gst/base/gstbasesrc.c (gst_base_src_start): Post an error if the source couldn't negotiate.

Original commit message from CVS:
2005-07-13  Andy Wingo  <wingo@pobox.com>

* gst/base/gstbasesrc.c (gst_base_src_start): Post an error if the
source couldn't negotiate.

ChangeLog

@@ -1,3 +1,15 @@
+2005-07-13  Andy Wingo  <wingo@pobox.com>
+
+	* gst/base/gstbasesrc.c (gst_base_src_start): Post an error if the
+	source couldn't negotiate.
+
+	* gst/parse/grammar.y: Revert 1.54->1.55, so we now do filtered
+	connections again.
+
+	* gst/gstutils.h:
+	* gst/gstutils.c (gst_element_link_pads_filtered): New old
+	function. I am channeling Hades. Put your boots on suckers!!!
+
 2005-07-13  Thomas Vander Stichele  <thomas at apestaart dot org>
 
 	* testsuite/caps/Makefile.am:

docs/gst/tmpl/gstminiobject.sgml

@@ -14,6 +14,9 @@ GstMiniObject
 
 </para>
 
+<!-- ##### SECTION Stability_Level ##### -->
+
+
 <!-- ##### STRUCT GstMiniObject ##### -->
 <para>
 

gst/base/gstbasesrc.c

@@ -883,6 +883,9 @@ could_not_start:
 could_not_negotiate:
   {
     GST_DEBUG_OBJECT (basesrc, "could not negotiate, stopping");
+    GST_ELEMENT_ERROR (basesrc, STREAM, FORMAT,
+        ("Could not connect source to pipeline"),
+        ("Check your filtered caps, if any"));
     gst_base_src_stop (basesrc);
     return FALSE;
   }

gst/gstutils.c

@@ -1228,6 +1228,68 @@ gst_element_link_pads (GstElement * src, const gchar * srcpadname,
   return FALSE;
 }
 
+/**
+ * gst_element_link_pads_filtered:
+ * @src: a #GstElement containing the source pad.
+ * @srcpadname: the name of the #GstPad in source element or NULL for any pad.
+ * @dest: the #GstElement containing the destination pad.
+ * @destpadname: the name of the #GstPad in destination element or NULL for any pad.
+ * @caps: the #GstCaps to filter the link, or #NULL for no filter.
+ *
+ * Links the two named pads of the source and destination elements. Side effect
+ * is that if one of the pads has no parent, it becomes a child of the parent of
+ * the other element. If they have different parents, the link fails. If @caps
+ * is not #NULL, makes sure that the caps of the link is a subset of @caps.
+ *
+ * Returns: TRUE if the pads could be linked, FALSE otherwise.
+ */
+gboolean
+gst_element_link_pads_filtered (GstElement * src, const gchar * srcpadname,
+    GstElement * dest, const gchar * destpadname, GstCaps * filter)
+{
+  /* checks */
+  g_return_val_if_fail (GST_IS_ELEMENT (src), FALSE);
+  g_return_val_if_fail (GST_IS_ELEMENT (dest), FALSE);
+  g_return_val_if_fail (filter == NULL || GST_IS_CAPS (filter), FALSE);
+
+  if (filter) {
+    GstElement *capsfilter;
+    GstObject *parent;
+
+    capsfilter = gst_element_factory_make ("capsfilter", NULL);
+    if (!capsfilter) {
+      GST_ERROR ("Could not make a capsfilter");
+      return FALSE;
+    }
+
+    parent = gst_object_get_parent (GST_OBJECT (src));
+    g_return_val_if_fail (GST_IS_BIN (parent), FALSE);
+
+    if (!gst_bin_add (GST_BIN (parent), capsfilter)) {
+      GST_ERROR ("Could not add capsfilter");
+      gst_object_unref (capsfilter);
+      gst_object_unref (parent);
+      return FALSE;
+    }
+
+    gst_object_unref (parent);
+
+    g_object_set (capsfilter, "filter-caps", filter, NULL);
+
+    if (gst_element_link_pads (src, srcpadname, capsfilter, "sink")
+        && gst_element_link_pads (capsfilter, "src", dest, destpadname)) {
+      return TRUE;
+    } else {
+      GST_INFO ("Could not link elements");
+      gst_bin_remove (GST_BIN (GST_OBJECT_PARENT (capsfilter)), capsfilter);
+      /* will unref and unlink as appropriate */
+      return FALSE;
+    }
+  } else {
+    return gst_element_link_pads (src, srcpadname, dest, destpadname);
+  }
+}
+
 /**
  * gst_element_link:
  * @src: a #GstElement containing the source pad.
@@ -1243,7 +1305,7 @@ gst_element_link_pads (GstElement * src, const gchar * srcpadname,
 gboolean
 gst_element_link (GstElement * src, GstElement * dest)
 {
-  return gst_element_link_pads (src, NULL, dest, NULL);
+  return gst_element_link_pads_filtered (src, NULL, dest, NULL, NULL);
 }
 
