1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef BASE_LOGGING_H_
6 #define BASE_LOGGING_H_
13 #include "base/base_export.h"
14 #include "base/basictypes.h"
15 #include "base/debug/debugger.h"
16 #include "build/build_config.h"
19 // Optional message capabilities
20 // -----------------------------
21 // Assertion failed messages and fatal errors are displayed in a dialog box
22 // before the application exits. However, running this UI creates a message
23 // loop, which causes application messages to be processed and potentially
24 // dispatched to existing application windows. Since the application is in a
25 // bad state when this assertion dialog is displayed, these messages may not
26 // get processed and hang the dialog, or the application might go crazy.
28 // Therefore, it can be beneficial to display the error dialog in a separate
29 // process from the main application. When the logging system needs to display
30 // a fatal error dialog box, it will look for a program called
31 // "DebugMessage.exe" in the same directory as the application executable. It
32 // will run this application with the message as the command line, and will
33 // not include the name of the application as is traditional for easier
36 // The code for DebugMessage.exe is only one line. In WinMain, do:
37 // MessageBox(NULL, GetCommandLineW(), L"Fatal Error", 0);
39 // If DebugMessage.exe is not found, the logging code will use a normal
40 // MessageBox, potentially causing the problems discussed above.
46 // Make a bunch of macros for logging. The way to log things is to stream
47 // things to LOG(<a particular severity level>). E.g.,
49 // LOG(INFO) << "Found " << num_cookies << " cookies";
51 // You can also do conditional logging:
53 // LOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
55 // The CHECK(condition) macro is active in both debug and release builds and
56 // effectively performs a LOG(FATAL) which terminates the process and
57 // generates a crashdump unless a debugger is attached.
59 // There are also "debug mode" logging macros like the ones above:
61 // DLOG(INFO) << "Found cookies";
63 // DLOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
65 // All "debug mode" logging is compiled away to nothing for non-debug mode
66 // compiles. LOG_IF and development flags also work well together
67 // because the code can be compiled away sometimes.
71 // LOG_ASSERT(assertion);
72 // DLOG_ASSERT(assertion);
74 // which is syntactic sugar for {,D}LOG_IF(FATAL, assert fails) << assertion;
76 // There are "verbose level" logging macros. They look like
78 // VLOG(1) << "I'm printed when you run the program with --v=1 or more";
79 // VLOG(2) << "I'm printed when you run the program with --v=2 or more";
81 // These always log at the INFO log level (when they log at all).
82 // The verbose logging can also be turned on module-by-module. For instance,
83 // --vmodule=profile=2,icon_loader=1,browser_*=3,*/chromeos/*=4 --v=0
85 // a. VLOG(2) and lower messages to be printed from profile.{h,cc}
86 // b. VLOG(1) and lower messages to be printed from icon_loader.{h,cc}
87 // c. VLOG(3) and lower messages to be printed from files prefixed with
89 // d. VLOG(4) and lower messages to be printed from files under a
90 // "chromeos" directory.
91 // e. VLOG(0) and lower messages to be printed from elsewhere
93 // The wildcarding functionality shown by (c) supports both '*' (match
94 // 0 or more characters) and '?' (match any single character)
95 // wildcards. Any pattern containing a forward or backward slash will
96 // be tested against the whole pathname and not just the module.
97 // E.g., "*/foo/bar/*=2" would change the logging level for all code
98 // in source files under a "foo/bar" directory.
100 // There's also VLOG_IS_ON(n) "verbose level" condition macro. To be used as
102 // if (VLOG_IS_ON(2)) {
103 // // do some logging preparation and logging
104 // // that can't be accomplished with just VLOG(2) << ...;
107 // There is also a VLOG_IF "verbose level" condition macro for sample
108 // cases, when some extra computation and preparation for logs is not
111 // VLOG_IF(1, (size > 1024))
112 // << "I'm printed when size is more than 1024 and when you run the "
113 // "program with --v=1 or more";
115 // We also override the standard 'assert' to use 'DLOG_ASSERT'.
119 // PLOG(ERROR) << "Couldn't do foo";
120 // DPLOG(ERROR) << "Couldn't do foo";
121 // PLOG_IF(ERROR, cond) << "Couldn't do foo";
122 // DPLOG_IF(ERROR, cond) << "Couldn't do foo";
123 // PCHECK(condition) << "Couldn't do foo";
124 // DPCHECK(condition) << "Couldn't do foo";
126 // which append the last system error to the message in string form (taken from
127 // GetLastError() on Windows and errno on POSIX).
129 // The supported severity levels for macros that allow you to specify one
130 // are (in increasing order of severity) INFO, WARNING, ERROR, and FATAL.
132 // Very important: logging a message at the FATAL severity level causes
133 // the program to terminate (after the message is logged).
