libsigrokdecode  0.2.0
sigrok protocol decoding library
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log.c
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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 srd_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_t srd_log_callback = 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_callback_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  srd_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  */
103 {
104  return srd_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  /* TODO: Error handling. */
131  snprintf((char *)&srd_log_domain, LOGDOMAIN_MAXLEN, "%s", logdomain);
132 
133  srd_dbg("Log domain set to '%s'.", (const char *)&srd_log_domain);
134 
135  return SRD_OK;
136 }
137 
138 /**
139  * Get the currently configured libsigrokdecode logdomain.
140  *
141  * @return A copy of the currently configured libsigrokdecode logdomain
142  * string. The caller is responsible for g_free()ing the string when
143  * it is no longer needed.
144  *
145  * @since 0.1.0
146  */
148 {
149  return g_strdup((const char *)&srd_log_domain);
150 }
151 
152 /**
153  * Set the libsigrokdecode log callback to the specified function.
154  *
155  * @param cb Function pointer to the log callback function to use.
156  * Must not be NULL.
157  * @param cb_data Pointer to private data to be passed on. This can be used
158  * by the caller to pass arbitrary data to the log functions.
159  * This pointer is only stored or passed on by libsigrokdecode,
160  * and is never used or interpreted in any way. The pointer
161  * is allowed to be NULL if the caller doesn't need/want to
162  * pass any data.
163  *
164  * @return SRD_OK upon success, SRD_ERR_ARG upon invalid arguments.
165  *
166  * @since 0.1.0
167  */
169 {
170  if (!cb) {
171  srd_err("log: %s: cb was NULL", __func__);
172  return SRD_ERR_ARG;
173  }
174 
175  /* Note: 'cb_data' is allowed to be NULL. */
176 
177  srd_log_callback = cb;
178  srd_log_callback_data = cb_data;
179 
180  return SRD_OK;
181 }
182 
183 /**
184  * Set the libsigrokdecode log callback to the default built-in one.
185  *
186  * Additionally, the internal 'srd_log_callback_data' pointer is set to NULL.
187  *
188  * @return SRD_OK upon success, a (negative) error code otherwise.
189  *
190  * @since 0.1.0
191  */
193 {
194  /*
195  * Note: No log output in this function, as it should safely work
196  * even if the currently set log callback is buggy/broken.
197  */
198  srd_log_callback = srd_logv;
199  srd_log_callback_data = NULL;
200 
201  return SRD_OK;
202 }
203 
204 static int srd_logv(void *cb_data, int loglevel, const char *format,
205  va_list args)
206 {
207  int ret;
208 
209  /* This specific log callback doesn't need the void pointer data. */
210  (void)cb_data;
211 
212  /* Only output messages of at least the selected loglevel(s). */
213  if (loglevel > srd_loglevel)
214  return SRD_OK; /* TODO? */
215 
216  if (srd_log_domain[0] != '\0')
217  fprintf(stderr, "%s", srd_log_domain);
218  ret = vfprintf(stderr, format, args);
219  fprintf(stderr, "\n");
220 
221  return ret;
222 }
223 
224 /** @private */
225 SRD_PRIV int srd_log(int loglevel, const char *format, ...)
226 {
227  int ret;
228  va_list args;
229 
230  va_start(args, format);
231  ret = srd_log_callback(srd_log_callback_data, loglevel, format, args);
232  va_end(args);
233 
234  return ret;
235 }
236 
237 /** @private */
238 SRD_PRIV int srd_spew(const char *format, ...)
239 {
240  int ret;
241  va_list args;
242 
243  va_start(args, format);
244  ret = srd_log_callback(srd_log_callback_data, SRD_LOG_SPEW,
245  format, args);
246  va_end(args);
247 
248  return ret;
249 }
250 
251 /** @private */
252 SRD_PRIV int srd_dbg(const char *format, ...)
253 {
254  int ret;
255  va_list args;
256 
257  va_start(args, format);
258  ret = srd_log_callback(srd_log_callback_data, SRD_LOG_DBG,
259  format, args);
260  va_end(args);
261 
262  return ret;
263 }
264 
265 /** @private */
266 SRD_PRIV int srd_info(const char *format, ...)
267 {
268  int ret;
269  va_list args;
270 
271  va_start(args, format);
272  ret = srd_log_callback(srd_log_callback_data, SRD_LOG_INFO,
273  format, args);
274  va_end(args);
275 
276  return ret;
277 }
278 
279 /** @private */
280 SRD_PRIV int srd_warn(const char *format, ...)
281 {
282  int ret;
283  va_list args;
284 
285  va_start(args, format);
286  ret = srd_log_callback(srd_log_callback_data, SRD_LOG_WARN,
287  format, args);
288  va_end(args);
289 
290  return ret;
291 }
292 
293 /** @private */
294 SRD_PRIV int srd_err(const char *format, ...)
295 {
296  int ret;
297  va_list args;
298 
299  va_start(args, format);
300  ret = srd_log_callback(srd_log_callback_data, SRD_LOG_ERR,
301  format, args);
302  va_end(args);
303 
304  return ret;
305 }
306 
307 /** @} */