 /**

gst/gstutils.h

@@ -252,6 +252,10 @@ gboolean		gst_element_link_pads           (GstElement *src, const gchar *srcpadn
 void                    gst_element_unlink_pads         (GstElement *src, const gchar *srcpadname,
 		                                         GstElement *dest, const gchar *destpadname);
 
+gboolean		gst_element_link_pads_filtered	(GstElement * src, const gchar * srcpadname,
+                                                         GstElement * dest, const gchar * destpadname,
+                                                         GstCaps *filter);
+
 /* util elementfactory functions */
 gboolean		gst_element_factory_can_src_caps(GstElementFactory *factory, const GstCaps *caps);
 gboolean		gst_element_factory_can_sink_caps(GstElementFactory *factory, const GstCaps *caps);

gst/parse/grammar.y

@@ -377,7 +377,7 @@ gst_parse_found_pad (GstElement *src, GstPad *pad, gpointer data)
                 GST_ELEMENT_NAME (src), link->src_pad,
                 GST_ELEMENT_NAME (link->sink), link->sink_pad);
 
-  if (gst_element_link_pads (src, link->src_pad, link->sink, link->sink_pad)) {
+  if (gst_element_link_pads_filtered (src, link->src_pad, link->sink, link->sink_pad, link->caps)) {
     /* do this here, we don't want to get any problems later on when unlocking states */
     GST_CAT_DEBUG (GST_CAT_PIPELINE, "delayed linking %s:%s to %s:%s worked", 
                	   GST_ELEMENT_NAME (src), link->src_pad,
@@ -447,8 +447,9 @@ gst_parse_perform_link (link_t *link, graph_t *graph)
 	        link->caps);
 
   if (!srcs || !sinks) {
-    if (gst_element_link_pads (src, srcs ? (const gchar *) srcs->data : NULL,
-                                        sink, sinks ? (const gchar *) sinks->data : NULL)) {
+    if (gst_element_link_pads_filtered (src, srcs ? (const gchar *) srcs->data : NULL,
+                                        sink, sinks ? (const gchar *) sinks->data : NULL,
+					link->caps)) {
       gst_parse_element_lock (sink, gst_element_is_locked_state (src));
       goto success;
     } else {
@@ -470,7 +471,7 @@ gst_parse_perform_link (link_t *link, graph_t *graph)
     const gchar *sink_pad = (const gchar *) sinks->data;
     srcs = g_slist_next (srcs);
     sinks = g_slist_next (sinks);
-    if (gst_element_link_pads (src, src_pad, sink, sink_pad)) {
+    if (gst_element_link_pads_filtered (src, src_pad, sink, sink_pad, link->caps)) {
       gst_parse_element_lock (sink, gst_element_is_locked_state (src));
       continue;
     } else {

libs/gst/base/gstbasesrc.c

@@ -883,6 +883,9 @@ could_not_start:
 could_not_negotiate:
   {
     GST_DEBUG_OBJECT (basesrc, "could not negotiate, stopping");
+    GST_ELEMENT_ERROR (basesrc, STREAM, FORMAT,
+        ("Could not connect source to pipeline"),
+        ("Check your filtered caps, if any"));
     gst_base_src_stop (basesrc);
     return FALSE;
   }