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log.h
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1 /*
2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg 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 GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVUTIL_LOG_H
22 #define AVUTIL_LOG_H
23 
24 #include <stdarg.h>
25 #include "avutil.h"
26 #include "attributes.h"
27 
28 typedef enum {
40  AV_CLASS_CATEGORY_NB, ///< not part of ABI/API
42 
43 struct AVOptionRanges;
44 
45 /**
46  * Describe the class of an AVClass context structure. That is an
47  * arbitrary struct of which the first field is a pointer to an
48  * AVClass struct (e.g. AVCodecContext, AVFormatContext etc.).
49  */
50 typedef struct AVClass {
51  /**
52  * The name of the class; usually it is the same name as the
53  * context structure type to which the AVClass is associated.
54  */
55  const char* class_name;
56 
57  /**
58  * A pointer to a function which returns the name of a context
59  * instance ctx associated with the class.
60  */
61  const char* (*item_name)(void* ctx);
62 
63  /**
64  * a pointer to the first option specified in the class if any or NULL
65  *
66  * @see av_set_default_options()
67  */
68  const struct AVOption *option;
69 
70  /**
71  * LIBAVUTIL_VERSION with which this structure was created.
72  * This is used to allow fields to be added without requiring major
73  * version bumps everywhere.
74  */
75 
76  int version;
77 
78  /**
79  * Offset in the structure where log_level_offset is stored.
80  * 0 means there is no such variable
81  */
83 
84  /**
85  * Offset in the structure where a pointer to the parent context for
86  * logging is stored. For example a decoder could pass its AVCodecContext
87  * to eval as such a parent context, which an av_log() implementation
88  * could then leverage to display the parent context.
89  * The offset can be NULL.
90  */
92 
93  /**
94  * Return next AVOptions-enabled child or NULL
95  */
96  void* (*child_next)(void *obj, void *prev);
97 
98  /**
99  * Return an AVClass corresponding to the next potential
100  * AVOptions-enabled child.
101  *
102  * The difference between child_next and this is that
103  * child_next iterates over _already existing_ objects, while
104  * child_class_next iterates over _all possible_ children.
105  */
106  const struct AVClass* (*child_class_next)(const struct AVClass *prev);
107 
108  /**
109  * Category used for visualization (like color)
110  * This is only set if the category is equal for all objects using this class.
111  * available since version (51 << 16 | 56 << 8 | 100)
112  */
114 
115  /**
116  * Callback to return the category.
117  * available since version (51 << 16 | 59 << 8 | 100)
118  */
120 
121  /**
122  * Callback to return the supported/allowed ranges.
123  * available since version (52.12)
124  */
125  int (*query_ranges)(struct AVOptionRanges **, void *obj, const char *key, int flags);
126 } AVClass;
127 
128 /**
129  * @addtogroup lavu_log
130  *
131  * @{
132  *
133  * @defgroup lavu_log_constants Logging Constants
134  *
135  * @{
136  */
137 
138 /**
139  * Print no output.
140  */
141 #define AV_LOG_QUIET -8
142 
143 /**
144  * Something went really wrong and we will crash now.
145  */
146 #define AV_LOG_PANIC 0
147 
148 /**
149  * Something went wrong and recovery is not possible.
150  * For example, no header was found for a format which depends
151  * on headers or an illegal combination of parameters is used.
152  */
153 #define AV_LOG_FATAL 8
154 
155 /**
156  * Something went wrong and cannot losslessly be recovered.
157  * However, not all future data is affected.
158  */
159 #define AV_LOG_ERROR 16
160 
161 /**
162  * Something somehow does not look correct. This may or may not
163  * lead to problems. An example would be the use of '-vstrict -2'.
164  */
165 #define AV_LOG_WARNING 24
166 
167 /**
168  * Standard information.
169  */
170 #define AV_LOG_INFO 32
171 
172 /**
173  * Detailed information.
174  */
175 #define AV_LOG_VERBOSE 40
176 
177 /**
178  * Stuff which is only useful for libav* developers.
179  */
180 #define AV_LOG_DEBUG 48
181 
182 #define AV_LOG_MAX_OFFSET (AV_LOG_DEBUG - AV_LOG_QUIET)
183 
184 /**
185  * @}
186  */
187 
188 /**
189  * Send the specified message to the log if the level is less than or equal
190  * to the current av_log_level. By default, all logging messages are sent to
191  * stderr. This behavior can be altered by setting a different logging callback
192  * function.
