log.c

   1 /*
   2  * This file is part of the libsigrokdecode project.
   3  *
   4  * Copyright (C) 2011-2012 Uwe Hermann <uwe@hermann-uwe.de>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #include "libsigrokdecode.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
  22 #include "libsigrokdecode-internal.h"
  23 #include <stdarg.h>
  24 #include <stdio.h>
  25
  26 /**
  27  * @file
  28  *
  29  * Controlling the libsigrokdecode message logging functionality.
  30  */
  31
  32 /**
  33  * @defgroup grp_logging Logging
  34  *
  35  * Controlling the libsigrokdecode message logging functionality.
  36  *
  37  * @{
  38  */
  39
  40 /* Currently selected libsigrokdecode loglevel. Default: SRD_LOG_WARN. */
  41 static int cur_loglevel = SRD_LOG_WARN; /* Show errors+warnings per default. */
  42
  43 /* Function prototype. */
  44 static int srd_logv(void *cb_data, int loglevel, const char *format,
  45                     va_list args);
  46
  47 /* Pointer to the currently selected log callback. Default: srd_logv(). */
  48 static srd_log_callback srd_log_cb = srd_logv;
  49
  50 /*
  51  * Pointer to private data that can be passed to the log callback.
  52  * This can be used (for example) by C++ GUIs to pass a "this" pointer.
  53  */
  54 static void *srd_log_cb_data = NULL;
  55
  56 /* Log domain (a short string that is used as prefix for all messages). */
  57 /** @cond PRIVATE */
  58 #define LOGDOMAIN_MAXLEN 30
  59 #define LOGDOMAIN_DEFAULT "srd: "
  60 /** @endcond */
  61 static char srd_log_domain[LOGDOMAIN_MAXLEN + 1] = LOGDOMAIN_DEFAULT;
  62
  63 /**
  64  * Set the libsigrokdecode loglevel.
  65  *
  66  * This influences the amount of log messages (debug messages, error messages,
  67  * and so on) libsigrokdecode will output. Using SRD_LOG_NONE disables all
  68  * messages.
  69  *
  70  * Note that this function itself will also output log messages. After the
  71  * loglevel has changed, it will output a debug message with SRD_LOG_DBG for
  72  * example. Whether this message is shown depends on the (new) loglevel.
  73  *
  74  * @param loglevel The loglevel to set (SRD_LOG_NONE, SRD_LOG_ERR,
  75  *                 SRD_LOG_WARN, SRD_LOG_INFO, SRD_LOG_DBG, or SRD_LOG_SPEW).
  76  *
  77  * @return SRD_OK upon success, SRD_ERR_ARG upon invalid loglevel.
  78  *
  79  * @since 0.1.0
  80  */
  81 SRD_API int srd_log_loglevel_set(int loglevel)
  82 {
  83         if (loglevel < SRD_LOG_NONE || loglevel > SRD_LOG_SPEW) {
  84                 srd_err("Invalid loglevel %d.", loglevel);
  85                 return SRD_ERR_ARG;
  86         }
  87
  88         cur_loglevel = loglevel;
  89
  90         srd_dbg("libsigrokdecode loglevel set to %d.", loglevel);
  91
  92         return SRD_OK;
  93 }
  94
  95 /**
  96  * Get the libsigrokdecode loglevel.
  97  *
  98  * @return The currently configured libsigrokdecode loglevel.
  99  *
 100  * @since 0.1.0
 101  */
 102 SRD_API int srd_log_loglevel_get(void)
 103 {
 104         return cur_loglevel;
 105 }
 106
 107 /**
 108  * Set the libsigrokdecode logdomain string.
 109  *
 110  * @param logdomain The string to use as logdomain for libsigrokdecode log
 111  *                  messages from now on. Must not be NULL. The maximum
 112  *                  length of the string is 30 characters (this does not
 113  *                  include the trailing NUL-byte). Longer strings are
 114  *                  silently truncated.
 115  *                  In order to not use a logdomain, pass an empty string.
 116  *                  The function makes its own copy of the input string, i.e.
 117  *                  the caller does not need to keep it around.
 118  *
 119  * @return SRD_OK upon success, SRD_ERR_ARG upon invalid logdomain.
 120  *
 121  * @since 0.1.0
 122  */
 123 SRD_API int srd_log_logdomain_set(const char *logdomain)
 124 {
 125         if (!logdomain) {
 126                 srd_err("log: %s: logdomain was NULL", __func__);
 127                 return SRD_ERR_ARG;
 128         }
 129
 130         snprintf((char *)&srd_log_domain, LOGDOMAIN_MAXLEN, "%s", logdomain);
 131
 132         srd_dbg("Log domain set to '%s'.", (const char *)&srd_log_domain);
 133
 134         return SRD_OK;
 135 }
 136
 137 /**
 138  * Get the currently configured libsigrokdecode logdomain.
 139  *
 140  * @return A copy of the currently configured libsigrokdecode logdomain
 141  *         string. The caller is responsible for g_free()ing the string when
 142  *         it is no longer needed.
