src/log.c

   1 /*
   2  * This file is part of the libsigrok 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 <stdarg.h>
  22 #include <stdio.h>
  23 #include <glib/gprintf.h>
  24 #include <libsigrok/libsigrok.h>
  25 #include "libsigrok-internal.h"
  26
  27 /** @cond PRIVATE */
  28 #define LOG_PREFIX "log"
  29 /** @endcond */
  30
  31 /**
  32  * @file
  33  *
  34  * Controlling the libsigrok message logging functionality.
  35  */
  36
  37 /**
  38  * @defgroup grp_logging Logging
  39  *
  40  * Controlling the libsigrok message logging functionality.
  41  *
  42  * @{
  43  */
  44
  45 /* Currently selected libsigrok loglevel. Default: SR_LOG_WARN. */
  46 static int cur_loglevel = SR_LOG_WARN; /* Show errors+warnings per default. */
  47
  48 /* Function prototype. */
  49 static int sr_logv(void *cb_data, int loglevel, const char *format,
  50                    va_list args);
  51
  52 /* Pointer to the currently selected log callback. Default: sr_logv(). */
  53 static sr_log_callback sr_log_cb = sr_logv;
  54
  55 /*
  56  * Pointer to private data that can be passed to the log callback.
  57  * This can be used (for example) by C++ GUIs to pass a "this" pointer.
  58  */
  59 static void *sr_log_cb_data = NULL;
  60
  61 /** @cond PRIVATE */
  62 #define LOGLEVEL_TIMESTAMP SR_LOG_DBG
  63 /** @endcond */
  64 static int64_t sr_log_start_time = 0;
  65
  66 /**
  67  * Set the libsigrok loglevel.
  68  *
  69  * This influences the amount of log messages (debug messages, error messages,
  70  * and so on) libsigrok will output. Using SR_LOG_NONE disables all messages.
  71  *
  72  * Note that this function itself will also output log messages. After the
  73  * loglevel has changed, it will output a debug message with SR_LOG_DBG for
  74  * example. Whether this message is shown depends on the (new) loglevel.
  75  *
  76  * @param loglevel The loglevel to set (SR_LOG_NONE, SR_LOG_ERR, SR_LOG_WARN,
  77  *                 SR_LOG_INFO, SR_LOG_DBG, or SR_LOG_SPEW).
  78  *
  79  * @return SR_OK upon success, SR_ERR_ARG upon invalid loglevel.
  80  *
  81  * @since 0.1.0
  82  */
  83 SR_API int sr_log_loglevel_set(int loglevel)
  84 {
  85         if (loglevel < SR_LOG_NONE || loglevel > SR_LOG_SPEW) {
  86                 sr_err("Invalid loglevel %d.", loglevel);
  87                 return SR_ERR_ARG;
  88         }
  89         /* Output time stamps relative to time at startup */
  90         if (loglevel >= LOGLEVEL_TIMESTAMP && sr_log_start_time == 0)
  91                 sr_log_start_time = g_get_monotonic_time();
  92
  93         cur_loglevel = loglevel;
  94
  95         sr_dbg("libsigrok loglevel set to %d.", loglevel);
  96
  97         return SR_OK;
  98 }
  99
 100 /**
 101  * Get the libsigrok loglevel.
 102  *
 103  * @return The currently configured libsigrok loglevel.
 104  *
 105  * @since 0.1.0
 106  */
 107 SR_API int sr_log_loglevel_get(void)
 108 {
 109         return cur_loglevel;
 110 }
 111
 112 /**
 113  * Set the libsigrok log callback to the specified function.
 114  *
 115  * @param cb Function pointer to the log callback function to use.
 116  *           Must not be NULL.
 117  * @param cb_data Pointer to private data to be passed on. This can be used by
 118  *                the caller to pass arbitrary data to the log functions. This
 119  *                pointer is only stored or passed on by libsigrok, and is
 120  *                never used or interpreted in any way. The pointer is allowed
 121  *                to be NULL if the caller doesn't need/want to pass any data.
 122  *
 123  * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments.
 124  *
 125  * @since 0.3.0
 126  */
 127 SR_API int sr_log_callback_set(sr_log_callback cb, void *cb_data)
 128 {
 129         if (!cb) {
 130                 sr_err("%s: cb was NULL", __func__);
 131                 return SR_ERR_ARG;
 132         }
 133
 134         /* Note: 'cb_data' is allowed to be NULL. */
 135
 136         sr_log_cb = cb;
 137         sr_log_cb_data = cb_data;
 138
 139         return SR_OK;
 140 }
 141
 142 /**
 143  * Set the libsigrok log callback to the default built-in one.