193  * @see av_log_set_callback
194  *
195  * @param avcl A pointer to an arbitrary struct of which the first field is a
196  * pointer to an AVClass struct.
197  * @param level The importance level of the message expressed using a @ref
198  * lavu_log_constants "Logging Constant".
199  * @param fmt The format string (printf-compatible) that specifies how
200  * subsequent arguments are converted to output.
201  */
202 void av_log(void *avcl, int level, const char *fmt, ...) av_printf_format(3, 4);
203 
204 
205 /**
206  * Send the specified message to the log if the level is less than or equal
207  * to the current av_log_level. By default, all logging messages are sent to
208  * stderr. This behavior can be altered by setting a different logging callback
209  * function.
210  * @see av_log_set_callback
211  *
212  * @param avcl A pointer to an arbitrary struct of which the first field is a
213  * pointer to an AVClass struct.
214  * @param level The importance level of the message expressed using a @ref
215  * lavu_log_constants "Logging Constant".
216  * @param fmt The format string (printf-compatible) that specifies how
217  * subsequent arguments are converted to output.
218  * @param vl The arguments referenced by the format string.
219  */
220 void av_vlog(void *avcl, int level, const char *fmt, va_list vl);
221 
222 /**
223  * Get the current log level
224  *
225  * @see lavu_log_constants
226  *
227  * @return Current log level
228  */
229 int av_log_get_level(void);
230 
231 /**
232  * Set the log level
233  *
234  * @see lavu_log_constants
235  *
236  * @param level Logging level
237  */
238 void av_log_set_level(int level);
239 
240 /**
241  * Set the logging callback
242  *
243  * @note The callback must be thread safe, even if the application does not use
244  * threads itself as some codecs are multithreaded.
245  *
246  * @see av_log_default_callback
247  *
248  * @param callback A logging function with a compatible signature.
249  */
250 void av_log_set_callback(void (*callback)(void*, int, const char*, va_list));
251 
252 /**
253  * Default logging callback
254  *
255  * It prints the message to stderr, optionally colorizing it.
256  *
257  * @param avcl A pointer to an arbitrary struct of which the first field is a
258  * pointer to an AVClass struct.
259  * @param level The importance level of the message expressed using a @ref
260  * lavu_log_constants "Logging Constant".
261  * @param fmt The format string (printf-compatible) that specifies how
262  * subsequent arguments are converted to output.
263  * @param vl The arguments referenced by the format string.
264  */
265 void av_log_default_callback(void *avcl, int level, const char *fmt,
266  va_list vl);
267 
268 /**
269  * Return the context name
270  *
271  * @param ctx The AVClass context
272  *
273  * @return The AVClass class_name
274  */
275 const char* av_default_item_name(void* ctx);
277 
278 /**
279  * Format a line of log the same way as the default callback.
280  * @param line buffer to receive the formated line
281  * @param line_size size of the buffer
282  * @param print_prefix used to store whether the prefix must be printed;
283  * must point to a persistent integer initially set to 1
284  */
285 void av_log_format_line(void *ptr, int level, const char *fmt, va_list vl,
286  char *line, int line_size, int *print_prefix);
287 
288 /**
289  * av_dlog macros
290  * Useful to print debug messages that shouldn't get compiled in normally.
291  */
292 
293 #ifdef DEBUG
294 # define av_dlog(pctx, ...) av_log(pctx, AV_LOG_DEBUG, __VA_ARGS__)
295 #else
296 # define av_dlog(pctx, ...) do { if (0) av_log(pctx, AV_LOG_DEBUG, __VA_ARGS__); } while (0)
297 #endif
298 
299 /**
300  * Skip repeated messages, this requires the user app to use av_log() instead of
301  * (f)printf as the 2 would otherwise interfere and lead to
302  * "Last message repeated x times" messages below (f)printf messages with some
303  * bad luck.
304  * Also to receive the last, "last repeated" line if any, the user app must
305  * call av_log(NULL, AV_LOG_QUIET, "%s", ""); at the end
306  */
307 #define AV_LOG_SKIP_REPEATED 1
308 void av_log_set_flags(int arg);
309 
310 /**
311  * @}
312  */
313 
314 #endif /* AVUTIL_LOG_H */