libsigrok  0.3.0
sigrok hardware access and backend library
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log.c
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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, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <stdarg.h>
22 #include <stdio.h>
23 #include "libsigrok.h"
24 /** @cond PRIVATE */
25 #define NO_LOG_WRAPPERS
26 /** @endcond */
27 #include "libsigrok-internal.h"
28 
29 /**
30  * @file
31  *
32  * Controlling the libsigrok message logging functionality.
33  */
34 
35 /**
36  * @defgroup grp_logging Logging
37  *
38  * Controlling the libsigrok message logging functionality.
39  *
40  * @{
41  */
42 
43 /* Currently selected libsigrok loglevel. Default: SR_LOG_WARN. */
44 static int cur_loglevel = SR_LOG_WARN; /* Show errors+warnings per default. */
45 
46 /* Function prototype. */
47 static int sr_logv(void *cb_data, int loglevel, const char *format,
48  va_list args);
49 
50 /* Pointer to the currently selected log callback. Default: sr_logv(). */
51 static sr_log_callback sr_log_cb = sr_logv;
52 
53 /*
54  * Pointer to private data that can be passed to the log callback.
55  * This can be used (for example) by C++ GUIs to pass a "this" pointer.
56  */
57 static void *sr_log_cb_data = NULL;
58 
59 /* Log domain (a short string that is used as prefix for all messages). */
60 /** @cond PRIVATE */
61 #define LOGDOMAIN_MAXLEN 30
62 #define LOGDOMAIN_DEFAULT "sr: "
63 /** @endcond */
64 static char sr_log_domain[LOGDOMAIN_MAXLEN + 1] = LOGDOMAIN_DEFAULT;
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 
90  cur_loglevel = loglevel;
91 
92  sr_dbg("libsigrok loglevel set to %d.", loglevel);
93 
94  return SR_OK;
95 }
96 
97 /**
98  * Get the libsigrok loglevel.
99  *
100  * @return The currently configured libsigrok loglevel.
101  *
102  * @since 0.1.0
103  */
105 {
106  return cur_loglevel;
107 }
108 
109 /**
110  * Set the libsigrok logdomain string.
111  *
112  * @param logdomain The string to use as logdomain for libsigrok log
113  * messages from now on. Must not be NULL. The maximum
114  * length of the string is 30 characters (this does not
115  * include the trailing NUL-byte). Longer strings are
116  * silently truncated.
117  * In order to not use a logdomain, pass an empty string.
118  * The function makes its own copy of the input string, i.e.
119  * the caller does not need to keep it around.
120  *
121  * @return SR_OK upon success, SR_ERR_ARG upon invalid logdomain.
122  *
123  * @since 0.1.0
124  */
125 SR_API int sr_log_logdomain_set(const char *logdomain)
126 {
127  if (!logdomain) {
128  sr_err("log: %s: logdomain was NULL", __func__);
129  return SR_ERR_ARG;
130  }
131 
132  /* TODO: Error handling. */
133  snprintf((char *)&sr_log_domain, LOGDOMAIN_MAXLEN, "%s", logdomain);
134 
135  sr_dbg("Log domain set to '%s'.", (const char *)&sr_log_domain);
136 
137  return SR_OK;
138 }
139 
140 /**
141  * Get the currently configured libsigrok logdomain.
142  *
143  * @return A copy of the currently configured libsigrok logdomain
144  * string. The caller is responsible for g_free()ing the string when
145  * it is no longer needed.
146  *
147  * @since 0.1.0
148  */
150 {
151  return g_strdup((const char *)&sr_log_domain);
152 }
153 
154 /**
155  * Set the libsigrok log callback to the specified function.
156  *
157  * @param cb Function pointer to the log callback function to use.
158  * Must not be NULL.
159  * @param cb_data Pointer to private data to be passed on. This can be used by
160  * the caller to pass arbitrary data to the log functions. This
161  * pointer is only stored or passed on by libsigrok, and is
162  * never used or interpreted in any way. The pointer is allowed
163  * to be NULL if the caller doesn't need/want to pass any data.
164  *
165  * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments.
166  *
167  * @since 0.3.0
168  */
170 {
171  if (!cb) {
172  sr_err("log: %s: cb was NULL", __func__);
173  return SR_ERR_ARG;
174  }
175 
176  /* Note: 'cb_data' is allowed to be NULL. */
177 
178  sr_log_cb = cb;
179  sr_log_cb_data = cb_data;
180 
181  return SR_OK;
182 }
183 
184 /**
185  * Set the libsigrok log callback to the default built-in one.
