pbutils: Missing plugin messages can contain the stream-id

In order to help users and applications, allow setting the stream-id for which
there is a missing plugin.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6886>

girs/GstPbutils-1.0.gir

@@ -4763,6 +4763,37 @@ installation mechanisms using one of the two above-mentioned functions.</doc>
         </parameter>
       </parameters>
     </function>
+    <function name="missing_plugin_message_get_stream_id" c:identifier="gst_missing_plugin_message_get_stream_id" version="1.26">
+      <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.c">Get the stream-id of the stream for which an element is missing.</doc>
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.h"/>
+      <return-value transfer-ownership="none" nullable="1">
+        <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.c">The stream-id or %NULL if none is specified.</doc>
+        <type name="utf8" c:type="const gchar*"/>
+      </return-value>
+      <parameters>
+        <parameter name="msg" transfer-ownership="none">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.c">A missing-plugin #GstMessage of type #GST_MESSAGE_ELEMENT</doc>
+          <type name="Gst.Message" c:type="GstMessage*"/>
+        </parameter>
+      </parameters>
+    </function>
+    <function name="missing_plugin_message_set_stream_id" c:identifier="gst_missing_plugin_message_set_stream_id" version="1.26">
+      <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.c">Set the stream-id of the stream for which an element is missing.</doc>
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.h"/>
+      <return-value transfer-ownership="none">
+        <type name="none" c:type="void"/>
+      </return-value>
+      <parameters>
+        <parameter name="msg" transfer-ownership="none">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.c">A missing-plugin #GstMessage of type #GST_MESSAGE_ELEMENT</doc>
+          <type name="Gst.Message" c:type="GstMessage*"/>
+        </parameter>
+        <parameter name="stream_id" transfer-ownership="none">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.c">The stream id for which an element is missing</doc>
+          <type name="utf8" c:type="const gchar*"/>
+        </parameter>
+      </parameters>
+    </function>
     <function name="missing_uri_sink_installer_detail_new" c:identifier="gst_missing_uri_sink_installer_detail_new">
       <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.c">Returns an opaque string containing all the details about the missing
 element to be passed to an external installer called via

subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.c

@@ -518,6 +518,49 @@ error:
   }
 }
 
+/**
+ * gst_missing_plugin_message_set_stream_id:
+ * @msg: A missing-plugin #GstMessage of type #GST_MESSAGE_ELEMENT
+ * @stream_id: The stream id for which an element is missing
+ *
+ * Set the stream-id of the stream for which an element is missing.
+ *
+ * Since: 1.26
+ */
+void
+gst_missing_plugin_message_set_stream_id (GstMessage * msg,
+    const gchar * stream_id)
+{
+  const GstStructure *structure;
+
+  g_return_if_fail (gst_is_missing_plugin_message (msg));
+
+  structure = gst_message_get_structure (msg);
+  gst_structure_set ((GstStructure *) structure, "stream-id", G_TYPE_STRING,
+      stream_id, NULL);
+}
+
+/**
+ * gst_missing_plugin_message_get_stream_id:
+ * @msg: A missing-plugin #GstMessage of type #GST_MESSAGE_ELEMENT
+ *
+ * Get the stream-id of the stream for which an element is missing.
+ *
+ * Since: 1.26
+ *
+ * Returns: (nullable): The stream-id or %NULL if none is specified.
+ */
+const gchar *
+gst_missing_plugin_message_get_stream_id (GstMessage * msg)
+{
+  const GstStructure *structure;
+
+  g_return_val_if_fail (gst_is_missing_plugin_message (msg), NULL);
+
+  structure = gst_message_get_structure (msg);
+  return gst_structure_get_string (structure, "stream-id");
+}
+
 /**
  * gst_missing_plugin_message_get_description:
  * @msg: a missing-plugin #GstMessage of type #GST_MESSAGE_ELEMENT

subprojects/gst-plugins-base/gst-libs/gst/pbutils/missing-plugins.h

@@ -49,6 +49,13 @@ GST_PBUTILS_API
 GstMessage * gst_missing_encoder_message_new    (GstElement    * element,
                                                  const GstCaps * encode_caps);
 
+GST_PBUTILS_API
+void gst_missing_plugin_message_set_stream_id(GstMessage *msg,
+                                              const gchar *stream_id);
+
+GST_PBUTILS_API
+const gchar *gst_missing_plugin_message_get_stream_id (GstMessage *msg);
+
 /*
  * functions for use by applications when dealing with missing-plugin messages
  */

subprojects/gst-plugins-base/tests/check/libs/pbutils.c

@@ -199,6 +199,7 @@ GST_START_TEST (test_pb_utils_post_missing_messages)
   msg = gst_missing_decoder_message_new (pipeline, caps);
   fail_unless (msg != NULL);
   fail_unless_equals_int (GST_MESSAGE_TYPE (msg), GST_MESSAGE_ELEMENT);
+  gst_missing_plugin_message_set_stream_id (msg, "teststreamid");
   fail_unless (gst_message_get_structure (msg) != NULL);
   s = gst_message_get_structure (msg);
   fail_unless (gst_structure_has_name (s, "missing-plugin"));
@@ -207,6 +208,8 @@ GST_START_TEST (test_pb_utils_post_missing_messages)
   fail_unless (gst_structure_has_field_typed (s, "detail", GST_TYPE_CAPS));
   fail_unless (gst_structure_has_field_typed (s, "name", G_TYPE_STRING));
   fail_unless (gst_structure_get_string (s, "name") != NULL);
+  fail_unless_equals_string (gst_missing_plugin_message_get_stream_id (msg),
+      "teststreamid");
   missing_msg_check_getters (msg);
   gst_message_unref (msg);