made piece picker less anal about speed categories, to improve performance

src/piece_picker.cpp

@@ -1071,21 +1071,31 @@ namespace libtorrent
 
 	namespace
 	{
-		bool exclusively_requested_from(piece_picker::downloading_piece const& p
+		// the first bool is true if this is the only peer that has requested and downloaded
+		// blocks from this piece.
+		// the second bool is true if this is the only active peer that is requesting
+		// and downloading blocks from this piece. Active means having a connection.
+		boost::tuple<bool, bool> requested_from(piece_picker::downloading_piece const& p
 			, int num_blocks_in_piece, void* peer)
 		{
+			bool exclusive = true;
+			bool exclusive_active = true;
 			for (int j = 0; j < num_blocks_in_piece; ++j)
 			{
 				piece_picker::block_info const& info = p.info[j];
 				if (info.state != piece_picker::block_info::state_none
-					&& info.peer != peer
-					&& info.peer != 0
-					&& static_cast<policy::peer*>(info.peer)->connection)
+					&& info.peer != peer)
 				{
-					return false;
+					exclusive = false;
+					if (info.peer == 0
+						|| static_cast<policy::peer*>(info.peer)->connection == 0)
+					{
+						exclusive_active = false;
+						return boost::make_tuple(exclusive, exclusive_active);
 					}
 				}
-			return true;
+			}
+			return boost::make_tuple(exclusive, exclusive_active);
 		}
 	}
 
@@ -1120,8 +1130,10 @@ namespace libtorrent
 				// is true if all the other pieces that are currently
 				// requested from this piece are from the same
 				// peer as 'peer'.
-				bool only_same_peer = exclusively_requested_from(*p
-					, num_blocks_in_piece, peer);
+				bool exclusive;
+				bool exclusive_active;
+				boost::tie(exclusive, exclusive_active)
+					= requested_from(*p, num_blocks_in_piece, peer);
 
 				// this means that this partial piece has
 				// been downloaded/requested partially from
@@ -1130,7 +1142,7 @@ namespace libtorrent
 				// blocks to the backup list. If the prioritized
 				// blocks aren't enough, blocks from this list
 				// will be picked.
-				if (prefer_whole_pieces && !only_same_peer)
+				if (prefer_whole_pieces && !exclusive)
 				{
 					if (int(backup_blocks.size()) >= num_blocks) continue;
 					for (int j = 0; j < num_blocks_in_piece; ++j)
@@ -1164,7 +1176,7 @@ namespace libtorrent
 					// if the state of the piece is none (the
 					// piece will in that case change state).
 					if (p->state != none && p->state != speed
-						&& !only_same_peer
+						&& !exclusive_active
 						&& !ignore_speed_categories)
 					{
 						if (int(backup_blocks.size()) >= num_blocks) continue;

test/test_bandwidth_limiter.cpp

@@ -149,7 +149,7 @@ struct peer_connection
 	bool m_prioritized;
 	bool m_ignore_limits;
 	bool m_abort;
-	stat m_stats;
+	libtorrent::stat m_stats;
 	io_service& m_ios;
 	std::string m_name;
 	int m_refs;
@@ -192,7 +192,7 @@ void run_test(io_service& ios, connections_t& v)
 	tick.async_wait(boost::bind(&do_tick, _1, boost::ref(tick), boost::ref(v)));
 
 	deadline_timer complete(ios);
-	complete.expires_from_now(seconds(stat::history * 2));
+	complete.expires_from_now(seconds(libtorrent::stat::history * 2));
 	complete.async_wait(boost::bind(&do_stop, boost::ref(tick), boost::ref(v)));
 
 	std::for_each(v.begin(), v.end()

test/test_piece_picker.cpp

@@ -188,9 +188,10 @@ int test_main()
 
 	piece_block expected4[] =
 	{
-		piece_block(2, 0), piece_block(2, 1)
-		, piece_block(2, 2), piece_block(2, 3)
+		piece_block(3, 0), piece_block(3, 1)
+		, piece_block(3, 2), piece_block(3, 3)
 	};
+
 	TEST_CHECK(std::equal(picked.begin()
 		, picked.end(), expected4));
 
@@ -204,12 +205,12 @@ int test_main()
 
 	piece_block expected5[] =
 	{
-		piece_block(2, 0), piece_block(2, 1)
-		, piece_block(2, 2), piece_block(2, 3)
-		, piece_block(3, 0), piece_block(3, 1)
+		piece_block(3, 0), piece_block(3, 1)
 		, piece_block(3, 2), piece_block(3, 3)
 		, piece_block(5, 0), piece_block(5, 1)
 		, piece_block(5, 2), piece_block(5, 3)
+		, piece_block(2, 0), piece_block(2, 1)
+		, piece_block(2, 2), piece_block(2, 3)
 	};
 
 	TEST_CHECK(std::equal(picked.begin()