support forced shutdown/destruction of torrent objects

include/libtorrent/peer_list.hpp

@@ -103,6 +103,8 @@ namespace libtorrent {
 		explicit peer_list(torrent_peer_allocator_interface& alloc);
 		~peer_list();
 
+		void clear();
+
 		// not copyable
 		peer_list(peer_list const&) = delete;
 		peer_list& operator=(peer_list const&) = delete;

include/libtorrent/torrent.hpp

@@ -448,6 +448,7 @@ namespace libtorrent {
 		// the necessary actions then.
 		void abort();
 		bool is_aborted() const { return m_abort; }
+		void panic();
 
 		void new_external_ip();
 

include/libtorrent/torrent_peer.hpp

@@ -57,7 +57,7 @@ namespace libtorrent {
 #if TORRENT_USE_ASSERTS
 		torrent_peer(torrent_peer const&) = default;
 		torrent_peer& operator=(torrent_peer const&) = default;
-		~torrent_peer() { in_use = false; }
+		~torrent_peer() { TORRENT_ASSERT(in_use); in_use = false; }
 #endif
 
 		std::int64_t total_download() const;

src/peer_list.cpp

@@ -125,6 +125,13 @@ namespace libtorrent {
 		thread_started();
 	}
 
+	void peer_list::clear()
+	{
+		for (auto const p : m_peers)
+			m_peer_allocator.free_peer_entry(p);
+		m_peers.clear();
+	}
+
 	peer_list::~peer_list()
 	{
 		for (auto const p : m_peers)

src/session_impl.cpp

@@ -6030,7 +6030,13 @@ namespace {
 //		TORRENT_ASSERT(is_not_thread());
 // TODO: asserts that no outstanding async operations are still in flight
 
-		TORRENT_ASSERT(m_torrents.empty());
+		// this can happen if we end the io_service run loop with an exception
+		for (auto& t : m_torrents)
+		{
+			t.second->panic();
+			t.second->abort();
+		}
+		m_torrents.clear();
 
 #if defined TORRENT_ASIO_DEBUGGING
 		FILE* f = fopen("wakeups.log", "w+");

src/torrent.cpp

@@ -4419,6 +4419,18 @@ namespace libtorrent {
 		m_state_subscription = false;
 	}
 
+	// this is called when we're destructing non-gracefully. i.e. we're _just_
+	// destructing everything.
+	void torrent::panic()
+	{
+		m_storage.reset();
+		// if there are any other peers allocated still, we need to clear them
+		// now. They can't be cleared later because the allocator will already
+		// have been destructed
+		if (m_peer_list) m_peer_list->clear();
+		m_connections.clear();
+	}
+
 	void torrent::set_super_seeding(bool on)
 	{
 		if (on == m_super_seeding) return;