fixed race condition in tracker manager

include/libtorrent/tracker_manager.hpp

@@ -194,11 +194,10 @@ namespace libtorrent
 			, address bind_interface
 			, boost::weak_ptr<request_callback> r);
 
-		request_callback& requester();
+		boost::shared_ptr<request_callback> requester();
 		virtual ~tracker_connection() {}
 
 		tracker_request const& tracker_req() const { return m_req; }
-		bool has_requester() const { return !m_requester.expired(); }
 
 		void fail(int code, char const* msg);
 		void fail_timeout();

src/http_tracker_connection.cpp

@@ -459,14 +459,16 @@ namespace libtorrent
 		m_send_buffer += "\r\n\r\n";
 
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester())
+
+		boost::shared_ptr<request_callback> cb = requester();
+		if (cb)
 		{
-			requester().debug_log("==> TRACKER_REQUEST [ str: " + m_send_buffer + " ]");
+			cb->debug_log("==> TRACKER_REQUEST [ str: " + m_send_buffer + " ]");
 			std::stringstream info_hash_str;
 			info_hash_str << req.info_hash;
-			requester().debug_log("info_hash: "
+			cb->debug_log("info_hash: "
 				+ boost::lexical_cast<std::string>(req.info_hash));
-			requester().debug_log("name lookup: " + hostname);
+			cb->debug_log("name lookup: " + hostname);
 		}
 #endif
 
@@ -491,8 +493,9 @@ namespace libtorrent
 	void http_tracker_connection::name_lookup(asio::error_code const& error
 		, tcp::resolver::iterator i) try
 	{
+		boost::shared_ptr<request_callback> cb = requester();
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester()) requester().debug_log("tracker name lookup handler called");
+		if (cb) cb->debug_log("tracker name lookup handler called");
 #endif
 		if (error == asio::error::operation_aborted) return;
 		if (m_timed_out) return;
@@ -504,7 +507,7 @@ namespace libtorrent
 		}
 		
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester()) requester().debug_log("tracker name lookup successful");
+		if (cb) cb->debug_log("tracker name lookup successful");
 #endif
 		restart_read_timeout();
 
@@ -519,11 +522,11 @@ namespace libtorrent
 		if (target == end)
 		{
 			assert(target_address.address().is_v4() != bind_interface().is_v4());
-			if (has_requester())
+			if (cb)
 			{
 				std::string tracker_address_type = target_address.address().is_v4() ? "IPv4" : "IPv6";
 				std::string bind_address_type = bind_interface().is_v4() ? "IPv4" : "IPv6";
-				requester().tracker_warning("the tracker only resolves to an "
+				cb->tracker_warning("the tracker only resolves to an "
 					+ tracker_address_type + " address, and you're listening on an "
 					+ bind_address_type + " socket. This may prevent you from receiving incoming connections.");
 			}
@@ -533,7 +536,7 @@ namespace libtorrent
 			target_address = *target;
 		}
 
-		if (has_requester()) requester().m_tracker_address = target_address;
+		if (cb) cb->m_tracker_address = target_address;
 		m_socket = instantiate_connection(m_name_lookup.io_service(), m_proxy);
 
 		if (m_proxy.type == proxy_settings::http
@@ -574,7 +577,8 @@ namespace libtorrent
 		}
 
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester()) requester().debug_log("tracker connection successful");
+		boost::shared_ptr<request_callback> cb = requester();
+		if (cb) cb->debug_log("tracker connection successful");
 #endif
 
 		restart_read_timeout();
@@ -598,7 +602,8 @@ namespace libtorrent
 		}
 
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester()) requester().debug_log("tracker send data completed");
+		boost::shared_ptr<request_callback> cb = requester();
+		if (cb) cb->debug_log("tracker send data completed");
 #endif
 		restart_read_timeout();
 		assert(m_buffer.size() - m_recv_pos > 0);
@@ -634,7 +639,8 @@ namespace libtorrent
 		restart_read_timeout();
 		assert(bytes_transferred > 0);
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester()) requester().debug_log("tracker connection reading "
+		boost::shared_ptr<request_callback> cb = requester();
+		if (cb) cb->debug_log("tracker connection reading "
 			+ boost::lexical_cast<std::string>(bytes_transferred));
 #endif
 
@@ -700,6 +706,8 @@ namespace libtorrent
 		}
 	
 		std::string location = m_parser.header<std::string>("location");
+
+		boost::shared_ptr<request_callback> cb = requester();
 		
 		if (m_parser.status_code() >= 300 && m_parser.status_code() < 400)
 		{
@@ -720,9 +728,9 @@ namespace libtorrent
 			}
 
