libsigrokdecode  0.5.1
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, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include <config.h>
21 #include "libsigrokdecode-internal.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
22 #include "libsigrokdecode.h"
23 #include <stdarg.h>
24 #include <stdio.h>
25 #include <glib/gprintf.h>
26 
27 /**
28  * @file
29  *
30  * Controlling the libsigrokdecode message logging functionality.
31  */
32 
33 /**
34  * @defgroup grp_logging Logging
35  *
36  * Controlling the libsigrokdecode message logging functionality.
37  *
38  * @{
39  */
40 
41 /* Currently selected libsigrokdecode loglevel. Default: SRD_LOG_WARN. */
42 static int cur_loglevel = SRD_LOG_WARN; /* Show errors+warnings per default. */
43 
44 /* Function prototype. */
45 static int srd_logv(void *cb_data, int loglevel, const char *format,
46  va_list args);
47 
48 /* Pointer to the currently selected log callback. Default: srd_logv(). */
49 static srd_log_callback srd_log_cb = srd_logv;
50 
51 /*
52  * Pointer to private data that can be passed to the log callback.
53  * This can be used (for example) by C++ GUIs to pass a "this" pointer.
54  */
55 static void *srd_log_cb_data = NULL;
56 
57 /**
58  * Set the libsigrokdecode loglevel.
59  *
60  * This influences the amount of log messages (debug messages, error messages,
61  * and so on) libsigrokdecode will output. Using SRD_LOG_NONE disables all
62  * messages.
63  *
64  * Note that this function itself will also output log messages. After the
65  * loglevel has changed, it will output a debug message with SRD_LOG_DBG for
66  * example. Whether this message is shown depends on the (new) loglevel.
67  *
68  * @param loglevel The loglevel to set (SRD_LOG_NONE, SRD_LOG_ERR,
69  * SRD_LOG_WARN, SRD_LOG_INFO, SRD_LOG_DBG, or SRD_LOG_SPEW).
70  *
71  * @return SRD_OK upon success, SRD_ERR_ARG upon invalid loglevel.
72  *
73  * @since 0.1.0
74  */
75 SRD_API int srd_log_loglevel_set(int loglevel)
76 {
77  if (loglevel < SRD_LOG_NONE || loglevel > SRD_LOG_SPEW) {
78  srd_err("Invalid loglevel %d.", loglevel);
79  return SRD_ERR_ARG;
80  }
81 
82  cur_loglevel = loglevel;
83 
84  srd_dbg("libsigrokdecode loglevel set to %d.", loglevel);
85 
86  return SRD_OK;
87 }
88 
89 /**
90  * Get the libsigrokdecode loglevel.
91  *
92  * @return The currently configured libsigrokdecode loglevel.
93  *
94  * @since 0.1.0
95  */
97 {
98  return cur_loglevel;
99 }
100 
101 /**
102  * Set the libsigrokdecode log callback to the specified function.
103  *
104  * @param cb Function pointer to the log callback function to use.
105  * Must not be NULL.
106  * @param cb_data Pointer to private data to be passed on. This can be used
107  * by the caller to pass arbitrary data to the log functions.
108  * This pointer is only stored or passed on by libsigrokdecode,
109  * and is never used or interpreted in any way. The pointer
110  * is allowed to be NULL if the caller doesn't need/want to
111  * pass any data.
112  *
113  * @return SRD_OK upon success, SRD_ERR_ARG upon invalid arguments.
114  *
115  * @since 0.3.0
116  */
118 {
119  if (!cb) {
120  srd_err("log: %s: cb was NULL", __func__);
121  return SRD_ERR_ARG;
122  }
123 
124  /* Note: 'cb_data' is allowed to be NULL. */
125 
126  srd_log_cb = cb;
127  srd_log_cb_data = cb_data;
128 
129  return SRD_OK;
130 }
131 
132 /**
133  * Set the libsigrokdecode log callback to the default built-in one.
134  *
135  * Additionally, the internal 'srd_log_cb_data' pointer is set to NULL.
136  *
137  * @return SRD_OK upon success, a (negative) error code otherwise.
138  *
139  * @since 0.1.0
140  */
142 {
143  /*
144  * Note: No log output in this function, as it should safely work
145  * even if the currently set log callback is buggy/broken.
146  */
147  srd_log_cb = srd_logv;
148  srd_log_cb_data = NULL;
149 
150  return SRD_OK;
151 }
152 
153 static int srd_logv(void *cb_data, int loglevel, const char *format,
154  va_list args)
155 {
156  /* This specific log callback doesn't need the void pointer data. */
157  (void)cb_data;
158 
159  /* Only output messages of at least the selected loglevel(s). */
160  if (loglevel > cur_loglevel)
161  return SRD_OK;
162 
163  if (fputs("srd: ", stderr) < 0
164  || g_vfprintf(stderr, format, args) < 0
165  || putc('\n', stderr) < 0)
166  return SRD_ERR;
167 
168  return SRD_OK;
169 }
170 
171 /** @private */
172 SRD_PRIV int srd_log(int loglevel, const char *format, ...)
173 {
174  int ret;
175  va_list args;
176 
177  va_start(args, format);
178  ret = srd_log_cb(srd_log_cb_data, loglevel, format, args);
179  va_end(args);
180 
181  return ret;
182 }
183 
184 /** @} */
#define SRD_API
int srd_log_loglevel_get(void)
Get the libsigrokdecode loglevel.
Definition: log.c:96
No error.
The public libsigrokdecode header file to be used by frontends.
Output warnings.
Function argument error.
int srd_log_callback_set_default(void)
Set the libsigrokdecode log callback to the default built-in one.
Definition: log.c:141
int srd_log_loglevel_set(int loglevel)
Set the libsigrokdecode loglevel.
Definition: log.c:75
Output very noisy debug messages.
int(* srd_log_callback)(void *cb_data, int loglevel, const char *format, va_list args)
#define SRD_PRIV
int srd_log_callback_set(srd_log_callback cb, void *cb_data)
Set the libsigrokdecode log callback to the specified function.
Definition: log.c:117
Generic/unspecified error.