135 // There is the special severity of DFATAL, which logs FATAL in debug mode,
136 // ERROR in normal mode.
140 // TODO(avi): do we want to do a unification of character types here?
142 typedef wchar_t PathChar
;
144 typedef char PathChar
;
147 // Where to record logging output? A flat file and/or system debug log
148 // via OutputDebugString.
149 enum LoggingDestination
{
151 LOG_TO_FILE
= 1 << 0,
152 LOG_TO_SYSTEM_DEBUG_LOG
= 1 << 1,
154 LOG_TO_ALL
= LOG_TO_FILE
| LOG_TO_SYSTEM_DEBUG_LOG
,
156 // On Windows, use a file next to the exe; on POSIX platforms, where
157 // it may not even be possible to locate the executable on disk, use
160 LOG_DEFAULT
= LOG_TO_FILE
,
161 #elif defined(OS_POSIX)
162 LOG_DEFAULT
= LOG_TO_SYSTEM_DEBUG_LOG
,
166 // Indicates that the log file should be locked when being written to.
167 // Unless there is only one single-threaded process that is logging to
168 // the log file, the file should be locked during writes to make each
169 // log output atomic. Other writers will block.
171 // All processes writing to the log file must have their locking set for it to
172 // work properly. Defaults to LOCK_LOG_FILE.
173 enum LogLockingState
{ LOCK_LOG_FILE
, DONT_LOCK_LOG_FILE
};
175 // On startup, should we delete or append to an existing log file (if any)?
176 // Defaults to APPEND_TO_OLD_LOG_FILE.
177 enum OldFileDeletionState
{ DELETE_OLD_LOG_FILE
, APPEND_TO_OLD_LOG_FILE
};
179 struct BASE_EXPORT LoggingSettings
{
180 // The defaults values are:
182 // logging_dest: LOG_DEFAULT
184 // lock_log: LOCK_LOG_FILE
185 // delete_old: APPEND_TO_OLD_LOG_FILE
188 LoggingDestination logging_dest
;
190 // The three settings below have an effect only when LOG_TO_FILE is
191 // set in |logging_dest|.
192 const PathChar
* log_file
;
193 LogLockingState lock_log
;
194 OldFileDeletionState delete_old
;
197 // Define different names for the BaseInitLoggingImpl() function depending on
198 // whether NDEBUG is defined or not so that we'll fail to link if someone tries
199 // to compile logging.cc with NDEBUG but includes logging.h without defining it,
202 #define BaseInitLoggingImpl BaseInitLoggingImpl_built_with_NDEBUG
204 #define BaseInitLoggingImpl BaseInitLoggingImpl_built_without_NDEBUG
207 // Implementation of the InitLogging() method declared below. We use a
208 // more-specific name so we can #define it above without affecting other code
209 // that has named stuff "InitLogging".
210 BASE_EXPORT
bool BaseInitLoggingImpl(const LoggingSettings
& settings
);
212 // Sets the log file name and other global logging state. Calling this function
213 // is recommended, and is normally done at the beginning of application init.
214 // If you don't call it, all the flags will be initialized to their default
215 // values, and there is a race condition that may leak a critical section
216 // object if two threads try to do the first log at the same time.
217 // See the definition of the enums above for descriptions and default values.
219 // The default log file is initialized to "debug.log" in the application
220 // directory. You probably don't want this, especially since the program
221 // directory may not be writable on an enduser's system.
223 // This function may be called a second time to re-direct logging (e.g after
224 // loging in to a user partition), however it should never be called more than
226 inline bool InitLogging(const LoggingSettings
& settings
) {
227 return BaseInitLoggingImpl(settings
);
230 // Sets the log level. Anything at or above this level will be written to the
231 // log file/displayed to the user (if applicable). Anything below this level
232 // will be silently ignored. The log level defaults to 0 (everything is logged
233 // up to level INFO) if this function is not called.
234 // Note that log messages for VLOG(x) are logged at level -x, so setting
235 // the min log level to negative values enables verbose logging.
236 BASE_EXPORT
void SetMinLogLevel(int level
);
238 // Gets the current log level.
239 BASE_EXPORT
int GetMinLogLevel();
241 // Gets the VLOG default verbosity level.
242 BASE_EXPORT
int GetVlogVerbosity();
244 // Gets the current vlog level for the given file (usually taken from
247 // Note that |N| is the size *with* the null terminator.
248 BASE_EXPORT
int GetVlogLevelHelper(const char* file_start
, size_t N
);
251 int GetVlogLevel(const char (&file
)[N
]) {
252 return GetVlogLevelHelper(file
, N
);
255 // Sets the common items you want to be prepended to each log message.
256 // process and thread IDs default to off, the timestamp defaults to on.
