base/logging.h

   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.
   4
   5 #ifndef BASE_LOGGING_H_
   6 #define BASE_LOGGING_H_
   7
   8 #include <cassert>
   9 #include <string>
  10 #include <cstring>
  11 #include <sstream>
  12
  13 #include "base/base_export.h"
  14 #include "base/basictypes.h"
  15 #include "base/debug/debugger.h"
  16 #include "build/build_config.h"
  17
  18 //
  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.
  27 //
  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
  34 // parsing.
  35 //
  36 // The code for DebugMessage.exe is only one line. In WinMain, do:
  37 //   MessageBox(NULL, GetCommandLineW(), L"Fatal Error", 0);
  38 //
  39 // If DebugMessage.exe is not found, the logging code will use a normal
  40 // MessageBox, potentially causing the problems discussed above.
  41
  42
  43 // Instructions
  44 // ------------
  45 //
  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.,
  48 //
  49 //   LOG(INFO) << "Found " << num_cookies << " cookies";
  50 //
  51 // You can also do conditional logging:
  52 //
  53 //   LOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
  54 //
  55 // The above will cause log messages to be output on the 1st, 11th, 21st, ...
  56 // times it is executed.  Note that the special COUNTER value is used to
  57 // identify which repetition is happening.
  58 //
  59 // The CHECK(condition) macro is active in both debug and release builds and
  60 // effectively performs a LOG(FATAL) which terminates the process and
  61 // generates a crashdump unless a debugger is attached.
  62 //
  63 // There are also "debug mode" logging macros like the ones above:
  64 //
  65 //   DLOG(INFO) << "Found cookies";
  66 //
  67 //   DLOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
  68 //
  69 // All "debug mode" logging is compiled away to nothing for non-debug mode
  70 // compiles.  LOG_IF and development flags also work well together
  71 // because the code can be compiled away sometimes.
  72 //
  73 // We also have
  74 //
  75 //   LOG_ASSERT(assertion);
  76 //   DLOG_ASSERT(assertion);
  77 //
  78 // which is syntactic sugar for {,D}LOG_IF(FATAL, assert fails) << assertion;
  79 //
  80 // There are "verbose level" logging macros.  They look like
  81 //
  82 //   VLOG(1) << "I'm printed when you run the program with --v=1 or more";
  83 //   VLOG(2) << "I'm printed when you run the program with --v=2 or more";
  84 //
  85 // These always log at the INFO log level (when they log at all).
  86 // The verbose logging can also be turned on module-by-module.  For instance,
  87 //    --vmodule=profile=2,icon_loader=1,browser_*=3,*/chromeos/*=4 --v=0
  88 // will cause:
  89 //   a. VLOG(2) and lower messages to be printed from profile.{h,cc}
  90 //   b. VLOG(1) and lower messages to be printed from icon_loader.{h,cc}
  91 //   c. VLOG(3) and lower messages to be printed from files prefixed with
  92 //      "browser"
  93 //   d. VLOG(4) and lower messages to be printed from files under a
  94 //     "chromeos" directory.
  95 //   e. VLOG(0) and lower messages to be printed from elsewhere
  96 //
  97 // The wildcarding functionality shown by (c) supports both '*' (match
  98 // 0 or more characters) and '?' (match any single character)
  99 // wildcards.  Any pattern containing a forward or backward slash will
 100 // be tested against the whole pathname and not just the module.
 101 // E.g., "*/foo/bar/*=2" would change the logging level for all code
 102 // in source files under a "foo/bar" directory.
 103 //
 104 // There's also VLOG_IS_ON(n) "verbose level" condition macro. To be used as
 105 //
 106 //   if (VLOG_IS_ON(2)) {
 107 //     // do some logging preparation and logging
 108 //     // that can't be accomplished with just VLOG(2) << ...;
 109 //   }
 110 //
 111 // There is also a VLOG_IF "verbose level" condition macro for sample
 112 // cases, when some extra computation and preparation for logs is not
 113 // needed.
 114 //
 115 //   VLOG_IF(1, (size > 1024))
 116 //      << "I'm printed when size is more than 1024 and when you run the "
 117 //         "program with --v=1 or more";
 118 //
 119 // We also override the standard 'assert' to use 'DLOG_ASSERT'.
 120 //
 121 // Lastly, there is:
 122 //
 123 //   PLOG(ERROR) << "Couldn't do foo";
 124 //   DPLOG(ERROR) << "Couldn't do foo";
 125 //   PLOG_IF(ERROR, cond) << "Couldn't do foo";
 126 //   DPLOG_IF(ERROR, cond) << "Couldn't do foo";
 127 //   PCHECK(condition) << "Couldn't do foo";
 128 //   DPCHECK(condition) << "Couldn't do foo";
 129 //
 130 // which append the last system error to the message in string form (taken from
 131 // GetLastError() on Windows and errno on POSIX).
 132 //
 133 // The supported severity levels for macros that allow you to specify one
 134 // are (in increasing order of severity) INFO, WARNING, ERROR, ERROR_REPORT,
 135 // and FATAL.
 136 //
 137 // Very important: logging a message at the FATAL severity level causes
 138 // the program to terminate (after the message is logged).
 139 //
 140 // Note the special severity of ERROR_REPORT only available/relevant in normal
 141 // mode, which displays error dialog without terminating the program. There is
 142 // no error dialog for severity ERROR or below in normal mode.
 143 //
 144 // There is also the special severity of DFATAL, which logs FATAL in
 145 // debug mode, ERROR in normal mode.
