1);
			}
		}
		if (m_ses.m_alerts.should_post<stats_alert>())
			m_ses.m_alerts.post_alert(stats_alert(get_handle(), tick_interval_ms, m_stat));

		accumulator += m_stat;
		m_total_uploaded += m_stat.last_payload_uploaded();
		m_total_downloaded += m_stat.last_payload_downloaded();
		m_stat.second_tick(tick_interval_ms);

		// if the rate is 0, there's no update because of network transfers
		if (m_stat.low_pass_upload_rate() > 0 || m_stat.low_pass_download_rate() > 0)
			state_updated();

		// this section determines whether the torrent is active or not. When it
		// changes state, it may also trigger the auto-manage logic to reconsider
		// which torrents should be queued and started. There is a low pass
		// filter in order to avoid flapping (auto_manage_startup).
		bool is_inactive = false;
		if (is_finished())
			is_inactive = m_stat.upload_payload_rate() < m_ses.m_settings.inactive_up_rate;
		else
			is_inactive = m_stat.download_payload_rate() < m_ses.m_settings.inactive_down_rate;

		if (is_inactive)
		{
			if (m_inactive_counter < 0) m_inactive_counter = 0;
			if (m_inactive_counter < INT16_MAX)
			{
				++m_inactive_counter;

				// if this torrent was just considered inactive, we may want 
				// to dequeue some other torrent
				if (m_inactive == false
					&& m_inactive_counter >= m_ses.m_settings.auto_manage_startup)
				{
					m_inactive = true;
					if (m_ses.m_settings.dont_count_slow_torrents)
						m_ses.trigger_auto_manage();
				}
			}
		}
		else
		{
			if (m_inactive_counter > 0) m_inactive_counter = 0;
			if (m_inactive_counter > INT16_MIN)
			{
				--m_inactive_counter;

				// if this torrent was just considered active, we may want 
				// to queue some other torrent
				if (m_inactive == true
					&& m_inactive_counter <= -m_ses.m_settings.auto_manage_startup)
				{
					m_inactive = false;
					if (m_ses.m_settings.dont_count_slow_torrents)
						m_ses.trigger_auto_manage();
				}
			}
		}
	}

	void torrent::maybe_connect_web_seeds()
	{
		if (m_abort) return;

		// if we have everything we want we don't need to connect to any web-seed
		if (!is_finished() && !m_web_seeds.empty() && m_files_checked
			&& int(m_connections.size()) < m_max_connections
			&& m_ses.num_connections() < m_ses.settings().connections_limit)
		{
			// keep trying web-seeds if there are any
			// first find out which web seeds we are connected to
			for (std::list<web_seed_entry>::iterator i = m_web_seeds.begin();
				i != m_web_seeds.end();)
			{
				std::list<web_seed_entry>::iterator w = i++;
				if (w->peer_info.connection) continue;
				if (w->retry > time_now()) continue;
				if (w->resolving) continue;

				connect_to_url_seed(w);
			}
		}
	}

	void torrent::recalc_share_mode()
	{
		TORRENT_ASSERT(share_mode());
		if (is_seed()) return;

		int pieces_in_torrent = m_torrent_file->num_pieces();
		int num_seeds = 0;
		int num_peers = 0;
		int num_downloaders = 0;
		int missing_pieces = 0;
		int num_interested = 0;
		for (std::set<peer_connection*>::iterator i = m_connections.begin()
			, end(m_connections.end()); i != end; ++i)
		{
			peer_connection* p = *i;
			if (p->is_connecting()) continue;
			++num_peers;
			if (p->is_seed())
			{
				++num_seeds;
				continue;
			}

			if (p->share_mode()) continue;

			if ((*i)->is_peer_interested()) ++num_interested;
			++num_downloaders;
			missing_pieces += pieces_in_torrent - p->num_have_pieces();
		}

		if (num_peers == 0) return;

		if (num_seeds * 100 / num_peers > 50
			&& (num_peers * 100 / m_max_connections > 90
				|| num_peers > 20))
		{
			// we are connected to more than 90% seeds (and we're beyond
			// 90% of the max number of connections). That will
			// limit our ability to upload. We need more downloaders.
			// disconnect some seeds so that we don't have more than 50%
			int to_disconnect = num_seeds - num_peers / 2;
			std::vector<peer_connection*> seeds;
			seeds.reserve(num_seeds);
			for (std::set<peer_connection*>::iterator i = m_connections.begin()
				, end(m_connections.end()); i != end; ++i)
			{
				peer_connection* p = *i;
				if (p->is_seed()) seeds.push_back(p);
			}

			std::random_shuffle(seeds.begin(), seeds.end());
			TORRENT_ASSERT(to_disconnect <= int(seeds.size()));
			for (int i = 0; i < to_disconnect; ++i)
				seeds[i]->disconnect(errors::upload_upload_connection);
		}

		if (num_downloaders == 0) return;

		// assume that the seeds are about as fast as us. During the time
		// we can download one piece, and upload one piece, each seed
		// can upload two pieces.
		missing_pieces -= 2 * num_seeds;

		if (missing_pieces <= 0) return;
		
		// missing_pieces represents our opportunity to download pieces
		// and share them more than once each

		// now, download at least one piece, otherwise download one more
		// piece if our downloaded (and downloading) pieces is less than 50%
		// of the uploaded bytes
		int num_downloaded_pieces = (std::max)(m_picker->num_have()
			, pieces_in_torrent - m_picker->num_filtered());

		if (num_downloaded_pieces * m_torrent_file->piece_length()
			* settings().share_mode_target > m_total_uploaded
			&& num_downloaded_pieces > 0)
			return;

		// don't have more pieces downloading in parallel than 5% of the total
		// number of pieces we have downloaded
		if (int(m_picker->get_download_queue().size()) > num_downloaded_pieces / 20)
			return;

		// one more important property is that there are enough pieces
		// that more than one peer wants to download
		// make sure that there are enough downloaders for the rarest
		// piece. Go through all pieces, figure out which one is the rarest
		// and how many peers that has that piece

		std::vector<int> rarest_pieces;

		int num_pieces = m_torrent_file->num_pieces();
		int rarest_rarity = INT_MAX;
		bool prio_updated = false;
		for (int i = 0; i < num_pieces; ++i)
		{
			piece_picker::piece_pos const& pp = m_picker->piece_stats(i);
			if (pp.peer_count == 0) continue;
			if (pp.filtered() && (pp.have() || pp.downloading))
			{
				m_picker->set_piece_priority(i, 1);
				prio_updated = true;
				continue;
			}
			// don't count pieces we already have or are downloading
			if (!pp.filtered() || pp.have()) continue;
			if (int(pp.peer_count) > rarest_rarity) continue;
			if (int(pp.peer_count) == rarest_rarity)
			{
				rarest_pieces.push_back(i);
				continue;
			}

			rarest_pieces.clear();
			rarest_rarity = pp.peer_count;
			rarest_pieces.push_back(i);
		}

		if (prio_updated)
			m_policy.recalculate_connect_candidates();