257 // If this function is not called, logging defaults to writing the timestamp
259 BASE_EXPORT
void SetLogItems(bool enable_process_id
, bool enable_thread_id
,
260 bool enable_timestamp
, bool enable_tickcount
);
262 // Sets whether or not you'd like to see fatal debug messages popped up in
263 // a dialog box or not.
264 // Dialogs are not shown by default.
265 BASE_EXPORT
void SetShowErrorDialogs(bool enable_dialogs
);
267 // Sets the Log Assert Handler that will be used to notify of check failures.
268 // The default handler shows a dialog box and then terminate the process,
269 // however clients can use this function to override with their own handling
270 // (e.g. a silent one for Unit Tests)
271 typedef void (*LogAssertHandlerFunction
)(const std::string
& str
);
272 BASE_EXPORT
void SetLogAssertHandler(LogAssertHandlerFunction handler
);
274 // Sets the Log Message Handler that gets passed every log message before
275 // it's sent to other log destinations (if any).
276 // Returns true to signal that it handled the message and the message
277 // should not be sent to other log destinations.
278 typedef bool (*LogMessageHandlerFunction
)(int severity
,
279 const char* file
, int line
, size_t message_start
, const std::string
& str
);
280 BASE_EXPORT
void SetLogMessageHandler(LogMessageHandlerFunction handler
);
281 BASE_EXPORT LogMessageHandlerFunction
GetLogMessageHandler();
283 typedef int LogSeverity
;
284 const LogSeverity LOG_VERBOSE
= -1; // This is level 1 verbosity
285 // Note: the log severities are used to index into the array of names,
286 // see log_severity_names.
287 const LogSeverity LOG_INFO
= 0;
288 const LogSeverity LOG_WARNING
= 1;
289 const LogSeverity LOG_ERROR
= 2;
290 const LogSeverity LOG_FATAL
= 3;
291 const LogSeverity LOG_NUM_SEVERITIES
= 4;
293 // LOG_DFATAL is LOG_FATAL in debug mode, ERROR in normal mode
295 const LogSeverity LOG_DFATAL
= LOG_ERROR
;
297 const LogSeverity LOG_DFATAL
= LOG_FATAL
;
300 // A few definitions of macros that don't generate much code. These are used
301 // by LOG() and LOG_IF, etc. Since these are used all over our code, it's
302 // better to have compact code for these operations.
303 #define COMPACT_GOOGLE_LOG_EX_INFO(ClassName, ...) \
304 logging::ClassName(__FILE__, __LINE__, logging::LOG_INFO , ##__VA_ARGS__)
305 #define COMPACT_GOOGLE_LOG_EX_WARNING(ClassName, ...) \
306 logging::ClassName(__FILE__, __LINE__, logging::LOG_WARNING , ##__VA_ARGS__)
307 #define COMPACT_GOOGLE_LOG_EX_ERROR(ClassName, ...) \
308 logging::ClassName(__FILE__, __LINE__, logging::LOG_ERROR , ##__VA_ARGS__)
309 #define COMPACT_GOOGLE_LOG_EX_FATAL(ClassName, ...) \
310 logging::ClassName(__FILE__, __LINE__, logging::LOG_FATAL , ##__VA_ARGS__)
311 #define COMPACT_GOOGLE_LOG_EX_DFATAL(ClassName, ...) \
312 logging::ClassName(__FILE__, __LINE__, logging::LOG_DFATAL , ##__VA_ARGS__)
314 #define COMPACT_GOOGLE_LOG_INFO \
315 COMPACT_GOOGLE_LOG_EX_INFO(LogMessage)
316 #define COMPACT_GOOGLE_LOG_WARNING \
317 COMPACT_GOOGLE_LOG_EX_WARNING(LogMessage)
318 #define COMPACT_GOOGLE_LOG_ERROR \
319 COMPACT_GOOGLE_LOG_EX_ERROR(LogMessage)
320 #define COMPACT_GOOGLE_LOG_FATAL \
321 COMPACT_GOOGLE_LOG_EX_FATAL(LogMessage)
322 #define COMPACT_GOOGLE_LOG_DFATAL \
323 COMPACT_GOOGLE_LOG_EX_DFATAL(LogMessage)
326 // wingdi.h defines ERROR to be 0. When we call LOG(ERROR), it gets
327 // substituted with 0, and it expands to COMPACT_GOOGLE_LOG_0. To allow us
328 // to keep using this syntax, we define this macro to do the same thing
329 // as COMPACT_GOOGLE_LOG_ERROR, and also define ERROR the same way that
330 // the Windows SDK does for consistency.
