added priority to disk io jobs

include/libtorrent/disk_io_thread.hpp

@@ -50,6 +50,7 @@ namespace libtorrent
 			, buffer_size(0)
 			, piece(0)
 			, offset(0)
+			, priority(0)
 		{}
 
 		enum action_t
@@ -72,6 +73,12 @@ namespace libtorrent
 		// to the error message
 		std::string str;
 
+		// priority decides whether or not this
+		// job will skip entries in the queue or
+		// not. It always skips in front of entries
+		// with lower priority
+		int priority;
+
 		// this is called when operation completes
 		boost::function<void(int, disk_io_job const&)> callback;
 	};