webmux: fix linking with shout2send element

Shout2send only accepts webm format, not matroska, but due
to a bug in matroskamux, webmmux's source pad is also created
with the matroska source pad template as pad template, which
makes the link function think it can't link webmmux to shout2send.

Also add unit test.

https://bugzilla.gnome.org/show_bug.cgi?id=689336

gst/matroska/matroska-mux.c

@@ -196,13 +196,11 @@ static GstStaticPadTemplate subtitlesink_templ =
 static GArray *used_uids;
 G_LOCK_DEFINE_STATIC (used_uids);
 
-#define parent_class gst_matroska_mux_parent_class
+static gpointer parent_class;   /* NULL */
-G_DEFINE_TYPE_WITH_CODE (GstMatroskaMux, gst_matroska_mux, GST_TYPE_ELEMENT,
-    G_IMPLEMENT_INTERFACE (GST_TYPE_TAG_SETTER, NULL)
-    G_IMPLEMENT_INTERFACE (GST_TYPE_TOC_SETTER, NULL)
-    );
 
 /* Matroska muxer destructor */
+static void gst_matroska_mux_class_init (GstMatroskaMuxClass * klass);
+static void gst_matroska_mux_init (GstMatroskaMux * mux, gpointer g_class);
 static void gst_matroska_mux_finalize (GObject * object);
 
 /* Pads collected callback */
@@ -248,6 +246,38 @@ static void
 gst_matroska_mux_write_simple_tag (const GstTagList * list, const gchar * tag,
     gpointer data);
 
+/* Cannot use boilerplate macros here because we need the full init function
+ * signature with the additional class argument, so we use the right template
+ * for the sink caps */
+GType
+gst_matroska_mux_get_type (void)
+{
+  static GType object_type;     /* 0 */
+
+  if (object_type == 0) {
+    static const GTypeInfo object_info = {
+      sizeof (GstMatroskaMuxClass),
+      NULL,                     /* base_init */
+      NULL,                     /* base_finalize */
+      (GClassInitFunc) gst_matroska_mux_class_init,
+      NULL,                     /* class_finalize */
+      NULL,                     /* class_data */
+      sizeof (GstMatroskaMux),
+      0,                        /* n_preallocs */
+      (GInstanceInitFunc) gst_matroska_mux_init
+    };
+    const GInterfaceInfo iface_info = { NULL };
+
+    object_type = g_type_register_static (GST_TYPE_ELEMENT,
+        "GstMatroskaMux", &object_info, (GTypeFlags) 0);
+
+    g_type_add_interface_static (object_type, GST_TYPE_TAG_SETTER, &iface_info);
+    g_type_add_interface_static (object_type, GST_TYPE_TOC_SETTER, &iface_info);
+  }
+
+  return object_type;
+}
+
 static void
 gst_matroska_mux_class_init (GstMatroskaMuxClass * klass)
 {
@@ -305,6 +335,8 @@ gst_matroska_mux_class_init (GstMatroskaMuxClass * klass)
       GST_DEBUG_FUNCPTR (gst_matroska_mux_request_new_pad);
   gstelement_class->release_pad =
       GST_DEBUG_FUNCPTR (gst_matroska_mux_release_pad);
+
+  parent_class = g_type_class_peek_parent (klass);
 }
 
 /**
@@ -405,20 +437,13 @@ gst_matroskamux_pad_init (GstMatroskamuxPad * pad)
  * End of pad option handler code
  **/
 
-/**
- * gst_matroska_mux_init:
- * @mux: #GstMatroskaMux that should be initialized.
- * @g_class: Class of the muxer.
- *
- * Matroska muxer constructor.
- */
 static void
-gst_matroska_mux_init (GstMatroskaMux * mux)
+gst_matroska_mux_init (GstMatroskaMux * mux, gpointer g_class)
 {
   GstPadTemplate *templ;
 
   templ =
-      gst_element_class_get_pad_template (GST_ELEMENT_GET_CLASS (mux), "src");
+      gst_element_class_get_pad_template (GST_ELEMENT_CLASS (g_class), "src");
   mux->srcpad = gst_pad_new_from_template (templ, "src");
 
   gst_pad_set_event_function (mux->srcpad, gst_matroska_mux_handle_src_event);

tests/check/elements/matroskamux.c

@@ -437,6 +437,31 @@ GST_START_TEST (test_reset)
 
 GST_END_TEST;
 
+GST_START_TEST (test_link_webmmux_webm_sink)
+{
+  static GstStaticPadTemplate webm_sinktemplate =
+      GST_STATIC_PAD_TEMPLATE ("sink",
+      GST_PAD_SINK,
+      GST_PAD_ALWAYS,
+      GST_STATIC_CAPS ("video/webm; audio/webm"));
+  GstElement *mux;
+
+  mux = gst_check_setup_element ("webmmux");
+  mysinkpad = setup_sink_pad (mux, &webm_sinktemplate, NULL);
+  fail_unless (mysinkpad != NULL);
+
+  fail_unless (gst_element_set_state (mux,
+          GST_STATE_PLAYING) == GST_STATE_CHANGE_SUCCESS,
+      "could not set to playing");
+
+  gst_element_set_state (mux, GST_STATE_NULL);
+
+  teardown_sink_pad (mux);
+  gst_check_teardown_element (mux);
+}
+
+GST_END_TEST;
+
 static Suite *
 matroskamux_suite (void)
 {
@@ -448,6 +473,7 @@ matroskamux_suite (void)
   tcase_add_test (tc_chain, test_vorbis_header);
   tcase_add_test (tc_chain, test_block_group);
   tcase_add_test (tc_chain, test_reset);
+  tcase_add_test (tc_chain, test_link_webmmux_webm_sink);
 
   return s;
 }