applied patch from Sergei Vorobyov to allow changing the limit on outstanding alerts

docs/manual.rst

@@ -151,6 +151,7 @@ The ``session`` class has the following synopsis::
 		std::auto_ptr<alert> pop_alert();
 		alert const* wait_for_alert(time_duration max_wait);
 		void set_alert_mask(int m);
+		size_t set_alert_queue_size_limit(size_t queue_size_limit_);
 
 		void add_extension(boost::function<
 			boost::shared_ptr<torrent_plugin>(torrent*)> ext);
@@ -742,14 +743,15 @@ with a DHT ping packet, and connect to those that responds first. On windows one
 can only connect to a few peers at a time because of a built in limitation (in XP
 Service pack 2).
 
-pop_alert() set_alert_mask() wait_for_alert()
+pop_alert() set_alert_mask() wait_for_alert() set_alert_queue_size_limit()
----------------------------------------------
+--------------------------------------------------------------------------
 
 	::
 
 		std::auto_ptr<alert> pop_alert();
 		alert const* wait_for_alert(time_duration max_wait);
 		void set_alert_mask(int m);
+		size_t set_alert_queue_size_limit(size_t queue_size_limit_);
 
 ``pop_alert()`` is used to ask the session if any errors or events has occurred. With
 ``set_alert_mask()`` you can filter which alerts to receive through ``pop_alert()``.
@@ -763,6 +765,9 @@ same pointer until the alert is popped by calling ``pop_alert``. This is useful
 leaving any alert dispatching mechanism independent of this blocking call, the dispatcher
 can be called and it can pop the alert independently.
 
+``set_alert_queue_size_limit()`` you can specify how many alerts can be awaiting for dispatching.
+If this limit is reached, new incoming alerts can not be received until alerts are popped
+by calling ``pop_alert``. Default value is 1000.
 
 add_extension()
 ---------------

include/libtorrent/alert.hpp

@@ -111,6 +111,8 @@ namespace libtorrent {
 	class TORRENT_EXPORT alert_manager
 	{
 	public:
+		enum { queue_size_limit_default = 1000 };
+
 		alert_manager();
 		~alert_manager();
 
@@ -125,11 +127,15 @@ namespace libtorrent {
 
 		void set_alert_mask(int m) { m_alert_mask = m; }
 
+		size_t alert_queue_size_limit() const { return m_queue_size_limit; }
+		size_t set_alert_queue_size_limit(size_t queue_size_limit_);
+
 	private:
 		std::queue<alert*> m_alerts;
 		mutable boost::mutex m_mutex;
 		boost::condition m_condition;
 		int m_alert_mask;
+		size_t m_queue_size_limit;
 	};
 
 	struct TORRENT_EXPORT unhandled_alert : std::exception

include/libtorrent/aux_/session_impl.hpp

@@ -212,6 +212,7 @@ namespace libtorrent
 			void done_checking(boost::shared_ptr<torrent> const& t);
 
 			void set_alert_mask(int m);
+			size_t set_alert_queue_size_limit(size_t queue_size_limit_);
 			std::auto_ptr<alert> pop_alert();
 
 			alert const* wait_for_alert(time_duration max_wait);

include/libtorrent/session.hpp

@@ -331,6 +331,7 @@ namespace libtorrent
 		void set_severity_level(alert::severity_t s) TORRENT_DEPRECATED;
 #endif
 		void set_alert_mask(int m);
+		size_t set_alert_queue_size_limit(size_t queue_size_limit_);
 
 		alert const* wait_for_alert(time_duration max_wait);
 

src/alert.cpp

@@ -35,8 +35,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/alert.hpp"
 #include <boost/thread/xtime.hpp>
 
-enum { queue_size_limit = 1000 };
-
 namespace libtorrent {
 
 	alert::alert() : m_timestamp(time_now()) {}
@@ -45,6 +43,7 @@ namespace libtorrent {
 
 	alert_manager::alert_manager()
 		: m_alert_mask(alert::error_notification)
+		, m_queue_size_limit(queue_size_limit_default)
 	{}
 
 	alert_manager::~alert_manager()
@@ -85,7 +84,7 @@ namespace libtorrent {
 	{
 		boost::mutex::scoped_lock lock(m_mutex);
 
-		if (m_alerts.size() >= queue_size_limit) return;
+		if (m_alerts.size() >= m_queue_size_limit) return;
 		m_alerts.push(alert_.clone().release());
 		m_condition.notify_all();
 	}
@@ -108,5 +107,13 @@ namespace libtorrent {
 		return !m_alerts.empty();
 	}
 
+	size_t alert_manager::set_alert_queue_size_limit(size_t queue_size_limit_)
+	{
+		boost::mutex::scoped_lock lock(m_mutex);
+
+		std::swap(m_queue_size_limit, queue_size_limit_);
+		return queue_size_limit_;
+	}
+
 } // namespace libtorrent
 

src/session.cpp

@@ -553,6 +553,11 @@ namespace libtorrent
 		m_impl->set_alert_mask(m);
 	}
 
+	size_t set_alert_queue_size_limit(size_t queue_size_limit_);
+	{
+		return m_impl->set_alert_queue_size_limit(queue_size_limit_);
+	}
+
 #ifndef TORRENT_NO_DEPRECATE
 	void session::set_severity_level(alert::severity_t s)
 	{

src/session_impl.cpp

@@ -2312,6 +2312,12 @@ namespace aux {
 		m_alerts.set_alert_mask(m);
 	}
 
+	size_t session_impl::set_alert_queue_size_limit(size_t queue_size_limit_)
+	{
+		mutex_t::scoped_lock l(m_mutex);
+		return m_alerts.set_alert_queue_size_limit(queue_size_limit_);
+	}
+
 	int session_impl::upload_rate_limit() const
 	{
 		mutex_t::scoped_lock l(m_mutex);