From 9811bb9aadee08b31fdbda2d158273e77bcfe622 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wim.taymans@gmail.com>
Date: Thu, 17 Apr 2003 22:29:31 +0000
Subject: [PATCH] Added a simple function gst_pad_recover_caps_error that a
 plugin should call from now on (instead of gst_element_erro...

Original commit message from CVS:
Added a simple function gst_pad_recover_caps_error that a plugin
should call from now on (instead of gst_element_error). This function
will emit a caps_nego_failed signal that the app can catch to resolve
the negotiation failure.
---
 gst/gstpad.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
 gst/gstpad.h | 11 +++++++----
 2 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/gst/gstpad.c b/gst/gstpad.c
index c6b660ff1b..79d71a33c3 100644
--- a/gst/gstpad.c
+++ b/gst/gstpad.c
@@ -1987,6 +1987,50 @@ gst_pad_recalc_allowed_caps (GstPad *pad)
   return TRUE;
 }
 
+/**
+ * gst_pad_recover_caps_error:
+ * @pad: a #GstPad that had a failed capsnego
+ * @allowed: possible caps for the link
+ *
+ * Attempt to recover from a failed caps negotiation. This function
+ * is typically called by a plugin that exhausted its list of caps
+ * and wants the application to resolve the issue. The application
+ * should connect to the pad's caps_nego_failed signal and should
+ * resolve the issue by connecting another element for example.
+ *
+ * Returns: TRUE when the issue was resolved, dumps detailed information
+ * on the console and returns FALSE otherwise.
+ */
+gboolean
+gst_pad_recover_caps_error (GstPad *pad, GstCaps *allowed)
+{
+  GstElement *parent;
+  
+  g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
+
+  /* see if someone can resolve this */
+  if (g_signal_has_handler_pending (G_OBJECT (pad), 
+	gst_real_pad_signals[REAL_CAPS_NEGO_FAILED], 0, FALSE))
+  {
+    /* clear pad caps first */
+    gst_caps_replace (&GST_PAD_CAPS (pad), NULL);
+
+    /* lets hope some signal manages to set the caps again */
+    g_signal_emit (G_OBJECT (pad), gst_real_pad_signals[REAL_CAPS_NEGO_FAILED], 0, allowed);
+
+    /* if the pad has caps now or is disabled, it's ok */
+    if (GST_PAD_CAPS (pad) != NULL || !GST_PAD_IS_ACTIVE (pad))
+      return TRUE;
+  }
+
+  /* report error */
+  parent = gst_pad_get_parent (pad);
+  gst_element_error (parent, "negotiation failed on pad %s:%s",
+		  GST_DEBUG_PAD_NAME (pad));
+
+  return FALSE;
+}
+
 /**
  * gst_pad_get_bufferpool:
  * @pad: a #GstPad to get the bufferpool from.
diff --git a/gst/gstpad.h b/gst/gstpad.h
index 307597ec1e..baed59e2c1 100644
--- a/gst/gstpad.h
+++ b/gst/gstpad.h
@@ -217,12 +217,13 @@ struct _GstRealPad {
 };
 
 struct _GstRealPadClass {
-  GstPadClass parent_class;
+  GstPadClass 	parent_class;
 
   /* signal callbacks */
-  void (*caps_nego_failed)	(GstPad *pad);
-  void (*linked)		(GstPad *pad, GstPad *peer);
-  void (*unlinked)		(GstPad *pad, GstPad *peer);
+  void		(*caps_nego_failed)	(GstPad *pad, GstCaps *caps);
+
+  void 		(*linked)		(GstPad *pad, GstPad *peer);
+  void 		(*unlinked)		(GstPad *pad, GstPad *peer);
 };
 
 struct _GstGhostPad {
@@ -446,6 +447,8 @@ gboolean		gst_pad_try_relink_filtered		(GstPad *srcpad, GstPad *sinkpad, GstCaps
 GstCaps*	     	gst_pad_get_allowed_caps       		(GstPad *pad);
 gboolean	     	gst_pad_recalc_allowed_caps    		(GstPad *pad);
 
+gboolean	     	gst_pad_recover_caps_error    		(GstPad *pad, GstCaps *allowed);
+
 /* data passing functions */
 void			gst_pad_push				(GstPad *pad, GstBuffer *buf);
 GstBuffer*		gst_pad_pull				(GstPad *pad);