		// now, rarest_pieces is a list of all pieces that are the rarest ones.
		// and rarest_rarity is the number of peers that have the rarest pieces

		// if there's only a single peer that doesn't have the rarest piece
		// it's impossible for us to download one piece and upload it
		// twice. i.e. we cannot get a positive share ratio
		if (num_peers - rarest_rarity < settings().share_mode_target) return;

		// we might be able to do better than a share ratio of 2 if there are
		// enough downloaders of the pieces we already have.
		// TODO: go through the pieces we have and count the total number
		// of downloaders we have. Only count peers that are interested in us
		// since some peers might not send have messages for pieces we have
		// it num_interested == 0, we need to pick a new piece

		// now, pick one of the rarest pieces to download
		int pick = random() % rarest_pieces.size();
		bool was_finished = is_finished();
		m_picker->set_piece_priority(rarest_pieces[pick], 1);
		update_peer_interest(was_finished);

		m_policy.recalculate_connect_candidates();
	}

	void torrent::refresh_explicit_cache(int cache_size)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (!ready_for_connections()) return;

		if (m_abort) return;
		TORRENT_ASSERT(m_storage);

		// rotate the cached pieces

		// add blocks_per_piece / 2 in order to round to closest whole piece
		int blocks_per_piece = m_torrent_file->piece_length() / block_size();
		int num_cache_pieces = (cache_size + blocks_per_piece / 2) / blocks_per_piece;
		if (num_cache_pieces > m_torrent_file->num_pieces())
			num_cache_pieces = m_torrent_file->num_pieces();

		std::vector<int> avail_vec;
		if (has_picker())
		{
			m_picker->get_availability(avail_vec);
		}
		else
		{
			// we don't keep track of availability, do it the expensive way
			// do a linear search from the first piece
			for (int i = 0; i < m_torrent_file->num_pieces(); ++i)
			{
				int availability = 0;
				if (!have_piece(i))
				{
					avail_vec.push_back(INT_MAX);
					continue;
				}

				for (const_peer_iterator j = this->begin(); j != this->end(); ++j)
					if ((*j)->has_piece(i)) ++availability;
				avail_vec.push_back(availability);
			}
		}

		// now pick the num_cache_pieces rarest pieces from avail_vec
		std::vector<std::pair<int, int> > pieces(m_torrent_file->num_pieces());
		for (int i = 0; i < m_torrent_file->num_pieces(); ++i)
		{
			pieces[i].second = i;
			if (!have_piece(i)) pieces[i].first = INT_MAX;
			else pieces[i].first = avail_vec[i];
		}

		// decrease the availability of the pieces that are
		// already in the read cache, to move them closer to
		// the beginning of the pieces list, and more likely
		// to be included in this round of cache pieces
		std::vector<cached_piece_info> ret;
		m_ses.m_disk_thread.get_cache_info(info_hash(), ret);
		// remove write cache entries
		ret.erase(std::remove_if(ret.begin(), ret.end()
			, boost::bind(&cached_piece_info::kind, _1) == cached_piece_info::write_cache)
			, ret.end());
		for (std::vector<cached_piece_info>::iterator i = ret.begin()
			, end(ret.end()); i != end; ++i)
		{
			--pieces[i->piece].first;
		}

		std::random_shuffle(pieces.begin(), pieces.end());
		std::stable_sort(pieces.begin(), pieces.end()
			, boost::bind(&std::pair<int, int>::first, _1) <
			boost::bind(&std::pair<int, int>::first, _2));
		avail_vec.clear();
		for (int i = 0; i < num_cache_pieces; ++i)
		{
			if (pieces[i].first == INT_MAX) break;
			avail_vec.push_back(pieces[i].second);
		}

		if (!avail_vec.empty())
		{
			// the number of pieces to cache for this torrent is proportional
			// the number of peers it has, divided by the total number of peers.
			// Each peer gets an equal share of the cache

			avail_vec.resize((std::min)(num_cache_pieces, int(avail_vec.size())));

			for (std::vector<int>::iterator i = avail_vec.begin()
				, end(avail_vec.end()); i != end; ++i)
				filesystem().async_cache(*i, boost::bind(&torrent::on_disk_cache_complete
					, shared_from_this(), _1, _2));
		}
	}

	void torrent::get_suggested_pieces(std::vector<int>& s) const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		if (settings().suggest_mode == session_settings::no_piece_suggestions)
		{
			s.clear();
			return;
		}

		std::vector<cached_piece_info> ret;
		m_ses.m_disk_thread.get_cache_info(info_hash(), ret);

		// remove write cache entries
		ret.erase(std::remove_if(ret.begin(), ret.end()
			, boost::bind(&cached_piece_info::kind, _1) == cached_piece_info::write_cache)
			, ret.end());

		// sort by how new the cached entry is, new pieces first
		std::sort(ret.begin(), ret.end()
			, boost::bind(&cached_piece_info::last_use, _1)
			< boost::bind(&cached_piece_info::last_use, _2));

		// cut off the oldest pieces that we don't want to suggest
		// if we have an explicit cache, it's much more likely to
		// stick around, so we should suggest all pieces
		int num_pieces_to_suggest = int(ret.size());
		if (num_pieces_to_suggest == 0) return;

		if (!settings().explicit_read_cache)
			num_pieces_to_suggest = (std::max)(1, int(ret.size() / 2));
		ret.resize(num_pieces_to_suggest);

		std::transform(ret.begin(), ret.end(), std::back_inserter(s)
			, boost::bind(&cached_piece_info::piece, _1));
	}

	void torrent::add_stats(stat const& s)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		// these stats are propagated to the session
		// stats the next time second_tick is called
		m_stat += s;
	}

