fix graceful pause issue. peers regularly check whether they should disconnect or not

include/libtorrent/peer_connection.hpp

@@ -813,6 +813,7 @@ namespace libtorrent
 			, peer_request r, boost::shared_ptr<torrent> t);
 		void on_seed_mode_hashed(disk_io_job const* j);
 		int request_timeout() const;
+		void check_graceful_pause();
 
 		int wanted_transfer(int channel);
 		int request_bandwidth(int channel, int bytes = 0);

src/peer_connection.cpp

@@ -1234,13 +1234,14 @@ namespace libtorrent
 		}
 
 		if (t->is_paused()
+			&& t->is_auto_managed()
 			&& m_settings.get_bool(settings_pack::incoming_starts_queued_torrents)
 			&& !t->is_aborted())
 		{
 			t->resume();
 		}
 
-		if (t->is_paused() || t->is_aborted())
+		if (t->is_paused() || t->is_aborted() || t->graceful_pause())
 		{
 			// paused torrents will not accept
 			// incoming connections unless they are auto managed
@@ -1510,6 +1511,9 @@ namespace libtorrent
 				m_suggested_pieces.erase(i);
 		}
 
+		check_graceful_pause();
+		if (is_disconnecting()) return;
+
 		if (m_request_queue.empty() && m_download_queue.size() < 2)
 		{
 			if (request_a_block(*t, *this))
@@ -2942,6 +2946,8 @@ namespace libtorrent
 			t->verify_piece(p.piece);
 		}
 
+		check_graceful_pause();
+
 		if (is_disconnecting()) return;
 
 		if (request_a_block(*t, *this))
@@ -2949,6 +2955,24 @@ namespace libtorrent
 		send_block_requests();
 	}
 
+	void peer_connection::check_graceful_pause()
+	{
+		// TODO: 3 instead of having to ask the torrent whether it's in graceful
+		// pause mode or not, the peers should keep that state (and the torrent
+		// should update them when it enters graceful pause). When a peer enters
+		// graceful pause mode, it should cancel all outstanding requests and
+		// clear its request queue.
+		boost::shared_ptr<torrent> t = m_torrent.lock();
+		if (!t || !t->graceful_pause()) return;
+
+		if (m_outstanding_bytes > 0) return;
+
+#ifndef TORRENT_DISABLE_LOGGING
+		peer_log(peer_log_alert::info, "GRACEFUL_PAUSE", "NO MORE DOWNLOAD");
+#endif
+		disconnect(errors::torrent_paused, op_bittorrent);
+	}
+
 	void peer_connection::on_disk_write_complete(disk_io_job const* j
 		, peer_request p, boost::shared_ptr<torrent> t)
 	{
@@ -3803,23 +3827,9 @@ namespace libtorrent
 
 		if (m_disconnecting) return;
 
-		if (t->graceful_pause() && m_outstanding_bytes == 0)
-		{
-#ifndef TORRENT_DISABLE_LOGGING
-			peer_log(peer_log_alert::info, "GRACEFUL_PAUSE", "NO MORE DOWNLOAD");
-#endif
-			disconnect(errors::torrent_paused, op_bittorrent);
-
-			// if this was the last connection, post the alert
-			// TODO: it would be nice if none of this logic would leak outside of
-			// the torrent object)
-			if (t->num_peers() == 0)
-			{
-				if (t->alerts().should_post<torrent_paused_alert>())
-					t->alerts().emplace_alert<torrent_paused_alert>(t->get_handle());
-			}
-			return;
-		}
+		// TODO: 3 once peers are properly put in graceful pause mode, they can
+		// cancel all outstanding requests and this test can be removed.
+		if (t->graceful_pause()) return;
 
 		// we can't download pieces in these states
 		if (t->state() == torrent_status::checking_files
@@ -6127,6 +6137,9 @@ namespace libtorrent
 		if (m_extension_outstanding_bytes > 0)
 			m_extension_outstanding_bytes -= (std::min)(m_extension_outstanding_bytes, int(bytes_transferred));
 
+		check_graceful_pause();
+		if (m_disconnecting) return;
+
 		int num_loops = 0;
 		do
 		{

src/request_blocks.cpp

@@ -73,6 +73,9 @@ namespace libtorrent
 		// initialized after we have the metadata
 		if (!t.are_files_checked()) return false;
 
+		// we don't want to request more blocks while trying to gracefully pause
+		if (t.graceful_pause()) return false;
+
 		TORRENT_ASSERT(c.peer_info_struct() != 0 || c.type() != peer_connection::bittorrent_connection);
 
 		bool time_critical_mode = t.num_time_critical_pieces() > 0;

src/torrent.cpp

@@ -6111,6 +6111,8 @@ namespace libtorrent
 			// disconnected. This will clear the graceful_pause_mode and post the
 			// torrent_paused_alert.
 			TORRENT_ASSERT(is_paused());
+
+			// this will post torrent_paused alert
 			set_allow_peers(false);
 		}
 
@@ -8180,7 +8182,7 @@ namespace libtorrent
 		if (m_connections.size() >= m_max_connections) return false;
 
 		// if we're paused, obviously we're not connecting to peers
-		if (is_paused() || m_abort) return false;
+		if (is_paused() || m_abort || m_graceful_pause_mode) return false;
 
 		if ((m_state == torrent_status::checking_files
 			|| m_state == torrent_status::checking_resume_data)
@@ -9609,7 +9611,7 @@ namespace libtorrent
 		INVARIANT_CHECK;
 
 		if (!m_allow_peers) return;
-		if (!graceful) set_allow_peers(false);
+		set_allow_peers(graceful ? true : false, graceful);
 
 		m_announce_to_dht = false;
 		m_announce_to_trackers = false;
@@ -9619,11 +9621,9 @@ namespace libtorrent
 		set_need_save_resume();
 		state_updated();
 
-		m_graceful_pause_mode = graceful;
 		update_gauge();
 		update_want_peers();
 		update_want_scrape();
-
 	}
 
 	void torrent::do_pause()