libsigrok  0.2.0
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 #include "libsigrok-internal.h"
25 
26 /**
27  * @file
28  *
29  * Controlling the libsigrok message logging functionality.
30  */
31 
32 /**
33  * @defgroup grp_logging Logging
34  *
35  * Controlling the libsigrok message logging functionality.
36  *
37  * @{
38  */
39 
40 /* Currently selected libsigrok loglevel. Default: SR_LOG_WARN. */
41 static int sr_loglevel = SR_LOG_WARN; /* Show errors+warnings per default. */
42 
43 /* Function prototype. */
44 static int sr_logv(void *cb_data, int loglevel, const char *format,
45  va_list args);
46 
47 /* Pointer to the currently selected log callback. Default: sr_logv(). */
48 static sr_log_callback_t sr_log_callback = sr_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 *sr_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 "sr: "
60 /** @endcond */
61 static char sr_log_domain[LOGDOMAIN_MAXLEN + 1] = LOGDOMAIN_DEFAULT;
62 
63 /**
64  * Set the libsigrok loglevel.
65  *
66  * This influences the amount of log messages (debug messages, error messages,
67  * and so on) libsigrok will output. Using SR_LOG_NONE disables all messages.
68  *
69  * Note that this function itself will also output log messages. After the
70  * loglevel has changed, it will output a debug message with SR_LOG_DBG for
71  * example. Whether this message is shown depends on the (new) loglevel.
72  *
73  * @param loglevel The loglevel to set (SR_LOG_NONE, SR_LOG_ERR, SR_LOG_WARN,
74  * SR_LOG_INFO, SR_LOG_DBG, or SR_LOG_SPEW).
75  *
76  * @return SR_OK upon success, SR_ERR_ARG upon invalid loglevel.
77  *
78  * @since 0.1.0
79  */
80 SR_API int sr_log_loglevel_set(int loglevel)
81 {
82  if (loglevel < SR_LOG_NONE || loglevel > SR_LOG_SPEW) {
83  sr_err("Invalid loglevel %d.", loglevel);
84  return SR_ERR_ARG;
85  }
86 
87  sr_loglevel = loglevel;
88 
89  sr_dbg("libsigrok loglevel set to %d.", loglevel);
90 
91  return SR_OK;
92 }
93 
94 /**
95  * Get the libsigrok loglevel.
96  *
97  * @return The currently configured libsigrok loglevel.
98  *
99  * @since 0.1.0
100  */
102 {
103  return sr_loglevel;
104 }
105 
106 /**
107  * Set the libsigrok logdomain string.
108  *
109  * @param logdomain The string to use as logdomain for libsigrok log
110  * messages from now on. Must not be NULL. The maximum
111  * length of the string is 30 characters (this does not
112  * include the trailing NUL-byte). Longer strings are
113  * silently truncated.
114  * In order to not use a logdomain, pass an empty string.
115  * The function makes its own copy of the input string, i.e.
116  * the caller does not need to keep it around.
117  *
118  * @return SR_OK upon success, SR_ERR_ARG upon invalid logdomain.
119  *
120  * @since 0.1.0
121  */
122 SR_API int sr_log_logdomain_set(const char *logdomain)
123 {
124  if (!logdomain) {
125  sr_err("log: %s: logdomain was NULL", __func__);
126  return SR_ERR_ARG;
127  }
128 
129  /* TODO: Error handling. */
130  snprintf((char *)&sr_log_domain, LOGDOMAIN_MAXLEN, "%s", logdomain);
131 
132  sr_dbg("Log domain set to '%s'.", (const char *)&sr_log_domain);
133 
134  return SR_OK;
135 }
136 
137 /**
138  * Get the currently configured libsigrok logdomain.