#if TORRENT_DEBUG_STREAMING > 0
	char const* esc(char const* code)
	{
		// this is a silly optimization
		// to avoid copying of strings
		enum { num_strings = 200 };
		static char buf[num_strings][20];
		static int round_robin = 0;
		char* ret = buf[round_robin];
		++round_robin;
		if (round_robin >= num_strings) round_robin = 0;
		ret[0] = '\033';
		ret[1] = '[';
		int i = 2;
		int j = 0;
		while (code[j]) ret[i++] = code[j++];
		ret[i++] = 'm';
		ret[i++] = 0;
		return ret;
	}

	int peer_index(libtorrent::tcp::endpoint addr
		, std::vector<libtorrent::peer_info> const& peers)
	{
		using namespace libtorrent;
		std::vector<peer_info>::const_iterator i = std::find_if(peers.begin()
			, peers.end(), boost::bind(&peer_info::ip, _1) == addr);
		if (i == peers.end()) return -1;

		return i - peers.begin();
	}

	void print_piece(libtorrent::partial_piece_info* pp
		, std::vector<libtorrent::peer_info> const& peers
		, std::vector<time_critical_piece> const& time_critical)
	{
		using namespace libtorrent;

		ptime now = time_now_hires();

		float deadline = 0.f;
		float last_request = 0.f;
		int timed_out = -1;

		int piece = pp->piece_index;
		std::vector<time_critical_piece>::const_iterator i
			= std::find_if(time_critical.begin(), time_critical.end()
				, boost::bind(&time_critical_piece::piece, _1) == piece);
		if (i != time_critical.end())
		{
			deadline = total_milliseconds(i->deadline - now) / 1000.f;
			last_request = total_milliseconds(now - i->last_requested) / 1000.f;
			timed_out = i->timed_out;
		}

		int num_blocks = pp->blocks_in_piece;

		printf("%5d: [", piece);
		for (int j = 0; j < num_blocks; ++j)
		{
			int index = pp ? peer_index(pp->blocks[j].peer(), peers) % 36 : -1;
			char chr = '+';
			if (index >= 0)
				chr = (index < 10)?'0' + index:'A' + index - 10;

			char const* color = "";
			char const* multi_req = "";

			if (pp->blocks[j].num_peers > 1)
				multi_req = esc("1");

			if (pp->blocks[j].bytes_progress > 0
				&& pp->blocks[j].state == block_info::requested)
			{
				color = esc("33;7");
				chr = '0' + (pp->blocks[j].bytes_progress * 10 / pp->blocks[j].block_size);
			}
			else if (pp->blocks[j].state == block_info::finished) color = esc("32;7");
			else if (pp->blocks[j].state == block_info::writing) color = esc("36;7");
			else if (pp->blocks[j].state == block_info::requested) color = esc("0");
			else { color = esc("0"); chr = ' '; }

			printf("%s%s%c%s", color, multi_req, chr, esc("0"));
		}
		printf("%s]", esc("0"));
		if (deadline != 0.f)
			printf(" deadline: %f last-req: %f timed_out: %d\n"
				, deadline, last_request, timed_out);
		else
			printf("\n");
	}
#endif // TORRENT_DEBUG_STREAMING

	struct busy_block_t
	{
		int peers;
		int index;
		bool operator<(busy_block_t rhs) const { return peers < rhs.peers; }
	};

	void pick_busy_blocks(int piece, int blocks_in_piece
		, int timed_out
		, std::vector<piece_block>& interesting_blocks
		, piece_picker::downloading_piece const& pi)
	{
		// if there aren't any free blocks in the piece, and the piece is
		// old enough, we may switch into busy mode for this piece. In this
		// case busy_blocks and busy_count are set to contain the eligible
		// busy blocks we may pick
		// first, figure out which blocks are eligible for picking
		// in "busy-mode"
		busy_block_t* busy_blocks
			= TORRENT_ALLOCA(busy_block_t, blocks_in_piece);
		int busy_count = 0;

		// pick busy blocks from the piece
		for (int k = 0; k < blocks_in_piece; ++k)
		{
			// only consider blocks that have been requested
			// and we're still waiting for them
			if (pi.info[k].state != piece_picker::block_info::state_requested)
				continue;

			piece_block b(piece, k);

			// only allow a single additional request per block, in order
			// to spread it out evenly across all stalled blocks
			if (pi.info[k].num_peers > timed_out)
				continue;

			busy_blocks[busy_count].peers = pi.info[k].num_peers; 
			busy_blocks[busy_count].index = k;
			++busy_count;

#if TORRENT_DEBUG_STREAMING > 1
			printf(" [%d (%d)]", b.block_index, pi.info[k].num_peers);
#endif
		}
#if TORRENT_DEBUG_STREAMING > 1
		printf("\n");
#endif

		// then sort blocks by the number of peers with requests
		// to the blocks (request the blocks with the fewest peers
		// first)
		std::sort(busy_blocks, busy_blocks + busy_count);

		// then insert them into the interesting_blocks vector
		for (int k = 0; k < busy_count; ++k)
		{
			interesting_blocks.push_back(
				piece_block(piece, busy_blocks[k].index));
		}
	}

	void pick_time_critical_block(std::vector<peer_connection*>& peers
		, std::vector<peer_connection*>& ignore_peers
		, std::set<peer_connection*>& peers_with_requests
		, piece_picker::downloading_piece const& pi
		, time_critical_piece* i
		, piece_picker* picker
		, int blocks_in_piece
		, int timed_out)
	{
		std::vector<piece_block> interesting_blocks;
		std::vector<piece_block> backup1;
		std::vector<piece_block> backup2;
		std::vector<int> ignore;

		ptime now = time_now();

		// loop until every block has been requested from this piece (i->piece)
		do
		{
			// if this peer's download time exceeds 2 seconds, we're done.
			// We don't want to build unreasonably long request queues
			if (!peers.empty() && peers[0]->download_queue_time() > milliseconds(2000))
			{
#if TORRENT_DEBUG_STREAMING > 1
				printf("queue time: %d ms, done\n"
					, int(total_milliseconds(peers[0]->download_queue_time())));
#endif
				break;
			}

			// pick the peer with the lowest download_queue_time that has i->piece
			std::vector<peer_connection*>::iterator p = std::find_if(peers.begin(), peers.end()
				, boost::bind(&peer_connection::has_piece, _1, i->piece));

			// obviously we'll have to skip it if we don't have a peer that has
			// this piece
			if (p == peers.end())
			{
#if TORRENT_DEBUG_STREAMING > 1
				printf("out of peers, done\n");
#endif
				break;
			}
			peer_connection& c = **p;

			interesting_blocks.clear();
			backup1.clear();
			backup2.clear();

			// specifically request blocks with no affinity towards fast or slow
			// pieces. If we would, the picked block might end up in one of
			// the backup lists
			picker->add_blocks(i->piece, c.get_bitfield(), interesting_blocks
				, backup1, backup2, blocks_in_piece, 0, c.peer_info_struct()
				, ignore, piece_picker::none, 0);

			interesting_blocks.insert(interesting_blocks.end()
				, backup1.begin(), backup1.end());
			interesting_blocks.insert(interesting_blocks.end()
				, backup2.begin(), backup2.end());

			bool busy_mode = false;

			if (interesting_blocks.empty())
			{
				busy_mode = true;

