added support for uTorrent interpretation of multi-tracker torrents (off by default)

ChangeLog

@@ -1,3 +1,4 @@
+	* added support for uTorrent interpretation of multi-tracker torrents
 	* handle torrents with duplicate filenames
 	* piece timeouts are adjusted to download rate limits
 	* encodes urls in torrent files that needs to be encoded

bindings/python/src/session_settings.cpp

@@ -41,6 +41,7 @@ void bind_session_settings()
         .def_readwrite("num_want", &session_settings::num_want)
         .def_readwrite("initial_picker_threshold", &session_settings::initial_picker_threshold)
         .def_readwrite("allowed_fast_set_size", &session_settings::allowed_fast_set_size)
+        .def_readwrite("max_queued_disk_bytes", &session_settings::max_queued_disk_bytes)
         .def_readwrite("handshake_timeout", &session_settings::handshake_timeout)
 #ifndef TORRENT_DISABLE_DHT
         .def_readwrite("use_dht_as_fallback", &session_settings::use_dht_as_fallback)
@@ -82,6 +83,7 @@ void bind_session_settings()
         .def_readwrite("auto_manage_startup", &session_settings::auto_manage_startup)
         .def_readwrite("rate_limit_ip_overhead", &session_settings::rate_limit_ip_overhead)
         .def_readwrite("announce_to_all_trackers", &session_settings::announce_to_all_trackers)
+        .def_readwrite("announce_to_all_tiers", &session_settings::announce_to_all_tiers)
         .def_readwrite("prefer_udp_trackers", &session_settings::prefer_udp_trackers)
         .def_readwrite("strict_super_seeding", &session_settings::strict_super_seeding)
         .def_readwrite("seeding_piece_quota", &session_settings::seeding_piece_quota)

docs/manual.rst

@@ -3486,6 +3486,8 @@ session_settings
 		bool rate_limit_ip_overhead;
 
 		bool announce_to_all_trackers;
+		bool announce_to_all_tiers;
+
 		bool prefer_udp_trackers;
 		bool strict_super_seeding;
 
@@ -3837,10 +3839,14 @@ drained from the rate limiters, to avoid exceeding the limits with the total tra
 ``announce_to_all_trackers`` controls how multi tracker torrents are
 treated. If this is set to true, all trackers in the same tier are
 announced to in parallel. If all trackers in tier 0 fails, all trackers
-in tier 1 are announced as well. This is the uTorrent behavior. If it's
-set to false, the behavior is as defined by the multi tracker
-specification. It defaults to false, which is the same behavior previous
-versions of libtorrent has had as well.
+in tier 1 are announced as well. If it's set to false, the behavior is as
+defined by the multi tracker specification. It defaults to false, which
+is the same behavior previous versions of libtorrent has had as well.
+
+``announce_to_all_tiers`` also controls how multi tracker torrents are
+treated. When this is set to true, one tracker from each tier is announced
+to. This is the uTorrent behavior. This is false by default in order
+to comply with the multi-tracker specification.
 
 ``prefer_udp_trackers`` is true by default. It means that trackers may
 be rearranged in a way that udp trackers are always tried before http

examples/client_test.cpp

@@ -763,7 +763,8 @@ int main(int argc, char* argv[])
 
 	settings.user_agent = "client_test/" LIBTORRENT_VERSION;
 	settings.auto_upload_slots_rate_based = true;
-	settings.announce_to_all_trackers = true;
+	//settings.announce_to_all_tiers = true;
+	//settings.announce_to_all_trackers = true;
 	settings.optimize_hashing_for_speed = false;
 	settings.disk_cache_algorithm = session_settings::largest_contiguous;
 

include/libtorrent/session_settings.hpp

@@ -154,6 +154,7 @@ namespace libtorrent
 			, auto_manage_startup(120)
 			, rate_limit_ip_overhead(true)
 			, announce_to_all_trackers(false)
+			, announce_to_all_tiers(false)
 			, prefer_udp_trackers(true)
 			, strict_super_seeding(false)
 			, seeding_piece_quota(3)
@@ -526,10 +527,18 @@ namespace libtorrent
 		// the limits with the total traffic
 		bool rate_limit_ip_overhead;
 
