fix for udp_socket observers and some dht warning fixes

include/libtorrent/aux_/session_impl.hpp

@@ -218,7 +218,7 @@ namespace libtorrent
 				, std::string const& logpath
 #endif
 				);
-			~session_impl();
+			virtual ~session_impl();
 			void init();
 			void start_session();
 

include/libtorrent/kademlia/dht_tracker.hpp

@@ -79,6 +79,7 @@ namespace libtorrent { namespace dht
 		// TODO: take a udp_socket_interface here instead. Move udp_socket_interface down into libtorrent core
 		dht_tracker(libtorrent::aux::session_impl& ses, rate_limited_udp_socket& sock
 			, dht_settings const& settings, entry const* state = 0);
+		virtual ~dht_tracker();
 
 		void start(entry const& bootstrap);
 		void stop();

include/libtorrent/udp_socket.hpp

@@ -146,7 +146,17 @@ namespace libtorrent
 	public:
 #endif
 
+		// observers on this udp socket
 		std::vector<udp_socket_observer*> m_observers;
+		std::vector<udp_socket_observer*> m_added_observers;
+
+		// this is true while iterating over the observers
+		// vector, invoking observer hooks. We may not
+		// add new observers during this time, since it
+		// may invalidate the iterator. If this is true,
+		// instead add new observers to m_added_observers
+		// and they will be added later
+		bool m_observers_locked;
 
 		void call_handler(error_code const& ec, udp::endpoint const& ep, char const* buf, int size);
 		void call_handler(error_code const& ec, const char* host, char const* buf, int size);
@@ -174,7 +184,6 @@ namespace libtorrent
 		void unwrap(error_code const& e, char const* buf, int size);
 
 #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
-		bool m_observers_locked;
 
 		// TODO: move this debug facility into a base class. It's used in a lot of places
 #if defined BOOST_HAS_PTHREADS

src/kademlia/dht_tracker.cpp

@@ -241,6 +241,8 @@ namespace libtorrent { namespace dht
 #endif
 	}
 
+	dht_tracker::~dht_tracker() {}
+
 	// defined in node.cpp
 	extern void nop();
 

src/udp_socket.cpp

@@ -54,7 +54,8 @@ using namespace libtorrent;
 
 udp_socket::udp_socket(asio::io_service& ios
 	, connection_queue& cc)
-	: m_ipv4_sock(ios)
+	: m_observers_locked(false)
+	, m_ipv4_sock(ios)
 	, m_buf_size(0)
 	, m_buf(0)
 #if TORRENT_USE_IPV6
@@ -75,7 +76,6 @@ udp_socket::udp_socket(asio::io_service& ios
 	, m_outstanding_ops(0)
 {
 #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
-	m_observers_locked = false;
 	m_magic = 0x1337;
 	m_started = false;
 	m_outstanding_when_aborted = -1;
@@ -228,73 +228,84 @@ void udp_socket::on_read(udp::socket* s)
 
 void udp_socket::call_handler(error_code const& ec, udp::endpoint const& ep, char const* buf, int size)
 {
-#if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
 	m_observers_locked = true;
-#endif
-	for (std::vector<udp_socket_observer*>::iterator i = m_observers.begin()
-		, end(m_observers.end()); i != end; ++i)
+	for (std::vector<udp_socket_observer*>::iterator i = m_observers.begin();
+		i != m_observers.end();)
 	{
+		bool ret = false;
 		TORRENT_TRY {
-
-		if ((*i)->incoming_packet(ec, ep, buf, size))
-			break;
-
+			ret = (*i)->incoming_packet(ec, ep, buf, size);
 		} TORRENT_CATCH (std::exception&) {}
+		if (*i == NULL) i = m_observers.erase(i);
+		else ++i;
+		if (ret) break;
+	}
+	if (!m_added_observers.empty())
+	{
+		m_observers.insert(m_observers.end(), m_added_observers.begin(), m_added_observers.end());
+		m_added_observers.clear();
 	}
-#if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
 	m_observers_locked = false;
-#endif
 }
 
 void udp_socket::call_handler(error_code const& ec, const char* host, char const* buf, int size)
 {
-#if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
 	m_observers_locked = true;
-#endif
-	for (std::vector<udp_socket_observer*>::iterator i = m_observers.begin()
-		, end(m_observers.end()); i != end; ++i)
+	for (std::vector<udp_socket_observer*>::iterator i = m_observers.begin();
+		i != m_observers.end();)
 	{
+		bool ret = false;
 		TORRENT_TRY {
-
-		if ((*i)->incoming_packet(ec, host, buf, size))
-			break;
-
+			ret = (*i)->incoming_packet(ec, host, buf, size);
 		} TORRENT_CATCH (std::exception&) {}
+		if (*i == NULL) i = m_observers.erase(i);
+		else ++i;
+		if (ret) break;
+	}
+	if (!m_added_observers.empty())
+	{
+		m_observers.insert(m_observers.end(), m_added_observers.begin(), m_added_observers.end());
+		m_added_observers.clear();
 	}
-#if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
 	m_observers_locked = false;
-#endif
 }
 
 void udp_socket::call_drained_handler()
 {
-#if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
 	m_observers_locked = true;
-#endif
-	for (std::vector<udp_socket_observer*>::iterator i = m_observers.begin()
-		, end(m_observers.end()); i != end; ++i)
+	for (std::vector<udp_socket_observer*>::iterator i = m_observers.begin();
+		i != m_observers.end();)
 	{
 		TORRENT_TRY {
 			(*i)->socket_drained();
 		} TORRENT_CATCH (std::exception&) {}
+		if (*i == NULL) i = m_observers.erase(i);
+		else ++i;
+	}
+	if (!m_added_observers.empty())
+	{
+		m_observers.insert(m_observers.end(), m_added_observers.begin(), m_added_observers.end());
+		m_added_observers.clear();
 	}
-#if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
 	m_observers_locked = false;
-#endif
 }
 
 void udp_socket::subscribe(udp_socket_observer* o)
 {
-	TORRENT_ASSERT(m_observers_locked == false);
 	TORRENT_ASSERT(std::find(m_observers.begin(), m_observers.end(), o) == m_observers.end());
+	if (m_observers_locked)
+		m_added_observers.push_back(o);
+	else
 		m_observers.push_back(o);
 }
 
 void udp_socket::unsubscribe(udp_socket_observer* o)
 {
-	TORRENT_ASSERT(m_observers_locked == false);
 	std::vector<udp_socket_observer*>::iterator i = std::find(m_observers.begin(), m_observers.end(), o);
 	if (i == m_observers.end()) return;
+	if (m_observers_locked)
+		*i = NULL;
+	else
 		m_observers.erase(i);
 }