 146
 147 namespace logging {
 148
 149 // TODO(avi): do we want to do a unification of character types here?
 150 #if defined(OS_WIN)
 151 typedef wchar_t PathChar;
 152 #else
 153 typedef char PathChar;
 154 #endif
 155
 156 // Where to record logging output? A flat file and/or system debug log
 157 // via OutputDebugString.
 158 enum LoggingDestination {
 159   LOG_NONE                = 0,
 160   LOG_TO_FILE             = 1 << 0,
 161   LOG_TO_SYSTEM_DEBUG_LOG = 1 << 1,
 162
 163   LOG_TO_ALL = LOG_TO_FILE | LOG_TO_SYSTEM_DEBUG_LOG,
 164
 165   // On Windows, use a file next to the exe; on POSIX platforms, where
 166   // it may not even be possible to locate the executable on disk, use
 167   // stderr.
 168 #if defined(OS_WIN)
 169   LOG_DEFAULT = LOG_TO_FILE,
 170 #elif defined(OS_POSIX)
 171   LOG_DEFAULT = LOG_TO_SYSTEM_DEBUG_LOG,
 172 #endif
 173 };
 174
 175 // Indicates that the log file should be locked when being written to.
 176 // Unless there is only one single-threaded process that is logging to
 177 // the log file, the file should be locked during writes to make each
 178 // log outut atomic. Other writers will block.
 179 //
 180 // All processes writing to the log file must have their locking set for it to
 181 // work properly. Defaults to LOCK_LOG_FILE.
 182 enum LogLockingState { LOCK_LOG_FILE, DONT_LOCK_LOG_FILE };
 183
 184 // On startup, should we delete or append to an existing log file (if any)?
 185 // Defaults to APPEND_TO_OLD_LOG_FILE.
 186 enum OldFileDeletionState { DELETE_OLD_LOG_FILE, APPEND_TO_OLD_LOG_FILE };
 187
 188 enum DcheckState {
 189   DISABLE_DCHECK_FOR_NON_OFFICIAL_RELEASE_BUILDS,
 190   ENABLE_DCHECK_FOR_NON_OFFICIAL_RELEASE_BUILDS
 191 };
 192
 193 struct BASE_EXPORT LoggingSettings {
 194   // The defaults values are:
 195   //
 196   //  logging_dest: LOG_DEFAULT
 197   //  log_file:     NULL
 198   //  lock_log:     LOCK_LOG_FILE
 199   //  delete_old:   APPEND_TO_OLD_LOG_FILE
 200   //  dcheck_state: DISABLE_DCHECK_FOR_NON_OFFICIAL_RELEASE_BUILDS
 201   LoggingSettings();
 202
 203   LoggingDestination logging_dest;
 204
 205   // The three settings below have an effect only when LOG_TO_FILE is
 206   // set in |logging_dest|.
 207   const PathChar* log_file;
 208   LogLockingState lock_log;
 209   OldFileDeletionState delete_old;
 210
 211   DcheckState dcheck_state;
 212 };
 213
 214 // Define different names for the BaseInitLoggingImpl() function depending on
 215 // whether NDEBUG is defined or not so that we'll fail to link if someone tries
 216 // to compile logging.cc with NDEBUG but includes logging.h without defining it,
 217 // or vice versa.
 218 #if NDEBUG
 219 #define BaseInitLoggingImpl BaseInitLoggingImpl_built_with_NDEBUG
 220 #else
 221 #define BaseInitLoggingImpl BaseInitLoggingImpl_built_without_NDEBUG
 222 #endif
 223
 224 // Implementation of the InitLogging() method declared below.  We use a
 225 // more-specific name so we can #define it above without affecting other code
 226 // that has named stuff "InitLogging".
 227 BASE_EXPORT bool BaseInitLoggingImpl(const LoggingSettings& settings);
 228
 229 // Sets the log file name and other global logging state. Calling this function
 230 // is recommended, and is normally done at the beginning of application init.
 231 // If you don't call it, all the flags will be initialized to their default
 232 // values, and there is a race condition that may leak a critical section
 233 // object if two threads try to do the first log at the same time.
 234 // See the definition of the enums above for descriptions and default values.
 235 //
 236 // The default log file is initialized to "debug.log" in the application
 237 // directory. You probably don't want this, especially since the program
 238 // directory may not be writable on an enduser's system.
 239 //
 240 // This function may be called a second time to re-direct logging (e.g after
 241 // loging in to a user partition), however it should never be called more than
 242 // twice.
 243 inline bool InitLogging(const LoggingSettings& settings) {
 244   return BaseInitLoggingImpl(settings);
 245 }
 246
 247 // Sets the log level. Anything at or above this level will be written to the
 248 // log file/displayed to the user (if applicable). Anything below this level
 249 // will be silently ignored. The log level defaults to 0 (everything is logged
 250 // up to level INFO) if this function is not called.
 251 // Note that log messages for VLOG(x) are logged at level -x, so setting
 252 // the min log level to negative values enables verbose logging.
 253 BASE_EXPORT void SetMinLogLevel(int level);
 254
 255 // Gets the current log level.
 256 BASE_EXPORT int GetMinLogLevel();
 257
 258 // Gets the VLOG default verbosity level.
 259 BASE_EXPORT int GetVlogVerbosity();
 260
 261 // Gets the current vlog level for the given file (usually taken from
 262 // __FILE__).
 263
 264 // Note that |N| is the size *with* the null terminator.