#if TORRENT_DEBUG_STREAMING > 1
				printf("interesting_blocks.empty()\n");
#endif

				// there aren't any free blocks to pick, and the piece isn't
				// old enough to pick busy blocks yet. break to continue to
				// the next piece.
				if (timed_out == 0)
				{
#if TORRENT_DEBUG_STREAMING > 1
					printf("not timed out, moving on to next piece\n");
#endif
					break;
				}

#if TORRENT_DEBUG_STREAMING > 1
				printf("pick busy blocks\n");
#endif

				pick_busy_blocks(i->piece, blocks_in_piece, timed_out
					, interesting_blocks, pi);
			}

			// we can't pick anything from this piece, we're done with it.
			// move on to the next one
			if (interesting_blocks.empty()) break;

			piece_block b = interesting_blocks.front();

			// in busy mode we need to make sure we don't do silly
			// things like requesting the same block twice from the
			// same peer
			std::vector<pending_block> const& dq = c.download_queue();

			bool already_requested = std::find_if(dq.begin(), dq.end()
				, has_block(b)) != dq.end();

			if (already_requested)
			{
				// if the piece is stalled, we may end up picking a block
				// that we've already requested from this peer. If so, we should
				// simply disregard this peer from this piece, since this peer
				// is likely to be causing the stall. We should request it
				// from the next peer in the list
				// the peer will be put back in the set for the next piece
				ignore_peers.push_back(*p);
				peers.erase(p);
#if TORRENT_DEBUG_STREAMING > 1
				printf("piece already requested by peer, try next peer\n");
#endif
				// try next peer
				continue;
			}

			std::vector<pending_block> const& rq = c.request_queue();

			bool already_in_queue = std::find_if(rq.begin(), rq.end()
				, has_block(b)) != rq.end();

			if (already_in_queue)
			{
				if (!c.make_time_critical(b))
				{
#if TORRENT_DEBUG_STREAMING > 1
					printf("piece already time-critical and in queue for peer, trying next peer\n");
#endif
					ignore_peers.push_back(*p);
					peers.erase(p);
					continue;
				}
				i->last_requested = now;

#if TORRENT_DEBUG_STREAMING > 1
				printf("piece already in queue for peer, making time-critical\n");
#endif

				// we inserted a new block in the request queue, this
				// makes us actually send it later
				peers_with_requests.insert(peers_with_requests.begin(), &c);
			}
			else
			{
				if (!c.add_request(b, peer_connection::req_time_critical
					| (busy_mode ? peer_connection::req_busy : 0)))
				{
#if TORRENT_DEBUG_STREAMING > 1
					printf("failed to request block [%d, %d]\n"
						, b.piece_index, b.block_index);
#endif
					ignore_peers.push_back(*p);
					peers.erase(p);
					continue;
				}

#if TORRENT_DEBUG_STREAMING > 1
				printf("requested block [%d, %d]\n"
					, b.piece_index, b.block_index);
#endif
				peers_with_requests.insert(peers_with_requests.begin(), &c);
			}

			if (!busy_mode) i->last_requested = now;

			if (i->first_requested == min_time()) i->first_requested = now;

			if (!c.can_request_time_critical())
			{
#if TORRENT_DEBUG_STREAMING > 1
				printf("peer cannot pick time critical pieces\n");
#endif
				peers.erase(p);
				// try next peer
				continue;
			}

			// resort p, since it will have a higher download_queue_time now
			while (p != peers.end()-1 && (*p)->download_queue_time()
				> (*(p+1))->download_queue_time())
			{
				std::iter_swap(p, p+1);
				++p;
			}
		} while (!interesting_blocks.empty());
	}

	void torrent::request_time_critical_pieces()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(!upload_mode());

		// build a list of peers and sort it by download_queue_time
		// we use this sorted list to determine which peer we should
		// request a block from. The earlier a peer is in the list,
		// the sooner we will fully download the block we request.
		std::vector<peer_connection*> peers;
		peers.reserve(m_connections.size());

		// some peers are marked as not being able to request time critical
		// blocks from. For instance, peers that have choked us, peers that are
		// on parole (i.e. they are believed to have sent us bad data), peers
		// that are being disconnected, in upload mode etc.
		std::remove_copy_if(m_connections.begin(), m_connections.end()
			, std::back_inserter(peers), !boost::bind(&peer_connection::can_request_time_critical, _1));

		// sort by the time we believe it will take this peer to send us all
		// blocks we've requested from it. The shorter time, the better candidate
		// it is to request a time critical block from.
		std::sort(peers.begin(), peers.end()
			, boost::bind(&peer_connection::download_queue_time, _1, 16*1024)
			< boost::bind(&peer_connection::download_queue_time, _2, 16*1024));

		// remove the bottom 10% of peers from the candidate set.
		// this is just to remove outliers that might stall downloads
		int new_size = (peers.size() * 9 + 9) / 10;
		TORRENT_ASSERT(new_size <= int(peers.size()));
		peers.resize(new_size);

		// remember all the peers we issued requests to, so we can commit them
		// at the end of this function. Instead of sending the requests right
		// away, we batch them up and send them in a single write to the TCP
		// socket, increasing the chance that they will all be sent in the same
		// packet.
		std::set<peer_connection*> peers_with_requests;

		// peers that should be temporarily ignored for a specific piece
		// in order to give priority to other peers. They should be used for
		// subsequent pieces, so they are stored in this vector until the
		// piece is done
		std::vector<peer_connection*> ignore_peers;

		ptime now = time_now_hires();

		// now, iterate over all time critical pieces, in order of importance, and
		// request them from the peers, in order of responsiveness. i.e. request
		// the most time critical pieces from the fastest peers.
		for (std::deque<time_critical_piece>::iterator i = m_time_critical_pieces.begin()
			, end(m_time_critical_pieces.end()); i != end; ++i)
		{
#if TORRENT_DEBUG_STREAMING > 1
			printf("considering %d\n", i->piece);
#endif

			if (peers.empty())
			{
#if TORRENT_DEBUG_STREAMING > 1
				printf("out of peers, done\n");
#endif
				break;
			}

			// the +1000 is to compensate for the fact that we only call this
			// function once per second, so if we need to request it 500 ms from
			// now, we should request it right away
			if (i != m_time_critical_pieces.begin() && i->deadline > now
				+ milliseconds(m_average_piece_time + m_piece_time_deviation * 4 + 1000))
			{
				// don't request pieces whose deadline is too far in the future
				// this is one of the termination conditions. We don't want to
				// send requests for all pieces in the torrent right away
#if TORRENT_DEBUG_STREAMING > 0
				printf("reached deadline horizon [%f + %f * 4 + 1]\n"
					, m_average_piece_time / 1000.f
					, m_piece_time_deviation / 1000.f);
#endif
				break;
			}

			piece_picker::downloading_piece pi;
			m_picker->piece_info(i->piece, pi);

