1 
2 #ifndef BASE_LOGGING_H_
3 #define BASE_LOGGING_H_
4 
5 #include <cassert>
6 #include <string>
7 #include <cstring>
8 #include <sstream>
9 
10 #include "quipper/base/macros.h"
11 #include "quipper/base/basictypes.h"
12 
13 //
14 // Logging macros designed to mimic those used in chromium_org/base.
15 //
16 
17 // Instructions
18 // ------------
19 //
20 // Make a bunch of macros for logging.  The way to log things is to stream
21 // things to LOG(<a particular severity level>).  E.g.,
22 //
23 //   LOG(INFO) << "Found " << num_cookies << " cookies";
24 //
25 // You can also do conditional logging:
26 //
27 //   LOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
28 //
29 // The CHECK(condition) macro is active in both debug and release builds and
30 // effectively performs a LOG(FATAL) which terminates the process and
31 // generates a crashdump unless a debugger is attached.
32 //
33 // There are also "debug mode" logging macros like the ones above:
34 //
35 //   DLOG(INFO) << "Found cookies";
36 //
37 //   DLOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
38 //
39 // All "debug mode" logging is compiled away to nothing for non-debug mode
40 // compiles.  LOG_IF and development flags also work well together
41 // because the code can be compiled away sometimes.
42 //
43 // We also have
44 //
45 //   LOG_ASSERT(assertion);
46 //   DLOG_ASSERT(assertion);
47 //
48 // which is syntactic sugar for {,D}LOG_IF(FATAL, assert fails) << assertion;
49 //
50 // There are "verbose level" logging macros.  They look like
51 //
52 //   VLOG(1) << "I'm printed when you run the program with --v=1 or more";
53 //   VLOG(2) << "I'm printed when you run the program with --v=2 or more";
54 //
55 // These always log at the INFO log level (when they log at all).
56 // The verbose logging can also be turned on module-by-module.  For instance,
57 //    --vmodule=profile=2,icon_loader=1,browser_*=3,*/chromeos/*=4 --v=0
58 // will cause:
59 //   a. VLOG(2) and lower messages to be printed from profile.{h,cc}
60 //   b. VLOG(1) and lower messages to be printed from icon_loader.{h,cc}
61 //   c. VLOG(3) and lower messages to be printed from files prefixed with
62 //      "browser"
63 //   d. VLOG(4) and lower messages to be printed from files under a
64 //     "chromeos" directory.
65 //   e. VLOG(0) and lower messages to be printed from elsewhere
66 //
67 // The wildcarding functionality shown by (c) supports both '*' (match
68 // 0 or more characters) and '?' (match any single character)
69 // wildcards.  Any pattern containing a forward or backward slash will
70 // be tested against the whole pathname and not just the module.
71 // E.g., "*/foo/bar/*=2" would change the logging level for all code
72 // in source files under a "foo/bar" directory.
73 //
74 // There's also VLOG_IS_ON(n) "verbose level" condition macro. To be used as
75 //
76 //   if (VLOG_IS_ON(2)) {
77 //     // do some logging preparation and logging
78 //     // that can't be accomplished with just VLOG(2) << ...;
79 //   }
80 //
81 // There is also a VLOG_IF "verbose level" condition macro for sample
82 // cases, when some extra computation and preparation for logs is not
83 // needed.
84 //
85 //   VLOG_IF(1, (size > 1024))
86 //      << "I'm printed when size is more than 1024 and when you run the "
87 //         "program with --v=1 or more";
88 //
89 // We also override the standard 'assert' to use 'DLOG_ASSERT'.
90 //
91 // Lastly, there is:
92 //
93 //   PLOG(ERROR) << "Couldn't do foo";
94 //   DPLOG(ERROR) << "Couldn't do foo";
95 //   PLOG_IF(ERROR, cond) << "Couldn't do foo";
96 //   DPLOG_IF(ERROR, cond) << "Couldn't do foo";
97 //   PCHECK(condition) << "Couldn't do foo";
98 //   DPCHECK(condition) << "Couldn't do foo";
99 //
100 // which append the last system error to the message in string form (taken from
101 // GetLastError() on Windows and errno on POSIX).
