remove mutex from tracker_manager (#690)

remove mutex from tracker_manager

include/libtorrent/tracker_manager.hpp

@@ -41,7 +41,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <string>
 #include <list>
 #include <utility>
-#include <mutex>
 
 #include <boost/shared_ptr.hpp>
 #include <boost/enable_shared_from_this.hpp>
@@ -66,6 +65,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/io_service.hpp"
 #include "libtorrent/aux_/array_view.hpp"
 #include "libtorrent/time.hpp"
+#include "libtorrent/debug.hpp"
 
 namespace libtorrent
 {
@@ -274,9 +274,6 @@ namespace libtorrent
 
 		int m_completion_timeout;
 
-		// TODO: 3 is this object really accessed from multiple threads?
-		mutable std::mutex m_mutex;
-
 		// used for timeouts
 		// this is set when the request has been sent
 		time_point m_start_time;
@@ -339,6 +336,7 @@ namespace libtorrent
 
 	class TORRENT_EXTRA_EXPORT tracker_manager final
 		: boost::noncopyable
+		, single_threaded
 	{
 	public:
 
@@ -398,8 +396,6 @@ namespace libtorrent
 
 	private:
 
-		mutable std::mutex m_mutex;
-
 		// maps transactionid to the udp_tracker_connection
 		// These must use shared_ptr to avoid a dangling reference
 		// if a connection is erased while a timeout event is in the queue

include/libtorrent/udp_tracker_connection.hpp

@@ -39,6 +39,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <string>
 #include <utility>
 #include <ctime>
+#include <mutex>
 
 #include <boost/shared_ptr.hpp>
 #include <boost/cstdint.hpp>

src/natpmp.cpp

@@ -79,7 +79,6 @@ natpmp::natpmp(io_service& ios
 	// for this array not to be reallocated, by passing
 	// around pointers to its elements. so reserve size for now
 	m_mappings.reserve(10);
-	TORRENT_ASSERT(is_single_thread());
 }
 
 void natpmp::start()

src/tracker_manager.cpp

@@ -235,8 +235,7 @@ namespace libtorrent
 
 	void tracker_manager::remove_request(tracker_connection const* c)
 	{
-		std::lock_guard<std::mutex> l(m_mutex);
-
+		TORRENT_ASSERT(is_single_thread());
 		http_conns_t::iterator i = std::find_if(m_http_conns.begin()
 			, m_http_conns.end()
 			, boost::bind(&boost::shared_ptr<http_tracker_connection>::get, _1) == c);
@@ -261,6 +260,7 @@ namespace libtorrent
 		boost::shared_ptr<udp_tracker_connection> c
 		, boost::uint64_t tid)
 	{
+		TORRENT_ASSERT(is_single_thread());
 		m_udp_conns.erase(c->transaction_id());
 		m_udp_conns[tid] = c;
 	}
@@ -270,7 +270,7 @@ namespace libtorrent
 		, tracker_request req
 		, boost::weak_ptr<request_callback> c)
 	{
-		std::lock_guard<std::mutex> l(m_mutex);
+		TORRENT_ASSERT(is_single_thread());
 		TORRENT_ASSERT(req.num_want >= 0);
 		TORRENT_ASSERT(!m_abort || req.event == tracker_request::stopped);
 		if (m_abort && req.event != tracker_request::stopped) return;
@@ -316,6 +316,7 @@ namespace libtorrent
 	bool tracker_manager::incoming_packet(udp::endpoint const& ep
 		, aux::array_view<char const> const buf)
 	{
+		TORRENT_ASSERT(is_single_thread());
 		// ignore packets smaller than 8 bytes
 		if (buf.size() < 8)
 		{
@@ -350,17 +351,17 @@ namespace libtorrent
 		return p->on_receive(ep, buf);
 	}
 
-	void tracker_manager::incoming_error(error_code const& ec
-		, udp::endpoint const& ep)
+	void tracker_manager::incoming_error(error_code const&
+		, udp::endpoint const&)
 	{
-		TORRENT_UNUSED(ec);
-		TORRENT_UNUSED(ep);
+		TORRENT_ASSERT(is_single_thread());
 		// TODO: 2 implement
 	}
 
 	bool tracker_manager::incoming_packet(char const* hostname
 		, aux::array_view<char const> const buf)
 	{
+		TORRENT_ASSERT(is_single_thread());
 		// ignore packets smaller than 8 bytes
 		if (buf.size() < 16) return false;
 
@@ -392,6 +393,7 @@ namespace libtorrent
 	void tracker_manager::send_hostname(char const* hostname, int const port
 		, array_view<char const> p, error_code& ec, int const flags)
 	{
+		TORRENT_ASSERT(is_single_thread());
 		m_send_fun_hostname(hostname, port, p, ec, flags);
 	}
 
@@ -399,13 +401,16 @@ namespace libtorrent
 		, array_view<char const> p
 		, error_code& ec, int const flags)
 	{
+		TORRENT_ASSERT(is_single_thread());
 		m_send_fun(ep, p, ec, flags);
 	}
 
 	void tracker_manager::abort_all_requests(bool all)
 	{
+		// this is called from the destructor too, which is not subject to the
+		// single-thread requirement.
+		TORRENT_ASSERT(all || is_single_thread());
 		// removes all connections except 'event=stopped'-requests
-		std::unique_lock<std::mutex> l(m_mutex);
 
 		m_abort = true;
 		http_conns_t close_http_connections;
@@ -441,7 +446,6 @@ namespace libtorrent
 			if (rc) rc->debug_log("aborting: %s", req.url.c_str());
 #endif
 		}
-		l.unlock();
 
 		for (http_conns_t::iterator i = close_http_connections.begin()
 			, end(close_http_connections.end()); i != end; ++i)
@@ -459,13 +463,13 @@ namespace libtorrent
 
 	bool tracker_manager::empty() const
 	{
-		std::lock_guard<std::mutex> l(m_mutex);
+		TORRENT_ASSERT(is_single_thread());
 		return m_http_conns.empty() && m_udp_conns.empty();
 	}
 
 	int tracker_manager::num_requests() const
 	{
-		std::lock_guard<std::mutex> l(m_mutex);
+		TORRENT_ASSERT(is_single_thread());
 		return int(m_http_conns.size() + m_udp_conns.size());
 	}
 }

src/udp_tracker_connection.cpp

@@ -34,6 +34,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include <vector>
 #include <cctype>
+#include <mutex>
 
 #include <boost/bind.hpp>
 #include <boost/tuple/tuple.hpp>

src/upnp.cpp

@@ -90,7 +90,6 @@ upnp::upnp(io_service& ios
 	, m_last_if_update(min_time())
 {
 	TORRENT_ASSERT(cb);
-	TORRENT_ASSERT(is_single_thread());
 }
 
 void upnp::start()
@@ -104,10 +103,7 @@ void upnp::start()
 	m_mappings.reserve(10);
 }
 
-upnp::~upnp()
-{
-	TORRENT_ASSERT(is_single_thread());
-}
+upnp::~upnp() {}
 
 void upnp::discover_device()
 {