bridge_native_rtp.c: Defer allocation and check if it fails in native_rtp_bridge_compatible().

Review: https://reviewboard.asterisk.org/r/4601/
........

Merged revisions 434508 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@434509 65c4cc65-6c06-0410-ace0-fbb531ad65f3

bridges/bridge_native_rtp.c

@@ -310,8 +310,8 @@ static int native_rtp_bridge_compatible(struct ast_bridge *bridge)
 	RAII_VAR(struct ast_rtp_instance *, instance1, NULL, ao2_cleanup);
 	RAII_VAR(struct ast_rtp_instance *, vinstance0, NULL, ao2_cleanup);
 	RAII_VAR(struct ast_rtp_instance *, vinstance1, NULL, ao2_cleanup);
-	RAII_VAR(struct ast_format_cap *, cap0, ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT), ao2_cleanup);
-	RAII_VAR(struct ast_format_cap *, cap1, ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT), ao2_cleanup);
+	RAII_VAR(struct ast_format_cap *, cap0, NULL, ao2_cleanup);
+	RAII_VAR(struct ast_format_cap *, cap1, NULL, ao2_cleanup);
 	int read_ptime0, read_ptime1, write_ptime0, write_ptime1;
 
 	/* We require two channels before even considering native bridging */
@@ -361,6 +361,12 @@ static int native_rtp_bridge_compatible(struct ast_bridge *bridge)
 		return 0;
 	}
 
+	cap0 = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT);
+	cap1 = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT);
+	if (!cap0 || !cap1) {
+		return 0;
+	}
+
 	/* Make sure that codecs match */
 	if (glue0->get_codec) {
 		glue0->get_codec(bc0->chan, cap0);