102 //
103 // The supported severity levels for macros that allow you to specify one
104 // are (in increasing order of severity) INFO, WARNING, ERROR, and FATAL.
105 //
106 // Very important: logging a message at the FATAL severity level causes
107 // the program to terminate (after the message is logged).
108 //
109 // There is the special severity of DFATAL, which logs FATAL in debug mode,
110 // ERROR in normal mode.
111 
112 #define BASE_EXPORT
113 
114 namespace logging {
115 
116 // Sets the log level. Anything at or above this level will be written to the
117 // log file/displayed to the user (if applicable). Anything below this level
118 // will be silently ignored. The log level defaults to 0 (everything is logged
119 // up to level INFO) if this function is not called.
120 // Note that log messages for VLOG(x) are logged at level -x, so setting
121 // the min log level to negative values enables verbose logging.
122 BASE_EXPORT void SetMinLogLevel(int level);
123 
124 // Gets the current log level.
125 BASE_EXPORT int GetMinLogLevel();
126 
127 // Gets the VLOG default verbosity level.
128 BASE_EXPORT int GetVlogVerbosity();
129 
130 typedef int LogSeverity;
131 const LogSeverity LOG_VERBOSE = -1;  // This is level 1 verbosity
132 // Note: the log severities are used to index into the array of names,
133 // see log_severity_names.
134 const LogSeverity LOG_INFO = 0;
135 const LogSeverity LOG_WARNING = 1;
136 const LogSeverity LOG_ERROR = 2;
137 const LogSeverity LOG_FATAL = 3;
138 const LogSeverity LOG_NUM_SEVERITIES = 4;
139 
140 // A few definitions of macros that don't generate much code. These are used
141 // by LOG() and LOG_IF, etc. Since these are used all over our code, it's
142 // better to have compact code for these operations.
143 #define COMPACT_GOOGLE_LOG_EX_INFO(ClassName, ...) \
144   logging::ClassName(__FILE__, __LINE__, logging::LOG_INFO , ##__VA_ARGS__)
145 #define COMPACT_GOOGLE_LOG_EX_WARNING(ClassName, ...) \
146   logging::ClassName(__FILE__, __LINE__, logging::LOG_WARNING , ##__VA_ARGS__)
147 #define COMPACT_GOOGLE_LOG_EX_ERROR(ClassName, ...) \
148   logging::ClassName(__FILE__, __LINE__, logging::LOG_ERROR , ##__VA_ARGS__)
149 #define COMPACT_GOOGLE_LOG_EX_FATAL(ClassName, ...) \
150   logging::ClassName(__FILE__, __LINE__, logging::LOG_FATAL , ##__VA_ARGS__)
151 #define COMPACT_GOOGLE_LOG_EX_DFATAL(ClassName, ...) \
152   logging::ClassName(__FILE__, __LINE__, logging::LOG_DFATAL , ##__VA_ARGS__)
153 
154 #define COMPACT_GOOGLE_LOG_INFO \
155   COMPACT_GOOGLE_LOG_EX_INFO(LogMessage)
156 #define COMPACT_GOOGLE_LOG_WARNING \
157   COMPACT_GOOGLE_LOG_EX_WARNING(LogMessage)
158 #define COMPACT_GOOGLE_LOG_ERROR \
159   COMPACT_GOOGLE_LOG_EX_ERROR(LogMessage)
160 #define COMPACT_GOOGLE_LOG_FATAL \
161   COMPACT_GOOGLE_LOG_EX_FATAL(LogMessage)
162 #define COMPACT_GOOGLE_LOG_DFATAL \
163   COMPACT_GOOGLE_LOG_EX_DFATAL(LogMessage)
164 
165 // As special cases, we can assume that LOG_IS_ON(FATAL) always holds. Also,
166 // LOG_IS_ON(DFATAL) always holds in debug mode. In particular, CHECK()s will
167 // always fire if they fail.
