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gst/gstobject.h (GST_OBJECT_REFCOUNT_VALUE): Just use the int.
Original commit message from CVS: 2005-10-02 Andy Wingo <wingo@pobox.com> * gst/gstobject.h (GST_OBJECT_REFCOUNT_VALUE): Just use the int. It is volatile, after all. * docs/design/part-gstghostpad.txt: Flesh out activation with ghost pads. * gst/base/gstbasesrc.c (gst_base_src_init): Use GST_DEBUG_FUNCPTR.
This commit is contained in:
Andy Wingo
parent
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commit
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5 changed files with 179 additions and 57 deletions
11
ChangeLog
11
ChangeLog
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@ -1,3 +1,14 @@
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2005-10-02 Andy Wingo <wingo@pobox.com>
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* gst/gstobject.h (GST_OBJECT_REFCOUNT_VALUE): Just use the int.
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It is volatile, after all.
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* docs/design/part-gstghostpad.txt: Flesh out activation with
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ghost pads.
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* gst/base/gstbasesrc.c (gst_base_src_init): Use
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GST_DEBUG_FUNCPTR.
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2005-10-02 Tim-Philipp Müller <tim at centricular dot net>
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* configure.ac:
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@ -5,7 +5,7 @@ Ghostpads
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existing elements. They are used to expose internal element pads
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on the complex element.
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Some design requirements
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Some design requirements
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- Must look like a real GstPad on both sides.
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- target of Ghostpad must be changeable
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@ -50,7 +50,7 @@ Ghostpads
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(--------------
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(- X --------) |
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(- X --------) |
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| | |------)
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| target *------------------> | sink |
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|------------| |------)
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@ -72,11 +72,11 @@ Ghostpads
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5) link/unlink and activate functions are set up
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on GstGhostPad.
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(- X --------)
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| |
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(- X --------)
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| |
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| target *------>//
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|------------|
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|------------|
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| internal *---->//
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(------------)
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@ -87,10 +87,10 @@ Ghostpads
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gst_ghost_pad_set_target (char *name, GstPad *newtarget)
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(- X --------)
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| |
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(- X --------)
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| |
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| target *------>//
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|------------|
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|------------|
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| internal *---->//
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(------------)
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@ -98,12 +98,12 @@ Ghostpads
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2) target is set to newtarget
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(--------
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(- X --------) |
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(- X --------) |
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| | |------)
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| target *------------->| sink |
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|------------| |------)
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| internal *--->// (--------
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(------------)
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(------------)
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* Setting target on an targetted unlinked ghostpad
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@ -111,23 +111,23 @@ Ghostpads
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gst_ghost_pad_set_target (char *name, GstPad *newtarget)
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(--------
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(- X --------) |
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(- X --------) |
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| | |------)
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| target *------------->| sink |
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|------------| |------)
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| internal *--->// (--------
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(------------)
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(------------)
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1) assert direction of newtarget == X direction
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2) target is set to newtarget
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(--------
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(- X --------) |
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(- X --------) |
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| | |------)
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| target *------------->| sink |
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|------------| |------)
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| internal *--->// (--------
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(------------)
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(------------)
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* Linking a pad to an untargetted ghostpad:
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@ -135,10 +135,10 @@ Ghostpads
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gst_pad_link (src, X)
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(- X --------)
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| |
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(- X --------)
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| |
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| target *------>//
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|------------|
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|------------|
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| internal *---->//
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(------------)
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-------)
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@ -157,12 +157,12 @@ Ghostpads
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e) Y is activated in the same mode as X
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f) core makes link from src to X
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(- X --------)
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| |
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(- X --------)
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| |
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| target *----->//
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>|------------|
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(real pad link) / | internal * |
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>|------------|
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(real pad link) / | internal * |
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/ (----------|-)
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/ |
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-------) / V
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@ -178,12 +178,12 @@ Ghostpads
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gst_pad_link (src, X)
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(--------
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(- X --------) |
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(- X --------) |
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| | |------)
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| target *------------->| sink |
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|------------| |------)
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| internal *--->// (--------
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(------------)
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(------------)
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-------)
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(-----|
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@ -202,7 +202,7 @@ Ghostpads
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g) core makes link from src to X
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(--------
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(- X --------) |
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(- X --------) |
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| | |------)
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| target *------------->| sink |
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>|------------| >|------)
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@ -221,12 +221,12 @@ Ghostpads
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gst_ghost_pad_set_target (char *name, GstPad *newtarget)
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(- X --------)
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| |
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(- X --------)
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| |
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| target *----->//
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>|------------|
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(real pad link) / | internal * |
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>|------------|
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(real pad link) / | internal * |
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/ (----------|-)
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/ |
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-------) / V
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@ -240,9 +240,9 @@ Ghostpads
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2) X target is set to newtarget
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3) Y (X internal) is linked to newtarget
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(--------
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(- X --------) |
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(- X --------) |
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| | |------)
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| target *------------->| sink |
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>|------------| >|------)
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@ -256,14 +256,14 @@ Ghostpads
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(-----| (----------)
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-------)
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* Setting target on targetted linked ghostpad:
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gst_ghost_pad_set_target (char *name, GstPad *newtarget)
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(--------
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(- X --------) |
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(- X --------) |
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| | |------)
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| target *------------->| sink |
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>|------------| >|------)
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@ -276,15 +276,15 @@ Ghostpads
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| src |<-------------* target |
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(-----| (----------)
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-------)
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1) assert direction of newtarget == X direction
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2) Y and X target are unlinked
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2) X target is set to newtarget
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3) Y (X internal) is linked to newtarget
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(--------
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(- X --------) |
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(- X --------) |
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| target *------------->| sink |
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>|------------| >|------)
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@ -298,4 +298,105 @@ Ghostpads
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(-----| (----------)
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-------)
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Activation
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==========
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Sometimes ghost pads should proxy activation functions. This thingie
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attempts to explain how it should work in the different cases.
