From 4ddbe44a0db100adbc570ffd2eb01e3abfa7fe0b Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Mon, 25 Jun 2012 03:31:11 +0000
Subject: [PATCH] fix bug in the udp socket observer use for DHT and add debug
 facilily for the observers

---
 include/libtorrent/udp_socket.hpp |  3 ++
 src/session_impl.cpp              | 12 ++------
 src/udp_socket.cpp                | 48 ++++++++++++++++++++++---------
 3 files changed, 40 insertions(+), 23 deletions(-)

diff --git a/include/libtorrent/udp_socket.hpp b/include/libtorrent/udp_socket.hpp
index 7579e8fcb..24dcd7fb8 100644
--- a/include/libtorrent/udp_socket.hpp
+++ b/include/libtorrent/udp_socket.hpp
@@ -174,6 +174,9 @@ 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
 		mutable pthread_t m_thread;
 #endif
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index 19345b632..5af059867 100644
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -1749,11 +1749,7 @@ namespace aux {
 		stop_upnp();
 		stop_natpmp();
 #ifndef TORRENT_DISABLE_DHT
-		if (m_dht)
-		{
-			m_dht->stop();
-			m_dht = 0;
-		}
+		stop_dht();
 		m_dht_announce_timer.cancel(ec);
 #endif
 		m_timer.cancel(ec);
@@ -5341,11 +5337,7 @@ namespace aux {
 	{
 		INVARIANT_CHECK;
 
-		if (m_dht)
-		{
-			m_dht->stop();
-			m_dht = 0;
-		}
+		stop_dht();
 		m_dht = new dht::dht_tracker(*this, m_udp_socket, m_dht_settings, &startup_state);
 
 		for (std::list<udp::endpoint>::iterator i = m_dht_router_nodes.begin()
diff --git a/src/udp_socket.cpp b/src/udp_socket.cpp
index 4cebfd921..3ec391488 100644
--- a/src/udp_socket.cpp
+++ b/src/udp_socket.cpp
@@ -75,6 +75,7 @@ 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;
@@ -95,6 +96,7 @@ udp_socket::~udp_socket()
 #endif
 	TORRENT_ASSERT_VAL(m_v4_outstanding == 0, m_v4_outstanding);
 	TORRENT_ASSERT(m_magic == 0x1337);
+	TORRENT_ASSERT(m_observers_locked == false);
 #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
 	m_magic = 0;
 #endif
@@ -226,6 +228,9 @@ 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)
 	{
@@ -236,10 +241,16 @@ void udp_socket::call_handler(error_code const& ec, udp::endpoint const& ep, cha
 
 		} TORRENT_CATCH (std::exception&) {}
 	}
+#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)
 	{
@@ -250,23 +261,16 @@ void udp_socket::call_handler(error_code const& ec, const char* host, char const
 
 		} TORRENT_CATCH (std::exception&) {}
 	}
-}
-
-void udp_socket::subscribe(udp_socket_observer* o)
-{
-	TORRENT_ASSERT(std::find(m_observers.begin(), m_observers.end(), o) == m_observers.end());
-	m_observers.push_back(o);
-}
-
-void udp_socket::unsubscribe(udp_socket_observer* o)
-{
-	std::vector<udp_socket_observer*>::iterator i = std::find(m_observers.begin(), m_observers.end(), o);
-	if (i == m_observers.end()) return;
-	m_observers.erase(i);
+#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)
 	{
@@ -274,6 +278,24 @@ void udp_socket::call_drained_handler()
 		(*i)->socket_drained();
 		} TORRENT_CATCH (std::exception&) {}
 	}
+#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());
+	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;
+	m_observers.erase(i);
 }
 
 void udp_socket::on_read_impl(udp::socket* s, udp::endpoint const& ep