 265 BASE_EXPORT int GetVlogLevelHelper(const char* file_start, size_t N);
 266
 267 template <size_t N>
 268 int GetVlogLevel(const char (&file)[N]) {
 269   return GetVlogLevelHelper(file, N);
 270 }
 271
 272 // Sets the common items you want to be prepended to each log message.
 273 // process and thread IDs default to off, the timestamp defaults to on.
 274 // If this function is not called, logging defaults to writing the timestamp
 275 // only.
 276 BASE_EXPORT void SetLogItems(bool enable_process_id, bool enable_thread_id,
 277                              bool enable_timestamp, bool enable_tickcount);
 278
 279 // Sets whether or not you'd like to see fatal debug messages popped up in
 280 // a dialog box or not.
 281 // Dialogs are not shown by default.
 282 BASE_EXPORT void SetShowErrorDialogs(bool enable_dialogs);
 283
 284 // Sets the Log Assert Handler that will be used to notify of check failures.
 285 // The default handler shows a dialog box and then terminate the process,
 286 // however clients can use this function to override with their own handling
 287 // (e.g. a silent one for Unit Tests)
 288 typedef void (*LogAssertHandlerFunction)(const std::string& str);
 289 BASE_EXPORT void SetLogAssertHandler(LogAssertHandlerFunction handler);
 290
 291 // Sets the Log Report Handler that will be used to notify of check failures
 292 // in non-debug mode. The default handler shows a dialog box and continues
 293 // the execution, however clients can use this function to override with their
 294 // own handling.
 295 typedef void (*LogReportHandlerFunction)(const std::string& str);
 296 BASE_EXPORT void SetLogReportHandler(LogReportHandlerFunction handler);
 297
 298 // Sets the Log Message Handler that gets passed every log message before
 299 // it's sent to other log destinations (if any).
 300 // Returns true to signal that it handled the message and the message
 301 // should not be sent to other log destinations.
 302 typedef bool (*LogMessageHandlerFunction)(int severity,
 303     const char* file, int line, size_t message_start, const std::string& str);
 304 BASE_EXPORT void SetLogMessageHandler(LogMessageHandlerFunction handler);
 305 BASE_EXPORT LogMessageHandlerFunction GetLogMessageHandler();
 306
 307 typedef int LogSeverity;
 308 const LogSeverity LOG_VERBOSE = -1;  // This is level 1 verbosity
 309 // Note: the log severities are used to index into the array of names,
 310 // see log_severity_names.
 311 const LogSeverity LOG_INFO = 0;
 312 const LogSeverity LOG_WARNING = 1;
 313 const LogSeverity LOG_ERROR = 2;
 314 const LogSeverity LOG_ERROR_REPORT = 3;
 315 const LogSeverity LOG_FATAL = 4;
 316 const LogSeverity LOG_NUM_SEVERITIES = 5;
 317
 318 // LOG_DFATAL is LOG_FATAL in debug mode, ERROR in normal mode
 319 #ifdef NDEBUG
 320 const LogSeverity LOG_DFATAL = LOG_ERROR;
 321 #else
 322 const LogSeverity LOG_DFATAL = LOG_FATAL;
 323 #endif
 324
 325 // A few definitions of macros that don't generate much code. These are used
 326 // by LOG() and LOG_IF, etc. Since these are used all over our code, it's
 327 // better to have compact code for these operations.
 328 #define COMPACT_GOOGLE_LOG_EX_INFO(ClassName, ...) \
 329   logging::ClassName(__FILE__, __LINE__, logging::LOG_INFO , ##__VA_ARGS__)
 330 #define COMPACT_GOOGLE_LOG_EX_WARNING(ClassName, ...) \
 331   logging::ClassName(__FILE__, __LINE__, logging::LOG_WARNING , ##__VA_ARGS__)
 332 #define COMPACT_GOOGLE_LOG_EX_ERROR(ClassName, ...) \
 333   logging::ClassName(__FILE__, __LINE__, logging::LOG_ERROR , ##__VA_ARGS__)
 334 #define COMPACT_GOOGLE_LOG_EX_ERROR_REPORT(ClassName, ...) \
 335   logging::ClassName(__FILE__, __LINE__, \
 336                      logging::LOG_ERROR_REPORT , ##__VA_ARGS__)
 337 #define COMPACT_GOOGLE_LOG_EX_FATAL(ClassName, ...) \
 338   logging::ClassName(__FILE__, __LINE__, logging::LOG_FATAL , ##__VA_ARGS__)
 339 #define COMPACT_GOOGLE_LOG_EX_DFATAL(ClassName, ...) \
 340   logging::ClassName(__FILE__, __LINE__, logging::LOG_DFATAL , ##__VA_ARGS__)
 341
 342 #define COMPACT_GOOGLE_LOG_INFO \
 343   COMPACT_GOOGLE_LOG_EX_INFO(LogMessage)
 344 #define COMPACT_GOOGLE_LOG_WARNING \
 345   COMPACT_GOOGLE_LOG_EX_WARNING(LogMessage)
 346 #define COMPACT_GOOGLE_LOG_ERROR \
 347   COMPACT_GOOGLE_LOG_EX_ERROR(LogMessage)
 348 #define COMPACT_GOOGLE_LOG_ERROR_REPORT \
 349   COMPACT_GOOGLE_LOG_EX_ERROR_REPORT(LogMessage)
 350 #define COMPACT_GOOGLE_LOG_FATAL \
 351   COMPACT_GOOGLE_LOG_EX_FATAL(LogMessage)
 352 #define COMPACT_GOOGLE_LOG_DFATAL \
 353   COMPACT_GOOGLE_LOG_EX_DFATAL(LogMessage)
 354
 355 #if defined(OS_WIN)
 356 // wingdi.h defines ERROR to be 0. When we call LOG(ERROR), it gets
 357 // substituted with 0, and it expands to COMPACT_GOOGLE_LOG_0. To allow us
 358 // to keep using this syntax, we define this macro to do the same thing
 359 // as COMPACT_GOOGLE_LOG_ERROR, and also define ERROR the same way that
 360 // the Windows SDK does for consistency.