+		// this announces to all trackers within the current
+		// tier. Trackers within a tier are supposed to share
+		// peers, this could be used for trackers that don't,
+		// and require the clients to announce to all of them.
+		bool announce_to_all_trackers;
+
 		// if set to true, multi tracker torrents are treated
 		// the same way uTorrent treats them. It defaults to
 		// false in order to comply with the extension definition.
-		bool announce_to_all_trackers;
+		// When this is enabled, one tracker from each tier is
+		// announced
+		bool announce_to_all_tiers;
 
 		// when this is set to true, if there is a tracker entry
 		// with udp:// protocol, it is preferred over the same

src/torrent.cpp

@@ -1157,15 +1157,35 @@ namespace libtorrent
 
 		ptime now = time_now();
 
+		// the tier is kept as INT_MAX until we find the first
+		// tracker that works, then it's set to that tracker's
+		// tier.
 		int tier = INT_MAX;
+
+		// have we sent an announce in this tier yet?
+		bool sent_announce = false;
+
 		for (int i = 0; i < int(m_trackers.size()); ++i)
 		{
 			announce_entry& ae = m_trackers[i];
-			if (ae.tier > tier) break;
-			if (ae.is_working()) tier = ae.tier;
+			if (m_settings.announce_to_all_tiers
+				&& sent_announce
+				&& ae.tier <= tier
+				&& tier != INT_MAX)
+				continue;
+
+			if (ae.tier > tier && !m_settings.announce_to_all_tiers) break;
+			if (ae.is_working()) { tier = ae.tier; sent_announce = false; }
 			if (!ae.can_announce(now))
 			{
-				if (ae.is_working() && !m_settings.announce_to_all_trackers) break;
+				if (ae.is_working())
+				{
+					sent_announce = true; // this counts
+
+					if (!m_settings.announce_to_all_trackers
+						&& !m_settings.announce_to_all_tiers)
+						break;
+				}
 				continue;
 			}
 			
@@ -1203,7 +1223,11 @@ namespace libtorrent
 					tracker_announce_alert(get_handle(), req.url, req.event));
 			}
 
-			if (ae.is_working() && !m_settings.announce_to_all_trackers) break;
+			sent_announce = true;
+			if (ae.is_working()
+				&& !m_settings.announce_to_all_trackers
+				&& !m_settings.announce_to_all_tiers)
+				break;
 		}
 		update_tracker_timer();
 	}
@@ -4854,15 +4878,29 @@ namespace libtorrent
 
 		ptime next_announce = max_time();
 		int tier = INT_MAX;
+
+		bool found_working = false;
+
 		for (std::vector<announce_entry>::iterator i = m_trackers.begin()
 			, end(m_trackers.end()); i != end; ++i)
 		{
-			if (i->tier > tier) break;
-			if (i->is_working()) tier = i->tier;
+			if (m_settings.announce_to_all_tiers
+				&& found_working
+				&& i->tier <= tier
+				&& tier != INT_MAX)
+				continue;
+
+			if (i->tier > tier && !m_settings.announce_to_all_tiers) break;
+			if (i->is_working()) { tier = i->tier; found_working = false; }
 			if (i->fails >= i->fail_limit && i->fail_limit != 0) continue;
-			if (i->updating) continue;
+			if (i->updating) { found_working = true; continue; }
 			if (i->next_announce < next_announce) next_announce = i->next_announce;
-			if (i->is_working() && !m_settings.announce_to_all_trackers) break;
+			if (i->is_working())
+			{
+				found_working = true;
+				if (!m_settings.announce_to_all_trackers
+					&& !m_settings.announce_to_all_tiers) break;
+			}
 		}
 		if (next_announce == max_time()) return;