ARI: Make bridges/{bridgeID}/play queue sound files

Previously multiple play actions against a bridge at one time would cause
the sounds to play simultaneously on the bridge. Now if a sound is already
playing, the play action will queue playback to occur after the completion
of other sounds currently on the queue.

(closes issue ASTERISK-22677)
Reported by: John Bigelow
Review: https://reviewboard.asterisk.org/r/3379/
........

Merged revisions 412639 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@412641 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/stasis_app.h

@@ -374,6 +374,15 @@ void stasis_app_control_execute_until_exhausted(
 	struct ast_channel *chan,
 	struct stasis_app_control *control);
 
+/*!
+ * \brief Check if a control is marked as done
+ * \since 12.2.0
+ *
+ * \param control Which control object is being evaluated
+ */
+int stasis_app_control_is_done(
+	struct stasis_app_control *control);
+
 /*!
  * \brief Returns the uniqueid of the channel associated with this control
  *
@@ -637,6 +646,30 @@ struct ast_channel *stasis_app_bridge_moh_channel(
 int stasis_app_bridge_moh_stop(
 	struct ast_bridge *bridge);
 
+/*!
+ * \brief Finds an existing ARI playback channel in a bridge
+ *
+ * \param bridge Bridge we want to find the playback channel for
+ *
+ * \return NULL if the playback channel can not be found for any reason.
+ * \return Pointer to the ;1 end of the playback channel chain.
+ */
+struct ast_channel *stasis_app_bridge_playback_channel_find(
+	struct ast_bridge *bridge);
+
+/*!
+ * \brief Adds a channel to the list of ARI playback channels for bridges.
+ *
+ * \param bridge Bridge we are adding the playback channel for
+ * \param chan Channel being added as a playback channel (must be ;1)
+ *
+ * \retval -1 failed to add channel for any reason
+ * \retval 0 on success
+ */
+int stasis_app_bridge_playback_channel_add(struct ast_bridge *bridge,
+	struct ast_channel *chan,
+	struct stasis_app_control *control);
+
 /*!
  * \brief Result codes used when adding/removing channels to/from bridges.
  */