From 070eacdd4f9798919f144b3861e631a8e13be866 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Olivier=20Cr=C3=AAte?= <olivier.crete@collabora.com>
Date: Wed, 20 Mar 2019 18:31:48 -0400
Subject: [PATCH] rtpstorage + rtpulpfecdec: Get the storage using a query as
 fallback

This allows it to be used using gst-launch for easier testing.
---
 gst/rtp/gstrtpstorage.c   | 19 +++++++++++++++++++
 gst/rtp/gstrtpulpfecdec.c | 29 ++++++++++++++++++++++++-----
 2 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/gst/rtp/gstrtpstorage.c b/gst/rtp/gstrtpstorage.c
index 4be1aec591..b43eb982c6 100644
--- a/gst/rtp/gstrtpstorage.c
+++ b/gst/rtp/gstrtpstorage.c
@@ -132,6 +132,23 @@ gst_rtp_storage_get_property (GObject * object, guint prop_id,
   }
 }
 
+static gboolean
+gst_rtp_storage_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
+{
+  GstRtpStorage *self = GST_RTP_STORAGE (parent);
+
+  if (GST_QUERY_TYPE (query) == GST_QUERY_CUSTOM) {
+    GstStructure *s = gst_query_writable_structure (query);
+
+    if (gst_structure_has_name (s, "GstRtpStorage")) {
+      gst_structure_set (s, "storage", G_TYPE_OBJECT, self->storage, NULL);
+      return TRUE;
+    }
+  }
+
+  return gst_pad_query_default (pad, parent, query);
+}
+
 static void
 gst_rtp_storage_init (GstRtpStorage * self)
 {
@@ -141,6 +158,8 @@ gst_rtp_storage_init (GstRtpStorage * self)
   GST_PAD_SET_PROXY_ALLOCATION (self->sinkpad);
   gst_pad_set_chain_function (self->sinkpad, gst_rtp_storage_chain);
 
+  gst_pad_set_query_function (self->srcpad, gst_rtp_storage_src_query);
+
   gst_element_add_pad (GST_ELEMENT (self), self->srcpad);
   gst_element_add_pad (GST_ELEMENT (self), self->sinkpad);
 
diff --git a/gst/rtp/gstrtpulpfecdec.c b/gst/rtp/gstrtpulpfecdec.c
index 4a73b6db9b..08d68fe975 100644
--- a/gst/rtp/gstrtpulpfecdec.c
+++ b/gst/rtp/gstrtpulpfecdec.c
@@ -30,10 +30,10 @@
  * element and attempt to recover packets declared lost through custom
  * 'GstRTPPacketLost' events, usually emitted by #GstRtpJitterBuffer.
  *
- * As such, this element cannot be usefully used from the command line,
- * because a reference to the upstream storage object needs to be
- * provided to it through its #GstRtpUlpFecDec:storage property, example
- * programs are available at
+ * If no storage is provided using the #GstRtpUlpFecDec:storage
+ * property, it will try to get it from an element upstream.
+ *
+ * Example programs are available at
  * <https://github.com/sdroege/gstreamer-rs/blob/master/examples/src/bin/rtpfecserver.rs>
  * and
  * <https://github.com/sdroege/gstreamer-rs/blob/master/examples/src/bin/rtpfecclient.rs>.
@@ -472,7 +472,26 @@ gst_rtp_ulpfec_dec_handle_sink_event (GstPad * pad, GstObject * parent,
     s = gst_event_writable_structure (event);
 
     g_assert (self->have_caps_ssrc);
-    g_assert (self->storage);
+
+    if (self->storage == NULL) {
+      GstQuery *q = gst_query_new_custom (GST_QUERY_CUSTOM,
+          gst_structure_new_empty ("GstRtpStorage"));
+
+      if (gst_pad_peer_query (self->sinkpad, q)) {
+        const GstStructure *s = gst_query_get_structure (q);
+
+        if (gst_structure_has_field_typed (s, "storage", G_TYPE_OBJECT)) {
+          gst_structure_get (s, "storage", G_TYPE_OBJECT, &self->storage, NULL);
+        }
+      }
+      gst_query_unref (q);
+    }
+
+    if (self->storage == NULL) {
+      GST_ELEMENT_WARNING (self, STREAM, FAILED, ("Internal storage not found"),
+          ("You need to add rtpstorage element upstream from rtpulpfecdec."));
+      return FALSE;
+    }
 
     if (!gst_structure_get (s,
             "seqnum", G_TYPE_UINT, &seqnum,