168 #define LOG_IS_ON(severity) \
169   ((::logging::LOG_ ## severity) >= ::logging::GetMinLogLevel())
170 
171 #define VLOG_IS_ON(verboselevel) false
172 
173 // Helper macro which avoids evaluating the arguments to a stream if
174 // the condition doesn't hold.
175 #define LAZY_STREAM(stream, condition)                                  \
176   !(condition) ? (void) 0 : ::logging::LogMessageVoidify() & (stream)
177 
178 // We use the preprocessor's merging operator, "##", so that, e.g.,
179 // LOG(INFO) becomes the token COMPACT_GOOGLE_LOG_INFO.  There's some funny
180 // subtle difference between ostream member streaming functions (e.g.,
181 // ostream::operator<<(int) and ostream non-member streaming functions
182 // (e.g., ::operator<<(ostream&, string&): it turns out that it's
183 // impossible to stream something like a string directly to an unnamed
184 // ostream. We employ a neat hack by calling the stream() member
185 // function of LogMessage which seems to avoid the problem.
186 #define LOG_STREAM(severity) COMPACT_GOOGLE_LOG_ ## severity.stream()
187 
188 #define LOG(severity) LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity))
189 #define LOG_IF(severity, condition) \
190   LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity) && (condition))
191 
192 // The VLOG macros log with negative verbosities.
193 #define VLOG_STREAM(verbose_level) \
194   logging::LogMessage(__FILE__, __LINE__, -verbose_level).stream()
195 
196 #define VLOG(verbose_level) \
197   LAZY_STREAM(VLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level))
198 
199 #define VLOG_IF(verbose_level, condition) \
200   LAZY_STREAM(VLOG_STREAM(verbose_level), \
201       VLOG_IS_ON(verbose_level) && (condition))
202 
203 // TODO(akalin): Add more VLOG variants, e.g. VPLOG.
204 
205 #define LOG_ASSERT(condition)  \
206   LOG_IF(FATAL, !(condition)) << "Assert failed: " #condition ". "
207 #define SYSLOG_ASSERT(condition) \
208   SYSLOG_IF(FATAL, !(condition)) << "Assert failed: " #condition ". "
209 
210 #define PLOG(severity)                                          \
211   LAZY_STREAM(PLOG_STREAM(severity), LOG_IS_ON(severity))
212 
213 #define PLOG_IF(severity, condition) \
214   LAZY_STREAM(PLOG_STREAM(severity), LOG_IS_ON(severity) && (condition))
215 
216 // The actual stream used isn't important.
217 #define EAT_STREAM_PARAMETERS                                           \
218   true ? (void) 0 : ::logging::LogMessageVoidify() & LOG_STREAM(FATAL)
219 
220 // CHECK dies with a fatal error if condition is not true.  It is *not*
221 // controlled by NDEBUG, so the check will be executed regardless of
222 // compilation mode.
223 //
224 // We make sure CHECK et al. always evaluates their arguments, as
225 // doing CHECK(FunctionWithSideEffect()) is a common idiom.
226 
227 #define CHECK(condition)                       \
228   LAZY_STREAM(LOG_STREAM(FATAL), !(condition)) \
229   << "Check failed: " #condition ". "
230 
231 #define PCHECK(condition) \
232   LAZY_STREAM(PLOG_STREAM(FATAL), !(condition)) \
233   << "Check failed: " #condition ". "
234 
235 // Helper macro for binary operators.
236 // Don't use this macro directly in your code, use CHECK_EQ et al below.
237 //
238 // TODO(akalin): Rewrite this so that constructs like if (...)
239 // CHECK_EQ(...) else { ... } work properly.