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-			if (has_requester()) requester().debug_log("Redirecting to \"" + location + "\"");
+			if (cb) cb->debug_log("Redirecting to \"" + location + "\"");
 #endif
-			if (has_requester()) requester().tracker_warning("Redirecting to \"" + location + "\"");
+			if (cb) cb->tracker_warning("Redirecting to \"" + location + "\"");
 			tracker_request req = tracker_req();
 
 			req.url = location;
@@ -745,20 +753,18 @@ namespace libtorrent
 		std::string content_encoding = m_parser.header<std::string>("content-encoding");
 
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester()) requester().debug_log("content-encoding: \"" + content_encoding + "\"");
+		if (cb) cb->debug_log("content-encoding: \"" + content_encoding + "\"");
 #endif
 
 		if (content_encoding == "gzip" || content_encoding == "x-gzip")
 		{
-			boost::shared_ptr<request_callback> r = m_requester.lock();
-			
-			if (!r)
+			if (!cb)
 			{
 				close();
 				return;
 			}
 			m_buffer.erase(m_buffer.begin(), m_buffer.begin() + m_parser.body_start());
-			if (inflate_gzip(m_buffer, tracker_request(), r.get(),
+			if (inflate_gzip(m_buffer, tracker_request(), cb.get(),
 				m_settings.tracker_maximum_response_length))
 			{
 				close();
@@ -835,7 +841,8 @@ namespace libtorrent
 
 	void http_tracker_connection::parse(entry const& e)
 	{
-		if (!has_requester()) return;
+		boost::shared_ptr<request_callback> cb = requester();
+		if (!cb) return;
 
 		try
 		{
@@ -852,8 +859,7 @@ namespace libtorrent
 			try
 			{
 				entry const& warning = e["warning message"];
-				if (has_requester())
-					requester().tracker_warning(warning.string());
+				cb->tracker_warning(warning.string());
 			}
 			catch(type_error const&) {}
 			
@@ -867,7 +873,7 @@ namespace libtorrent
 				entry scrape_data = e["files"][ih];
 				int complete = scrape_data["complete"].integer();
 				int incomplete = scrape_data["incomplete"].integer();
-				requester().tracker_response(tracker_request(), peer_list, 0, complete
+				cb->tracker_response(tracker_request(), peer_list, 0, complete
 					, incomplete);
 				return;
 			}
@@ -914,16 +920,16 @@ namespace libtorrent
 			try { incomplete = e["incomplete"].integer(); }
 			catch(type_error&) {}
 			
-			requester().tracker_response(tracker_request(), peer_list, interval, complete
+			cb->tracker_response(tracker_request(), peer_list, interval, complete
 				, incomplete);
 		}
 		catch(type_error& e)
 		{
-			requester().tracker_request_error(tracker_request(), m_parser.status_code(), e.what());
+			cb->tracker_request_error(tracker_request(), m_parser.status_code(), e.what());
 		}
 		catch(std::runtime_error& e)
 		{
-			requester().tracker_request_error(tracker_request(), m_parser.status_code(), e.what());
+			cb->tracker_request_error(tracker_request(), m_parser.status_code(), e.what());
 		}
 	}
 

src/tracker_manager.cpp

@@ -365,23 +365,22 @@ namespace libtorrent
 		, m_req(req)
 	{}
 
-	request_callback& tracker_connection::requester()
+	boost::shared_ptr<request_callback> tracker_connection::requester()
 	{
-		boost::shared_ptr<request_callback> r = m_requester.lock();
-		assert(r);
-		return *r;
+		return m_requester.lock();
 	}
 
 	void tracker_connection::fail(int code, char const* msg)
 	{
-		if (has_requester()) requester().tracker_request_error(
-			m_req, code, msg);
+		boost::shared_ptr<request_callback> cb = requester();
+		if (cb) cb->tracker_request_error(m_req, code, msg);
 		close();
 	}
 
 	void tracker_connection::fail_timeout()
 	{
-		if (has_requester()) requester().tracker_request_timed_out(m_req);
+		boost::shared_ptr<request_callback> cb = requester();
+		if (cb) cb->tracker_request_timed_out(m_req);
 		close();
 	}
 	
@@ -548,7 +547,8 @@ namespace libtorrent
 
 			m_connections.push_back(con);
 