 143  *
 144  * @since 0.1.0
 145  */
 146 SRD_API char *srd_log_logdomain_get(void)
 147 {
 148         return g_strdup((const char *)&srd_log_domain);
 149 }
 150
 151 /**
 152  * Set the libsigrokdecode log callback to the specified function.
 153  *
 154  * @param cb Function pointer to the log callback function to use.
 155  *           Must not be NULL.
 156  * @param cb_data Pointer to private data to be passed on. This can be used
 157  *                by the caller to pass arbitrary data to the log functions.
 158  *                This pointer is only stored or passed on by libsigrokdecode,
 159  *                and is never used or interpreted in any way. The pointer
 160  *                is allowed to be NULL if the caller doesn't need/want to
 161  *                pass any data.
 162  *
 163  * @return SRD_OK upon success, SRD_ERR_ARG upon invalid arguments.
 164  *
 165  * @since 0.3.0
 166  */
 167 SRD_API int srd_log_callback_set(srd_log_callback cb, void *cb_data)
 168 {
 169         if (!cb) {
 170                 srd_err("log: %s: cb was NULL", __func__);
 171                 return SRD_ERR_ARG;
 172         }
 173
 174         /* Note: 'cb_data' is allowed to be NULL. */
 175
 176         srd_log_cb = cb;
 177         srd_log_cb_data = cb_data;
 178
 179         return SRD_OK;
 180 }
 181
 182 /**
 183  * Set the libsigrokdecode log callback to the default built-in one.
 184  *
 185  * Additionally, the internal 'srd_log_cb_data' pointer is set to NULL.
 186  *
 187  * @return SRD_OK upon success, a (negative) error code otherwise.
 188  *
 189  * @since 0.1.0
 190  */
 191 SRD_API int srd_log_callback_set_default(void)
 192 {
 193         /*
 194          * Note: No log output in this function, as it should safely work
 195          * even if the currently set log callback is buggy/broken.
 196          */
 197         srd_log_cb = srd_logv;
 198         srd_log_cb_data = NULL;
 199
 200         return SRD_OK;
 201 }
 202
 203 static int srd_logv(void *cb_data, int loglevel, const char *format,
 204                     va_list args)
 205 {
 206         int ret;
 207
 208         /* This specific log callback doesn't need the void pointer data. */
 209         (void)cb_data;
 210
 211         /* Only output messages of at least the selected loglevel(s). */
 212         if (loglevel > cur_loglevel)
 213                 return SRD_OK;
 214
 215         if (srd_log_domain[0] != '\0')
 216                 fprintf(stderr, "%s", srd_log_domain);
 217         ret = vfprintf(stderr, format, args);
 218         fprintf(stderr, "\n");
 219
 220         return ret;
 221 }
 222
 223 /** @private */
 224 SRD_PRIV int srd_log(int loglevel, const char *format, ...)
 225 {
 226         int ret;
 227         va_list args;
 228
 229         va_start(args, format);
 230         ret = srd_log_cb(srd_log_cb_data, loglevel, format, args);
 231         va_end(args);
 232
 233         return ret;
 234 }
 235
 236 /** @private */
 237 SRD_PRIV int srd_spew(const char *format, ...)
 238 {
 239         int ret;
 240         va_list args;
 241
 242         va_start(args, format);
 243         ret = srd_log_cb(srd_log_cb_data, SRD_LOG_SPEW, format, args);
 244         va_end(args);
 245
 246         return ret;
 247 }
 248
 249 /** @private */
 250 SRD_PRIV int srd_dbg(const char *format, ...)
 251 {
 252         int ret;
 253         va_list args;
 254
 255         va_start(args, format);
 256         ret = srd_log_cb(srd_log_cb_data, SRD_LOG_DBG, format, args);
 257         va_end(args);
 258
 259         return ret;
 260 }
 261
 262 /** @private */
 263 SRD_PRIV int srd_info(const char *format, ...)
 264 {
 265         int ret;
 266         va_list args;
 267
 268         va_start(args, format);
 269         ret = srd_log_cb(srd_log_cb_data, SRD_LOG_INFO, format, args);
 270         va_end(args);
 271
 272         return ret;
 273 }
 274
 275 /** @private */
 276 SRD_PRIV int srd_warn(const char *format, ...)
 277 {
 278         int ret;
 279         va_list args;
 280
 281         va_start(args, format);
 282         ret = srd_log_cb(srd_log_cb_data, SRD_LOG_WARN, format, args);
 283         va_end(args);
 284
 285         return ret;
 286 }
 287
 288 /** @private */
 289 SRD_PRIV int srd_err(const char *format, ...)
 290 {
 291         int ret;
 292         va_list args;
 293
 294         va_start(args, format);
 295         ret = srd_log_cb(srd_log_cb_data, SRD_LOG_ERR, format, args);
 296         va_end(args);
 297
 298         return ret;
 299 }
 300
 301 /** @} */