core/bridge_channel: Substitute Variables In Features Application Map

Say you wanted to include variables in an application map and have those
variables substituted and passed along to the application being executed;
currently this does not happen.

This patch adds this ability to pass channel variable values to an
application before being executed.

ASTERISK-22608 #close
Reported by: Michael L. Young
patches:
  features_substitute_arguments_v2.diff
                                     uploaded by Michael L. Young (license 5026)

Review: https://reviewboard.asterisk.org/r/3819/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@419252 65c4cc65-6c06-0410-ace0-fbb531ad65f3

CHANGES

@@ -137,6 +137,9 @@ Features
    features were provided exclusively by the caller of ast_bridge_join()
    outside of "basic" type bridges.
 
+ * Channel variables are now substituted in arguments passed to applications
+   run by using dynamic features.
+
 JACK_HOOK
 ------------------
  * The JACK_HOOK function now supports audio with a sample rate higher than

main/bridge_channel.c

@@ -1020,7 +1020,16 @@ static int run_app_helper(struct ast_channel *chan, const char *app_name, const
 		if (!app) {
 			ast_log(LOG_WARNING, "Could not find application (%s)\n", app_name);
 		} else {
-			res = pbx_exec(chan, app, app_args);
+			struct ast_str *substituted_args = ast_str_create(16);
+
+			if (substituted_args) {
+				ast_str_substitute_variables(&substituted_args, 0, chan, app_args);
+				res = pbx_exec(chan, app, ast_str_buffer(substituted_args));
+				ast_free(substituted_args);
+			} else {
+				ast_log(LOG_WARNING, "Could not substitute application argument variables for %s\n", app_name);
+				res = pbx_exec(chan, app, app_args);
+			}
 		}
 	}
 	return res;