332 #define COMPACT_GOOGLE_LOG_EX_0(ClassName, ...) \
333 COMPACT_GOOGLE_LOG_EX_ERROR(ClassName , ##__VA_ARGS__)
334 #define COMPACT_GOOGLE_LOG_0 COMPACT_GOOGLE_LOG_ERROR
335 // Needed for LOG_IS_ON(ERROR).
336 const LogSeverity LOG_0
= LOG_ERROR
;
339 // As special cases, we can assume that LOG_IS_ON(FATAL) always holds. Also,
340 // LOG_IS_ON(DFATAL) always holds in debug mode. In particular, CHECK()s will
341 // always fire if they fail.
342 #define LOG_IS_ON(severity) \
343 ((::logging::LOG_ ## severity) >= ::logging::GetMinLogLevel())
345 // We can't do any caching tricks with VLOG_IS_ON() like the
346 // google-glog version since it requires GCC extensions. This means
347 // that using the v-logging functions in conjunction with --vmodule
349 #define VLOG_IS_ON(verboselevel) \
350 ((verboselevel) <= ::logging::GetVlogLevel(__FILE__))
352 // Helper macro which avoids evaluating the arguments to a stream if
353 // the condition doesn't hold.
354 #define LAZY_STREAM(stream, condition) \
355 !(condition) ? (void) 0 : ::logging::LogMessageVoidify() & (stream)
357 // We use the preprocessor's merging operator, "##", so that, e.g.,
358 // LOG(INFO) becomes the token COMPACT_GOOGLE_LOG_INFO. There's some funny
359 // subtle difference between ostream member streaming functions (e.g.,
360 // ostream::operator<<(int) and ostream non-member streaming functions
361 // (e.g., ::operator<<(ostream&, string&): it turns out that it's
362 // impossible to stream something like a string directly to an unnamed
363 // ostream. We employ a neat hack by calling the stream() member
364 // function of LogMessage which seems to avoid the problem.
365 #define LOG_STREAM(severity) COMPACT_GOOGLE_LOG_ ## severity.stream()
367 #define LOG(severity) LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity))
368 #define LOG_IF(severity, condition) \
369 LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity) && (condition))
371 #define SYSLOG(severity) LOG(severity)
372 #define SYSLOG_IF(severity, condition) LOG_IF(severity, condition)
374 // The VLOG macros log with negative verbosities.
375 #define VLOG_STREAM(verbose_level) \
376 logging::LogMessage(__FILE__, __LINE__, -verbose_level).stream()
378 #define VLOG(verbose_level) \
379 LAZY_STREAM(VLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level))
381 #define VLOG_IF(verbose_level, condition) \
382 LAZY_STREAM(VLOG_STREAM(verbose_level), \
383 VLOG_IS_ON(verbose_level) && (condition))
386 #define VPLOG_STREAM(verbose_level) \
387 logging::Win32ErrorLogMessage(__FILE__, __LINE__, -verbose_level, \
388 ::logging::GetLastSystemErrorCode()).stream()
389 #elif defined(OS_POSIX)
390 #define VPLOG_STREAM(verbose_level) \
391 logging::ErrnoLogMessage(__FILE__, __LINE__, -verbose_level, \
392 ::logging::GetLastSystemErrorCode()).stream()
395 #define VPLOG(verbose_level) \
396 LAZY_STREAM(VPLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level))
398 #define VPLOG_IF(verbose_level, condition) \
399 LAZY_STREAM(VPLOG_STREAM(verbose_level), \
400 VLOG_IS_ON(verbose_level) && (condition))
402 // TODO(akalin): Add more VLOG variants, e.g. VPLOG.
404 #define LOG_ASSERT(condition) \
405 LOG_IF(FATAL, !(condition)) << "Assert failed: " #condition ". "
406 #define SYSLOG_ASSERT(condition) \
407 SYSLOG_IF(FATAL, !(condition)) << "Assert failed: " #condition ". "
410 #define PLOG_STREAM(severity) \
411 COMPACT_GOOGLE_LOG_EX_ ## severity(Win32ErrorLogMessage, \
412 ::logging::GetLastSystemErrorCode()).stream()
413 #elif defined(OS_POSIX)
414 #define PLOG_STREAM(severity) \
415 COMPACT_GOOGLE_LOG_EX_ ## severity(ErrnoLogMessage, \
416 ::logging::GetLastSystemErrorCode()).stream()
419 #define PLOG(severity) \
420 LAZY_STREAM(PLOG_STREAM(severity), LOG_IS_ON(severity))
422 #define PLOG_IF(severity, condition) \
423 LAZY_STREAM(PLOG_STREAM(severity), LOG_IS_ON(severity) && (condition))
425 // The actual stream used isn't important.
