Signal emission in multi-threading environment

["Ben Lau" <xbenlau gmail com>]

hi all,

   I am implementing a GObject (a simple video player) that creates a
GStreamer pipeline for video processing. Soon it receives a new
GstBuffer of video frame from the pipeline, it will emit a signal. As
GStreamer processes the pipeline with multiple threads.  The signal
handler may not be involved inside the main thread. If my GObject
calls g_signal_emit() within the handler, then client's callback
function may also not be involved from the main thread.

  If the callback uses any Gdk/Gtk functions, then it may cause a race
condition. Ofcoz it could be avoided by using
gdk_threads_enter/gdk_threads_leave pair. However, I want to hide the
multi-threading issue from user ,so that they don't need to care
about.

 To achieve this purpose, the signal should be emitted within the main
thread. Could anybody suggest a method to ensure that a signal is
emitted within the main thread?

 I am thinking about to create a GSource to attach to the main
context. Soon a new frame is ready, it will dispatch the event to my
video player in main thread. But I wonder would it have any other
simpler method to achieve the goal?

Thanks for any advise.