240 #define CHECK_OP(name, op, val1, val2)                          \
241   if (std::string* _result =                                    \
242       logging::Check##name##Impl((val1), (val2),                \
243                                  #val1 " " #op " " #val2))      \
244     logging::LogMessage(__FILE__, __LINE__, _result).stream()
245 
246 // Build the error message string.  This is separate from the "Impl"
247 // function template because it is not performance critical and so can
248 // be out of line, while the "Impl" code should be inline.  Caller
249 // takes ownership of the returned string.
250 template<class t1, class t2>
MakeCheckOpString(const t1 & v1,const t2 & v2,const char * names)251 std::string* MakeCheckOpString(const t1& v1, const t2& v2, const char* names) {
252   std::ostringstream ss;
253   ss << names << " (" << v1 << " vs. " << v2 << ")";
254   std::string* msg = new std::string(ss.str());
255   return msg;
256 }
257 
258 // MSVC doesn't like complex extern templates and DLLs.
259 #if !defined(COMPILER_MSVC)
260 // Commonly used instantiations of MakeCheckOpString<>. Explicitly instantiated
261 // in logging.cc.
262 extern template BASE_EXPORT std::string* MakeCheckOpString<int, int>(
263     const int&, const int&, const char* names);
264 extern template BASE_EXPORT
265 std::string* MakeCheckOpString<unsigned long, unsigned long>(
266     const unsigned long&, const unsigned long&, const char* names);
267 extern template BASE_EXPORT
268 std::string* MakeCheckOpString<unsigned long, unsigned int>(
269     const unsigned long&, const unsigned int&, const char* names);
270 extern template BASE_EXPORT
271 std::string* MakeCheckOpString<unsigned int, unsigned long>(
272     const unsigned int&, const unsigned long&, const char* names);
273 extern template BASE_EXPORT
274 std::string* MakeCheckOpString<std::string, std::string>(
275     const std::string&, const std::string&, const char* name);
276 #endif
277 
278 // Helper functions for CHECK_OP macro.
279 // The (int, int) specialization works around the issue that the compiler
280 // will not instantiate the template version of the function on values of
281 // unnamed enum type - see comment below.
282 #define DEFINE_CHECK_OP_IMPL(name, op) \
283   template <class t1, class t2> \
284   inline std::string* Check##name##Impl(const t1& v1, const t2& v2, \
285                                         const char* names) { \
286     if (v1 op v2) return NULL; \
287     else return MakeCheckOpString(v1, v2, names); \
288   } \
289   inline std::string* Check##name##Impl(int v1, int v2, const char* names) { \
290     if (v1 op v2) return NULL; \
291     else return MakeCheckOpString(v1, v2, names); \
292   }
293 DEFINE_CHECK_OP_IMPL(EQ, ==)
294 DEFINE_CHECK_OP_IMPL(NE, !=)
295 DEFINE_CHECK_OP_IMPL(LE, <=)
296 DEFINE_CHECK_OP_IMPL(LT, < )
297 DEFINE_CHECK_OP_IMPL(GE, >=)
298 DEFINE_CHECK_OP_IMPL(GT, > )
299 #undef DEFINE_CHECK_OP_IMPL
300 
301 #define CHECK_EQ(val1, val2) CHECK_OP(EQ, ==, val1, val2)
302 #define CHECK_NE(val1, val2) CHECK_OP(NE, !=, val1, val2)
303 #define CHECK_LE(val1, val2) CHECK_OP(LE, <=, val1, val2)
304 #define CHECK_LT(val1, val2) CHECK_OP(LT, < , val1, val2)
305 #define CHECK_GE(val1, val2) CHECK_OP(GE, >=, val1, val2)
306 #define CHECK_GT(val1, val2) CHECK_OP(GT, > , val1, val2)
307 
308 #if defined(NDEBUG)
309 #define ENABLE_DLOG 0
310 #else
311 #define ENABLE_DLOG 1
312 #endif
313 
314 #if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON)
315 #define DCHECK_IS_ON 0
316 #else
317 #define DCHECK_IS_ON 1
318 #endif
319 
320 // Definitions for DLOG et al.