426 #define EAT_STREAM_PARAMETERS \
427 true ? (void) 0 : ::logging::LogMessageVoidify() & LOG_STREAM(FATAL)
429 // CHECK dies with a fatal error if condition is not true. It is *not*
430 // controlled by NDEBUG, so the check will be executed regardless of
433 // We make sure CHECK et al. always evaluates their arguments, as
434 // doing CHECK(FunctionWithSideEffect()) is a common idiom.
436 #if defined(OFFICIAL_BUILD) && defined(NDEBUG) && !defined(OS_ANDROID)
438 // Make all CHECK functions discard their log strings to reduce code
439 // bloat for official release builds.
441 // TODO(akalin): This would be more valuable if there were some way to
442 // remove BreakDebugger() from the backtrace, perhaps by turning it
443 // into a macro (like __debugbreak() on Windows).
444 #define CHECK(condition) \
445 !(condition) ? ::base::debug::BreakDebugger() : EAT_STREAM_PARAMETERS
447 #define PCHECK(condition) CHECK(condition)
449 #define CHECK_OP(name, op, val1, val2) CHECK((val1) op (val2))
453 #define CHECK(condition) \
454 LAZY_STREAM(LOG_STREAM(FATAL), !(condition)) \
455 << "Check failed: " #condition ". "
457 #define PCHECK(condition) \
458 LAZY_STREAM(PLOG_STREAM(FATAL), !(condition)) \
459 << "Check failed: " #condition ". "
461 // Helper macro for binary operators.
462 // Don't use this macro directly in your code, use CHECK_EQ et al below.
464 // TODO(akalin): Rewrite this so that constructs like if (...)
465 // CHECK_EQ(...) else { ... } work properly.
466 #define CHECK_OP(name, op, val1, val2) \
467 if (std::string* _result = \
468 logging::Check##name##Impl((val1), (val2), \
469 #val1 " " #op " " #val2)) \
470 logging::LogMessage(__FILE__, __LINE__, _result).stream()
474 // Build the error message string. This is separate from the "Impl"
475 // function template because it is not performance critical and so can
476 // be out of line, while the "Impl" code should be inline. Caller
477 // takes ownership of the returned string.
478 template<class t1
, class t2
>
479 std::string
* MakeCheckOpString(const t1
& v1
, const t2
& v2
, const char* names
) {
480 std::ostringstream ss
;
481 ss
<< names
<< " (" << v1
<< " vs. " << v2
<< ")";
482 std::string
* msg
= new std::string(ss
.str());
486 // Commonly used instantiations of MakeCheckOpString<>. Explicitly instantiated
488 extern template BASE_EXPORT
std::string
* MakeCheckOpString
<int, int>(
489 const int&, const int&, const char* names
);
490 extern template BASE_EXPORT
491 std::string
* MakeCheckOpString
<unsigned long, unsigned long>(
492 const unsigned long&, const unsigned long&, const char* names
);
493 extern template BASE_EXPORT
494 std::string
* MakeCheckOpString
<unsigned long, unsigned int>(
495 const unsigned long&, const unsigned int&, const char* names
);
496 extern template BASE_EXPORT
497 std::string
* MakeCheckOpString
<unsigned int, unsigned long>(
498 const unsigned int&, const unsigned long&, const char* names
);
499 extern template BASE_EXPORT
500 std::string
* MakeCheckOpString
<std::string
, std::string
>(
501 const std::string
&, const std::string
&, const char* name
);
503 // Helper functions for CHECK_OP macro.
504 // The (int, int) specialization works around the issue that the compiler
505 // will not instantiate the template version of the function on values of
506 // unnamed enum type - see comment below.
507 #define DEFINE_CHECK_OP_IMPL(name, op) \
508 template <class t1, class t2> \
509 inline std::string* Check##name##Impl(const t1& v1, const t2& v2, \
510 const char* names) { \
511 if (v1 op v2) return NULL; \
512 else return MakeCheckOpString(v1, v2, names); \
514 inline std::string* Check##name##Impl(int v1, int v2, const char* names) { \
515 if (v1 op v2) return NULL; \
516 else return MakeCheckOpString(v1, v2, names); \
518 DEFINE_CHECK_OP_IMPL(EQ
, ==)
519 DEFINE_CHECK_OP_IMPL(NE
, !=)
520 DEFINE_CHECK_OP_IMPL(LE
, <=)
521 DEFINE_CHECK_OP_IMPL(LT
, < )
522 DEFINE_CHECK_OP_IMPL(GE
, >=)
523 DEFINE_CHECK_OP_IMPL(GT
, > )
524 #undef DEFINE_CHECK_OP_IMPL
526 #define CHECK_EQ(val1, val2) CHECK_OP(EQ, ==, val1, val2)
527 #define CHECK_NE(val1, val2) CHECK_OP(NE, !=, val1, val2)
528 #define CHECK_LE(val1, val2) CHECK_OP(LE, <=, val1, val2)
529 #define CHECK_LT(val1, val2) CHECK_OP(LT, < , val1, val2)
530 #define CHECK_GE(val1, val2) CHECK_OP(GE, >=, val1, val2)
531 #define CHECK_GT(val1, val2) CHECK_OP(GT, > , val1, val2)
532 #define CHECK_IMPLIES(val1, val2) CHECK(!(val1) || (val2))
535 #define ENABLE_DLOG 0
537 #define ENABLE_DLOG 1
540 #if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON)
541 #define DCHECK_IS_ON 0
543 #define DCHECK_IS_ON 1
546 // Definitions for DLOG et al.
