added wait_for_alert() to session. If there is at least one alert in the queue, it returns the front one in the queue, if the queue is empty, it waits until a new alert is posted and returns that one, or returns 0 if the time expires first.

include/libtorrent/alert.hpp

@@ -43,6 +43,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #endif
 
 #include <boost/thread/mutex.hpp>
+#include <boost/thread/condition.hpp>
 
 #include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
 #include <boost/preprocessor/repetition/enum.hpp>
@@ -99,10 +100,13 @@ namespace libtorrent {
 		void set_severity(alert::severity_t severity);
 		bool should_post(alert::severity_t severity) const;
 
+		alert const* wait_for_alert(time_duration max_wait);
+
 	private:
 		std::queue<alert*> m_alerts;
 		alert::severity_t m_severity;
 		mutable boost::mutex m_mutex;
+		boost::condition m_condition;
 	};
 
 	struct TORRENT_EXPORT unhandled_alert : std::exception

include/libtorrent/aux_/session_impl.hpp

@@ -280,6 +280,8 @@ namespace libtorrent
 			void set_severity_level(alert::severity_t s);
 			std::auto_ptr<alert> pop_alert();
 
+			alert const* wait_for_alert(time_duration max_wait);
+
 			int upload_rate_limit() const;
 			int download_rate_limit() const;
 

include/libtorrent/session.hpp

@@ -60,6 +60,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/session_status.hpp"
 #include "libtorrent/version.hpp"
 #include "libtorrent/fingerprint.hpp"
+#include "libtorrent/time.hpp"
 
 #include "libtorrent/storage.hpp"
 
@@ -264,6 +265,8 @@ namespace libtorrent
 		std::auto_ptr<alert> pop_alert();
 		void set_severity_level(alert::severity_t s);
 
+		alert const* wait_for_alert(time_duration max_wait);
+
 		connection_queue& get_connection_queue();
 
 		// starts/stops UPnP, NATPMP or LSD port mappers

include/libtorrent/time.hpp

@@ -98,6 +98,7 @@ namespace libtorrent
 		time_duration() {}
 		time_duration operator/(int rhs) const { return time_duration(diff / rhs); }
 		explicit time_duration(boost::int64_t d) : diff(d) {}
+		time_duration& operator-=(time_duration const& c) { diff -= c.diff; return *this; }
 		boost::int64_t diff;
 	};
 

src/alert.cpp

@@ -33,6 +33,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/pch.hpp"
 
 #include "libtorrent/alert.hpp"
+#include <boost/thread/xtime.hpp>
 
 namespace libtorrent {
 
@@ -77,6 +78,30 @@ namespace libtorrent {
 		}
 	}
 
+	alert const* alert_manager::wait_for_alert(time_duration max_wait)
+	{
+		boost::mutex::scoped_lock lock(m_mutex);
+
+		if (!m_alerts.empty()) return m_alerts.front();
+		
+		int secs = total_seconds(max_wait);
+		max_wait -= seconds(secs);
+		boost::xtime xt;
+		boost::xtime_get(&xt, boost::TIME_UTC);
+		xt.sec += secs;
+		boost::int64_t nsec = xt.nsec + total_microseconds(max_wait) * 1000;
+		if (nsec > 1000000000)
+		{
+			nsec -= 1000000000;
+			xt.sec += 1;
+		}
+		xt.nsec = nsec;
+		if (!m_condition.timed_wait(lock, xt)) return 0;
+		TORRENT_ASSERT(!m_alerts.empty());
+		if (m_alerts.empty()) return 0;
+		return m_alerts.front();
+	}
+
 	void alert_manager::post_alert(const alert& alert_)
 	{
 		boost::mutex::scoped_lock lock(m_mutex);
@@ -90,6 +115,7 @@ namespace libtorrent {
 			delete result;
 		}
 		m_alerts.push(alert_.clone().release());
+		m_condition.notify_all();
 	}
 
 	std::auto_ptr<alert> alert_manager::get()

src/session.cpp

@@ -422,6 +422,11 @@ namespace libtorrent
 		return m_impl->pop_alert();
 	}
 
+	alert const* session::wait_for_alert(time_duration max_wait)
+	{
+		return m_impl->wait_for_alert(max_wait);
+	}
+
 	void session::set_severity_level(alert::severity_t s)
 	{
 		m_impl->set_severity_level(s);