321 
322 #if ENABLE_DLOG
323 
324 #define DLOG_IS_ON(severity) LOG_IS_ON(severity)
325 #define DLOG_IF(severity, condition) LOG_IF(severity, condition)
326 #define DLOG_ASSERT(condition) LOG_ASSERT(condition)
327 #define DPLOG_IF(severity, condition) PLOG_IF(severity, condition)
328 #define DVLOG_IF(verboselevel, condition) VLOG_IF(verboselevel, condition)
329 #define DVPLOG_IF(verboselevel, condition) VPLOG_IF(verboselevel, condition)
330 
331 #else  // ENABLE_DLOG
332 
333 // If ENABLE_DLOG is off, we want to avoid emitting any references to
334 // |condition| (which may reference a variable defined only if NDEBUG
335 // is not defined).  Contrast this with DCHECK et al., which has
336 // different behavior.
337 
338 #define DLOG_IS_ON(severity) false
339 #define DLOG_IF(severity, condition) EAT_STREAM_PARAMETERS
340 #define DLOG_ASSERT(condition) EAT_STREAM_PARAMETERS
341 #define DPLOG_IF(severity, condition) EAT_STREAM_PARAMETERS
342 #define DVLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS
343 #define DVPLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS
344 
345 #endif  // ENABLE_DLOG
346 
347 // DEBUG_MODE is for uses like
348 //   if (DEBUG_MODE) foo.CheckThatFoo();
349 // instead of
350 //   #ifndef NDEBUG
351 //     foo.CheckThatFoo();
352 //   #endif
353 //
354 // We tie its state to ENABLE_DLOG.
355 enum { DEBUG_MODE = ENABLE_DLOG };
356 
357 #undef ENABLE_DLOG
358 
359 #define DLOG(severity)                                          \
360   LAZY_STREAM(LOG_STREAM(severity), DLOG_IS_ON(severity))
361 
362 #define DPLOG(severity)                                         \
363   LAZY_STREAM(PLOG_STREAM(severity), DLOG_IS_ON(severity))
364 
365 #define DVLOG(verboselevel) DVLOG_IF(verboselevel, VLOG_IS_ON(verboselevel))
366 
367 #define DVPLOG(verboselevel) DVPLOG_IF(verboselevel, VLOG_IS_ON(verboselevel))
368 
369 // Definitions for DCHECK et al.
370 
371 #if DCHECK_IS_ON
372 
373 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
374   COMPACT_GOOGLE_LOG_EX_FATAL(ClassName , ##__VA_ARGS__)
375 #define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_FATAL
376 const LogSeverity LOG_DCHECK = LOG_FATAL;
377 
378 #else  // DCHECK_IS_ON
379 
380 // These are just dummy values.
381 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
382   COMPACT_GOOGLE_LOG_EX_INFO(ClassName , ##__VA_ARGS__)
383 #define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_INFO
384 const LogSeverity LOG_DCHECK = LOG_INFO;
385 
386 #endif  // DCHECK_IS_ON
387 
388 // DCHECK et al. make sure to reference |condition| regardless of
389 // whether DCHECKs are enabled; this is so that we don't get unused
390 // variable warnings if the only use of a variable is in a DCHECK.
391 // This behavior is different from DLOG_IF et al.
392 
393 #define DCHECK(condition)                                         \
394   LAZY_STREAM(LOG_STREAM(DCHECK), DCHECK_IS_ON && !(condition))   \
395   << "Check failed: " #condition ". "
396 
397 #define DPCHECK(condition)                                        \
398   LAZY_STREAM(PLOG_STREAM(DCHECK), DCHECK_IS_ON && !(condition))  \
399   << "Check failed: " #condition ". "
400 
401 // Helper macro for binary operators.
