transmission/libtransmission/error.h

/*
 * This file Copyright (C) 2013-2014 Mnemosyne LLC
 *
 * It may be used under the GNU GPL versions 2 or 3
 * or any future license endorsed by Mnemosyne LLC.
 *
 * $Id$
 */

#ifndef TR_ERROR_H
#define TR_ERROR_H

#include <stdarg.h>

#ifdef __cplusplus
extern "C" {
#endif

#ifndef TR_GNUC_PRINTF
 #ifdef __GNUC__
  #define TR_GNUC_PRINTF(fmt, args) __attribute__ ((format (printf, fmt, args)))
 #else
  #define TR_GNUC_PRINTF(fmt, args)
 #endif
#endif

/**
 * @addtogroup error Error reporting
 * @{
 */

/** @brief Structure holding error information. */
typedef struct tr_error
{
  /** @brief Error code, platform-specific */
  int    code;
  /** @brief Error message */
  char * message;
}
tr_error;

/**
 * @brief Create new error object using `printf`-style formatting.
 *
 * @param[in] code           Error code (platform-specific).
 * @param[in] message_format Error message format string.
 * @param[in] ...            Format arguments.
 *
 * @return Newly allocated error object on success, `NULL` otherwise.
 */
tr_error * tr_error_new                (int           code,
                                        const char  * message_format,
                                                      ...) TR_GNUC_PRINTF (2, 3);

/**
 * @brief Create new error object using literal error message.
 *
 * @param[in] code    Error code (platform-specific).
 * @param[in] message Error message.
 *
 * @return Newly allocated error object on success, `NULL` otherwise.
 */
tr_error * tr_error_new_literal        (int           code,
                                        const char  * message);

/**
 * @brief Create new error object using `vprintf`-style formatting.
 *
 * @param[in] code           Error code (platform-specific).
 * @param[in] message_format Error message format string.
 * @param[in] args           Format arguments.
 *
 * @return Newly allocated error object on success, `NULL` otherwise.
 */
tr_error * tr_error_new_valist         (int           code,
                                        const char  * message_format,
                                        va_list       args);

/**
 * @brief Free memory used by error object.
 *
 * @param[in] error Error object to be freed.
 */
void       tr_error_free               (tr_error    * error);

/**
 * @brief Create and set new error object using `printf`-style formatting.
 *
 * If passed pointer to error object is `NULL`, do nothing.
 *
 * @param[in,out] error          Pointer to error object to be set.
 * @param[in]     code           Error code (platform-specific).
 * @param[in]     message_format Error message format string.
 * @param[in]     ...            Format arguments.
 */
void       tr_error_set                (tr_error   ** error,
                                        int           code,
                                        const char  * message_format,
                                                      ...) TR_GNUC_PRINTF (3, 4);

/**
 * @brief Create and set new error object using literal error message.
 *
 * If passed pointer to error object is `NULL`, do nothing.
 *
 * @param[in,out] error   Pointer to error object to be set.
 * @param[in]     code    Error code (platform-specific).
 * @param[in]     message Error message.
 */
void       tr_error_set_literal        (tr_error   ** error,
                                        int           code,
                                        const char  * message);

/**
 * @brief Propagate existing error object upwards.
 *
 * If passed pointer to new error object is not `NULL`, copy old error object to
 * new error object and free old error object. Otherwise, just free old error
 * object.
 *
 * @param[in,out] new_error Pointer to error object to be set.
 * @param[in,out] old_error Error object to be propagated. Cleared on return.
 */
void       tr_error_propagate          (tr_error   ** new_error,
                                        tr_error   ** old_error);

/**
 * @brief Clear error object.
 *
 * Free error object being pointed and set pointer to `NULL`. If passed pointer
 * is `NULL`, do nothing.
 *
 * @param[in,out] error Pointer to error object to be cleared.
 */
void       tr_error_clear              (tr_error   ** error);

/**
 * @brief Prefix message of exising error object.
 *
 * If passed pointer to error object is not `NULL`, prefix its message with
 * `printf`-style formatted text. Otherwise, do nothing.
 *
 * @param[in,out] error         Pointer to error object to be set.
 * @param[in]     prefix_format Prefix format string.
 * @param[in]     ...           Format arguments.
 */
void       tr_error_prefix             (tr_error   ** error,
                                        const char  * prefix_format,
                                                      ...) TR_GNUC_PRINTF (2, 3);

/**
 * @brief Prefix message and propagate existing error object upwards.
 *
 * If passed pointer to new error object is not `NULL`, copy old error object to
 * new error object, prefix its message with `printf`-style formatted text, and
 * free old error object. Otherwise, just free old error object.
 *
 * @param[in,out] new_error Pointer to error object to be set.
 * @param[in,out] old_error     Error object to be propagated. Cleared on return.
 * @param[in] prefix_format Prefix format string.
 * @param[in] ... Format arguments.
 */
void       tr_error_propagate_prefixed (tr_error   ** new_error,
                                        tr_error   ** old_error,
                                        const char  * prefix_format,
                                                      ...) TR_GNUC_PRINTF (3, 4);

/** @} */

#ifdef __cplusplus
}
#endif

#endif