 361 #define ERROR 0
 362 #define COMPACT_GOOGLE_LOG_EX_0(ClassName, ...) \
 363   COMPACT_GOOGLE_LOG_EX_ERROR(ClassName , ##__VA_ARGS__)
 364 #define COMPACT_GOOGLE_LOG_0 COMPACT_GOOGLE_LOG_ERROR
 365 // Needed for LOG_IS_ON(ERROR).
 366 const LogSeverity LOG_0 = LOG_ERROR;
 367 #endif
 368
 369 // As special cases, we can assume that LOG_IS_ON(ERROR_REPORT) and
 370 // LOG_IS_ON(FATAL) always hold.  Also, LOG_IS_ON(DFATAL) always holds
 371 // in debug mode.  In particular, CHECK()s will always fire if they
 372 // fail.
 373 #define LOG_IS_ON(severity) \
 374   ((::logging::LOG_ ## severity) >= ::logging::GetMinLogLevel())
 375
 376 // We can't do any caching tricks with VLOG_IS_ON() like the
 377 // google-glog version since it requires GCC extensions.  This means
 378 // that using the v-logging functions in conjunction with --vmodule
 379 // may be slow.
 380 #define VLOG_IS_ON(verboselevel) \
 381   ((verboselevel) <= ::logging::GetVlogLevel(__FILE__))
 382
 383 // Helper macro which avoids evaluating the arguments to a stream if
 384 // the condition doesn't hold.
 385 #define LAZY_STREAM(stream, condition)                                  \
 386   !(condition) ? (void) 0 : ::logging::LogMessageVoidify() & (stream)
 387
 388 // We use the preprocessor's merging operator, "##", so that, e.g.,
 389 // LOG(INFO) becomes the token COMPACT_GOOGLE_LOG_INFO.  There's some funny
 390 // subtle difference between ostream member streaming functions (e.g.,
 391 // ostream::operator<<(int) and ostream non-member streaming functions
 392 // (e.g., ::operator<<(ostream&, string&): it turns out that it's
 393 // impossible to stream something like a string directly to an unnamed
 394 // ostream. We employ a neat hack by calling the stream() member
 395 // function of LogMessage which seems to avoid the problem.
 396 #define LOG_STREAM(severity) COMPACT_GOOGLE_LOG_ ## severity.stream()
 397
 398 #define LOG(severity) LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity))
 399 #define LOG_IF(severity, condition) \
 400   LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity) && (condition))
 401
 402 #define SYSLOG(severity) LOG(severity)
 403 #define SYSLOG_IF(severity, condition) LOG_IF(severity, condition)
 404
 405 // The VLOG macros log with negative verbosities.
 406 #define VLOG_STREAM(verbose_level) \
 407   logging::LogMessage(__FILE__, __LINE__, -verbose_level).stream()
 408
 409 #define VLOG(verbose_level) \
 410   LAZY_STREAM(VLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level))
 411
 412 #define VLOG_IF(verbose_level, condition) \
 413   LAZY_STREAM(VLOG_STREAM(verbose_level), \
 414       VLOG_IS_ON(verbose_level) && (condition))
 415
 416 #if defined (OS_WIN)
 417 #define VPLOG_STREAM(verbose_level) \
 418   logging::Win32ErrorLogMessage(__FILE__, __LINE__, -verbose_level, \
 419     ::logging::GetLastSystemErrorCode()).stream()
 420 #elif defined(OS_POSIX)
 421 #define VPLOG_STREAM(verbose_level) \
 422   logging::ErrnoLogMessage(__FILE__, __LINE__, -verbose_level, \
 423     ::logging::GetLastSystemErrorCode()).stream()
 424 #endif
 425
 426 #define VPLOG(verbose_level) \
 427   LAZY_STREAM(VPLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level))
 428
 429 #define VPLOG_IF(verbose_level, condition) \
 430   LAZY_STREAM(VPLOG_STREAM(verbose_level), \
 431     VLOG_IS_ON(verbose_level) && (condition))
 432
 433 // TODO(akalin): Add more VLOG variants, e.g. VPLOG.
 434
 435 #define LOG_ASSERT(condition)  \
 436   LOG_IF(FATAL, !(condition)) << "Assert failed: " #condition ". "
 437 #define SYSLOG_ASSERT(condition) \
 438   SYSLOG_IF(FATAL, !(condition)) << "Assert failed: " #condition ". "
 439
 440 #if defined(OS_WIN)
 441 #define LOG_GETLASTERROR_STREAM(severity) \
 442   COMPACT_GOOGLE_LOG_EX_ ## severity(Win32ErrorLogMessage, \
 443       ::logging::GetLastSystemErrorCode()).stream()
 444 #define LOG_GETLASTERROR(severity) \
 445   LAZY_STREAM(LOG_GETLASTERROR_STREAM(severity), LOG_IS_ON(severity))
 446 #define LOG_GETLASTERROR_MODULE_STREAM(severity, module) \
 447   COMPACT_GOOGLE_LOG_EX_ ## severity(Win32ErrorLogMessage, \
 448       ::logging::GetLastSystemErrorCode(), module).stream()
 449 #define LOG_GETLASTERROR_MODULE(severity, module)                       \
 450   LAZY_STREAM(LOG_GETLASTERROR_STREAM(severity, module),                \
 451               LOG_IS_ON(severity))
 452 // PLOG_STREAM is used by PLOG, which is the usual error logging macro
 453 // for each platform.