402 // Don't use this macro directly in your code, use DCHECK_EQ et al below.
403 #define DCHECK_OP(name, op, val1, val2)                         \
404   if (DCHECK_IS_ON)                                             \
405     if (std::string* _result =                                  \
406         logging::Check##name##Impl((val1), (val2),              \
407                                    #val1 " " #op " " #val2))    \
408       logging::LogMessage(                                      \
409           __FILE__, __LINE__, ::logging::LOG_DCHECK,            \
410           _result).stream()
411 
412 // Equality/Inequality checks - compare two values, and log a
413 // LOG_DCHECK message including the two values when the result is not
414 // as expected.  The values must have operator<<(ostream, ...)
415 // defined.
416 //
417 // You may append to the error message like so:
418 //   DCHECK_NE(1, 2) << ": The world must be ending!";
419 //
420 // We are very careful to ensure that each argument is evaluated exactly
421 // once, and that anything which is legal to pass as a function argument is
422 // legal here.  In particular, the arguments may be temporary expressions
423 // which will end up being destroyed at the end of the apparent statement,
424 // for example:
425 //   DCHECK_EQ(string("abc")[1], 'b');
426 //
427 // WARNING: These may not compile correctly if one of the arguments is a pointer
428 // and the other is NULL. To work around this, simply static_cast NULL to the
429 // type of the desired pointer.
430 
431 #define DCHECK_EQ(val1, val2) DCHECK_OP(EQ, ==, val1, val2)
432 #define DCHECK_NE(val1, val2) DCHECK_OP(NE, !=, val1, val2)
433 #define DCHECK_LE(val1, val2) DCHECK_OP(LE, <=, val1, val2)
434 #define DCHECK_LT(val1, val2) DCHECK_OP(LT, < , val1, val2)
435 #define DCHECK_GE(val1, val2) DCHECK_OP(GE, >=, val1, val2)
436 #define DCHECK_GT(val1, val2) DCHECK_OP(GT, > , val1, val2)
437 
438 #if defined(NDEBUG) && defined(OS_CHROMEOS)
439 #define NOTREACHED() LOG(ERROR) << "NOTREACHED() hit in " << \
440     __FUNCTION__ << ". "
441 #else
442 #define NOTREACHED() DCHECK(false)
443 #endif
444 
445 // Redefine the standard assert to use our nice log files
446 #undef assert
447 #define assert(x) DLOG_ASSERT(x)
448 
449 // This class more or less represents a particular log message.  You
450 // create an instance of LogMessage and then stream stuff to it.
451 // When you finish streaming to it, ~LogMessage is called and the
452 // full message gets streamed to the appropriate destination.
453 //
454 // You shouldn't actually use LogMessage's constructor to log things,
455 // though.  You should use the LOG() macro (and variants thereof)
456 // above.
457 class BASE_EXPORT LogMessage {
458  public:
459   // Used for LOG(severity).
460   LogMessage(const char* file, int line, LogSeverity severity);
461 
462   // Used for CHECK_EQ(), etc. Takes ownership of the given string.
463   // Implied severity = LOG_FATAL.
464   LogMessage(const char* file, int line, std::string* result);
465 
466   // Used for DCHECK_EQ(), etc. Takes ownership of the given string.
467   LogMessage(const char* file, int line, LogSeverity severity,
468              std::string* result);
469 
470   ~LogMessage();
471 
stream()472   std::ostream& stream() { return stream_; }
473 
474  private:
475   void Init(const char* file, int line);
476 
477   LogSeverity severity_;
478   std::ostringstream stream_;
479   size_t message_start_;  // Offset of the start of the message (past prefix
480                           // info).
481   // The file and line information passed in to the constructor.
482   const char* file_;
483   const int line_;
484 
485 #if defined(OS_WIN)
486   // Stores the current value of GetLastError in the constructor and restores
487   // it in the destructor by calling SetLastError.
