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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) /* NOLINT */
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) /* NOLINT */
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