 454 #define PLOG_STREAM(severity) LOG_GETLASTERROR_STREAM(severity)
 455 #elif defined(OS_POSIX)
 456 #define LOG_ERRNO_STREAM(severity) \
 457   COMPACT_GOOGLE_LOG_EX_ ## severity(ErrnoLogMessage, \
 458       ::logging::GetLastSystemErrorCode()).stream()
 459 #define LOG_ERRNO(severity) \
 460   LAZY_STREAM(LOG_ERRNO_STREAM(severity), LOG_IS_ON(severity))
 461 // PLOG_STREAM is used by PLOG, which is the usual error logging macro
 462 // for each platform.
 463 #define PLOG_STREAM(severity) LOG_ERRNO_STREAM(severity)
 464 #endif
 465
 466 #define PLOG(severity)                                          \
 467   LAZY_STREAM(PLOG_STREAM(severity), LOG_IS_ON(severity))
 468
 469 #define PLOG_IF(severity, condition) \
 470   LAZY_STREAM(PLOG_STREAM(severity), LOG_IS_ON(severity) && (condition))
 471
 472 #if !defined(NDEBUG)
 473 // Debug builds always include DCHECK and DLOG.
 474 #undef LOGGING_IS_OFFICIAL_BUILD
 475 #define LOGGING_IS_OFFICIAL_BUILD 0
 476 #elif defined(OFFICIAL_BUILD)
 477 // Official release builds always disable and remove DCHECK and DLOG.
 478 #undef LOGGING_IS_OFFICIAL_BUILD
 479 #define LOGGING_IS_OFFICIAL_BUILD 1
 480 #elif !defined(LOGGING_IS_OFFICIAL_BUILD)
 481 // Unless otherwise specified, unofficial release builds include
 482 // DCHECK and DLOG.
 483 #define LOGGING_IS_OFFICIAL_BUILD 0
 484 #endif
 485
 486 // The actual stream used isn't important.
 487 #define EAT_STREAM_PARAMETERS                                           \
 488   true ? (void) 0 : ::logging::LogMessageVoidify() & LOG_STREAM(FATAL)
 489
 490 // CHECK dies with a fatal error if condition is not true.  It is *not*
 491 // controlled by NDEBUG, so the check will be executed regardless of
 492 // compilation mode.
 493 //
 494 // We make sure CHECK et al. always evaluates their arguments, as
 495 // doing CHECK(FunctionWithSideEffect()) is a common idiom.
 496
 497 #if LOGGING_IS_OFFICIAL_BUILD
 498
 499 // Make all CHECK functions discard their log strings to reduce code
 500 // bloat for official builds.
 501
 502 // TODO(akalin): This would be more valuable if there were some way to
 503 // remove BreakDebugger() from the backtrace, perhaps by turning it
 504 // into a macro (like __debugbreak() on Windows).
 505 #define CHECK(condition)                                                \
 506   !(condition) ? ::base::debug::BreakDebugger() : EAT_STREAM_PARAMETERS
 507
 508 #define PCHECK(condition) CHECK(condition)
 509
 510 #define CHECK_OP(name, op, val1, val2) CHECK((val1) op (val2))
 511
 512 #else
 513
 514 #define CHECK(condition)                       \
 515   LAZY_STREAM(LOG_STREAM(FATAL), !(condition)) \
 516   << "Check failed: " #condition ". "
 517
 518 #define PCHECK(condition) \
 519   LAZY_STREAM(PLOG_STREAM(FATAL), !(condition)) \
 520   << "Check failed: " #condition ". "
 521
 522 // Helper macro for binary operators.
 523 // Don't use this macro directly in your code, use CHECK_EQ et al below.
 524 //
 525 // TODO(akalin): Rewrite this so that constructs like if (...)
 526 // CHECK_EQ(...) else { ... } work properly.
 527 #define CHECK_OP(name, op, val1, val2)                          \
 528   if (std::string* _result =                                    \
 529       logging::Check##name##Impl((val1), (val2),                \
 530                                  #val1 " " #op " " #val2))      \
 531     logging::LogMessage(__FILE__, __LINE__, _result).stream()
 532
 533 #endif
 534
 535 // Build the error message string.  This is separate from the "Impl"
 536 // function template because it is not performance critical and so can
 537 // be out of line, while the "Impl" code should be inline.  Caller
 538 // takes ownership of the returned string.
 539 template<class t1, class t2>
 540 std::string* MakeCheckOpString(const t1& v1, const t2& v2, const char* names) {
 541   std::ostringstream ss;
 542   ss << names << " (" << v1 << " vs. " << v2 << ")";
 543   std::string* msg = new std::string(ss.str());
 544   return msg;
 545 }
 546
 547 // MSVC doesn't like complex extern templates and DLLs.
 548 #if !defined(COMPILER_MSVC)
 549 // Commonly used instantiations of MakeCheckOpString<>. Explicitly instantiated
 550 // in logging.cc.