488   // This is useful since the LogMessage class uses a lot of Win32 calls
489   // that will lose the value of GLE and the code that called the log function
490   // will have lost the thread error value when the log call returns.
491   class SaveLastError {
492    public:
493     SaveLastError();
494     ~SaveLastError();
495 
get_error()496     unsigned long get_error() const { return last_error_; }
497 
498    protected:
499     unsigned long last_error_;
500   };
501 
502   SaveLastError last_error_;
503 #endif
504 
505   DISALLOW_COPY_AND_ASSIGN(LogMessage);
506 };
507 
508 // A non-macro interface to the log facility; (useful
509 // when the logging level is not a compile-time constant).
LogAtLevel(int const log_level,std::string const & msg)510 inline void LogAtLevel(int const log_level, std::string const &msg) {
511   LogMessage(__FILE__, __LINE__, log_level).stream() << msg;
512 }
513 
514 // This class is used to explicitly ignore values in the conditional
515 // logging macros.  This avoids compiler warnings like "value computed
516 // is not used" and "statement has no effect".
517 class LogMessageVoidify {
518  public:
LogMessageVoidify()519   LogMessageVoidify() { }
520   // This has to be an operator with a precedence lower than << but
521   // higher than ?:
522   void operator&(std::ostream&) { }
523 };
524 
525 #if defined(OS_WIN)
526 typedef unsigned long SystemErrorCode;
527 #elif defined(OS_POSIX)
528 typedef int SystemErrorCode;
529 #endif
530 
531 // Alias for ::GetLastError() on Windows and errno on POSIX. Avoids having to
532 // pull in windows.h just for GetLastError() and DWORD.
533 BASE_EXPORT SystemErrorCode GetLastSystemErrorCode();
534 BASE_EXPORT std::string SystemErrorCodeToString(SystemErrorCode error_code);
535 
536 #if defined(OS_WIN)
537 // Appends a formatted system message of the GetLastError() type.
538 class BASE_EXPORT Win32ErrorLogMessage {
539  public:
540   Win32ErrorLogMessage(const char* file,
541                        int line,
542                        LogSeverity severity,
543                        SystemErrorCode err);
544 
545   // Appends the error message before destructing the encapsulated class.
546   ~Win32ErrorLogMessage();
547 
stream()548   std::ostream& stream() { return log_message_.stream(); }
549 
550  private:
551   SystemErrorCode err_;
552   LogMessage log_message_;
553 
554   DISALLOW_COPY_AND_ASSIGN(Win32ErrorLogMessage);
555 };
556 #elif defined(OS_POSIX)
557 // Appends a formatted system message of the errno type
558 class BASE_EXPORT ErrnoLogMessage {
559  public:
560   ErrnoLogMessage(const char* file,
561                   int line,
562                   LogSeverity severity,
563                   SystemErrorCode err);
564 
565   // Appends the error message before destructing the encapsulated class.
566   ~ErrnoLogMessage();
567 
stream()568   std::ostream& stream() { return log_message_.stream(); }
569 
570  private:
571   SystemErrorCode err_;
572   LogMessage log_message_;
573 
574   DISALLOW_COPY_AND_ASSIGN(ErrnoLogMessage);
575 };
576 #endif  // OS_WIN
577 
578 // Closes the log file explicitly if open.
579 // NOTE: Since the log file is opened as necessary by the action of logging
580 //       statements, there's no guarantee that it will stay closed
581 //       after this call.
582 BASE_EXPORT void CloseLogFile();
583 
584 // Async signal safe logging mechanism.
585 BASE_EXPORT void RawLog(int level, const char* message);
586 
587 #define RAW_LOG(level, message) logging::RawLog(logging::LOG_ ## level, message)
588 
589 #define RAW_CHECK(condition)                                                   \
590   do {                                                                         \
591     if (!(condition))                                                          \
592       logging::RawLog(logging::LOG_FATAL, "Check failed: " #condition "\n");   \
593   } while (0)
594 
595 #if defined(OS_WIN)
596 // Returns the default log file path.