550 #define DLOG_IS_ON(severity) LOG_IS_ON(severity)
551 #define DLOG_IF(severity, condition) LOG_IF(severity, condition)
552 #define DLOG_ASSERT(condition) LOG_ASSERT(condition)
553 #define DPLOG_IF(severity, condition) PLOG_IF(severity, condition)
554 #define DVLOG_IF(verboselevel, condition) VLOG_IF(verboselevel, condition)
555 #define DVPLOG_IF(verboselevel, condition) VPLOG_IF(verboselevel, condition)
559 // If ENABLE_DLOG is off, we want to avoid emitting any references to
560 // |condition| (which may reference a variable defined only if NDEBUG
561 // is not defined). Contrast this with DCHECK et al., which has
562 // different behavior.
564 #define DLOG_IS_ON(severity) false
565 #define DLOG_IF(severity, condition) EAT_STREAM_PARAMETERS
566 #define DLOG_ASSERT(condition) EAT_STREAM_PARAMETERS
567 #define DPLOG_IF(severity, condition) EAT_STREAM_PARAMETERS
568 #define DVLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS
569 #define DVPLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS
571 #endif // ENABLE_DLOG
573 // DEBUG_MODE is for uses like
574 // if (DEBUG_MODE) foo.CheckThatFoo();
577 // foo.CheckThatFoo();
580 // We tie its state to ENABLE_DLOG.
581 enum { DEBUG_MODE
= ENABLE_DLOG
};
585 #define DLOG(severity) \
586 LAZY_STREAM(LOG_STREAM(severity), DLOG_IS_ON(severity))
588 #define DPLOG(severity) \
589 LAZY_STREAM(PLOG_STREAM(severity), DLOG_IS_ON(severity))
591 #define DVLOG(verboselevel) DVLOG_IF(verboselevel, VLOG_IS_ON(verboselevel))
593 #define DVPLOG(verboselevel) DVPLOG_IF(verboselevel, VLOG_IS_ON(verboselevel))
595 // Definitions for DCHECK et al.
599 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
600 COMPACT_GOOGLE_LOG_EX_FATAL(ClassName , ##__VA_ARGS__)
601 #define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_FATAL
602 const LogSeverity LOG_DCHECK
= LOG_FATAL
;
604 #else // DCHECK_IS_ON
606 // These are just dummy values.
607 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
608 COMPACT_GOOGLE_LOG_EX_INFO(ClassName , ##__VA_ARGS__)
609 #define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_INFO
610 const LogSeverity LOG_DCHECK
= LOG_INFO
;
612 #endif // DCHECK_IS_ON
614 // DCHECK et al. make sure to reference |condition| regardless of
615 // whether DCHECKs are enabled; this is so that we don't get unused
616 // variable warnings if the only use of a variable is in a DCHECK.
617 // This behavior is different from DLOG_IF et al.
619 #define DCHECK(condition) \
620 LAZY_STREAM(LOG_STREAM(DCHECK), DCHECK_IS_ON ? !(condition) : false) \
621 << "Check failed: " #condition ". "
623 #define DPCHECK(condition) \
624 LAZY_STREAM(PLOG_STREAM(DCHECK), DCHECK_IS_ON ? !(condition) : false) \
625 << "Check failed: " #condition ". "
627 // Helper macro for binary operators.
628 // Don't use this macro directly in your code, use DCHECK_EQ et al below.
629 #define DCHECK_OP(name, op, val1, val2) \
631 if (std::string* _result = \
632 logging::Check##name##Impl((val1), (val2), \
633 #val1 " " #op " " #val2)) \
634 logging::LogMessage( \
635 __FILE__, __LINE__, ::logging::LOG_DCHECK, \
638 // Equality/Inequality checks - compare two values, and log a
639 // LOG_DCHECK message including the two values when the result is not
640 // as expected. The values must have operator<<(ostream, ...)