 551 extern template BASE_EXPORT std::string* MakeCheckOpString<int, int>(
 552     const int&, const int&, const char* names);
 553 extern template BASE_EXPORT
 554 std::string* MakeCheckOpString<unsigned long, unsigned long>(
 555     const unsigned long&, const unsigned long&, const char* names);
 556 extern template BASE_EXPORT
 557 std::string* MakeCheckOpString<unsigned long, unsigned int>(
 558     const unsigned long&, const unsigned int&, const char* names);
 559 extern template BASE_EXPORT
 560 std::string* MakeCheckOpString<unsigned int, unsigned long>(
 561     const unsigned int&, const unsigned long&, const char* names);
 562 extern template BASE_EXPORT
 563 std::string* MakeCheckOpString<std::string, std::string>(
 564     const std::string&, const std::string&, const char* name);
 565 #endif
 566
 567 // Helper functions for CHECK_OP macro.
 568 // The (int, int) specialization works around the issue that the compiler
 569 // will not instantiate the template version of the function on values of
 570 // unnamed enum type - see comment below.
 571 #define DEFINE_CHECK_OP_IMPL(name, op) \
 572   template <class t1, class t2> \
 573   inline std::string* Check##name##Impl(const t1& v1, const t2& v2, \
 574                                         const char* names) { \
 575     if (v1 op v2) return NULL; \
 576     else return MakeCheckOpString(v1, v2, names); \
 577   } \
 578   inline std::string* Check##name##Impl(int v1, int v2, const char* names) { \
 579     if (v1 op v2) return NULL; \
 580     else return MakeCheckOpString(v1, v2, names); \
 581   }
 582 DEFINE_CHECK_OP_IMPL(EQ, ==)
 583 DEFINE_CHECK_OP_IMPL(NE, !=)
 584 DEFINE_CHECK_OP_IMPL(LE, <=)
 585 DEFINE_CHECK_OP_IMPL(LT, < )
 586 DEFINE_CHECK_OP_IMPL(GE, >=)
 587 DEFINE_CHECK_OP_IMPL(GT, > )
 588 #undef DEFINE_CHECK_OP_IMPL
 589
 590 #define CHECK_EQ(val1, val2) CHECK_OP(EQ, ==, val1, val2)
 591 #define CHECK_NE(val1, val2) CHECK_OP(NE, !=, val1, val2)
 592 #define CHECK_LE(val1, val2) CHECK_OP(LE, <=, val1, val2)
 593 #define CHECK_LT(val1, val2) CHECK_OP(LT, < , val1, val2)
 594 #define CHECK_GE(val1, val2) CHECK_OP(GE, >=, val1, val2)
 595 #define CHECK_GT(val1, val2) CHECK_OP(GT, > , val1, val2)
 596
 597 #if LOGGING_IS_OFFICIAL_BUILD
 598 // In order to have optimized code for official builds, remove DLOGs and
 599 // DCHECKs.
 600 #define ENABLE_DLOG 0
 601 #define ENABLE_DCHECK 0
 602
 603 #elif defined(NDEBUG)
 604 // Otherwise, if we're a release build, remove DLOGs but not DCHECKs
 605 // (since those can still be turned on via a command-line flag).
 606 #define ENABLE_DLOG 0
 607 #define ENABLE_DCHECK 1
 608
 609 #else
 610 // Otherwise, we're a debug build so enable DLOGs and DCHECKs.
 611 #define ENABLE_DLOG 1
 612 #define ENABLE_DCHECK 1
 613 #endif
 614
 615 // Definitions for DLOG et al.
 616
 617 #if ENABLE_DLOG
 618
 619 #define DLOG_IS_ON(severity) LOG_IS_ON(severity)
 620 #define DLOG_IF(severity, condition) LOG_IF(severity, condition)
 621 #define DLOG_ASSERT(condition) LOG_ASSERT(condition)
 622 #define DPLOG_IF(severity, condition) PLOG_IF(severity, condition)
 623 #define DVLOG_IF(verboselevel, condition) VLOG_IF(verboselevel, condition)
 624 #define DVPLOG_IF(verboselevel, condition) VPLOG_IF(verboselevel, condition)
 625
 626 #else  // ENABLE_DLOG
 627
 628 // If ENABLE_DLOG is off, we want to avoid emitting any references to
 629 // |condition| (which may reference a variable defined only if NDEBUG
 630 // is not defined).  Contrast this with DCHECK et al., which has
 631 // different behavior.
 632
 633 #define DLOG_IS_ON(severity) false
 634 #define DLOG_IF(severity, condition) EAT_STREAM_PARAMETERS
 635 #define DLOG_ASSERT(condition) EAT_STREAM_PARAMETERS
 636 #define DPLOG_IF(severity, condition) EAT_STREAM_PARAMETERS
 637 #define DVLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS
 638 #define DVPLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS
 639
 640 #endif  // ENABLE_DLOG
 641
 642 // DEBUG_MODE is for uses like
 643 //   if (DEBUG_MODE) foo.CheckThatFoo();
 644 // instead of
 645 //   #ifndef NDEBUG
 646 //     foo.CheckThatFoo();
 647 //   #endif
 648 //
 649 // We tie its state to ENABLE_DLOG.