597 BASE_EXPORT std::wstring GetLogFileFullPath();
598 #endif
599 
600 }  // namespace logging
601 
602 // Note that "The behavior of a C++ program is undefined if it adds declarations
603 // or definitions to namespace std or to a namespace within namespace std unless
604 // otherwise specified." --C++11[namespace.std]
605 //
606 // We've checked that this particular definition has the intended behavior on
607 // our implementations, but it's prone to breaking in the future, and please
608 // don't imitate this in your own definitions without checking with some
609 // standard library experts.
610 namespace std {
611 // These functions are provided as a convenience for logging, which is where we
612 // use streams (it is against Google style to use streams in other places). It
613 // is designed to allow you to emit non-ASCII Unicode strings to the log file,
614 // which is normally ASCII. It is relatively slow, so try not to use it for
615 // common cases. Non-ASCII characters will be converted to UTF-8 by these
616 // operators.
617 BASE_EXPORT std::ostream& operator<<(std::ostream& out, const wchar_t* wstr);
618 inline std::ostream& operator<<(std::ostream& out, const std::wstring& wstr) {
619   return out << wstr.c_str();
620 }
621 }  // namespace std
622 
623 // The NOTIMPLEMENTED() macro annotates codepaths which have
624 // not been implemented yet.
625 //
626 // The implementation of this macro is controlled by NOTIMPLEMENTED_POLICY:
627 //   0 -- Do nothing (stripped by compiler)
628 //   1 -- Warn at compile time
629 //   2 -- Fail at compile time
630 //   3 -- Fail at runtime (DCHECK)
631 //   4 -- [default] LOG(ERROR) at runtime
632 //   5 -- LOG(ERROR) at runtime, only once per call-site
633 
634 #ifndef NOTIMPLEMENTED_POLICY
635 #if defined(OS_ANDROID) && defined(OFFICIAL_BUILD)
636 #define NOTIMPLEMENTED_POLICY 0
637 #else
638 // WebView: Hide NOTIMPLEMENTED entirely in Android release branch.
639 #define NOTIMPLEMENTED_POLICY 0
640 #endif
641 #endif
642 
643 #if defined(COMPILER_GCC)
644 // On Linux, with GCC, we can use __PRETTY_FUNCTION__ to get the demangled name
645 // of the current function in the NOTIMPLEMENTED message.
646 #define NOTIMPLEMENTED_MSG "Not implemented reached in " << __PRETTY_FUNCTION__
647 #else
648 #define NOTIMPLEMENTED_MSG "NOT IMPLEMENTED"
649 #endif
650 
651 #if NOTIMPLEMENTED_POLICY == 0
652 #define NOTIMPLEMENTED() EAT_STREAM_PARAMETERS
653 #elif NOTIMPLEMENTED_POLICY == 1
654 // TODO, figure out how to generate a warning
655 #define NOTIMPLEMENTED() COMPILE_ASSERT(false, NOT_IMPLEMENTED)
656 #elif NOTIMPLEMENTED_POLICY == 2
657 #define NOTIMPLEMENTED() COMPILE_ASSERT(false, NOT_IMPLEMENTED)
658 #elif NOTIMPLEMENTED_POLICY == 3
659 #define NOTIMPLEMENTED() NOTREACHED()
660 #elif NOTIMPLEMENTED_POLICY == 4
661 #define NOTIMPLEMENTED() LOG(ERROR) << NOTIMPLEMENTED_MSG
662 #elif NOTIMPLEMENTED_POLICY == 5
663 #define NOTIMPLEMENTED() do {\
664   static bool logged_once = false;\
665   LOG_IF(ERROR, !logged_once) << NOTIMPLEMENTED_MSG;\
666   logged_once = true;\
667 } while(0);\
668 EAT_STREAM_PARAMETERS
669 #endif
670 
671 #endif  // BASE_LOGGING_H_
672