-			if (con->has_requester()) con->requester().m_manager = this;
+			boost::shared_ptr<request_callback> cb = con->requester();
+			if (cb) cb->m_manager = this;
 		}
 		catch (std::exception& e)
 		{

src/udp_tracker_connection.cpp

@@ -110,8 +110,9 @@ namespace libtorrent
 			return;
 		}
 
+		boost::shared_ptr<request_callback> cb = requester();
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester()) requester().debug_log("udp tracker name lookup successful");
+		if (cb) cb->debug_log("udp tracker name lookup successful");
 #endif
 		restart_read_timeout();
 		
@@ -126,11 +127,11 @@ namespace libtorrent
 		if (target == end)
 		{
 			assert(target_address.address().is_v4() != bind_interface().is_v4());
-			if (has_requester())
+			if (cb)
 			{
 				std::string tracker_address_type = target_address.address().is_v4() ? "IPv4" : "IPv6";
 				std::string bind_address_type = bind_interface().is_v4() ? "IPv4" : "IPv6";
-				requester().tracker_warning("the tracker only resolves to an "
+				cb->tracker_warning("the tracker only resolves to an "
 					+ tracker_address_type + " address, and you're listening on an "
 					+ bind_address_type + " socket. This may prevent you from receiving incoming connections.");
 			}
@@ -140,7 +141,7 @@ namespace libtorrent
 			target_address = *target;
 		}
 		
-		if (has_requester()) requester().m_tracker_address = tcp::endpoint(target_address.address(), target_address.port());
+		if (cb) cb->m_tracker_address = tcp::endpoint(target_address.address(), target_address.port());
 		m_target = target_address;
 		m_socket.reset(new datagram_socket(m_name_lookup.io_service()));
 		m_socket->open(target_address.protocol());
@@ -163,9 +164,10 @@ namespace libtorrent
 	void udp_tracker_connection::send_udp_connect()
 	{
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester())
+		boost::shared_ptr<request_callback> cb = requester();
+		if (cb)
 		{
-			requester().debug_log("==> UDP_TRACKER_CONNECT ["
+			cb->debug_log("==> UDP_TRACKER_CONNECT ["
 				+ lexical_cast<std::string>(tracker_req().info_hash) + "]");
 		}
 #endif
@@ -259,9 +261,10 @@ namespace libtorrent
 		m_connection_id = detail::read_int64(ptr);
 
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester())
+		boost::shared_ptr<request_callback> cb = requester();
+		if (cb)
 		{
-			requester().debug_log("<== UDP_TRACKER_CONNECT_RESPONSE ["
+			cb->debug_log("<== UDP_TRACKER_CONNECT_RESPONSE ["
 				+ lexical_cast<std::string>(m_connection_id) + "]");
 		}
 #endif
@@ -321,9 +324,10 @@ namespace libtorrent
 		detail::write_uint16(0, out);
 
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester())
+		boost::shared_ptr<request_callback> cb = requester();
+		if (cb)
 		{
-			requester().debug_log("==> UDP_TRACKER_ANNOUNCE ["
+			cb->debug_log("==> UDP_TRACKER_ANNOUNCE ["
 				+ lexical_cast<std::string>(req.info_hash) + "]");
 		}
 #endif
@@ -431,14 +435,15 @@ namespace libtorrent
 			return;
 		}
 
+		boost::shared_ptr<request_callback> cb = requester();
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
-		if (has_requester())
+		if (cb)
 		{
-			requester().debug_log("<== UDP_TRACKER_ANNOUNCE_RESPONSE");
+			cb->debug_log("<== UDP_TRACKER_ANNOUNCE_RESPONSE");
 		}
 #endif
 
-		if (!has_requester())
+		if (!cb)
 		{
 			m_man.remove_request(this);
 			return;
@@ -459,7 +464,7 @@ namespace libtorrent
 			peer_list.push_back(e);
 		}
 
-		requester().tracker_response(tracker_req(), peer_list, interval
+		cb->tracker_response(tracker_req(), peer_list, interval
 			, complete, incomplete);
 
 		m_man.remove_request(this);
@@ -534,14 +539,15 @@ namespace libtorrent
 		/*int downloaded = */detail::read_int32(buf);
 		int incomplete = detail::read_int32(buf);
 
-		if (!has_requester())
+		boost::shared_ptr<request_callback> cb = requester();
+		if (!cb)
 		{
 			m_man.remove_request(this);
 			return;
 		}
 		
 		std::vector<peer_entry> peer_list;
-		requester().tracker_response(tracker_req(), peer_list, 0
+		cb->tracker_response(tracker_req(), peer_list, 0
 			, complete, incomplete);
 
 		m_man.remove_request(this);