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, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include "libsigrokdecode-internal.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
  22 #include "libsigrokdecode.h"
  23 #include <stdarg.h>
  24 #include <stdio.h>
  25 #include <glib/gprintf.h>
  26
  27 /**
  28  * @file
  29  *
  30  * Controlling the libsigrokdecode message logging functionality.
  31  */
  32
  33 /**
  34  * @defgroup grp_logging Logging
  35  *
  36  * Controlling the libsigrokdecode message logging functionality.
  37  *
  38  * @{
  39  */
  40
  41 /* Currently selected libsigrokdecode loglevel. Default: SRD_LOG_WARN. */
  42 static int cur_loglevel = SRD_LOG_WARN; /* Show errors+warnings per default. */
  43
  44 /* Function prototype. */
  45 static int srd_logv(void *cb_data, int loglevel, const char *format,
  46                     va_list args);
  47
  48 /* Pointer to the currently selected log callback. Default: srd_logv(). */
  49 static srd_log_callback srd_log_cb = srd_logv;
  50
  51 /*
  52  * Pointer to private data that can be passed to the log callback.
  53  * This can be used (for example) by C++ GUIs to pass a "this" pointer.
  54  */
  55 static void *srd_log_cb_data = NULL;
  56
  57 /**
  58  * Set the libsigrokdecode loglevel.
  59  *
  60  * This influences the amount of log messages (debug messages, error messages,
  61  * and so on) libsigrokdecode will output. Using SRD_LOG_NONE disables all
  62  * messages.
  63  *
  64  * Note that this function itself will also output log messages. After the
  65  * loglevel has changed, it will output a debug message with SRD_LOG_DBG for
  66  * example. Whether this message is shown depends on the (new) loglevel.
  67  *
  68  * @param loglevel The loglevel to set (SRD_LOG_NONE, SRD_LOG_ERR,
  69  *                 SRD_LOG_WARN, SRD_LOG_INFO, SRD_LOG_DBG, or SRD_LOG_SPEW).
  70  *
  71  * @return SRD_OK upon success, SRD_ERR_ARG upon invalid loglevel.
  72  *
  73  * @since 0.1.0
  74  */
  75 SRD_API int srd_log_loglevel_set(int loglevel)
  76 {
  77         if (loglevel < SRD_LOG_NONE || loglevel > SRD_LOG_SPEW) {
  78                 srd_err("Invalid loglevel %d.", loglevel);
  79                 return SRD_ERR_ARG;
  80         }
  81
  82         cur_loglevel = loglevel;
  83
  84         srd_dbg("libsigrokdecode loglevel set to %d.", loglevel);
  85
  86         return SRD_OK;
  87 }
  88
  89 /**
  90  * Get the libsigrokdecode loglevel.
  91  *
  92  * @return The currently configured libsigrokdecode loglevel.
  93  *
  94  * @since 0.1.0
  95  */
  96 SRD_API int srd_log_loglevel_get(void)
  97 {
  98         return cur_loglevel;
  99 }
 100
 101 /**
 102  * Set the libsigrokdecode log callback to the specified function.
 103  *
 104  * @param cb Function pointer to the log callback function to use.
 105  *           Must not be NULL.
 106  * @param cb_data Pointer to private data to be passed on. This can be used
 107  *                by the caller to pass arbitrary data to the log functions.
 108  *                This pointer is only stored or passed on by libsigrokdecode,
 109  *                and is never used or interpreted in any way. The pointer
 110  *                is allowed to be NULL if the caller doesn't need/want to
 111  *                pass any data.
 112  *
 113  * @return SRD_OK upon success, SRD_ERR_ARG upon invalid arguments.
 114  *
 115  * @since 0.3.0
 116  */
 117 SRD_API int srd_log_callback_set(srd_log_callback cb, void *cb_data)
 118 {
 119         if (!cb) {
 120                 srd_err("log: %s: cb was NULL", __func__);
 121                 return SRD_ERR_ARG;
 122         }
 123
 124         /* Note: 'cb_data' is allowed to be NULL. */
 125
 126         srd_log_cb = cb;
 127         srd_log_cb_data = cb_data;
 128
 129         return SRD_OK;
 130 }
 131
 132 /**
 133  * Get the libsigrokdecode log callback routine and callback data.
 134  *
 135  * @param[out] cb Pointer to a function pointer to receive the log callback
 136  *      function. Optional, can be NULL.
 137  * @param[out] cb_data Pointer to a void pointer to receive the log callback's
 138  *      additional arguments. Optional, can be NULL.
 139  *
 140  * @return SRD_OK upon success.
 141  *
 142  * @since 0.5.2
 143  */
 144 SRD_API int srd_log_callback_get(srd_log_callback *cb, void **cb_data)
 145 {
 146         if (cb)
 147                 *cb = srd_log_cb;
 148         if (cb_data)
 149                 *cb_data = srd_log_cb_data;
 150
 151         return SRD_OK;
 152 }
 153
 154 /**
 155  * Set the libsigrokdecode log callback to the default built-in one.
 156  *
 157  * Additionally, the internal 'srd_log_cb_data' pointer is set to NULL.
 158  *
 159  * @return SRD_OK upon success, a (negative) error code otherwise.
 160  *
 161  * @since 0.1.0
 162  */
 163 SRD_API int srd_log_callback_set_default(void)
 164 {
 165         /*
 166          * Note: No log output in this function, as it should safely work
 167          * even if the currently set log callback is buggy/broken.
 168          */
 169         srd_log_cb = srd_logv;
 170         srd_log_cb_data = NULL;
 171
 172         return SRD_OK;
 173 }
 174
 175 static int srd_logv(void *cb_data, int loglevel, const char *format,
 176                     va_list args)
 177 {
 178         /* This specific log callback doesn't need the void pointer data. */
 179         (void)cb_data;
 180
 181         (void)loglevel;
 182
 183         if (fputs("srd: ", stderr) < 0
 184                         || g_vfprintf(stderr, format, args) < 0
 185                         || putc('\n', stderr) < 0)
 186                 return SRD_ERR;
 187
 188         fflush(stderr);
 189
 190         return SRD_OK;
 191 }
 192
 193 /** @private */
 194 SRD_PRIV int srd_log(int loglevel, const char *format, ...)
 195 {
 196         int ret;
 197         va_list args;
 198
 199         /* Only output messages of at least the selected loglevel(s). */
 200         if (loglevel > cur_loglevel)
 201                 return SRD_OK;
 202
 203         va_start(args, format);
 204         ret = srd_log_cb(srd_log_cb_data, loglevel, format, args);
 205         va_end(args);
 206
 207         return ret;
 208 }
 209
 210 /** @} */