libsigrok
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log.c
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1 /*
2  * This file is part of the sigrok 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 "sigrok.h"
24 #include "sigrok-internal.h"
25 
26 /* Currently selected libsigrok loglevel. Default: SR_LOG_WARN. */
27 static int sr_loglevel = SR_LOG_WARN; /* Show errors+warnings per default. */
28 
29 /* Function prototype. */
30 static int sr_logv(void *cb_data, int loglevel, const char *format,
31  va_list args);
32 
33 /* Pointer to the currently selected log callback. Default: sr_logv(). */
34 static sr_log_callback_t sr_log_callback = sr_logv;
35 
36 /*
37  * Pointer to private data that can be passed to the log callback.
38  * This can be used (for example) by C++ GUIs to pass a "this" pointer.
39  */
40 static void *sr_log_callback_data = NULL;
41 
42 /* Log domain (a short string that is used as prefix for all messages). */
43 #define LOGDOMAIN_MAXLEN 30
44 #define LOGDOMAIN_DEFAULT "sr: "
45 static char sr_log_domain[LOGDOMAIN_MAXLEN + 1] = LOGDOMAIN_DEFAULT;
46 
47 /**
48  * Set the libsigrok loglevel.
49  *
50  * This influences the amount of log messages (debug messages, error messages,
51  * and so on) libsigrok will output. Using SR_LOG_NONE disables all messages.
52  *
53  * Note that this function itself will also output log messages. After the
54  * loglevel has changed, it will output a debug message with SR_LOG_DBG for
55  * example. Whether this message is shown depends on the (new) loglevel.
56  *
57  * @param loglevel The loglevel to set (SR_LOG_NONE, SR_LOG_ERR, SR_LOG_WARN,
58  * SR_LOG_INFO, SR_LOG_DBG, or SR_LOG_SPEW).
59  *
60  * @return SR_OK upon success, SR_ERR_ARG upon invalid loglevel.
61  */
62 SR_API int sr_log_loglevel_set(int loglevel)
63 {
64  if (loglevel < SR_LOG_NONE || loglevel > SR_LOG_SPEW) {
65  sr_err("Invalid loglevel %d.", loglevel);
66  return SR_ERR_ARG;
67  }
68 
69  sr_loglevel = loglevel;
70 
71  sr_dbg("libsigrok loglevel set to %d.", loglevel);
72 
73  return SR_OK;
74 }
75 
76 /**
77  * Get the libsigrok loglevel.
78  *
79  * @return The currently configured libsigrok loglevel.
80  */
82 {
83  return sr_loglevel;
84 }
85 
86 /**
87  * Set the libsigrok logdomain string.
88  *
89  * @param logdomain The string to use as logdomain for libsigrok log
90  * messages from now on. Must not be NULL. The maximum
91  * length of the string is 30 characters (this does not
92  * include the trailing NUL-byte). Longer strings are
93  * silently truncated.
94  * In order to not use a logdomain, pass an empty string.
95  * The function makes its own copy of the input string, i.e.
96  * the caller does not need to keep it around.
97  *
98  * @return SR_OK upon success, SR_ERR_ARG upon invalid logdomain.
99  */
100 SR_API int sr_log_logdomain_set(const char *logdomain)
101 {
102  if (!logdomain) {
103  sr_err("log: %s: logdomain was NULL", __func__);
104  return SR_ERR_ARG;
105  }
106 
107  /* TODO: Error handling. */
108  snprintf((char *)&sr_log_domain, LOGDOMAIN_MAXLEN, "%s", logdomain);
109 
110  sr_dbg("Log domain set to '%s'.", (const char *)&sr_log_domain);
111 
112  return SR_OK;
113 }
114 
115 /**
116  * Get the currently configured libsigrok logdomain.
117  *
118  * @return A copy of the currently configured libsigrok logdomain
119  * string. The caller is responsible for g_free()ing the string when
120  * it is no longer needed.
