clean up logic around waiting for disk write queue to fall below low watermark. optimize peer disconnect. Fix integer overflow bug in uTP/TCP mixed mode algorithm. Fixed some invariant checks for closing connections issues

include/libtorrent/peer_connection.hpp

@@ -601,6 +601,10 @@ namespace libtorrent
 		size_type downloaded_since_unchoke() const
 		{ return m_statistics.total_payload_download() - m_downloaded_at_last_unchoke; }
 
+		// called when the disk write buffer is drained again, and we can
+		// start downloading payload again
+		void on_disk();
+
 		enum sync_t { read_async, read_sync };
 		void setup_receive(sync_t sync = read_sync);
 

src/peer_connection.cpp

@@ -4524,12 +4524,20 @@ namespace libtorrent
 		m_channel_state[upload_channel] = peer_info::bw_network;
 	}
 
+	void peer_connection::on_disk()
+	{
+		if (m_channel_state[download_channel] != peer_info::bw_disk) return;
+		boost::intrusive_ptr<peer_connection> me(this);
+	
+		m_channel_state[download_channel] = peer_info::bw_idle;
+		setup_receive();
+	}
+
 	void peer_connection::setup_receive(sync_t sync)
 	{
 		INVARIANT_CHECK;
 
-		if (m_channel_state[download_channel] != peer_info::bw_idle
-			&& m_channel_state[download_channel] != peer_info::bw_disk) return;
+		if (m_channel_state[download_channel] != peer_info::bw_idle) return;
 
 		shared_ptr<torrent> t = m_torrent.lock();
 		
@@ -4864,6 +4872,13 @@ namespace libtorrent
 		, std::size_t bytes_transferred)
 	{
 		TORRENT_ASSERT(m_ses.is_network_thread());
+
+		// keep ourselves alive in until this function exits in
+		// case we disconnect
+		// this needs to be created before the invariant check,
+		// to keep the object alive through the exit check
+		boost::intrusive_ptr<peer_connection> me(self());
+
 		INVARIANT_CHECK;
 
 #ifdef TORRENT_VERBOSE_LOGGING
@@ -4873,10 +4888,6 @@ namespace libtorrent
 #if defined TORRENT_ASIO_DEBUGGING
 		complete_async("peer_connection::on_receive_data");
 #endif
-		// keep ourselves alive in until this function exits in
-		// case we disconnect
-		boost::intrusive_ptr<peer_connection> me(self());
-
 		TORRENT_ASSERT(m_channel_state[download_channel] == peer_info::bw_network);
 		m_channel_state[download_channel] = peer_info::bw_idle;
 

src/session_impl.cpp

@@ -2217,11 +2217,10 @@ namespace aux {
 		TORRENT_ASSERT(p->is_disconnecting());
 
 		if (!p->is_choked() && !p->ignore_unchoke_slots()) --m_num_unchoked;
-//		connection_map::iterator i = std::lower_bound(m_connections.begin(), m_connections.end()
-//			, p, boost::bind(&boost::intrusive_ptr<peer_connection>::get, _1) < p);
-//		if (i->get() != p) i == m_connections.end();
-		connection_map::iterator i = std::find_if(m_connections.begin(), m_connections.end()
-			, boost::bind(&boost::intrusive_ptr<peer_connection>::get, _1) == p);
+		TORRENT_ASSERT(p->refcount() > 0);
+
+		boost::intrusive_ptr<peer_connection> sp((peer_connection*)p);
+		connection_map::iterator i = m_connections.find(sp);
 		if (i != m_connections.end()) m_connections.erase(i);
 	}
 
@@ -2295,7 +2294,7 @@ namespace aux {
 		{
 			// setup_receive() may disconnect the connection
 			// and clear it out from the m_connections list
-			(*i)->setup_receive();
+			(*i)->on_disk();
 		}
 	}
 
@@ -2427,8 +2426,10 @@ namespace aux {
 					else
 					{
 						if (num_tcp_peers == 0) num_tcp_peers = 1;
-						int upload_rate = (std::max)(m_stat.upload_rate(), 20000);
-						int download_rate = (std::max)(m_stat.download_rate(), 20000);
+						// these are 64 bits since they are multiplied by the number
+						// of peers, which otherwise might overflow an int
+						boost::uint64_t upload_rate = (std::max)(m_stat.upload_rate(), 20000);
+						boost::uint64_t download_rate = (std::max)(m_stat.download_rate(), 20000);
 						if (m_upload_channel.throttle()) upload_rate = m_upload_channel.throttle();
 						if (m_download_channel.throttle()) download_rate = m_download_channel.throttle();
 						
@@ -4316,8 +4317,6 @@ namespace aux {
 
 	void session_impl::update_connections_limit()
 	{
-		INVARIANT_CHECK;
-
 		if (m_settings.connections_limit <= 0)
 		{
 			m_settings.connections_limit = (std::numeric_limits<int>::max)();