log.h

/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2007,2008 yvind Harboe                                 *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   Copyright (C) 2008 by Spencer Oliver                                  *
 *   spen@spen-soft.co.uk                                                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#ifndef ERROR_H
#define ERROR_H

#include "command.h"

/* logging priorities 
 * LOG_LVL_SILENT - turn off all output. In lieu of try + catch this can be used as a 
 *                  feeble ersatz.
 * LOG_LVL_USER - user messages. Could be anything from information 
 *                to progress messags. These messages do not represent
 *                incorrect or unexpected behaviour, just normal execution. 
 * LOG_LVL_ERROR - fatal errors, that are likely to cause program abort
 * LOG_LVL_WARNING - non-fatal errors, that may be resolved later
 * LOG_LVL_INFO - state information, etc.
 * LOG_LVL_DEBUG - debug statements, execution trace
 */
enum log_levels
{
	LOG_LVL_SILENT = -3,
	LOG_LVL_OUTPUT = -2,
	LOG_LVL_USER = -1,
	LOG_LVL_ERROR = 0,
	LOG_LVL_WARNING = 1,
	LOG_LVL_INFO = 2,
	LOG_LVL_DEBUG = 3
};

extern void log_printf(enum log_levels level, const char *file, int line, 
	const char *function, const char *format, ...) 
__attribute__ ((format (printf, 5, 6)));
extern void log_printf_lf(enum log_levels level, const char *file, int line,
	const char *function, const char *format, ...) 
__attribute__ ((format (printf, 5, 6)));
extern int log_register_commands(struct command_context_s *cmd_ctx);
extern int log_init(struct command_context_s *cmd_ctx);
extern int set_log_output(struct command_context_s *cmd_ctx, FILE *output);
extern void keep_alive(void);
extern void kept_alive(void);
extern void alive_sleep(int ms);
extern void busy_sleep(int ms);

typedef void (*log_callback_fn)(void *priv, const char *file, int line,
		const char *function, const char *string);

typedef struct log_callback_s
{
	log_callback_fn fn;
	void *priv;
	struct log_callback_s *next;
} log_callback_t;

extern int log_add_callback(log_callback_fn fn, void *priv);
extern int log_remove_callback(log_callback_fn fn, void *priv);

char *alloc_vprintf(const char *fmt, va_list ap);
char *alloc_printf(const char *fmt, ...);

extern int debug_level;

/* Avoid fn call and building parameter list if we're not outputting the information.
 * Matters on feeble CPUs for DEBUG/INFO statements that are involved frequently */

#define LOG_LEVEL_IS( FOO )  ((debug_level) >= (FOO))

#define LOG_DEBUG(expr ...) \
		((debug_level >= LOG_LVL_DEBUG) ? log_printf_lf (LOG_LVL_DEBUG, __FILE__, __LINE__, __FUNCTION__, expr) , 0 : 0)

#define LOG_INFO(expr ...) \
		log_printf_lf (LOG_LVL_INFO, __FILE__, __LINE__, __FUNCTION__, expr)

#define LOG_INFO_N(expr ...) \
		log_printf (LOG_LVL_INFO, __FILE__, __LINE__, __FUNCTION__, expr)

#define LOG_WARNING(expr ...) \
		log_printf_lf (LOG_LVL_WARNING, __FILE__, __LINE__, __FUNCTION__, expr)

#define LOG_ERROR(expr ...) \
		log_printf_lf (LOG_LVL_ERROR, __FILE__, __LINE__, __FUNCTION__, expr)

#define LOG_USER(expr ...) \
		log_printf_lf (LOG_LVL_USER, __FILE__, __LINE__, __FUNCTION__, expr)

#define LOG_USER_N(expr ...) \
		log_printf (LOG_LVL_USER, __FILE__, __LINE__, __FUNCTION__, expr)

#define LOG_OUTPUT(expr ...) \
		log_printf (LOG_LVL_OUTPUT, __FILE__, __LINE__, __FUNCTION__, expr)

/* general failures
 * error codes < 100
 */
#define ERROR_OK					(0)
#define ERROR_INVALID_ARGUMENTS		ERROR_COMMAND_SYNTAX_ERROR
#define ERROR_NO_CONFIG_FILE		(-2)
#define ERROR_BUF_TOO_SMALL			(-3)
/* see "Error:" log entry for meaningful message to the user. The caller should 
 * make no assumptions about what went wrong and try to handle the problem.
 */
#define ERROR_FAIL					(-4)

#endif /* LOG_H */