 650 enum { DEBUG_MODE = ENABLE_DLOG };
 651
 652 #undef ENABLE_DLOG
 653
 654 #define DLOG(severity)                                          \
 655   LAZY_STREAM(LOG_STREAM(severity), DLOG_IS_ON(severity))
 656
 657 #if defined(OS_WIN)
 658 #define DLOG_GETLASTERROR(severity) \
 659   LAZY_STREAM(LOG_GETLASTERROR_STREAM(severity), DLOG_IS_ON(severity))
 660 #define DLOG_GETLASTERROR_MODULE(severity, module)                      \
 661   LAZY_STREAM(LOG_GETLASTERROR_STREAM(severity, module),                \
 662               DLOG_IS_ON(severity))
 663 #elif defined(OS_POSIX)
 664 #define DLOG_ERRNO(severity)                                    \
 665   LAZY_STREAM(LOG_ERRNO_STREAM(severity), DLOG_IS_ON(severity))
 666 #endif
 667
 668 #define DPLOG(severity)                                         \
 669   LAZY_STREAM(PLOG_STREAM(severity), DLOG_IS_ON(severity))
 670
 671 #define DVLOG(verboselevel) DVLOG_IF(verboselevel, VLOG_IS_ON(verboselevel))
 672
 673 #define DVPLOG(verboselevel) DVPLOG_IF(verboselevel, VLOG_IS_ON(verboselevel))
 674
 675 // Definitions for DCHECK et al.
 676
 677 #if ENABLE_DCHECK
 678
 679 #if defined(NDEBUG)
 680
 681 BASE_EXPORT DcheckState get_dcheck_state();
 682 BASE_EXPORT void set_dcheck_state(DcheckState state);
 683
 684 #if defined(DCHECK_ALWAYS_ON)
 685
 686 #define DCHECK_IS_ON() true
 687 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
 688   COMPACT_GOOGLE_LOG_EX_FATAL(ClassName , ##__VA_ARGS__)
 689 #define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_FATAL
 690 const LogSeverity LOG_DCHECK = LOG_FATAL;
 691
 692 #else
 693
 694 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
 695   COMPACT_GOOGLE_LOG_EX_ERROR_REPORT(ClassName , ##__VA_ARGS__)
 696 #define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_ERROR_REPORT
 697 const LogSeverity LOG_DCHECK = LOG_ERROR_REPORT;
 698 #define DCHECK_IS_ON()                                                  \
 699   ((::logging::get_dcheck_state() ==                                        \
 700     ::logging::ENABLE_DCHECK_FOR_NON_OFFICIAL_RELEASE_BUILDS) &&        \
 701    LOG_IS_ON(DCHECK))
 702
 703 #endif  // defined(DCHECK_ALWAYS_ON)
 704
 705 #else  // defined(NDEBUG)
 706
 707 // On a regular debug build, we want to have DCHECKs enabled.
 708 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
 709   COMPACT_GOOGLE_LOG_EX_FATAL(ClassName , ##__VA_ARGS__)
 710 #define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_FATAL
 711 const LogSeverity LOG_DCHECK = LOG_FATAL;
 712 #define DCHECK_IS_ON() true
 713
 714 #endif  // defined(NDEBUG)
 715
 716 #else  // ENABLE_DCHECK
 717
 718 // These are just dummy values since DCHECK_IS_ON() is always false in
 719 // this case.
 720 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
 721   COMPACT_GOOGLE_LOG_EX_INFO(ClassName , ##__VA_ARGS__)
 722 #define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_INFO
 723 const LogSeverity LOG_DCHECK = LOG_INFO;
 724 #define DCHECK_IS_ON() false
 725
 726 #endif  // ENABLE_DCHECK
 727 #undef ENABLE_DCHECK
 728
 729 // DCHECK et al. make sure to reference |condition| regardless of
 730 // whether DCHECKs are enabled; this is so that we don't get unused
 731 // variable warnings if the only use of a variable is in a DCHECK.
 732 // This behavior is different from DLOG_IF et al.
 733
 734 #define DCHECK(condition)                                           \
 735   LAZY_STREAM(LOG_STREAM(DCHECK), DCHECK_IS_ON() && !(condition))   \
 736   << "Check failed: " #condition ". "
 737
 738 #define DPCHECK(condition)                                          \
 739   LAZY_STREAM(PLOG_STREAM(DCHECK), DCHECK_IS_ON() && !(condition))  \
 740   << "Check failed: " #condition ". "
 741
 742 // Helper macro for binary operators.
 743 // Don't use this macro directly in your code, use DCHECK_EQ et al below.
 744 #define DCHECK_OP(name, op, val1, val2)                         \
 745   if (DCHECK_IS_ON())                                           \
 746     if (std::string* _result =                                  \
 747         logging::Check##name##Impl((val1), (val2),              \
 748                                    #val1 " " #op " " #val2))    \
 749       logging::LogMessage(                                      \
 750           __FILE__, __LINE__, ::logging::LOG_DCHECK,            \
 751           _result).stream()
 752
 753 // Equality/Inequality checks - compare two values, and log a
 754 // LOG_DCHECK message including the two values when the result is not
 755 // as expected.  The values must have operator<<(ostream, ...)
 756 // defined.
 757 //
 758 // You may append to the error message like so:
 759 //   DCHECK_NE(1, 2) << ": The world must be ending!";
 760 //
 761 // We are very careful to ensure that each argument is evaluated exactly
 762 // once, and that anything which is legal to pass as a function argument is
 763 // legal here.  In particular, the arguments may be temporary expressions
 764 // which will end up being destroyed at the end of the apparent statement,
 765 // for example:
 766 //   DCHECK_EQ(string("abc")[1], 'b');
 767 //
 768 // WARNING: These may not compile correctly if one of the arguments is a pointer
 769 // and the other is NULL. To work around this, simply static_cast NULL to the
 770 // type of the desired pointer.
