rtspconnection: gst_rtsp_watch_wait_backlog

New method that wait until there is room in backlog queue.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=725898

docs/libs/gst-plugins-base-libs-sections.txt

@@ -1490,6 +1490,7 @@ gst_rtsp_watch_send_message
 gst_rtsp_watch_write_data
 gst_rtsp_watch_get_send_backlog
 gst_rtsp_watch_set_send_backlog
+gst_rtsp_watch_wait_backlog
 </SECTION>
 
 <SECTION>

gst-libs/gst/rtsp/gstrtspconnection.c

@@ -2999,6 +2999,7 @@ struct _GstRTSPWatch
   guint write_id;
   gsize max_bytes;
   guint max_messages;
+  GCond queue_not_full;
 
   GstRTSPWatchFuncs funcs;
 
@@ -3006,6 +3007,9 @@ struct _GstRTSPWatch
   GDestroyNotify notify;
 };
 
+#define IS_BACKLOG_FULL(w) (((w)->max_bytes != 0 && (w)->messages_bytes >= (w)->max_bytes) || \
+      ((w)->max_messages != 0 && (w)->messages->length >= (w)->max_messages))
+
 static gboolean
 gst_rtsp_source_prepare (GSource * source, gint * timeout)
 {
@@ -3283,6 +3287,9 @@ gst_rtsp_source_dispatch_write (GPollableOutputStream * stream,
 
     res = write_bytes (conn->output_stream, watch->write_data,
         &watch->write_off, watch->write_size, FALSE, conn->cancellable);
+
+    if (!IS_BACKLOG_FULL (watch))
+      g_cond_signal (&watch->queue_not_full);
     g_mutex_unlock (&watch->mutex);
 
     if (res == GST_RTSP_EINTR)
@@ -3341,7 +3348,9 @@ gst_rtsp_source_finalize (GSource * source)
   g_queue_free (watch->messages);
   watch->messages = NULL;
   watch->messages_bytes = 0;
+
   g_free (watch->write_data);
+  g_cond_clear (&watch->queue_not_full);
 
   if (watch->readsrc)
     g_source_unref (watch->readsrc);
@@ -3402,6 +3411,7 @@ gst_rtsp_watch_new (GstRTSPConnection * conn,
 
   g_mutex_init (&result->mutex);
   result->messages = g_queue_new ();
+  g_cond_init (&result->queue_not_full);
 
   gst_rtsp_watch_reset (result);
   result->keep_running = TRUE;
@@ -3522,6 +3532,8 @@ gst_rtsp_watch_set_send_backlog (GstRTSPWatch * watch,
   g_mutex_lock (&watch->mutex);
   watch->max_bytes = bytes;
   watch->max_messages = messages;
+  if (!IS_BACKLOG_FULL (watch))
+    g_cond_signal (&watch->queue_not_full);
   g_mutex_unlock (&watch->mutex);
 
   GST_DEBUG ("set backlog to bytes %" G_GSIZE_FORMAT ", messages %u",
@@ -3605,9 +3617,7 @@ gst_rtsp_watch_write_data (GstRTSPWatch * watch, const guint8 * data,
   }
 
   /* check limits */
-  if ((watch->max_bytes != 0 && watch->messages_bytes >= watch->max_bytes) ||
-      (watch->max_messages != 0
-          && watch->messages->length >= watch->max_messages))
+  if (IS_BACKLOG_FULL (watch))
     goto too_much_backlog;
 
   /* make a record with the data and id for sending async */
@@ -3705,3 +3715,47 @@ gst_rtsp_watch_send_message (GstRTSPWatch * watch, GstRTSPMessage * message,
   return gst_rtsp_watch_write_data (watch,
       (guint8 *) g_string_free (str, FALSE), size, id);
 }
+
+/**
+ * gst_rtsp_watch_wait_backlog:
+ * @watch: a #GstRTSPWatch
+ * @timeout: a #GTimeVal timeout
+ *
+ * Wait until there is place in the backlog queue or @timeout is reached.
+ *
+ * If @timeout is #NULL this function can block forever. If @timeout
+ * contains a valid timeout, this function will return #GST_RTSP_ETIMEOUT
+ * after the timeout expired.
+ *
+ * The typically use of this function is when gst_rtsp_watch_write_data
+ * returns GST_RTSP_ENOMEM. The caller then calls this function to wait for
+ * free space in the backlog queue and try again.
+ *
+ * Returns: #GST_RTSP_OK when if there is room in queue.
+ *          #GST_RTSP_ETIMEOUT when @timeout was reached.
+ *          #GST_RTSP_EINVAL when called with invalid parameters.
+ *
+ * Since: 1.4
+ */
+GstRTSPResult
+gst_rtsp_watch_wait_backlog (GstRTSPWatch * watch, GTimeVal * timeout)
+{
+  gint64 end_time;
+  GstClockTime to;
+
+  g_return_val_if_fail (watch != NULL, GST_RTSP_EINVAL);
+
+  to = timeout ? GST_TIMEVAL_TO_TIME (*timeout) : 0;
+  end_time = g_get_monotonic_time () + GST_TIME_AS_USECONDS (to);
+
+  g_mutex_lock (&watch->mutex);
+  while (IS_BACKLOG_FULL (watch)) {
+    if (!g_cond_wait_until (&watch->queue_not_full, &watch->mutex, end_time)) {
+      g_mutex_unlock (&watch->mutex);
+      return GST_RTSP_ETIMEOUT;
+    }
+  }
+  g_mutex_unlock (&watch->mutex);
+
+  return GST_RTSP_OK;
+}

gst-libs/gst/rtsp/gstrtspconnection.h

@@ -214,6 +214,8 @@ GstRTSPResult      gst_rtsp_watch_write_data         (GstRTSPWatch *watch,
 GstRTSPResult      gst_rtsp_watch_send_message       (GstRTSPWatch *watch,
                                                       GstRTSPMessage *message,
                                                       guint *id);
+GstRTSPResult      gst_rtsp_watch_wait_backlog       (GstRTSPWatch * watch,
+                                                      GTimeVal *timeout);
 
 G_END_DECLS
 

win32/common/libgstrtsp.def

@@ -119,4 +119,5 @@ EXPORTS
 	gst_rtsp_watch_send_message
 	gst_rtsp_watch_set_send_backlog
 	gst_rtsp_watch_unref
+	gst_rtsp_watch_wait_backlog
 	gst_rtsp_watch_write_data