			// the number of "times" this piece has timed out.
			int timed_out = 0;

			int blocks_in_piece = m_picker->blocks_in_piece(i->piece);

#if TORRENT_DEBUG_STREAMING > 0
			i->timed_out = timed_out;
#endif
			int free_to_request = blocks_in_piece
				- pi.finished - pi.writing - pi.requested;

			if (free_to_request == 0)
			{
				if (i->last_requested == min_time())
					i->last_requested = now;

				// if it's been more than half of the typical download time
				// of a piece since we requested the last block, allow
				// one more request per block
				if (m_average_piece_time > 0)
					timed_out = total_milliseconds(now - i->last_requested)
						/ (std::max)(int(m_average_piece_time + m_piece_time_deviation / 2), 1);

#if TORRENT_DEBUG_STREAMING > 0
				i->timed_out = timed_out;
#endif
				// every block in this piece is already requested
				// there's no need to consider this piece, unless it
				// appears to be stalled.
				if (pi.requested == 0 || timed_out == 0)
				{
#if TORRENT_DEBUG_STREAMING > 1
					printf("skipping %d (full) [req: %d timed_out: %d ]\n"
						, i->piece, pi.requested
						, timed_out);
#endif

					// if requested is 0, it meants all blocks have been received, and
					// we're just waiting for it to flush them to disk.
					// if last_requested is recent enough, we should give it some
					// more time
					// skip to the next piece
					continue;
				}

				// it's been too long since we requested the last block from
				// this piece. Allow re-requesting blocks from this piece
#if TORRENT_DEBUG_STREAMING > 1
				printf("timed out [average-piece-time: %d ms ]\n"
					, m_average_piece_time);
#endif
			}

			// pick all blocks for this piece. the peers list is kept up to date
			// and sorted. when we issue a request to a peer, its download queue
			// time will increase and it may need to be bumped in the peers list,
			// since it's ordered by download queue time
			pick_time_critical_block(peers, ignore_peers
				, peers_with_requests
				, pi, &*i, m_picker.get()
				, blocks_in_piece, timed_out);

			// put back the peers we ignored into the peer list for the next piece
			if (!ignore_peers.empty())
			{
				peers.insert(peers.begin(), ignore_peers.begin(), ignore_peers.end());
				ignore_peers.clear();

				// TODO: instead of resorting the whole list, insert the peers
				// directly into the right place
				std::sort(peers.begin(), peers.end()
					, boost::bind(&peer_connection::download_queue_time, _1, 16*1024)
					< boost::bind(&peer_connection::download_queue_time, _2, 16*1024));
			}

			// if this peer's download time exceeds 2 seconds, we're done.
			// We don't want to build unreasonably long request queues
			if (!peers.empty() && peers[0]->download_queue_time() > milliseconds(2000))
				break;
		}

		// commit all the time critical requests
		for (std::set<peer_connection*>::iterator i = peers_with_requests.begin()
			, end(peers_with_requests.end()); i != end; ++i)
		{
			(*i)->send_block_requests();
		}
	}

	std::set<std::string> torrent::web_seeds(web_seed_entry::type_t type) const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		std::set<std::string> ret;
		for (std::list<web_seed_entry>::const_iterator i = m_web_seeds.begin()
			, end(m_web_seeds.end()); i != end; ++i)
		{
			if (i->peer_info.banned) continue;
			if (i->type != type) continue;
			ret.insert(i->url);
		}
		return ret;
	}

	void torrent::remove_web_seed(std::string const& url, web_seed_entry::type_t type)
	{
		std::list<web_seed_entry>::iterator i = std::find_if(m_web_seeds.begin(), m_web_seeds.end()
			, (boost::bind(&web_seed_entry::url, _1)
				== url && boost::bind(&web_seed_entry::type, _1) == type));
		if (i != m_web_seeds.end()) remove_web_seed(i);
	}

	void torrent::disconnect_web_seed(peer_connection* p)
	{
		std::list<web_seed_entry>::iterator i = std::find_if(m_web_seeds.begin(), m_web_seeds.end()
			, (boost::bind(&policy::peer::connection, boost::bind(&web_seed_entry::peer_info, _1)) == p));
		// this happens if the web server responded with a redirect
		// or with something incorrect, so that we removed the web seed
		// immediately, before we disconnected
		if (i == m_web_seeds.end()) return;

		TORRENT_ASSERT(i->resolving == false);

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
		debug_log("disconnect web seed: \"%s\"", i->url.c_str());
#endif
		TORRENT_ASSERT(i->peer_info.connection);
		i->peer_info.connection = 0;
	}

	void torrent::remove_web_seed(peer_connection* p)
	{
		std::list<web_seed_entry>::iterator i = std::find_if(m_web_seeds.begin(), m_web_seeds.end()
			, (boost::bind(&policy::peer::connection, boost::bind(&web_seed_entry::peer_info, _1)) == p));
		TORRENT_ASSERT(i != m_web_seeds.end());
		if (i == m_web_seeds.end()) return;
		p->set_peer_info(0);
		if (has_picker()) picker().clear_peer(&i->peer_info);
		m_web_seeds.erase(i);
	}

	void torrent::retry_web_seed(peer_connection* p, int retry)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		std::list<web_seed_entry>::iterator i = std::find_if(m_web_seeds.begin(), m_web_seeds.end()
			, (boost::bind(&policy::peer::connection, boost::bind(&web_seed_entry::peer_info, _1)) == p));

		TORRENT_ASSERT(i != m_web_seeds.end());
		if (i == m_web_seeds.end()) return;
		if (retry == 0) retry = m_ses.settings().urlseed_wait_retry;
		i->retry = time_now() + seconds(retry);
	}

	bool torrent::try_connect_peer()
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(want_more_peers());
		bool ret = m_policy.connect_one_peer(m_ses.session_time());
		return ret;
	}

	void torrent::add_peer(tcp::endpoint const& adr, int source)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		peer_id id(0);
		m_policy.add_peer(adr, id, source, 0);

		state_updated();
	}

	void torrent::async_verify_piece(int piece_index, boost::function<void(int)> const& f)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
//		INVARIANT_CHECK;

