[gstreamermm: 80/167] [peper0] Pad::chain and Pad::push functions corrected

[Murray Cumming <murrayc src gnome org>]

commit de7ed051fbffe2ca5a8034f4077a8fac79c9ff87
Author: Marcin Kolny at Flytronic <marcin kolny flytronic pl>
Date:   Tue Jul 30 13:22:54 2013 +0200

    [peper0] Pad::chain and Pad::push functions corrected

 gstreamer/src/pad.ccg |   21 +++++++++++++++------
 gstreamer/src/pad.hg  |    6 +++---
 2 files changed, 18 insertions(+), 9 deletions(-)
---
diff --git a/gstreamer/src/pad.ccg b/gstreamer/src/pad.ccg
index b1d881a..66ef3db 100644
--- a/gstreamer/src/pad.ccg
+++ b/gstreamer/src/pad.ccg
@@ -133,10 +133,15 @@ FlowReturn Pad::get_range(guint64 offset, guint size, Glib::RefPtr<Gst::Buffer>&
   return FlowReturn(result);
 }
 
-FlowReturn Pad::push(const Glib::RefPtr<Gst::Buffer>& buffer)
+FlowReturn Pad::push(Glib::RefPtr<Gst::Buffer>& buffer)
 {
-  buffer->reference();
-  return FlowReturn(gst_pad_push(gobj(), buffer->gobj()));
+    GstBuffer *buffer_gobj = buffer->gobj();
+    /* gst_pad_push takes ownership of given "buffer". It is recommended (for performance reasons) that the 
buffer given to gst_pad_push() has
+     * only one reference, since in other cases it will be copied whenever "make_writable" will be called.
+     */
+    buffer->reference();  //allocate additional ref for gst_pad_push()
+    buffer.reset();  //take away buffer from the caller
+    return FlowReturn(gst_pad_push(gobj(), buffer_gobj));
 }
 
 bool Pad::push_event(const Glib::RefPtr<Gst::Event>& event)
@@ -169,9 +174,11 @@ bool Pad::query_duration(Format& format) const
   return gst_pad_query_duration(const_cast<GstPad*>(gobj()), (GstFormat)format, 0);
 }
 
-FlowReturn Pad::chain(const Glib::RefPtr<Gst::Buffer>& buffer)
+FlowReturn Pad::chain(Glib::RefPtr<Gst::Buffer>& buffer)
 {
-  buffer->reference();
+  GstBuffer *buffer_gobj = buffer->gobj();
+  buffer->reference();  //hold reference for gst_pad_chain()
+  buffer.reset();       //free caller's reference
   return FlowReturn(gst_pad_chain(gobj(), buffer->gobj()));
 }
 
@@ -187,9 +194,11 @@ GstFlowReturn Pad_Chain_gstreamermm_callback(GstPad* pad, GstObject* parent, Gst
 
   try
   {
+    Glib::RefPtr<Buffer> buffer_wrapped = Glib::wrap(buffer, false);  //manage object
+
     return static_cast<GstFlowReturn>(
       pad_wrapper->slot_chain(Glib::wrap(pad, true),  //take copy
-                              Glib::wrap(buffer, false)  //manage object
+                              buffer_wrapped
                            ));
   }
   catch(...)
diff --git a/gstreamer/src/pad.hg b/gstreamer/src/pad.hg
index caa7b2e..9f319c5 100644
--- a/gstreamer/src/pad.hg
+++ b/gstreamer/src/pad.hg
@@ -123,7 +123,7 @@ public:
    */
   typedef sigc::slot< bool, const Glib::RefPtr<Gst::Pad>&, const Glib::RefPtr<Gst::MiniObject>& > SlotData;
 
-  typedef sigc::slot< Gst::FlowReturn, const Glib::RefPtr<Gst::Pad>&, const Glib::RefPtr<Gst::Buffer>& > 
SlotChain;
+  typedef sigc::slot< Gst::FlowReturn, const Glib::RefPtr<Gst::Pad>&, Glib::RefPtr<Gst::Buffer>& > SlotChain;
 
   /** Creates a new pad with the given name in the given direction.
    *
@@ -253,7 +253,7 @@ public:
    * @param buffer The Gst::Buffer to push.
    * @return A Gst::FlowReturn from the peer pad. MT safe.
    */
-  FlowReturn push(const Glib::RefPtr<Gst::Buffer>& buffer);
+  FlowReturn push(Glib::RefPtr<Gst::Buffer>& buffer);
   _IGNORE(gst_pad_push)
 
   // This method is written manually because an extra ref is necessary
@@ -366,7 +366,7 @@ public:
   _WRAP_METHOD(Glib::ListHandle< Glib::RefPtr<const Gst::Pad> > get_internal_links_default() const, 
gst_pad_get_internal_links_default)
 
   // This method is written manually because an extra ref is necessary
-  FlowReturn chain(const Glib::RefPtr<Gst::Buffer>& buffer);
+  FlowReturn chain(Glib::RefPtr<Gst::Buffer>& buffer);
   _IGNORE(gst_pad_chain)
 
   _WRAP_METHOD(bool pause_task() , gst_pad_pause_task)