src/session_impl.cpp

@@ -2251,6 +2251,11 @@ namespace detail
 			return m_alerts.get();
 		return std::auto_ptr<alert>(0);
 	}
+	
+	alert const* session_impl::wait_for_alert(time_duration max_wait)
+	{
+		return m_alerts.wait_for_alert(max_wait);
+	}
 
 	void session_impl::set_severity_level(alert::severity_t s)
 	{

test/test_swarm.cpp

@@ -1,6 +1,7 @@
 #include "libtorrent/session.hpp"
 #include "libtorrent/session_settings.hpp"
 #include "libtorrent/hasher.hpp"
+#include "libtorrent/alert_types.hpp"
 #include <boost/thread.hpp>
 #include <boost/tuple/tuple.hpp>
 #include <boost/filesystem/operations.hpp>
@@ -19,10 +20,14 @@ void test_swarm()
 	session ses2(fingerprint("LT", 0, 1, 0, 0), std::make_pair(49000, 50000));
 	session ses3(fingerprint("LT", 0, 1, 0, 0), std::make_pair(50000, 51000));
 
+	ses1.set_severity_level(alert::debug);
+	ses2.set_severity_level(alert::debug);
+	ses3.set_severity_level(alert::debug);
+	
 	// this is to avoid everything finish from a single peer
 	// immediately. To make the swarm actually connect all
 	// three peers before finishing.
-	float rate_limit = 40000;
+	float rate_limit = 100000;
 	ses1.set_upload_rate_limit(int(rate_limit));
 	ses2.set_download_rate_limit(int(rate_limit));
 	ses3.set_download_rate_limit(int(rate_limit));
@@ -55,7 +60,7 @@ void test_swarm()
 	int count_dl_rates2 = 0;
 	int count_dl_rates3 = 0;
 
-	for (int i = 0; i < 65; ++i)
+	for (int i = 0; i < 25; ++i)
 	{
 		std::auto_ptr<alert> a;
 		a = ses1.pop_alert();
@@ -74,12 +79,12 @@ void test_swarm()
 		torrent_status st2 = tor2.status();
 		torrent_status st3 = tor3.status();
 
-		if (st2.progress < 1.f && st2.progress > 0.3f)
+		if (st2.progress < 1.f && st2.progress > 0.5f)
 		{
 			sum_dl_rate2 += st2.download_payload_rate;
 			++count_dl_rates2;
 		}
-		if (st3.progress < 1.f && st3.progress > 0.3f)
+		if (st3.progress < 1.f && st3.progress > 0.5f)
 		{
 			sum_dl_rate3 += st3.download_rate;
 			++count_dl_rates3;
@@ -111,14 +116,38 @@ void test_swarm()
 	std::cerr << "average rate: " << (average2 / 1000.f) << "kB/s - "
 		<< (average3 / 1000.f) << "kB/s" << std::endl;
 
-	TEST_CHECK(std::fabs(average2 - float(rate_limit)) < 3000.f);
-	TEST_CHECK(std::fabs(average3 - float(rate_limit)) < 3000.f);
+	TEST_CHECK(std::fabs(average2 - float(rate_limit)) < 5000.f);
+	TEST_CHECK(std::fabs(average3 - float(rate_limit)) < 5000.f);
 	if (tor2.is_seed() && tor3.is_seed()) std::cerr << "done\n";
 
 	// make sure the files are deleted
 	ses1.remove_torrent(tor1, session::delete_files);
 	ses2.remove_torrent(tor2, session::delete_files);
 	ses3.remove_torrent(tor3, session::delete_files);
+
+	std::auto_ptr<alert> a = ses1.pop_alert();
+	ptime end = time_now() + seconds(20);
+	while (a.get() == 0 || dynamic_cast<torrent_deleted_alert*>(a.get()) == 0)
+	{
+		if (ses1.wait_for_alert(end - time_now()) == 0)
+		{
+			std::cerr << "wait_for_alert() expired" << std::endl;
+			break;
+		}
+		a = ses1.pop_alert();
+		assert(a.get());
+		std::cerr << a->msg() << std::endl;
+		if (dynamic_cast<torrent_deleted_alert*>(a.get()) != 0) break;
+	}
+
+	TEST_CHECK(dynamic_cast<torrent_deleted_alert*>(a.get()) != 0);
+
+	ptime start = time_now();
+	alert const* ret = ses1.wait_for_alert(seconds(2));
+	TEST_CHECK(ret == 0);
+	if (ret != 0) std::cerr << ret->msg() << std::endl;
+	TEST_CHECK(time_now() - start < seconds(3));
+	TEST_CHECK(time_now() - start > seconds(2));
 }
 
 int test_main()