643 // You may append to the error message like so:
644 // DCHECK_NE(1, 2) << ": The world must be ending!";
646 // We are very careful to ensure that each argument is evaluated exactly
647 // once, and that anything which is legal to pass as a function argument is
648 // legal here. In particular, the arguments may be temporary expressions
649 // which will end up being destroyed at the end of the apparent statement,
651 // DCHECK_EQ(string("abc")[1], 'b');
653 // WARNING: These may not compile correctly if one of the arguments is a pointer
654 // and the other is NULL. To work around this, simply static_cast NULL to the
655 // type of the desired pointer.
657 #define DCHECK_EQ(val1, val2) DCHECK_OP(EQ, ==, val1, val2)
658 #define DCHECK_NE(val1, val2) DCHECK_OP(NE, !=, val1, val2)
659 #define DCHECK_LE(val1, val2) DCHECK_OP(LE, <=, val1, val2)
660 #define DCHECK_LT(val1, val2) DCHECK_OP(LT, < , val1, val2)
661 #define DCHECK_GE(val1, val2) DCHECK_OP(GE, >=, val1, val2)
662 #define DCHECK_GT(val1, val2) DCHECK_OP(GT, > , val1, val2)
663 #define DCHECK_IMPLIES(val1, val2) DCHECK(!(val1) || (val2))
665 #if defined(NDEBUG) && defined(OS_CHROMEOS)
666 #define NOTREACHED() LOG(ERROR) << "NOTREACHED() hit in " << \
669 #define NOTREACHED() DCHECK(false)
672 // Redefine the standard assert to use our nice log files
674 #define assert(x) DLOG_ASSERT(x)
676 // This class more or less represents a particular log message. You
677 // create an instance of LogMessage and then stream stuff to it.
678 // When you finish streaming to it, ~LogMessage is called and the
679 // full message gets streamed to the appropriate destination.
681 // You shouldn't actually use LogMessage's constructor to log things,
682 // though. You should use the LOG() macro (and variants thereof)
684 class BASE_EXPORT LogMessage
{
686 // Used for LOG(severity).
687 LogMessage(const char* file
, int line
, LogSeverity severity
);
689 // Used for CHECK_EQ(), etc. Takes ownership of the given string.
690 // Implied severity = LOG_FATAL.
691 LogMessage(const char* file
, int line
, std::string
* result
);
693 // Used for DCHECK_EQ(), etc. Takes ownership of the given string.
694 LogMessage(const char* file
, int line
, LogSeverity severity
,
695 std::string
* result
);
699 std::ostream
& stream() { return stream_
; }
702 void Init(const char* file
, int line
);
704 LogSeverity severity_
;
705 std::ostringstream stream_
;
706 size_t message_start_
; // Offset of the start of the message (past prefix
708 // The file and line information passed in to the constructor.
713 // Stores the current value of GetLastError in the constructor and restores
714 // it in the destructor by calling SetLastError.
715 // This is useful since the LogMessage class uses a lot of Win32 calls
716 // that will lose the value of GLE and the code that called the log function
717 // will have lost the thread error value when the log call returns.
718 class SaveLastError
{
723 unsigned long get_error() const { return last_error_
; }
726 unsigned long last_error_
;
729 SaveLastError last_error_
;
732 DISALLOW_COPY_AND_ASSIGN(LogMessage
);
735 // A non-macro interface to the log facility; (useful
736 // when the logging level is not a compile-time constant).
737 inline void LogAtLevel(int const log_level
, std::string
const &msg
) {
738 LogMessage(__FILE__
, __LINE__
, log_level
).stream() << msg
;
741 // This class is used to explicitly ignore values in the conditional
742 // logging macros. This avoids compiler warnings like "value computed
743 // is not used" and "statement has no effect".
744 class LogMessageVoidify
{
746 LogMessageVoidify() { }
747 // This has to be an operator with a precedence lower than << but
749 void operator&(std::ostream
&) { }
753 typedef unsigned long SystemErrorCode
;
754 #elif defined(OS_POSIX)
755 typedef int SystemErrorCode
;
758 // Alias for ::GetLastError() on Windows and errno on POSIX. Avoids having to
759 // pull in windows.h just for GetLastError() and DWORD.
760 BASE_EXPORT SystemErrorCode
GetLastSystemErrorCode();
761 BASE_EXPORT
std::string
SystemErrorCodeToString(SystemErrorCode error_code
);
764 // Appends a formatted system message of the GetLastError() type.
765 class BASE_EXPORT Win32ErrorLogMessage
{
767 Win32ErrorLogMessage(const char* file
,
769 LogSeverity severity
,
770 SystemErrorCode err
);
772 // Appends the error message before destructing the encapsulated class.
