include/vlc_messages.h

   1 /*****************************************************************************
   2  * vlc_messages.h: messages interface
   3  * This library provides basic functions for threads to interact with user
   4  * interface, such as message output.
   5  *****************************************************************************
   6  * Copyright (C) 1999, 2000, 2001, 2002 VLC authors and VideoLAN
   7  *
   8  * Authors: Vincent Seguin <seguin@via.ecp.fr>
   9  *          Samuel Hocevar <sam@zoy.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU Lesser General Public License as published by
  13  * the Free Software Foundation; either version 2.1 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19  * GNU Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public License
  22  * along with this program; if not, write to the Free Software Foundation,
  23  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  24  *****************************************************************************/
  25
  26 #ifndef VLC_MESSAGES_H_
  27 #define VLC_MESSAGES_H_
  28
  29 #include <stdarg.h>
  30
  31 /**
  32  * \defgroup messages Logging
  33  * \ingroup os
  34  * \brief Message logs
  35  *
  36  * Functions for modules to emit log messages.
  37  *
  38  * @{
  39  * \file
  40  * Logging functions
  41  */
  42
  43 /** Message types */
  44 enum vlc_log_type
  45 {
  46     VLC_MSG_INFO=0, /**< Important information */
  47     VLC_MSG_ERR,    /**< Error */
  48     VLC_MSG_WARN,   /**< Warning */
  49     VLC_MSG_DBG,    /**< Debug */
  50 };
  51
  52 /**
  53  * Log message
  54  */
  55 typedef struct vlc_log_t
  56 {
  57     uintptr_t   i_object_id; /**< Emitter (temporarily) unique object ID or 0 */
  58     const char *psz_object_type; /**< Emitter object type name */
  59     const char *psz_module; /**< Emitter module (source code) */
  60     const char *psz_header; /**< Additional header (used by VLM media) */
  61     const char *file; /**< Source code file name or NULL */
  62     int line; /**< Source code file line number or -1 */
  63     const char *func; /**< Source code calling function name or NULL */
  64     unsigned long tid; /**< Emitter thread ID */
  65 } vlc_log_t;
  66
  67 /**
  68  * Emit a log message.
  69  *
  70  * \param obj VLC object emitting the message or NULL
  71  * \param type VLC_MSG_* message type (info, error, warning or debug)
  72  * \param module name of module from which the message come
  73  *               (normally vlc_module_name)
  74  * \param file source module file name (normally __FILE__) or NULL
  75  * \param line function call source line number (normally __LINE__) or 0
  76  * \param func calling function name (normally __func__) or NULL
  77  * \param format printf-like message format
  78  */
  79 VLC_API void vlc_object_Log(vlc_object_t *obj, int prio, const char *module,
  80                             const char *file, unsigned line, const char *func,
  81                             const char *format, ...) VLC_FORMAT(7, 8);
  82
  83 /**
  84  * Emit a log message.
  85  *
  86  * This function is the variable argument list equivalent to vlc_object_Log().
  87  */
  88 VLC_API void vlc_object_vaLog(vlc_object_t *obj, int prio, const char *module,
  89                              const char *file, unsigned line, const char *func,
  90                               const char *format, va_list ap);
  91
  92 #define msg_GenericVa(o, p, fmt, ap) \
  93     vlc_object_vaLog(VLC_OBJECT(o), p, vlc_module_name, __FILE__, __LINE__, \
  94                      __func__, fmt, ap)
  95
  96 #define msg_Generic(o, p, ...) \
  97     vlc_object_Log(VLC_OBJECT(o), p, vlc_module_name, __FILE__, __LINE__, \
  98                    __func__, __VA_ARGS__)
  99 #define msg_Info(p_this, ...) \
 100     msg_Generic(p_this, VLC_MSG_INFO, __VA_ARGS__)
 101 #define msg_Err(p_this, ...) \
 102     msg_Generic(p_this, VLC_MSG_ERR, __VA_ARGS__)
 103 #define msg_Warn(p_this, ...) \
 104     msg_Generic(p_this, VLC_MSG_WARN, __VA_ARGS__)
 105 #define msg_Dbg(p_this, ...) \
 106     msg_Generic(p_this, VLC_MSG_DBG, __VA_ARGS__)
 107
 108 #ifndef __cplusplus
 109 extern const char vlc_module_name[];
 110 #else
 111 extern "C" const char vlc_module_name[];
 112 #endif
 113
 114 VLC_API const char *vlc_strerror(int);
 115 VLC_API const char *vlc_strerror_c(int);
 116
 117 /**
 118  * \defgroup logger Logger
 119  * \brief Message log back-end.
 120  *
 121  * @{
 122  */
 123
 124 struct vlc_logger;
 125
 126 VLC_API void vlc_Log(struct vlc_logger *const *logger, int prio,
 127                      const char *type, const char *module,
 128                      const char *file, unsigned line, const char *func,
 129                      const char *format, ...) VLC_FORMAT(8, 9);
 130 VLC_API void vlc_vaLog(struct vlc_logger *const *logger, int prio,
 131                        const char *type, const char *module,
 132                        const char *file, unsigned line, const char *func,
 133                        const char *format, va_list ap);
 134
 135 #define vlc_log_gen(logger, prio, ...) \
 136         vlc_Log(&(logger), prio, "generic", vlc_module_name, \
 137                 __FILE__, __LINE__, __func__, __VA_ARGS__)
 138 #define vlc_info(logger, ...)    vlc_log_gen(logger, VLC_MSG_INFO, __VA_ARGS__)
 139 #define vlc_error(logger, ...)   vlc_log_gen(logger, VLC_MSG_ERR,  __VA_ARGS__)
 140 #define vlc_warning(logger, ...) vlc_log_gen(logger, VLC_MSG_WARN, __VA_ARGS__)
 141 #define vlc_debug(logger, ...)   vlc_log_gen(logger, VLC_MSG_DBG,  __VA_ARGS__)
 142
 143 /**
 144  * Message logging callback signature.
 145  * \param data data pointer as provided to vlc_msg_SetCallback().
 146  * \param type message type (VLC_MSG_* values from enum vlc_log_type)
 147  * \param item meta information
 148  * \param fmt format string
 149  * \param args format string arguments
 150  */
 151 typedef void (*vlc_log_cb) (void *data, int type, const vlc_log_t *item,
 152                             const char *fmt, va_list args);
 153
 154 struct vlc_logger_operations
 155 {
 156     vlc_log_cb log;
 157     void (*destroy)(void *data);
 158 };
 159
 160 /**
 161  * Creates a prefixed message log.
 162  *
 163  * This creates a message log that prefixes all its messages and forwards them
 164  * in another log.
 165  * \param parent message log to inject into
 166  * \param str nul-terminated prefix (a.k.a. "header")
 167  * \return a new message log on success or @c NULL on error
 168  */
 169 VLC_API struct vlc_logger *vlc_LogHeaderCreate(struct vlc_logger *parent,
 170                                                const char *str) VLC_USED;
 171
 172 /**
 173  * Destroys a message log.
 174  */
 175 VLC_API void vlc_LogDestroy(struct vlc_logger *);
 176
 177 /**
 178  * @}
 179  */
 180 /**
 181  * @}
 182  */
 183 #endif