		TORRENT_ASSERT(m_storage);
		TORRENT_ASSERT(m_storage->refcount() > 0);
		TORRENT_ASSERT(piece_index >= 0);
		TORRENT_ASSERT(piece_index < m_torrent_file->num_pieces());
		TORRENT_ASSERT(piece_index < (int)m_picker->num_pieces());
		TORRENT_ASSERT(!m_picker || !m_picker->have_piece(piece_index));
#ifdef TORRENT_DEBUG
		if (m_picker)
		{
			int blocks_in_piece = m_picker->blocks_in_piece(piece_index);
			for (int i = 0; i < blocks_in_piece; ++i)
			{
				TORRENT_ASSERT(m_picker->num_peers(piece_block(piece_index, i)) == 0);
			}
		}
#endif

		m_storage->async_hash(piece_index, boost::bind(&torrent::on_piece_verified
			, shared_from_this(), _1, _2, f));
#if TORRENT_USE_INVARIANT_CHECKS
		check_invariant();
#endif
	}

	void torrent::on_piece_verified(int ret, disk_io_job const& j
		, boost::function<void(int)> f)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		// return value:
		// 0: success, piece passed hash check
		// -1: disk failure
		// -2: hash check failed

		state_updated();

		if (ret == -1) handle_disk_error(j);
		f(ret);
	}

	tcp::endpoint torrent::current_tracker() const
	{
		return m_tracker_address;
	}

	announce_entry* torrent::find_tracker(tracker_request const& r)
	{
		std::vector<announce_entry>::iterator i = std::find_if(
			m_trackers.begin(), m_trackers.end()
			, boost::bind(&announce_entry::url, _1) == r.url);
		if (i == m_trackers.end()) return 0;
		return &*i;
	}

#if !TORRENT_NO_FPU
	void torrent::file_progress(std::vector<float>& fp) const
	{
		fp.clear();
		if (!valid_metadata()) return;
	
		fp.resize(m_torrent_file->num_files(), 1.f);
		if (is_seed()) return;

		std::vector<size_type> progress;
		file_progress(progress);
		for (int i = 0; i < m_torrent_file->num_files(); ++i)
		{
			file_entry const& f = m_torrent_file->file_at(i);
			if (f.size == 0) fp[i] = 1.f;
			else fp[i] = float(progress[i]) / f.size;
		}
	}
#endif

	void torrent::file_progress(std::vector<size_type>& fp, int flags) const
	{
		if (!valid_metadata())
		{
			fp.clear();
			return;
		}
	
		fp.resize(m_torrent_file->num_files(), 0);

		if (is_seed())
		{
			for (int i = 0; i < m_torrent_file->num_files(); ++i)
				fp[i] = m_torrent_file->files().file_size(i);
			return;
		}
		
		if (flags & torrent_handle::piece_granularity)
		{
			std::copy(m_file_progress.begin(), m_file_progress.end(), fp.begin());
			return;
		}

		TORRENT_ASSERT(has_picker());

		for (int i = 0; i < m_torrent_file->num_files(); ++i)
		{
			peer_request ret = m_torrent_file->files().map_file(i, 0, 0);
			size_type size = m_torrent_file->files().file_size(i);
			TORRENT_ASSERT(ret.piece >= 0);
			TORRENT_ASSERT(ret.piece < m_picker->num_pieces());
			if (ret.piece < 0 || ret.piece >= m_picker->num_pieces())
			{
				// this is not supposed to happen.
				fp[i] = 0;
				continue;
			}

			size_type done = 0;
			while (size > 0)
			{
				TORRENT_ASSERT(ret.piece < m_picker->num_pieces());
				TORRENT_ASSERT(ret.piece >= 0);

				size_type bytes_step = (std::min)(size_type(m_torrent_file->piece_size(ret.piece)
					- ret.start), size);

				if (m_picker->have_piece(ret.piece)) done += bytes_step;
				++ret.piece;
				ret.start = 0;
				size -= bytes_step;
			}
			TORRENT_ASSERT(size == 0);

			fp[i] = done;
		}

		const std::vector<piece_picker::downloading_piece>& q
			= m_picker->get_download_queue();

		file_storage const& fs = m_torrent_file->files();
		for (std::vector<piece_picker::downloading_piece>::const_iterator
			i = q.begin(), end(q.end()); i != end; ++i)
		{
			size_type offset = size_type(i->index) * m_torrent_file->piece_length();
			int file = fs.file_index_at_offset(offset);
			int num_blocks = m_picker->blocks_in_piece(i->index);
			piece_picker::block_info const* info = i->info;
			for (int k = 0; k < num_blocks; ++k)
			{
				TORRENT_ASSERT(file < fs.num_files());
				TORRENT_ASSERT(offset == size_type(i->index) * m_torrent_file->piece_length()
					+ k * block_size());
				TORRENT_ASSERT(offset < m_torrent_file->total_size());
				while (offset >= fs.file_offset(file) + fs.file_size(file))
				{
					++file;
				}
				TORRENT_ASSERT(file < fs.num_files());

				size_type block = block_size();

				if (info[k].state == piece_picker::block_info::state_none)
				{
					offset += block;
					continue;
				}

				if (info[k].state == piece_picker::block_info::state_requested)
				{
					block = 0;
					policy::peer* p = static_cast<policy::peer*>(info[k].peer);
					if (p && p->connection)
					{
						boost::optional<piece_block_progress> pbp
							= p->connection->downloading_piece_progress();
						if (pbp && pbp->piece_index == i->index && pbp->block_index == k)
							block = pbp->bytes_downloaded;
						TORRENT_ASSERT(block <= block_size());
					}

					if (block == 0)
					{
						offset += block_size();
						continue;
					}
				}

				if (offset + block > fs.file_offset(file) + fs.file_size(file))
				{
					int left_over = int(block_size() - block);
					// split the block on multiple files
					while (block > 0)
					{
						TORRENT_ASSERT(offset <= fs.file_offset(file) + fs.file_size(file));
						size_type slice = (std::min)(fs.file_offset(file) + fs.file_size(file) - offset
							, block);
						fp[file] += slice;
						offset += slice;
						block -= slice;
						TORRENT_ASSERT(offset <= fs.file_offset(file) + fs.file_size(file));
						if (offset == fs.file_offset(file) + fs.file_size(file))
						{
							++file;
							if (file == fs.num_files())
							{
								offset += block;
								break;
							}
						}
					}
					offset += left_over;
					TORRENT_ASSERT(offset == size_type(i->index) * m_torrent_file->piece_length()
						+ (k+1) * block_size());
				}
				else
				{
					fp[file] += block;
					offset += block_size();
				}
				TORRENT_ASSERT(file <= m_torrent_file->num_files());
			}
		}
	}
	