773 ~Win32ErrorLogMessage();
775 std::ostream
& stream() { return log_message_
.stream(); }
778 SystemErrorCode err_
;
779 LogMessage log_message_
;
781 DISALLOW_COPY_AND_ASSIGN(Win32ErrorLogMessage
);
783 #elif defined(OS_POSIX)
784 // Appends a formatted system message of the errno type
785 class BASE_EXPORT ErrnoLogMessage
{
787 ErrnoLogMessage(const char* file
,
789 LogSeverity severity
,
790 SystemErrorCode err
);
792 // Appends the error message before destructing the encapsulated class.
795 std::ostream
& stream() { return log_message_
.stream(); }
798 SystemErrorCode err_
;
799 LogMessage log_message_
;
801 DISALLOW_COPY_AND_ASSIGN(ErrnoLogMessage
);
805 // Closes the log file explicitly if open.
806 // NOTE: Since the log file is opened as necessary by the action of logging
807 // statements, there's no guarantee that it will stay closed
809 BASE_EXPORT
void CloseLogFile();
811 // Async signal safe logging mechanism.
812 BASE_EXPORT
void RawLog(int level
, const char* message
);
814 #define RAW_LOG(level, message) logging::RawLog(logging::LOG_ ## level, message)
816 #define RAW_CHECK(condition) \
819 logging::RawLog(logging::LOG_FATAL, "Check failed: " #condition "\n"); \
823 // Returns the default log file path.
824 BASE_EXPORT
std::wstring
GetLogFileFullPath();
827 } // namespace logging
829 // Note that "The behavior of a C++ program is undefined if it adds declarations
830 // or definitions to namespace std or to a namespace within namespace std unless
831 // otherwise specified." --C++11[namespace.std]
833 // We've checked that this particular definition has the intended behavior on
834 // our implementations, but it's prone to breaking in the future, and please
835 // don't imitate this in your own definitions without checking with some
836 // standard library experts.
838 // These functions are provided as a convenience for logging, which is where we
839 // use streams (it is against Google style to use streams in other places). It
840 // is designed to allow you to emit non-ASCII Unicode strings to the log file,
841 // which is normally ASCII. It is relatively slow, so try not to use it for
842 // common cases. Non-ASCII characters will be converted to UTF-8 by these
844 BASE_EXPORT
std::ostream
& operator<<(std::ostream
& out
, const wchar_t* wstr
);
845 inline std::ostream
& operator<<(std::ostream
& out
, const std::wstring
& wstr
) {
846 return out
<< wstr
.c_str();
850 // The NOTIMPLEMENTED() macro annotates codepaths which have
851 // not been implemented yet.
853 // The implementation of this macro is controlled by NOTIMPLEMENTED_POLICY:
854 // 0 -- Do nothing (stripped by compiler)
855 // 1 -- Warn at compile time
856 // 2 -- Fail at compile time
857 // 3 -- Fail at runtime (DCHECK)
858 // 4 -- [default] LOG(ERROR) at runtime
859 // 5 -- LOG(ERROR) at runtime, only once per call-site
861 #ifndef NOTIMPLEMENTED_POLICY
862 #if defined(OS_ANDROID) && defined(OFFICIAL_BUILD)
863 #define NOTIMPLEMENTED_POLICY 0
865 // Select default policy: LOG(ERROR)
866 #define NOTIMPLEMENTED_POLICY 4
870 #if defined(COMPILER_GCC)
871 // On Linux, with GCC, we can use __PRETTY_FUNCTION__ to get the demangled name
872 // of the current function in the NOTIMPLEMENTED message.
873 #define NOTIMPLEMENTED_MSG "Not implemented reached in " << __PRETTY_FUNCTION__
875 #define NOTIMPLEMENTED_MSG "NOT IMPLEMENTED"
878 #if NOTIMPLEMENTED_POLICY == 0
879 #define NOTIMPLEMENTED() EAT_STREAM_PARAMETERS
880 #elif NOTIMPLEMENTED_POLICY == 1
881 // TODO, figure out how to generate a warning
882 #define NOTIMPLEMENTED() COMPILE_ASSERT(false, NOT_IMPLEMENTED)
883 #elif NOTIMPLEMENTED_POLICY == 2
884 #define NOTIMPLEMENTED() COMPILE_ASSERT(false, NOT_IMPLEMENTED)
885 #elif NOTIMPLEMENTED_POLICY == 3
886 #define NOTIMPLEMENTED() NOTREACHED()
887 #elif NOTIMPLEMENTED_POLICY == 4
888 #define NOTIMPLEMENTED() LOG(ERROR) << NOTIMPLEMENTED_MSG
889 #elif NOTIMPLEMENTED_POLICY == 5
890 #define NOTIMPLEMENTED() do {\
891 static bool logged_once = false;\
892 LOG_IF(ERROR, !logged_once) << NOTIMPLEMENTED_MSG;\
895 EAT_STREAM_PARAMETERS
898 #endif // BASE_LOGGING_H_