139  *
140  * @return A copy of the currently configured libsigrok 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  */
147 {
148  return g_strdup((const char *)&sr_log_domain);
149 }
150 
151 /**
152  * Set the libsigrok 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 by
157  * the caller to pass arbitrary data to the log functions. This
158  * pointer is only stored or passed on by libsigrok, and is
159  * never used or interpreted in any way. The pointer is allowed
160  * to be NULL if the caller doesn't need/want to pass any data.
161  *
162  * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments.
163  *
164  * @since 0.1.0
165  */
167 {
168  if (!cb) {
169  sr_err("log: %s: cb was NULL", __func__);
170  return SR_ERR_ARG;
171  }
172 
173  /* Note: 'cb_data' is allowed to be NULL. */
174 
175  sr_log_callback = cb;
176  sr_log_callback_data = cb_data;
177 
178  return SR_OK;
179 }
180 
181 /**
182  * Set the libsigrok log callback to the default built-in one.
183  *
184  * Additionally, the internal 'sr_log_callback_data' pointer is set to NULL.
185  *
186  * @return SR_OK upon success, a negative error code otherwise.
187  *
188  * @since 0.1.0
189  */
191 {
192  /*
193  * Note: No log output in this function, as it should safely work
194  * even if the currently set log callback is buggy/broken.
195  */
196  sr_log_callback = sr_logv;
197  sr_log_callback_data = NULL;
198 
199  return SR_OK;
200 }
201 
202 static int sr_logv(void *cb_data, int loglevel, const char *format, va_list args)
203 {
204  int ret;
205 
206  /* This specific log callback doesn't need the void pointer data. */
207  (void)cb_data;
208 
209  /* Only output messages of at least the selected loglevel(s). */
210  if (loglevel > sr_loglevel)
211  return SR_OK; /* TODO? */
212 
213  if (sr_log_domain[0] != '\0')
214  fprintf(stderr, "%s", sr_log_domain);
215  ret = vfprintf(stderr, format, args);
216  fprintf(stderr, "\n");
217 
218  return ret;
219 }
220 
221 /** @private */
222 SR_PRIV int sr_log(int loglevel, const char *format, ...)
223 {
224  int ret;
225  va_list args;
226 
227  va_start(args, format);
228  ret = sr_log_callback(sr_log_callback_data, loglevel, format, args);
229  va_end(args);
230 
231  return ret;
232 }
233 
234 /** @private */
235 SR_PRIV int sr_spew(const char *format, ...)
236 {
237  int ret;
238  va_list args;
239 
240  va_start(args, format);
241  ret = sr_log_callback(sr_log_callback_data, SR_LOG_SPEW, format, args);
242  va_end(args);
243 
244  return ret;
245 }
246 
247 /** @private */
248 SR_PRIV int sr_dbg(const char *format, ...)
249 {
250  int ret;
251  va_list args;
252 
253  va_start(args, format);
254  ret = sr_log_callback(sr_log_callback_data, SR_LOG_DBG, format, args);
255  va_end(args);
256 
257  return ret;
258 }
259 
260 /** @private */
261 SR_PRIV int sr_info(const char *format, ...)
262 {
263  int ret;
264  va_list args;
265 
266  va_start(args, format);
267  ret = sr_log_callback(sr_log_callback_data, SR_LOG_INFO, format, args);
268  va_end(args);
269 
270  return ret;
271 }
272 
273 /** @private */
274 SR_PRIV int sr_warn(const char *format, ...)
275 {
276  int ret;
277  va_list args;
278 
279  va_start(args, format);
280  ret = sr_log_callback(sr_log_callback_data, SR_LOG_WARN, format, args);
281  va_end(args);
282 
283  return ret;
284 }
285 
286 /** @private */
287 SR_PRIV int sr_err(const char *format, ...)
288 {
289  int ret;
290  va_list args;
291 
292  va_start(args, format);
293  ret = sr_log_callback(sr_log_callback_data, SR_LOG_ERR, format, args);
294  va_end(args);
295 
296  return ret;
297 }
298 
299 /** @} */