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+---+ +----+ +----+ +----+
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| A +-----+ B | | C |-------+ D |
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+---+ +---=+ +=---+ +----+
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+--=-----------------------------=-+
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| +=---+ +----+ +----+ +---=+ |
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| | a +---+ b ==== c +--+ d | |
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| +----+ +----+ +----+ +----+ |
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+----------------------------------+
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state change goes from right to left
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<-----------------------------------------------------------
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All of the labeled boxes are pads. The dashes (---) show pad links, and
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the double-lines (===) are internal connections. The box around a, b, c,
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and d is a bin. B and C are ghost pads, and a and d are proxy pads. The
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arrow represents the direction of a state change algorithm. Not counting
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the bin, there are three elements involved here -- the parent of D, the
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parent of A, and the parent of b and c.
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Now, in the state change from READY to PAUSED, assuming the pipeline
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does not have a live source, all of the pads will end up activated at
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the end. There are 4 possible activation modes:
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1) AD and ab in PUSH, cd and CD in PUSH
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2) AD and ab in PUSH, cd and CD in PULL
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3) AD and ab in PULL, cd and CD in PUSH
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4) AD and ab in PULL, cd and CD in PULL
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When activating (1), the state change algorithm will first visit the
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parent of D and activate D in push mode. Then it visits the bin. The bin
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will first change the state of its child before activating its pads.
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That means c will be activated in push mode. [*] At this point, d and C
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should also be active in push mode, because it could be that activating
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c in push mode starts a thread, which starts pushing to pads which
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aren't ready yet. Then b is activated in push mode. Then, the bin
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activates C in push mode, which should already be in push mode, so
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nothing is done. It then activates B in push mode, which activates b in
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push mode, but it's already there, then activates a in push mode as
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well. The order of activating a and b does not matter in this case.
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Then, finally, the state change algorithm moves to the parent of A,
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activates A in push mode, and dataflow begins.
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[*] Not yet implemented.
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Activation mode (2) is implausible, so we can ignore it for now. That
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leaves us with the rest.
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(3) is the same as (1) until you get to activating b. Activating b will
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proxy directly to activating a, which will activate B and A as well.
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Then when the state change algorithm gets to B and A it sees that they
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are already active, so it ignores them.
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Similarly in (4), activating D will cause the activation of all of the
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rest of the pads, in this order: C d c b a B A. Then when the state
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change gets to the other elements they are already active, and in fact
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data flow is already occuring.
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So, from these scenarios, we can distill how ghost pad activation
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functions should work:
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Ghost source pads (e.g. C):
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push:
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called by: element state change handler
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behavior: just return TRUE
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pull:
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called by: peer's activatepull
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behavior: change the internal pad, which proxies to its peer e.g. C
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changes d which changes c.
