sdp: Add API to remove media from a SDP message

Based on initial patch by Stefano Buora.
https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/579

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4670>

girs/GstSdp-1.0.gir

@@ -3374,6 +3374,25 @@ from a #GstSDPMessage.</doc>
           </parameter>
         </parameters>
       </method>
+      <method name="remove_media" c:identifier="gst_sdp_message_remove_media" version="1.24">
+        <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/sdp/gstsdpmessage.c">Remove the media at @idx from the array of medias in @msg if found.</doc>
+        <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/sdp/gstsdpmessage.h"/>
+        <return-value transfer-ownership="none">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/sdp/gstsdpmessage.c">#GST_SDP_OK when the specified media is found at @idx and removed,
+#GST_SDP_EINVAL otherwise.</doc>
+          <type name="SDPResult" c:type="GstSDPResult"/>
+        </return-value>
+        <parameters>
+          <instance-parameter name="msg" transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/sdp/gstsdpmessage.c">a #GstSDPMessage</doc>
+            <type name="SDPMessage" c:type="GstSDPMessage*"/>
+          </instance-parameter>
+          <parameter name="idx" transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/sdp/gstsdpmessage.c">the media index</doc>
+            <type name="guint" c:type="guint"/>
+          </parameter>
+        </parameters>
+      </method>
       <method name="remove_phone" c:identifier="gst_sdp_message_remove_phone" version="1.2">
         <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/sdp/gstsdpmessage.c">Remove the phone number in @msg at index @idx.</doc>
         <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/sdp/gstsdpmessage.h"/>

subprojects/gst-plugins-base/gst-libs/gst/sdp/gstsdpmessage.c

@@ -1790,6 +1790,33 @@ gst_sdp_message_add_media (GstSDPMessage * msg, GstSDPMedia * media)
   return GST_SDP_OK;
 }
 
+/**
+ * gst_sdp_message_remove_media:
+ * @msg: a #GstSDPMessage
+ * @idx: the media index
+ *
+ * Remove the media at @idx from the array of medias in @msg if found.
+ *
+ * Returns: #GST_SDP_OK when the specified media is found at @idx and removed,
+ * #GST_SDP_EINVAL otherwise.
+ *
+ * Since: 1.24
+ */
+GstSDPResult
+gst_sdp_message_remove_media (GstSDPMessage * msg, guint idx)
+{
+  GstSDPMedia *media = NULL;
+
+  g_return_val_if_fail (msg != NULL, GST_SDP_EINVAL);
+  g_return_val_if_fail (idx <= gst_sdp_message_medias_len (msg),
+      GST_SDP_EINVAL);
+
+  media = &g_array_index (msg->medias, GstSDPMedia, idx);
+  gst_sdp_media_uninit (media);
+  g_array_remove_index (msg->medias, idx);
+  return GST_SDP_OK;
+}
+
 /* media access */
 
 /**

subprojects/gst-plugins-base/gst-libs/gst/sdp/gstsdpmessage.h

@@ -572,6 +572,9 @@ const GstSDPMedia*      gst_sdp_message_get_media           (const GstSDPMessage
 GST_SDP_API
 GstSDPResult            gst_sdp_message_add_media           (GstSDPMessage *msg, GstSDPMedia *media);
 
+GST_SDP_API
+GstSDPResult            gst_sdp_message_remove_media        (GstSDPMessage *msg, guint idx);
+
 GST_SDP_API
 GstSDPResult            gst_sdp_message_dump                (const GstSDPMessage *msg);
 

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

@@ -933,6 +933,56 @@ GST_START_TEST (media_from_caps_with_source_filters)
   gst_sdp_message_free (message);
 }
 
+GST_END_TEST
+GST_START_TEST (media_remove)
+{
+  GstSDPResult ret = GST_SDP_OK;
+  GstSDPMessage *message;
+  const gchar *media;
+  GstSDPMedia *media_video, *media_audio;
+  const GstSDPMedia *result_audio;
+  GstCaps *caps_video, *caps_audio;
+
+  /* Add two medias, firts a video and then audio */
+  caps_video = gst_caps_from_string (caps_video_string1);
+  caps_audio = gst_caps_from_string (caps_audio_string);
+
+  gst_sdp_media_new (&media_video);
+  fail_unless (media_video != NULL);
+  gst_sdp_media_new (&media_audio);
+  fail_unless (media_audio != NULL);
+
+  ret = gst_sdp_media_set_media_from_caps (caps_video, media_video);
+  fail_unless (ret == GST_SDP_OK);
+  gst_caps_unref (caps_video);
+  ret = gst_sdp_media_set_media_from_caps (caps_audio, media_audio);
+  fail_unless (ret == GST_SDP_OK);
+  gst_caps_unref (caps_audio);
+
+  gst_sdp_message_new (&message);
+  gst_sdp_message_add_media (message, media_video);
+  gst_sdp_message_add_media (message, media_audio);
+
+  fail_unless_equals_int (gst_sdp_message_medias_len (message), 2);
+
+  /* Remove the first media (video) */
+  ret = gst_sdp_message_remove_media (message, 0);
+  fail_unless (ret == GST_SDP_OK);
+
+  /* Audio media is the only one left */
+  fail_unless_equals_int (gst_sdp_message_medias_len (message), 1);
+
+  result_audio = gst_sdp_message_get_media (message, 0);
+  fail_unless (result_audio != NULL);
+
+  media = gst_sdp_media_get_media (result_audio);
+  fail_unless_equals_string (media, "audio");
+
+  gst_sdp_media_free (media_audio);
+  gst_sdp_media_free (media_video);
+  gst_sdp_message_free (message);
+}
+
 GST_END_TEST
 /*
  * End of test cases
@@ -963,6 +1013,7 @@ sdp_suite (void)
   tcase_add_test (tc_chain, caps_multiple_rid_parse);
   tcase_add_test (tc_chain, caps_multiple_rid_parse_with_params);
   tcase_add_test (tc_chain, media_from_caps_with_source_filters);
+  tcase_add_test (tc_chain, media_remove);
 
   return s;
 }