186  *
187  * Additionally, the internal 'sr_log_cb_data' pointer is set to NULL.
188  *
189  * @return SR_OK upon success, a negative error code otherwise.
190  *
191  * @since 0.1.0
192  */
194 {
195  /*
196  * Note: No log output in this function, as it should safely work
197  * even if the currently set log callback is buggy/broken.
198  */
199  sr_log_cb = sr_logv;
200  sr_log_cb_data = NULL;
201 
202  return SR_OK;
203 }
204 
205 static int sr_logv(void *cb_data, int loglevel, const char *format, 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 > cur_loglevel)
214  return SR_OK; /* TODO? */
215 
216  if (sr_log_domain[0] != '\0')
217  fprintf(stderr, "%s", sr_log_domain);
218  ret = vfprintf(stderr, format, args);
219  fprintf(stderr, "\n");
220 
221  return ret;
222 }
223 
224 /** @private */
225 SR_PRIV int sr_log(int loglevel, const char *format, ...)
226 {
227  int ret;
228  va_list args;
229 
230  va_start(args, format);
231  ret = sr_log_cb(sr_log_cb_data, loglevel, format, args);
232  va_end(args);
233 
234  return ret;
235 }
236 
237 /** @private */
238 SR_PRIV int sr_spew(const char *format, ...)
239 {
240  int ret;
241  va_list args;
242 
243  va_start(args, format);
244  ret = sr_log_cb(sr_log_cb_data, SR_LOG_SPEW, format, args);
245  va_end(args);
246 
247  return ret;
248 }
249 
250 /** @private */
251 SR_PRIV int sr_dbg(const char *format, ...)
252 {
253  int ret;
254  va_list args;
255 
256  va_start(args, format);
257  ret = sr_log_cb(sr_log_cb_data, SR_LOG_DBG, format, args);
258  va_end(args);
259 
260  return ret;
261 }
262 
263 /** @private */
264 SR_PRIV int sr_info(const char *format, ...)
265 {
266  int ret;
267  va_list args;
268 
269  va_start(args, format);
270  ret = sr_log_cb(sr_log_cb_data, SR_LOG_INFO, format, args);
271  va_end(args);
272 
273  return ret;
274 }
275 
276 /** @private */
277 SR_PRIV int sr_warn(const char *format, ...)
278 {
279  int ret;
280  va_list args;
281 
282  va_start(args, format);
283  ret = sr_log_cb(sr_log_cb_data, SR_LOG_WARN, format, args);
284  va_end(args);
285 
286  return ret;
287 }
288 
289 /** @private */
290 SR_PRIV int sr_err(const char *format, ...)
291 {
292  int ret;
293  va_list args;
294 
295  va_start(args, format);
296  ret = sr_log_cb(sr_log_cb_data, SR_LOG_ERR, format, args);
297  va_end(args);
298 
299  return ret;
300 }
301 
302 /** @} */
Output very noisy debug messages.
Definition: libsigrok.h:101
No error.
Definition: libsigrok.h:67
The public libsigrok header file to be used by frontends.
Output informational messages.
Definition: libsigrok.h:99
Output warnings.
Definition: libsigrok.h:98
Output error messages.
Definition: libsigrok.h:97
int sr_log_loglevel_set(int loglevel)
Set the libsigrok loglevel.
Definition: log.c:83
int sr_log_loglevel_get(void)
Get the libsigrok loglevel.
Definition: log.c:104
char * sr_log_logdomain_get(void)
Get the currently configured libsigrok logdomain.
Definition: log.c:149
#define SR_PRIV
Definition: libsigrok.h:129
int sr_log_logdomain_set(const char *logdomain)
Set the libsigrok logdomain string.
Definition: log.c:125
Output debug messages.
Definition: libsigrok.h:100
Function argument error.
Definition: libsigrok.h:70
int(* sr_log_callback)(void *cb_data, int loglevel, const char *format, va_list args)
Definition: proto.h:36
int sr_log_callback_set_default(void)
Set the libsigrok log callback to the default built-in one.
Definition: log.c:193
int sr_log_callback_set(sr_log_callback cb, void *cb_data)
Set the libsigrok log callback to the specified function.
Definition: log.c:169
#define SR_API
Definition: libsigrok.h:122