[gst-devel] gstreamer thread problem?

[woo john]

hi,
  i am reading the plugin writer's guide. i am confused about scheduling 
mode.

  It is clear for me that a filter or sink element can has its own 
thread(act as puller).There is a simple example in the PWG to explain this 
case.

  My question is :

1 whether a source element can work at pull mode or push mode ?

  2 if it is at pull mode, is there a thread assigned for it?
    if it is at push mode, is there a thread assigned for it?

  3 As i know,I can insert a queue between a source element and the 
downstream elements. In this case,what mode does the source element work? 
pull or push?

  thanks in advance!

woo.