Add filename alias support to the Config Options API

This adds the ability to handle a single filename alias for a config
file. This is useful if a config filename has changed, but the old
filename should be supported for backwards compatibility.

Review: https://reviewboard.asterisk.org/r/1981/ 


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@368920 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/config_options.h

@@ -136,9 +136,11 @@ typedef int (*aco_pre_apply_config)(void);
  */
 typedef void *(*aco_snapshot_alloc)(void);
 
+/*! \brief The representation of a single configuration file to be processed */
 struct aco_file {
-	const char *filename;
+	const char *filename; /*!< \brief The filename to be processed */
-	const char **preload;
+	const char *alias;    /*!< \brief An alias filename to be tried if 'filename' cannot be found */
+	const char **preload; /*!< \brief A null-terminated oredered array of categories to be loaded first */
 	struct aco_type *types[]; /*!< The list of types for this config. Required. Use a sentinel! */
 };
 

main/config_options.c

@@ -434,7 +434,13 @@ enum aco_process_status aco_process_config(struct aco_info *info, int reload)
 	}
 
 	while (res != ACO_PROCESS_ERROR && (file = info->files[x++])) {
-		if (!(cfg = ast_config_load(file->filename, cfg_flags))) {
+		const char *filename = file->filename;
+try_alias:
+		if (!(cfg = ast_config_load(filename, cfg_flags))) {
+			if (file->alias && strcmp(file->alias, filename)) {
+				filename = file->alias;
+				goto try_alias;
+			}
 			ast_log(LOG_ERROR, "Unable to load config file '%s'\n", file->filename);
 			res = ACO_PROCESS_ERROR;
 			break;
@@ -447,6 +453,10 @@ enum aco_process_status aco_process_config(struct aco_info *info, int reload)
 			res = ACO_PROCESS_ERROR;
 			break;
 		} else if (cfg == CONFIG_STATUS_FILEMISSING) {
+			if (file->alias && strcmp(file->alias, filename)) {
+				filename = file->alias;
+				goto try_alias;
+			}
 			ast_log(LOG_ERROR, "%s is missing! Cannot load %s\n", file->filename, info->module);
 			res = ACO_PROCESS_ERROR;
 			break;