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Internal sink pads (e.g. d):
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push:
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called by: nobody (doesn't seem possible)
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behavior: n/a
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pull:
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called by: ghost pad
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behavior: proxy to peer first
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Internal src pads (e.g. a):
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push:
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called by: ghost pad
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behavior: activate peer in push mode
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pull:
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called by: peer's activatepull
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behavior: proxy to ghost pad, which proxies to its peer (e.g. a
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calls B which calls A)
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Ghost sink pads (e.g. B):
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push:
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called by: element state change handler
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behavior: change the internal pad, which proxies to peer (e.g. B
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changes a which changes b)
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pull:
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called by: internal pad
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behavior: proxy to peer
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@ -193,14 +193,19 @@ gst_base_src_init (GstBaseSrc * basesrc, gpointer g_class)
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pad = gst_pad_new_from_template (pad_template, "src");
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GST_DEBUG_OBJECT (basesrc, "setting functions on src pad");
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gst_pad_set_activatepush_function (pad, gst_base_src_activate_push);
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gst_pad_set_activatepull_function (pad, gst_base_src_activate_pull);
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gst_pad_set_event_function (pad, gst_base_src_event_handler);
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gst_pad_set_query_function (pad, gst_base_src_query);
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gst_pad_set_checkgetrange_function (pad, gst_base_src_check_get_range);
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gst_pad_set_getrange_function (pad, gst_base_src_get_range);
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gst_pad_set_getcaps_function (pad, gst_base_src_getcaps);
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gst_pad_set_setcaps_function (pad, gst_base_src_setcaps);
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gst_pad_set_activatepush_function (pad,
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GST_DEBUG_FUNCPTR (gst_base_src_activate_push));
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gst_pad_set_activatepull_function (pad,
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GST_DEBUG_FUNCPTR (gst_base_src_activate_pull));
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gst_pad_set_event_function (pad,
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GST_DEBUG_FUNCPTR (gst_base_src_event_handler));
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gst_pad_set_query_function (pad, GST_DEBUG_FUNCPTR (gst_base_src_query));
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gst_pad_set_checkgetrange_function (pad,
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GST_DEBUG_FUNCPTR (gst_base_src_check_get_range));
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gst_pad_set_getrange_function (pad,
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GST_DEBUG_FUNCPTR (gst_base_src_get_range));
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gst_pad_set_getcaps_function (pad, GST_DEBUG_FUNCPTR (gst_base_src_getcaps));
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gst_pad_set_setcaps_function (pad, GST_DEBUG_FUNCPTR (gst_base_src_setcaps));
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/* hold pointer to pad */
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basesrc->srcpad = pad;
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@ -66,7 +66,7 @@ typedef enum
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#ifdef GST_HAVE_GLIB_2_8
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#define GST_OBJECT_REFCOUNT(obj) (((GObject*)(obj))->ref_count)
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#define GST_OBJECT_REFCOUNT_VALUE(obj) (g_atomic_int_get (&((GObject*)(obj))->ref_count))
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#define GST_OBJECT_REFCOUNT_VALUE(obj) GST_OBJECT_REFCOUNT(obj)
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#else
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#define GST_OBJECT_REFCOUNT(obj) ((GST_OBJECT_CAST(obj))->refcount)
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#define GST_OBJECT_REFCOUNT_VALUE(obj) (g_atomic_int_get (&(GST_OBJECT_CAST(obj))->refcount))
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@ -193,14 +193,19 @@ gst_base_src_init (GstBaseSrc * basesrc, gpointer g_class)
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pad = gst_pad_new_from_template (pad_template, "src");
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GST_DEBUG_OBJECT (basesrc, "setting functions on src pad");
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gst_pad_set_activatepush_function (pad, gst_base_src_activate_push);
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gst_pad_set_activatepull_function (pad, gst_base_src_activate_pull);
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gst_pad_set_event_function (pad, gst_base_src_event_handler);
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gst_pad_set_query_function (pad, gst_base_src_query);
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gst_pad_set_checkgetrange_function (pad, gst_base_src_check_get_range);
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gst_pad_set_getrange_function (pad, gst_base_src_get_range);
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gst_pad_set_getcaps_function (pad, gst_base_src_getcaps);
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gst_pad_set_setcaps_function (pad, gst_base_src_setcaps);
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gst_pad_set_activatepush_function (pad,
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GST_DEBUG_FUNCPTR (gst_base_src_activate_push));
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gst_pad_set_activatepull_function (pad,
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GST_DEBUG_FUNCPTR (gst_base_src_activate_pull));
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gst_pad_set_event_function (pad,
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GST_DEBUG_FUNCPTR (gst_base_src_event_handler));
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gst_pad_set_query_function (pad, GST_DEBUG_FUNCPTR (gst_base_src_query));
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gst_pad_set_checkgetrange_function (pad,
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GST_DEBUG_FUNCPTR (gst_base_src_check_get_range));
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gst_pad_set_getrange_function (pad,
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GST_DEBUG_FUNCPTR (gst_base_src_get_range));
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gst_pad_set_getcaps_function (pad, GST_DEBUG_FUNCPTR (gst_base_src_getcaps));
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gst_pad_set_setcaps_function (pad, GST_DEBUG_FUNCPTR (gst_base_src_setcaps));
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/* hold pointer to pad */
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basesrc->srcpad = pad;
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