fix shutdown issue caused by peer connections being kept alive by disk buffer pool callbacks

include/libtorrent/disk_buffer_pool.hpp

@@ -135,7 +135,7 @@ namespace libtorrent
 		// of buffers in use drops below the low watermark,
 		// we start calling these functions back
 		// TODO: try to remove the observers, only using the async_allocate handlers
-		std::vector<boost::shared_ptr<disk_observer> > m_observers;
+		std::vector<boost::weak_ptr<disk_observer> > m_observers;
 
 		// these handlers are executed when a new buffer is available
 		std::vector<handler_t> m_handlers;

src/disk_buffer_pool.cpp

@@ -64,8 +64,10 @@ POSSIBILITY OF SUCH DAMAGE.
 
 namespace libtorrent
 {
+	namespace {
+
 	// this is posted to the network thread
-	static void watermark_callback(std::vector<boost::shared_ptr<disk_observer> >* cbs
+	void watermark_callback(std::vector<boost::weak_ptr<disk_observer> >* cbs
 		, std::vector<disk_buffer_pool::handler_t>* handlers)
 	{
 		if (handlers)
@@ -78,13 +80,18 @@ namespace libtorrent
 
 		if (cbs != NULL)
 		{
-			for (std::vector<boost::shared_ptr<disk_observer> >::iterator i = cbs->begin()
+			for (std::vector<boost::weak_ptr<disk_observer> >::iterator i = cbs->begin()
 				, end(cbs->end()); i != end; ++i)
-				(*i)->on_disk();
+			{
+				boost::shared_ptr<disk_observer> o = i->lock();
+				if (o) o->on_disk();
+			}
 			delete cbs;
 		}
 	}
 
+	} // anonymous namespace
+
 	disk_buffer_pool::disk_buffer_pool(int block_size, io_service& ios
 		, boost::function<void()> const& trigger_trim)
 		: m_block_size(block_size)
@@ -183,7 +190,7 @@ namespace libtorrent
 		{
 			l.unlock();
 			m_ios.post(boost::bind(&watermark_callback
-				, static_cast<std::vector<boost::shared_ptr<disk_observer> >*>(NULL)
+				, static_cast<std::vector<boost::weak_ptr<disk_observer> >*>(NULL)
 				, slice));
 			return;
 		}
@@ -195,13 +202,13 @@ namespace libtorrent
 		{
 			l.unlock();
 			m_ios.post(boost::bind(&watermark_callback
-				, static_cast<std::vector<boost::shared_ptr<disk_observer> >*>(NULL)
+				, static_cast<std::vector<boost::weak_ptr<disk_observer> >*>(NULL)
 				, handlers));
 			return;
 		}
 
-		std::vector<boost::shared_ptr<disk_observer> >* cbs
+		std::vector<boost::weak_ptr<disk_observer> >* cbs
-			= new std::vector<boost::shared_ptr<disk_observer> >();
+			= new std::vector<boost::weak_ptr<disk_observer> >();
 		m_observers.swap(*cbs);
 		l.unlock();
 		m_ios.post(boost::bind(&watermark_callback, cbs, handlers));

src/session_impl.cpp

@@ -1153,17 +1153,6 @@ namespace aux {
 			TORRENT_ASSERT_VAL(conn == int(m_connections.size()) + 1, conn);
 		}
 
-		m_download_rate.close();
-		m_upload_rate.close();
-
-		// #error closing the udp socket here means that
-		// the uTP connections cannot be closed gracefully
-		m_udp_socket.close();
-		m_external_udp_port = 0;
-#ifdef TORRENT_USE_OPENSSL
-		m_ssl_udp_socket.close();
-#endif
-
 		// we need to give all the sockets an opportunity to actually have their handlers
 		// called and cancelled before we continue the shutdown. This is a bit
 		// complicated, if there are no "undead" peers, it's safe tor resume the
@@ -1179,6 +1168,15 @@ namespace aux {
 
 	void session_impl::abort_stage2()
 	{
+		m_download_rate.close();
+		m_upload_rate.close();
+
+		m_udp_socket.close();
+		m_external_udp_port = 0;
+#ifdef TORRENT_USE_OPENSSL
+		m_ssl_udp_socket.close();
+#endif
+
 		// it's OK to detach the threads here. The disk_io_thread
 		// has an internal counter and won't release the network
 		// thread until they're all dead (via m_work).