121  */
123 {
124  return g_strdup((const char *)&sr_log_domain);
125 }
126 
127 /**
128  * Set the libsigrok log callback to the specified function.
129  *
130  * @param cb Function pointer to the log callback function to use.
131  * Must not be NULL.
132  * @param cb_data Pointer to private data to be passed on. This can be used by
133  * the caller to pass arbitrary data to the log functions. This
134  * pointer is only stored or passed on by libsigrok, and is
135  * never used or interpreted in any way. The pointer is allowed
136  * to be NULL if the caller doesn't need/want to pass any data.
137  *
138  * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments.
139  */
141 {
142  if (!cb) {
143  sr_err("log: %s: cb was NULL", __func__);
144  return SR_ERR_ARG;
145  }
146 
147  /* Note: 'cb_data' is allowed to be NULL. */
148 
149  sr_log_callback = cb;
150  sr_log_callback_data = cb_data;
151 
152  return SR_OK;
153 }
154 
155 /**
156  * Set the libsigrok log callback to the default built-in one.
157  *
158  * Additionally, the internal 'sr_log_callback_data' pointer is set to NULL.
159  *
160  * @return SR_OK upon success, a negative error code otherwise.
161  */
163 {
164  /*
165  * Note: No log output in this function, as it should safely work
166  * even if the currently set log callback is buggy/broken.
167  */
168  sr_log_callback = sr_logv;
169  sr_log_callback_data = NULL;
170 
171  return SR_OK;
172 }
173 
174 static int sr_logv(void *cb_data, int loglevel, const char *format, va_list args)
175 {
176  int ret;
177 
178  /* This specific log callback doesn't need the void pointer data. */
179  (void)cb_data;
180 
181  /* Only output messages of at least the selected loglevel(s). */
182  if (loglevel > sr_loglevel)
183  return SR_OK; /* TODO? */
184 
185  if (sr_log_domain[0] != '\0')
186  fprintf(stderr, "%s", sr_log_domain);
187  ret = vfprintf(stderr, format, args);
188  fprintf(stderr, "\n");
189 
190  return ret;
191 }
192 
193 SR_PRIV int sr_log(int loglevel, const char *format, ...)
194 {
195  int ret;
196  va_list args;
197 
198  va_start(args, format);
199  ret = sr_log_callback(sr_log_callback_data, loglevel, format, args);
200  va_end(args);
201 
202  return ret;
203 }
204 
205 SR_PRIV int sr_spew(const char *format, ...)
206 {
207  int ret;
208  va_list args;
209 
210  va_start(args, format);
211  ret = sr_log_callback(sr_log_callback_data, SR_LOG_SPEW, format, args);
212  va_end(args);
213 
214  return ret;
215 }
216 
217 SR_PRIV int sr_dbg(const char *format, ...)
218 {
219  int ret;
220  va_list args;
221 
222  va_start(args, format);
223  ret = sr_log_callback(sr_log_callback_data, SR_LOG_DBG, format, args);
224  va_end(args);
225 
226  return ret;
227 }
228 
229 SR_PRIV int sr_info(const char *format, ...)
230 {
231  int ret;
232  va_list args;
233 
234  va_start(args, format);
235  ret = sr_log_callback(sr_log_callback_data, SR_LOG_INFO, format, args);
236  va_end(args);
237 
238  return ret;
239 }
240 
241 SR_PRIV int sr_warn(const char *format, ...)
242 {
243  int ret;
244  va_list args;
245 
246  va_start(args, format);
247  ret = sr_log_callback(sr_log_callback_data, SR_LOG_WARN, format, args);
248  va_end(args);
249 
250  return ret;
251 }
252 
253 SR_PRIV int sr_err(const char *format, ...)
254 {
255  int ret;
256  va_list args;
257 
258  va_start(args, format);
259  ret = sr_log_callback(sr_log_callback_data, SR_LOG_ERR, format, args);
260  va_end(args);
261 
262  return ret;
263 }