	void torrent::new_external_ip()
	{
		m_policy.clear_peer_prio();
	}

	void torrent::set_state(torrent_status::state_t s)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
#if TORRENT_USE_ASSERTS
		if (s != torrent_status::checking_files
			&& s != torrent_status::queued_for_checking)
		{
			// the only valid transition away from queued_for_checking
			// is to checking_files. One exception is to finished
			// in case all the files are marked with priority 0
			if (m_queued_for_checking)
			{
				std::vector<int> pieces;
				m_picker->piece_priorities(pieces);
				// make sure all pieces have priority 0
				TORRENT_ASSERT(std::accumulate(pieces.begin(), pieces.end(), 0) == 0);
			}
		}
		if (s == torrent_status::seeding)
			TORRENT_ASSERT(is_seed());

		if (s == torrent_status::seeding)
			TORRENT_ASSERT(is_seed());
		if (s == torrent_status::finished)
			TORRENT_ASSERT(is_finished());
		if (s == torrent_status::downloading && m_state == torrent_status::finished)
			TORRENT_ASSERT(!is_finished());
#endif

		if (int(m_state) == s) return;

		if (m_ses.m_alerts.should_post<state_changed_alert>())
		{
			m_ses.m_alerts.post_alert(state_changed_alert(get_handle()
				, s, (torrent_status::state_t)m_state));
		}

		if (s == torrent_status::finished
			&& m_ses.m_alerts.should_post<torrent_finished_alert>())
		{
			alerts().post_alert(torrent_finished_alert(
				get_handle()));
		}


		m_state = s;

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
		debug_log("set_state() %d", m_state);
#endif

		update_guage();

		state_updated();

#ifndef TORRENT_DISABLE_EXTENSIONS
		for (extension_list_t::iterator i = m_extensions.begin()
			, end(m_extensions.end()); i != end; ++i)
		{
			TORRENT_TRY {
				(*i)->on_state(m_state);
			} TORRENT_CATCH (std::exception&) {}
		}
#endif
	}

#ifndef TORRENT_DISABLE_EXTENSIONS
	void torrent::notify_extension_add_peer(tcp::endpoint const& ip
		, int src, int flags)
	{
		for (extension_list_t::iterator i = m_extensions.begin()
			, end(m_extensions.end()); i != end; ++i)
		{
			TORRENT_TRY {
				(*i)->on_add_peer(ip, src, flags);
			} TORRENT_CATCH (std::exception&) {}
		}
	}
#endif

	void torrent::state_updated()
	{
		// if this fails, this function is probably called 
		// from within the torrent constructor, which it
		// shouldn't be. Whichever function ends up calling
		// this should probably be moved to torrent::start()
		TORRENT_ASSERT(shared_from_this());

		// we can't call state_updated() while the session
		// is building the status update alert
		TORRENT_ASSERT(!m_ses.m_posting_torrent_updates);

		// we're either not subscribing to this torrent, or
		// it has already been updated this round, no need to
		// add it to the list twice
		if (!m_state_subscription) return;
		if (m_in_state_updates)
		{
#ifndef TORRENT_DISABLE_INVARIANT_CHECKS
			TORRENT_ASSERT(m_ses.in_state_updates(shared_from_this()));
#endif
			return;
		}

		m_ses.add_to_update_queue(shared_from_this());
		m_in_state_updates = true;
	}

	void torrent::status(torrent_status* st, boost::uint32_t flags)
	{
		INVARIANT_CHECK;

		ptime now = time_now();

		st->handle = get_handle();
		st->info_hash = info_hash();

		if (flags & torrent_handle::query_name)
			st->name = name();

		if (flags & torrent_handle::query_save_path)
			st->save_path = save_path();

		if (flags & torrent_handle::query_torrent_file)
			st->torrent_file = m_torrent_file;

		st->has_incoming = m_has_incoming;
		if (m_error) st->error = convert_from_native(m_error.message()) + ": " + m_error_file;
		st->seed_mode = m_seed_mode;
		st->moving_storage = m_moving_storage;

		st->added_time = m_added_time;
		st->completed_time = m_completed_time;

		st->last_scrape = m_last_scrape;
		st->share_mode = m_share_mode;
		st->upload_mode = m_upload_mode;
		st->up_bandwidth_queue = 0;
		st->down_bandwidth_queue = 0;
		st->priority = m_priority;

		st->num_peers = int(m_connections.size()) - m_num_connecting;

		st->list_peers = m_policy.num_peers();
		st->list_seeds = m_policy.num_seeds();
		st->connect_candidates = m_policy.num_connect_candidates();
		st->seed_rank = seed_rank(settings());

		st->all_time_upload = m_total_uploaded;
		st->all_time_download = m_total_downloaded;

		// activity time
		st->finished_time = m_finished_time;
		st->active_time = m_active_time;
		st->seeding_time = m_seeding_time;
		st->time_since_upload = m_last_upload;
		st->time_since_download = m_last_download;

		st->storage_mode = (storage_mode_t)m_storage_mode;

		st->num_complete = (m_complete == 0xffffff) ? -1 : m_complete;
		st->num_incomplete = (m_incomplete == 0xffffff) ? -1 : m_incomplete;
		st->paused = is_torrent_paused();
		st->auto_managed = m_auto_managed;
		st->sequential_download = m_sequential_download;
		st->is_seeding = is_seed();
		st->is_finished = is_finished();
		st->super_seeding = m_super_seeding;
		st->has_metadata = valid_metadata();
		bytes_done(*st, flags & torrent_handle::query_accurate_download_counters);
		TORRENT_ASSERT(st->total_wanted_done >= 0);
		TORRENT_ASSERT(st->total_done >= st->total_wanted_done);

		// payload transfer
		st->total_payload_download = m_stat.total_payload_download();
		st->total_payload_upload = m_stat.total_payload_upload();

		// total transfer
		st->total_download = m_stat.total_payload_download()
			+ m_stat.total_protocol_download();
		st->total_upload = m_stat.total_payload_upload()
			+ m_stat.total_protocol_upload();

		// failed bytes
		st->total_failed_bytes = m_total_failed_bytes;
		st->total_redundant_bytes = m_total_redundant_bytes;