 144  *
 145  * Additionally, the internal 'sr_log_cb_data' pointer is set to NULL.
 146  *
 147  * @return SR_OK upon success, a negative error code otherwise.
 148  *
 149  * @since 0.1.0
 150  */
 151 SR_API int sr_log_callback_set_default(void)
 152 {
 153         /*
 154          * Note: No log output in this function, as it should safely work
 155          * even if the currently set log callback is buggy/broken.
 156          */
 157         sr_log_cb = sr_logv;
 158         sr_log_cb_data = NULL;
 159
 160         return SR_OK;
 161 }
 162
 163 /**
 164  * Get the libsigrok log callback routine and callback data.
 165  *
 166  * @param[out] cb Pointer to a function pointer to receive the log callback
 167  *      function. Optional, can be NULL.
 168  * @param[out] cb_data Pointer to a void pointer to receive the log callback's
 169  *      additional arguments. Optional, can be NULL.
 170  *
 171  * @return SR_OK upon success.
 172  *
 173  * @since 0.6.0
 174  */
 175 SR_API int sr_log_callback_get(sr_log_callback *cb, void **cb_data)
 176 {
 177         if (cb)
 178                 *cb = sr_log_cb;
 179         if (cb_data)
 180                 *cb_data = sr_log_cb_data;
 181
 182         return SR_OK;
 183 }
 184
 185 static int sr_logv(void *cb_data, int loglevel, const char *format, va_list args)
 186 {
 187         int ret;
 188         uint64_t elapsed_us, minutes;
 189         unsigned int rest_us, seconds, microseconds;
 190         char *raw_output, *output, c;
 191         ssize_t print_len;
 192         size_t raw_len;
 193         const char *raw_ptr;
 194         char *out_ptr;
 195
 196         /* This specific log callback doesn't need the void pointer data. */
 197         (void)cb_data;
 198
 199         (void)loglevel;
 200
 201         /* Prefix with 'sr:'. Optionally prefix with timestamp. */
 202         ret = fputs("sr: ", stderr);
 203         if (ret < 0)
 204                 return SR_ERR;
 205         if (cur_loglevel >= LOGLEVEL_TIMESTAMP) {
 206                 elapsed_us = g_get_monotonic_time() - sr_log_start_time;
 207
 208                 minutes = elapsed_us / G_TIME_SPAN_MINUTE;
 209                 rest_us = elapsed_us % G_TIME_SPAN_MINUTE;
 210                 seconds = rest_us / G_TIME_SPAN_SECOND;
 211                 microseconds = rest_us % G_TIME_SPAN_SECOND;
 212
 213                 ret = g_fprintf(stderr, "[%.2" PRIu64 ":%.2u.%.6u] ",
 214                                 minutes, seconds, microseconds);
 215                 if (ret < 0)
 216                         return SR_ERR;
 217         }
 218
 219         /* Print the caller's message into a local buffer. */
 220         raw_output = NULL;
 221         print_len = g_vasprintf(&raw_output, format, args);
 222         if (print_len < 0) {
 223                 g_free(raw_output);
 224                 return SR_ERR;
 225         }
 226         raw_len = (size_t)print_len;
 227
 228         /* Copy the string. Strip unwanted line breaks. */
 229         output = g_malloc(raw_len + 1);
 230         if (!output) {
 231                 g_free(raw_output);
 232                 return SR_ERR;
 233         }
 234         out_ptr = output;
 235         raw_ptr = raw_output;
 236         while (*raw_ptr) {
 237                 c = *raw_ptr++;
 238                 if (c == '\r' || c == '\n')
 239                         continue;
 240                 *out_ptr++ = c;
 241         }
 242         *out_ptr = '\0';
 243         g_free(raw_output);
 244
 245         /* Print the trimmed output text. */
 246         g_fprintf(stderr, "%s\n", output);
 247         fflush(stderr);
 248         g_free(output);
 249
 250         return SR_OK;
 251 }
 252
 253 /** @private */
 254 SR_PRIV int sr_log(int loglevel, const char *format, ...)
 255 {
 256         int ret;
 257         va_list args;
 258
 259         /* Only output messages of at least the selected loglevel(s). */
 260         if (loglevel > cur_loglevel)
 261                 return SR_OK;
 262
 263         /* Silently succeed when no logging callback is registered. */
 264         if (!sr_log_cb)
 265                 return SR_OK;
 266
 267         va_start(args, format);
 268         ret = sr_log_cb(sr_log_cb_data, loglevel, format, args);
 269         va_end(args);
 270
 271         return ret;
 272 }
 273
 274 /** @} */