attempt at fixing shutdown hang caused by connection_queue

include/libtorrent/connection_queue.hpp

@@ -67,6 +67,22 @@ public:
 	int limit() const;
 	void close();
 	int size() const { return m_queue.size(); }
+	int num_connecting() const { return m_num_connecting; }
+#if defined TORRENT_ASIO_DEBUGGING
+	float next_timeout() const { return total_milliseconds(m_timer.expires_at() - time_now_hires()) / 1000.f; }
+	float max_timeout() const
+	{
+		ptime max_timeout = min_time();
+		for (std::list<entry>::const_iterator i = m_queue.begin()
+			, end(m_queue.end()); i != end; ++i)
+		{
+			if (!i->connecting) continue;
+			if (i->expires > max_timeout) max_timeout = i->expires;
+		}
+		if (max_timeout == min_time()) return 0.f;
+		return total_milliseconds(max_timeout - time_now_hires()) / 1000.f;
+	}
+#endif
 
 #ifdef TORRENT_DEBUG
 	void check_invariant() const;
@@ -85,6 +101,9 @@ private:
 		entry(): connecting(false), ticket(0), expires(max_time()), priority(0) {}
 		// called when the connection is initiated
 		// this is when the timeout countdown starts
+		// TODO: if we don't actually need the connection queue
+		// to hold ownership of objects, replace these boost functions
+		// with pointer to a pure virtual interface class
 		boost::function<void(int)> on_connect;
 		// called if done hasn't been called within the timeout
 		// or if the connection queue aborts. This means there
@@ -100,6 +119,9 @@ private:
 		int priority;
 	};
 
+	// TODO: split this into a queue and connecting map. The key for the map
+	// is the ticket. Most field in entry would only be necessary for the
+	// connecting map.
 	std::list<entry> m_queue;
 
 	// the next ticket id a connection will be given
@@ -108,6 +130,9 @@ private:
 	int m_half_open_limit;
 	bool m_abort;
 
+	// the number of outstanding timers
+	int m_num_timers;
+
 	deadline_timer m_timer;
 
 	mutable mutex_t m_mutex;

src/connection_queue.cpp

@@ -49,6 +49,7 @@ namespace libtorrent
 		, m_num_connecting(0)
 		, m_half_open_limit(0)
 		, m_abort(false)
+		, m_num_timers(0)
 		, m_timer(ios)
 #ifdef TORRENT_DEBUG
 		, m_in_timeout_function(false)
@@ -155,7 +156,7 @@ namespace libtorrent
 				continue;
 			}
 			TORRENT_TRY {
-				e.on_timeout();
+				e.on_connect(-1);
 			} TORRENT_CATCH(std::exception&) {}
 			tmp.pop_front();
 		}
@@ -227,6 +228,7 @@ namespace libtorrent
 				error_code ec;
 				m_timer.expires_at(expire, ec);
 				m_timer.async_wait(boost::bind(&connection_queue::on_timeout, this, _1));
+				++m_num_timers;
 			}
 			i->connecting = true;
 			++m_num_connecting;
@@ -275,6 +277,7 @@ namespace libtorrent
 		complete_async("connection_queue::on_timeout");
 #endif
 		mutex_t::scoped_lock l(m_mutex);
+		--m_num_timers;
 
 		INVARIANT_CHECK;
 #ifdef TORRENT_DEBUG
@@ -282,7 +285,7 @@ namespace libtorrent
 #endif
 
 		TORRENT_ASSERT(!e || e == error::operation_aborted);
-		if (e) return;
+		if (e && m_num_connecting == 0 && m_num_timers > 0) return;
 
 		ptime next_expire = max_time();
 		ptime now = time_now_hires() + milliseconds(100);
@@ -327,6 +330,7 @@ namespace libtorrent
 			error_code ec;
 			m_timer.expires_at(next_expire, ec);
 			m_timer.async_wait(boost::bind(&connection_queue::on_timeout, this, _1));
+			++m_num_timers;
 		}
 		try_connect(l);
 	}

src/http_connection.cpp

@@ -93,6 +93,7 @@ http_connection::http_connection(io_service& ios, connection_queue& cc
 
 http_connection::~http_connection()
 {
+	TORRENT_ASSERT(m_connection_ticket == -1);
 #ifdef TORRENT_USE_OPENSSL
 	if (m_own_ssl_context) delete m_ssl_ctx;
 #endif
@@ -378,23 +379,14 @@ void http_connection::start(std::string const& hostname, std::string const& port
 
 void http_connection::on_connect_timeout()
 {
-	if (m_connection_ticket > -1) m_cc.done(m_connection_ticket);
-	m_connection_ticket = -1;
+	TORRENT_ASSERT(m_connection_ticket > -1);
 
 	// keep ourselves alive even if the callback function
 	// deletes this object
 	boost::shared_ptr<http_connection> me(shared_from_this());
 
-	if (!m_endpoints.empty())
-	{
-		error_code ec;
-		m_sock.close(ec);
-	} 
-	else
-	{ 
-		callback(asio::error::timed_out);
-		close();
-	}
+	error_code ec;
+	m_sock.close(ec);
 }
 
 void http_connection::on_timeout(boost::weak_ptr<http_connection> p
@@ -550,6 +542,12 @@ void http_connection::queue_connect()
 
 void http_connection::connect(int ticket, tcp::endpoint target_address)
 {
+	if (ticket == -1)
+	{
+		close();
+		return;
+	}
+
 	m_connection_ticket = ticket;
 	if (m_proxy.proxy_hostnames
 		&& (m_proxy.type == proxy_settings::socks5

src/peer_connection.cpp

@@ -5245,6 +5245,12 @@ namespace libtorrent
 		(*m_ses.m_logger) << time_now_string() << " ON_CONNECT: " << print_endpoint(m_remote) << "\n";
 #endif
 
+		if (ticket == -1)
+		{
+			disconnect(asio::error::operation_aborted);
+			return;		
+		}
+
 		m_connection_ticket = ticket;
 		boost::shared_ptr<torrent> t = m_torrent.lock();
 

src/session_impl.cpp

@@ -5495,7 +5495,9 @@ namespace aux {
 		{
 			sleep(1000);
 			++counter;
-			printf("\n==== Waiting to shut down: %d ==== conn-queue: %d\n\n", counter, m_half_open.size());
+			printf("\n==== Waiting to shut down: %d ==== conn-queue: %d connecting: %d timeout (next: %f max: %f)\n\n"
+				, counter, m_half_open.size(), m_half_open.num_connecting(), m_half_open.next_timeout()
+				, m_half_open.max_timeout());
 		}
 		async_dec_threads();
 #endif

src/udp_socket.cpp

@@ -776,6 +776,11 @@ void udp_socket::on_connect(int ticket)
 
 	if (m_abort) return;
 	if (is_closed()) return;
+	if (ticket == -1)
+	{
+		close();
+		return;
+	}
 
 #if defined TORRENT_ASIO_DEBUGGING
 	add_outstanding_async("udp_socket::on_connected");