config.h

asterisk 是一个很有知名度开源软件

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <[e-mail]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 * \brief Configuration File Parser
 */

#ifndef _ASTERISK_CONFIG_H
#define _ASTERISK_CONFIG_H

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

#include "asterisk/utils.h"

struct ast_config;

struct ast_category;

/*! Options for ast_config_load()
 */
enum {
	/*! Load the configuration, including comments */
	CONFIG_FLAG_WITHCOMMENTS  = (1 << 0),
	/*! On a reload, give us a -1 if the file hasn't changed. */
	CONFIG_FLAG_FILEUNCHANGED = (1 << 1),
	/*! Don't attempt to cache mtime on this config file. */
	CONFIG_FLAG_NOCACHE       = (1 << 2),
};

#define	CONFIG_STATUS_FILEUNCHANGED	(void *)-1

/*! \brief Structure for variables, used for configurations and for channel variables 
*/
struct ast_variable {
	const char *name;
	const char *value;
	struct ast_variable *next;

	char *file;

	int lineno;
	int object;		/*!< 0 for variable, 1 for object */
	int blanklines; 	/*!< Number of blanklines following entry */
	struct ast_comment *precomments;
	struct ast_comment *sameline;
	struct ast_comment *trailing; /*!< the last object in the list will get assigned any trailing comments when EOF is hit */
	char stuff[0];
};

typedef struct ast_config *config_load_func(const char *database, const char *table, const char *configfile, struct ast_config *config, struct ast_flags flags, const char *suggested_include_file, const char *who_asked);
typedef struct ast_variable *realtime_var_get(const char *database, const char *table, va_list ap);
typedef struct ast_config *realtime_multi_get(const char *database, const char *table, va_list ap);
typedef int realtime_update(const char *database, const char *table, const char *keyfield, const char *entity, va_list ap);
typedef int realtime_store(const char *database, const char *table, va_list ap);
typedef int realtime_destroy(const char *database, const char *table, const char *keyfield, const char *entity, va_list ap);

/*! \brief Configuration engine structure, used to define realtime drivers */
struct ast_config_engine {
	char *name;
	config_load_func *load_func;
	realtime_var_get *realtime_func;
	realtime_multi_get *realtime_multi_func;
	realtime_update *update_func;
	realtime_store *store_func;
	realtime_destroy *destroy_func;
	struct ast_config_engine *next;
};

/*! \brief Load a config file 
 * \param filename path of file to open.  If no preceding '/' character, path is considered relative to AST_CONFIG_DIR
 * Create a config structure from a given configuration file.
 * \param who_asked The module which is making this request.
 * \param flags Optional flags:
 * CONFIG_FLAG_WITHCOMMENTS - load the file with comments intact;
 * CONFIG_FLAG_FILEUNCHANGED - check the file mtime and return CONFIG_STATUS_FILEUNCHANGED if the mtime is the same; or
 * CONFIG_FLAG_NOCACHE - don't cache file mtime (main purpose of this option is to save memory on temporary files).
 *
 * \retval an ast_config data structure on success
 * \retval NULL on error
 */
struct ast_config *ast_config_load2(const char *filename, const char *who_asked, struct ast_flags flags);

#define ast_config_load(filename, flags)	ast_config_load2(filename, __FILE__, flags)

/*! \brief Destroys a config 
 * \param config pointer to config data structure
 * Free memory associated with a given config
 *
 */
void ast_config_destroy(struct ast_config *config);

/*! \brief returns the root ast_variable of a config
 * \param config pointer to an ast_config data structure
 * \param cat name of the category for which you want the root
 *
 * Returns the category specified
 */
struct ast_variable *ast_category_root(struct ast_config *config, char *cat);

/*! \brief Goes through categories 
 * \param config Which config structure you wish to "browse"
 * \param prev A pointer to a previous category.
 * This function is kind of non-intuitive in it's use.  To begin, one passes NULL as the second argument.  It will return a pointer to the string of the first category in the file.  From here on after, one must then pass the previous usage's return value as the second pointer, and it will return a pointer to the category name afterwards.
 *
 * \retval a category on success
 * \retval NULL on failure/no-more-categories
 */
char *ast_category_browse(struct ast_config *config, const char *prev);

/*! 
 * \brief Goes through variables
 * Somewhat similar in intent as the ast_category_browse.
 * List variables of config file category
 *
 * \retval ast_variable list on success
 * \retval NULL on failure
 */
struct ast_variable *ast_variable_browse(const struct ast_config *config, const char *category);

/*!
 * \brief given a pointer to a category, return the root variable.
 * This is equivalent to ast_variable_browse(), but more efficient if we
 * already have the struct ast_category * (e.g. from ast_category_get())
 */
struct ast_variable *ast_category_first(struct ast_category *cat);

/*! 
 * \brief Gets a variable 
 * \param config which (opened) config to use
 * \param category category under which the variable lies
 * \param variable which variable you wish to get the data for
 * Goes through a given config file in the given category and searches for the given variable
 *
 * \retval The variable value on success 
 * \retval NULL if unable to find it.
 */
const char *ast_variable_retrieve(const struct ast_config *config, const char *category, const char *variable);

/*! 
 * \brief Retrieve a category if it exists
 * \param config which config to use
 * \param category_name name of the category you're looking for
 * This will search through the categories within a given config file for a match.
 *
 * \retval pointer to category if found
 * \retval NULL if not.
 */
struct ast_category *ast_category_get(const struct ast_config *config, const char *category_name);

/*! 
 * \brief Check for category duplicates 
 * \param config which config to use
 * \param category_name name of the category you're looking for
 * This will search through the categories within a given config file for a match.
 *
 * \return non-zero if found
 */
int ast_category_exist(const struct ast_config *config, const char *category_name);

/*! 
 * \brief Retrieve realtime configuration 
 * \param family which family/config to lookup
 * This will use builtin configuration backends to look up a particular 
 * entity in realtime and return a variable list of its parameters.  Note
 * that unlike the variables in ast_config, the resulting list of variables
 * MUST be freed with ast_variables_destroy() as there is no container.
 */
struct ast_variable *ast_load_realtime(const char *family, ...);
struct ast_variable *ast_load_realtime_all(const char *family, ...);

/*! 
 * \brief Retrieve realtime configuration 
 * \param family which family/config to lookup
 * This will use builtin configuration backends to look up a particular 
 * entity in realtime and return a variable list of its parameters. Unlike
 * the ast_load_realtime, this function can return more than one entry and
 * is thus stored inside a taditional ast_config structure rather than 
 * just returning a linked list of variables.
 */
struct ast_config *ast_load_realtime_multientry(const char *family, ...);

/*! 
 * \brief Update realtime configuration 
 * \param family which family/config to be updated
 * \param keyfield which field to use as the key
 * \param lookup which value to look for in the key field to match the entry.
 * This function is used to update a parameter in realtime configuration space.
 *
 */
int ast_update_realtime(const char *family, const char *keyfield, const char *lookup, ...);

/*! 
 * \brief Create realtime configuration 
 * \param family which family/config to be created