added alert for torrent state changes. Fixes #360

examples/client_test.cpp

@@ -584,6 +584,10 @@ libtorrent::torrent_handle get_active_torrent(handles_t const& handles)
 	return i->second;
 }
 
+static char const* state_str[] =
+	{"checking (q)", "checking", "connecting", "dl metadata"
+	, "downloading", "finished", "seeding", "allocating"};
+
 int main(int ac, char* av[])
 {
 #if BOOST_VERSION < 103400
@@ -1181,6 +1185,12 @@ int main(int ac, char* av[])
 						if (h.is_paused() && !h.is_auto_managed()) ses.remove_torrent(h);
 					}
 				}
+				else if (state_changed_alert* p = dynamic_cast<state_changed_alert*>(a.get()))
+				{
+					std::string name;
+					if (p->handle.is_valid()) name = p->handle.name();
+					event_string << "(" << name << ") " << p->msg() << " " << state_str[p->state];
+				}
 				else if (torrent_alert* p = dynamic_cast<torrent_alert*>(a.get()))
 				{
 					std::string name;
@@ -1266,13 +1276,7 @@ int main(int ac, char* av[])
 
 				if (paused && !auto_managed) out << "paused";
 				else if (paused && auto_managed) out << "queued";
-				else
-				{
-					static char const* state_str[] =
-						{"checking (q)", "checking", "connecting", "dl metadata"
-						, "downloading", "finished", "seeding", "allocating"};
-					out << state_str[s.state];
-				}
+				else out << state_str[s.state];
 
 				int seeds = 0;
 				int downloaders = 0;

include/libtorrent/alert_types.hpp

@@ -68,6 +68,21 @@ namespace libtorrent
 		std::string name;
 	};
 
+	struct TORRENT_EXPORT state_changed_alert: torrent_alert
+	{
+		state_changed_alert(torrent_handle const& h
+			, torrent_status::state_t const& state_
+			, std::string const& msg)
+			: torrent_alert(h, alert::info, msg)
+			, state(state_)
+		{}
+
+		virtual std::auto_ptr<alert> clone() const
+		{ return std::auto_ptr<alert>(new state_changed_alert(*this)); }
+
+		torrent_status::state_t state;
+	};
+
 	struct TORRENT_EXPORT tracker_alert: torrent_alert
 	{
 		tracker_alert(torrent_handle const& h

include/libtorrent/torrent.hpp

@@ -167,6 +167,7 @@ namespace libtorrent
 		bool is_aborted() const { return m_abort; }
 
 		torrent_status::state_t state() const { return m_state; }
+		void set_state(torrent_status::state_t s);
 
 		session_settings const& settings() const;
 		

src/torrent.cpp

@@ -446,7 +446,7 @@ namespace libtorrent
 		std::copy(url_seeds.begin(), url_seeds.end(), std::inserter(m_web_seeds
 			, m_web_seeds.begin()));
 
-		m_state = torrent_status::queued_for_checking;
+		set_state(torrent_status::queued_for_checking);
 
 		if (m_resume_entry.type() == lazy_entry::dict_t)
 		{
@@ -654,7 +654,7 @@ namespace libtorrent
 			, int((m_torrent_file->total_size()+m_block_size-1)/m_block_size));
 		// assume that we don't have anything
 		m_files_checked = false;
-		m_state = torrent_status::queued_for_checking;
+		set_state(torrent_status::queued_for_checking);
 
 		if (m_auto_managed)
 			set_queue_position((std::numeric_limits<int>::max)());
@@ -691,7 +691,7 @@ namespace libtorrent
 
 	void torrent::start_checking()
 	{
-		m_state = torrent_status::checking_files;
+		set_state(torrent_status::checking_files);
 
 		m_storage->async_check_files(bind(
 			&torrent::on_piece_checked
@@ -3061,7 +3061,7 @@ namespace libtorrent
 				, "torrent has finished downloading"));
 		}
 
-		m_state = torrent_status::finished;
+		set_state(torrent_status::finished);
 		set_queue_position(-1);
 
 		// we have to call completed() before we start
@@ -3102,7 +3102,7 @@ namespace libtorrent
 		INVARIANT_CHECK;
 	
 		TORRENT_ASSERT(!is_finished());
-		m_state = torrent_status::downloading;
+		set_state(torrent_status::downloading);
 		set_queue_position((std::numeric_limits<int>::max)());
 	}
 
@@ -3116,7 +3116,7 @@ namespace libtorrent
 		// make the next tracker request
 		// be a completed-event
 		m_event = tracker_request::completed;
-		m_state = torrent_status::seeding;
+		set_state(torrent_status::seeding);
 		force_tracker_request();
 	}
 
@@ -3188,7 +3188,7 @@ namespace libtorrent
 		TORRENT_ASSERT(m_torrent_file->is_valid());
 		INVARIANT_CHECK;
 
-		m_state = torrent_status::connecting_to_tracker;
+		set_state(torrent_status::connecting_to_tracker);
 
 		if (!is_seed())
 		{
@@ -4039,6 +4039,17 @@ namespace libtorrent
 		}
 	}
 	
+	void torrent::set_state(torrent_status::state_t s)
+	{
+		if (m_state == s) return;
+		m_state = s;
+		if (m_ses.m_alerts.should_post(alert::info))
+		{
+			m_ses.m_alerts.post_alert(state_changed_alert(get_handle()
+				, s, "torrent status changed"));
+		}
+	}
+
 	torrent_status torrent::status() const
 	{
 		INVARIANT_CHECK;