pipeline: Properly error out when linking fails

In the rendering case we were getting random issues and often the
pipeline was not be able to preroll as some pad were not linked inside
encodebin.

https://bugzilla.gnome.org/show_bug.cgi?id=795422

1 files changed, 70 insertions, 16 deletions

diff --git a/ges/ges-pipeline.c b/ges/ges-pipeline.c
index 6d49ce2a..94c9f4cb 100644
--- a/ges/ges-pipeline.c
+++ b/ges/ges-pipeline.c
@@ -43,6 +43,7 @@ GST_DEBUG_CATEGORY_STATIC (ges_pipeline_debug);
 #define GST_CAT_DEFAULT ges_pipeline_debug
 
 #define DEFAULT_TIMELINE_MODE  GES_PIPELINE_MODE_PREVIEW
+#define IN_RENDERING_MODE(timeline) ((timeline->priv->mode) & (GES_PIPELINE_MODE_RENDER | GES_PIPELINE_MODE_SMART_RENDER))
 
 /* Structure corresponding to a timeline - sink link */
 
@@ -520,6 +521,56 @@ _link_tracks (GESPipeline * pipeline)
 
   for (tmp = pipeline->priv->timeline->tracks; tmp; tmp = tmp->next)
     _link_track (pipeline, tmp->data);
+
+  if (IN_RENDERING_MODE (pipeline)) {
+    GString *unlinked_issues = NULL;
+    GstIterator *pads;
+    gboolean done = FALSE;
+    GValue paditem = { 0, };
+
+    pads = gst_element_iterate_sink_pads (pipeline->priv->encodebin);
+    while (!done) {
+      switch (gst_iterator_next (pads, &paditem)) {
+        case GST_ITERATOR_OK:
+        {
+          GstPad *testpad = g_value_get_object (&paditem);
+          if (!gst_pad_is_linked (testpad)) {
+            GstCaps *sinkcaps = gst_pad_query_caps (testpad, NULL);
+            gchar *caps_string = gst_caps_to_string (sinkcaps);
+            gchar *path_string =
+                gst_object_get_path_string (GST_OBJECT (testpad));
+            gst_caps_unref (sinkcaps);
+
+            if (!unlinked_issues)
+              unlinked_issues =
+                  g_string_new ("Following encodebin pads are not linked:\n");
+
+            g_string_append_printf (unlinked_issues, " - %s: %s", path_string,
+                caps_string);
+            g_free (caps_string);
+            g_free (path_string);
+          }
+          g_value_reset (&paditem);
+        }
+          break;
+        case GST_ITERATOR_DONE:
+        case GST_ITERATOR_ERROR:
+          done = TRUE;
+          break;
+        case GST_ITERATOR_RESYNC:
+          gst_iterator_resync (pads);
+          break;
+      }
+    }
+    g_value_reset (&paditem);
+    gst_iterator_free (pads);
+
+    if (unlinked_issues) {
+      GST_ELEMENT_ERROR (pipeline, STREAM, FAILED, (NULL), ("%s",
+              unlinked_issues->str));
+      g_string_free (unlinked_issues, TRUE);
+    }
+  }
 }
 
 static void
@@ -554,8 +605,7 @@ ges_pipeline_change_state (GstElement * element, GstStateChange transition)
         ret = GST_STATE_CHANGE_FAILURE;
         goto done;
       }
-      if (self->priv->mode & (GES_PIPELINE_MODE_RENDER |
-              GES_PIPELINE_MODE_SMART_RENDER)) {
+      if (IN_RENDERING_MODE (self)) {
         GST_DEBUG ("rendering => Updating pipeline caps");
         /* Set caps on all tracks according to profile if present */
         if (!ges_pipeline_update_caps (self)) {
@@ -728,8 +778,10 @@ _link_track (GESPipeline * self, GESTrack * track)
 
   gst_caps_unref (caps);
 
-  if (G_UNLIKELY (!track)) {
-    GST_WARNING_OBJECT (self, "Couldn't find coresponding track !");
+  if (G_UNLIKELY (!pad)) {
+    GST_ELEMENT_ERROR (self, STREAM, FAILED, (NULL),
+        ("Trying to link %" GST_PTR_FORMAT
+            " but no pad is exposed for it.", track));
     return;
   }
 
@@ -774,7 +826,8 @@ _link_track (GESPipeline * self, GESTrack * track)
   sinkpad = gst_element_get_static_pad (chain->tee, "sink");
   lret = gst_pad_link (pad, sinkpad);
   if (lret != GST_PAD_LINK_OK) {
-    GST_ERROR_OBJECT (self, "Could not link the tee (%i)", lret);
+    GST_ELEMENT_ERROR (self, CORE, NEGOTIATION,
+        (NULL), ("Could not link the tee (%s)", gst_pad_link_get_name (lret)));
     goto error;
   }
 
@@ -807,15 +860,19 @@ _link_track (GESPipeline * self, GESTrack * track)
     if (G_UNLIKELY (!(sinkpad =
                 gst_element_get_request_pad (self->priv->playsink,
                     sinkpad_name)))) {
-      GST_ERROR_OBJECT (self, "Couldn't get a pad from the playsink !");
+      GST_ELEMENT_ERROR (self, CORE, NEGOTIATION,
+          (NULL), ("Could not get a pad from playsink for %s", sinkpad_name));
       goto error;
     }
 
     tmppad = gst_element_get_request_pad (chain->tee, "src_%u");
-    if (G_UNLIKELY (gst_pad_link_full (tmppad, sinkpad,
-                GST_PAD_LINK_CHECK_NOTHING) != GST_PAD_LINK_OK)) {
-      GST_ERROR_OBJECT (self, "Couldn't link track pad to encodebin");
+    lret = gst_pad_link_full (tmppad, sinkpad, GST_PAD_LINK_CHECK_NOTHING);
+    if (G_UNLIKELY (lret != GST_PAD_LINK_OK)) {
       gst_object_unref (tmppad);
+      GST_ELEMENT_ERROR (self, CORE, NEGOTIATION,
+          (NULL),
+          ("Could not link %" GST_PTR_FORMAT " and %" GST_PTR_FORMAT " (%s)",
+              tmppad, sinkpad, gst_pad_link_get_name (lret)));
       goto error;
     }
     gst_object_unref (tmppad);
@@ -831,9 +888,7 @@ _link_track (GESPipeline * self, GESTrack * track)
   }
 
   /* Connect to encodebin */
-  if (self->
-      priv->mode & (GES_PIPELINE_MODE_RENDER | GES_PIPELINE_MODE_SMART_RENDER))
-  {
+  if (IN_RENDERING_MODE (self)) {
     GstPad *tmppad;
     GST_DEBUG_OBJECT (self, "Connecting to encodebin");
 
@@ -849,15 +904,14 @@ _link_track (GESPipeline * self, GESTrack * track)
             &sinkpad);
 
         if (G_UNLIKELY (sinkpad == NULL)) {
-          GST_INFO_OBJECT (self, "Couldn't get a pad from encodebin for: %"
-              GST_PTR_FORMAT, caps);
-          gst_caps_unref (caps);
           gst_element_set_locked_state (GST_ELEMENT (track), TRUE);
 
           self->priv->not_rendered_tracks =
               g_list_append (self->priv->not_rendered_tracks, track);
 
-
+          GST_INFO_OBJECT (self,
+              "Couldn't get a pad from encodebin for: %" GST_PTR_FORMAT, caps);
+          gst_caps_unref (caps);
           goto error;
         }