		// transfer rate
		st->download_rate = m_stat.download_rate();
		st->upload_rate = m_stat.upload_rate();
		st->download_payload_rate = m_stat.download_payload_rate();
		st->upload_payload_rate = m_stat.upload_payload_rate();

		if (m_waiting_tracker && !is_paused())
			st->next_announce = boost::posix_time::seconds(
				total_seconds(next_announce() - now));
		else
			st->next_announce = boost::posix_time::seconds(0);

		if (st->next_announce.is_negative())
			st->next_announce = boost::posix_time::seconds(0);

		st->announce_interval = boost::posix_time::seconds(0);

		st->current_tracker.clear();
		if (m_last_working_tracker >= 0)
		{
			TORRENT_ASSERT(m_last_working_tracker < int(m_trackers.size()));
			st->current_tracker = m_trackers[m_last_working_tracker].url;
		}
		else
		{
			std::vector<announce_entry>::const_iterator i;
			for (i = m_trackers.begin(); i != m_trackers.end(); ++i)
			{
				if (!i->updating) continue;
				st->current_tracker = i->url;
				break;
			}
		}

		if ((flags & torrent_handle::query_verified_pieces))
		{
			st->verified_pieces = m_verified;
		}

		st->num_uploads = m_num_uploads;
		st->uploads_limit = m_max_uploads == (1<<24)-1 ? -1 : m_max_uploads;
		st->num_connections = int(m_connections.size());
		st->connections_limit = m_max_connections == (1<<24)-1 ? -1 : m_max_connections;
		// if we don't have any metadata, stop here

		st->queue_position = queue_position();
		st->need_save_resume = need_save_resume_data();
		st->ip_filter_applies = m_apply_ip_filter;

		st->state = (torrent_status::state_t)m_state;

		if (!valid_metadata())
		{
			st->state = torrent_status::downloading_metadata;
			st->progress_ppm = m_progress_ppm;
#if !TORRENT_NO_FPU
			st->progress = m_progress_ppm / 1000000.f;
#endif
			st->block_size = 0;
			return;
		}

		st->block_size = block_size();

		if (m_state == torrent_status::checking_files)
		{
			st->progress_ppm = m_progress_ppm;
#if !TORRENT_NO_FPU
			st->progress = m_progress_ppm / 1000000.f;
#endif
		}
		else if (st->total_wanted == 0)
		{
			st->progress_ppm = 1000000;
			st->progress = 1.f;
		}
		else
		{
			st->progress_ppm = st->total_wanted_done * 1000000
				/ st->total_wanted;
#if !TORRENT_NO_FPU
			st->progress = st->progress_ppm / 1000000.f;
#endif
		}

		if (has_picker() && (flags & torrent_handle::query_pieces))
		{
			st->sparse_regions = m_picker->sparse_regions();
			int num_pieces = m_picker->num_pieces();
			st->pieces.resize(num_pieces, false);
			for (int i = 0; i < num_pieces; ++i)
				if (m_picker->have_piece(i)) st->pieces.set_bit(i);
		}
		else if (is_seed())
		{
			int num_pieces = m_torrent_file->num_pieces();
			st->pieces.resize(num_pieces, true);
		}
		st->num_pieces = num_have();
		st->num_seeds = num_seeds();
		if ((flags & torrent_handle::query_distributed_copies) && m_picker.get())
		{
			boost::tie(st->distributed_full_copies, st->distributed_fraction) =
				m_picker->distributed_copies();
#if TORRENT_NO_FPU
			st->distributed_copies = -1.f;
#else
			st->distributed_copies = st->distributed_full_copies
				+ float(st->distributed_fraction) / 1000;
#endif
		}
		else
		{
			st->distributed_full_copies = -1;
			st->distributed_fraction = -1;
			st->distributed_copies = -1.f;
		}

		st->last_seen_complete = m_swarm_last_seen_complete;
	}

	void torrent::add_redundant_bytes(int b, torrent::wasted_reason_t reason)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(b > 0);
		m_total_redundant_bytes += b;
		m_ses.add_redundant_bytes(b, reason);
//		TORRENT_ASSERT(m_total_redundant_bytes + m_total_failed_bytes
//			<= m_stat.total_payload_download());
	}

	void torrent::add_failed_bytes(int b)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		TORRENT_ASSERT(b > 0);
		m_total_failed_bytes += b;
		m_ses.add_failed_bytes(b);
//		TORRENT_ASSERT(m_total_redundant_bytes + m_total_failed_bytes
//			<= m_stat.total_payload_download());
	}

	int torrent::num_seeds() const
	{
		TORRENT_ASSERT(m_ses.is_network_thread());
		INVARIANT_CHECK;

		int ret = 0;
		for (std::set<peer_connection*>::const_iterator i = m_connections.begin()
			, end(m_connections.end()); i != end; ++i)
			if ((*i)->is_seed()) ++ret;
		return ret;
	}

	void torrent::tracker_request_error(tracker_request const& r
		, int response_code, error_code const& ec, const std::string& msg
		, int retry_interval)
	{
		TORRENT_ASSERT(m_ses.is_network_thread());

		INVARIANT_CHECK;

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
		debug_log("*** tracker error: (%d) %s %s", ec.value(), ec.message().c_str(), msg.c_str());
#endif
		if (r.kind == tracker_request::announce_request)
		{
			announce_entry* ae = find_tracker(r);
			if (ae)
			{
				ae->failed(settings(), retry_interval);
				ae->last_error = ec;
				ae->message = msg;
				int tracker_index = ae - &m_trackers[0];
#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
				debug_log("*** increment tracker fail count [%d]", ae->fails);
#endif
				// never talk to this tracker again
				if (response_code == 410) ae->fail_limit = 1;

				deprioritize_tracker(tracker_index);
			}
			if (m_ses.m_alerts.should_post<tracker_error_alert>())
			{
				m_ses.m_alerts.post_alert(tracker_error_alert(get_handle()
					, ae?ae->fails:0, response_code, r.url, ec, msg));
			}
		}
		else if (r.kind == tracker_request::scrape_request)
		{
			if (response_code == 410)
			{
				// never talk to this tracker again
				announce_entry* ae = find_tracker(r);
				if (ae) ae->fail_limit = 1;
			}

			if (m_ses.m_alerts.should_post<scrape_failed_alert>())
			{
				m_ses.m_alerts.post_alert(scrape_failed_alert(get_handle(), r.url, ec));
			}
		}
		// announce to the next working tracker
		if ((!m_abort && !is_paused()) || r.event == tracker_request::stopped)
			announce_with_tracker(r.event);
		update_tracker_timer(time_now());
	}

#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
	void torrent::debug_log(const char* fmt, ...) const
	{
		if (!m_ses.m_logger) return;

		va_list v;	
		va_start(v, fmt);
	
		char usr[1024];
		vsnprintf(usr, sizeof(usr), fmt, v);
		va_end(v);
		char buf[1280];
		snprintf(buf, sizeof(buf), "%s: %s: %s\n", time_now_string()
			, to_hex(info_hash().to_string()).substr(0, 6).c_str(), usr);
		(*m_ses.m_logger) << buf;
	}
#endif

}