 771
 772 #define DCHECK_EQ(val1, val2) DCHECK_OP(EQ, ==, val1, val2)
 773 #define DCHECK_NE(val1, val2) DCHECK_OP(NE, !=, val1, val2)
 774 #define DCHECK_LE(val1, val2) DCHECK_OP(LE, <=, val1, val2)
 775 #define DCHECK_LT(val1, val2) DCHECK_OP(LT, < , val1, val2)
 776 #define DCHECK_GE(val1, val2) DCHECK_OP(GE, >=, val1, val2)
 777 #define DCHECK_GT(val1, val2) DCHECK_OP(GT, > , val1, val2)
 778
 779 #if defined(NDEBUG) && defined(OS_CHROMEOS)
 780 #define NOTREACHED() LOG(ERROR) << "NOTREACHED() hit in " << \
 781     __FUNCTION__ << ". "
 782 #else
 783 #define NOTREACHED() DCHECK(false)
 784 #endif
 785
 786 // Redefine the standard assert to use our nice log files
 787 #undef assert
 788 #define assert(x) DLOG_ASSERT(x)
 789
 790 // This class more or less represents a particular log message.  You
 791 // create an instance of LogMessage and then stream stuff to it.
 792 // When you finish streaming to it, ~LogMessage is called and the
 793 // full message gets streamed to the appropriate destination.
 794 //
 795 // You shouldn't actually use LogMessage's constructor to log things,
 796 // though.  You should use the LOG() macro (and variants thereof)
 797 // above.
 798 class BASE_EXPORT LogMessage {
 799  public:
 800   LogMessage(const char* file, int line, LogSeverity severity, int ctr);
 801
 802   // Two special constructors that generate reduced amounts of code at
 803   // LOG call sites for common cases.
 804   //
 805   // Used for LOG(INFO): Implied are:
 806   // severity = LOG_INFO, ctr = 0
 807   //
 808   // Using this constructor instead of the more complex constructor above
 809   // saves a couple of bytes per call site.
 810   LogMessage(const char* file, int line);
 811
 812   // Used for LOG(severity) where severity != INFO.  Implied
 813   // are: ctr = 0
 814   //
 815   // Using this constructor instead of the more complex constructor above
 816   // saves a couple of bytes per call site.
 817   LogMessage(const char* file, int line, LogSeverity severity);
 818
 819   // A special constructor used for check failures.  Takes ownership
 820   // of the given string.
 821   // Implied severity = LOG_FATAL
 822   LogMessage(const char* file, int line, std::string* result);
 823
 824   // A special constructor used for check failures, with the option to
 825   // specify severity.  Takes ownership of the given string.
 826   LogMessage(const char* file, int line, LogSeverity severity,
 827              std::string* result);
 828
 829   ~LogMessage();
 830
 831   std::ostream& stream() { return stream_; }
 832
 833  private:
 834   void Init(const char* file, int line);
 835
 836   LogSeverity severity_;
 837   std::ostringstream stream_;
 838   size_t message_start_;  // Offset of the start of the message (past prefix
 839                           // info).
 840   // The file and line information passed in to the constructor.
 841   const char* file_;
 842   const int line_;
 843
 844 #if defined(OS_WIN)
 845   // Stores the current value of GetLastError in the constructor and restores
 846   // it in the destructor by calling SetLastError.
 847   // This is useful since the LogMessage class uses a lot of Win32 calls
 848   // that will lose the value of GLE and the code that called the log function
 849   // will have lost the thread error value when the log call returns.
 850   class SaveLastError {
 851    public:
 852     SaveLastError();
 853     ~SaveLastError();
 854
 855     unsigned long get_error() const { return last_error_; }
 856
 857    protected:
 858     unsigned long last_error_;
 859   };
 860
 861   SaveLastError last_error_;
 862 #endif
 863
 864   DISALLOW_COPY_AND_ASSIGN(LogMessage);
 865 };
 866
 867 // A non-macro interface to the log facility; (useful
 868 // when the logging level is not a compile-time constant).
 869 inline void LogAtLevel(int const log_level, std::string const &msg) {
 870   LogMessage(__FILE__, __LINE__, log_level).stream() << msg;
 871 }
 872
 873 // This class is used to explicitly ignore values in the conditional
 874 // logging macros.  This avoids compiler warnings like "value computed
 875 // is not used" and "statement has no effect".
 876 class LogMessageVoidify {
 877  public:
 878   LogMessageVoidify() { }
 879   // This has to be an operator with a precedence lower than << but
 880   // higher than ?:
 881   void operator&(std::ostream&) { }
 882 };
 883
 884 #if defined(OS_WIN)
 885 typedef unsigned long SystemErrorCode;
 886 #elif defined(OS_POSIX)
 887 typedef int SystemErrorCode;
 888 #endif
 889
 890 // Alias for ::GetLastError() on Windows and errno on POSIX. Avoids having to
 891 // pull in windows.h just for GetLastError() and DWORD.
 892 BASE_EXPORT SystemErrorCode GetLastSystemErrorCode();
 893
 894 #if defined(OS_WIN)
 895 // Appends a formatted system message of the GetLastError() type.
 896 class BASE_EXPORT Win32ErrorLogMessage {
 897  public:
 898   Win32ErrorLogMessage(const char* file,
 899                        int line,
 900                        LogSeverity severity,
 901                        SystemErrorCode err,
 902                        const char* module);
 903
 904   Win32ErrorLogMessage(const char* file,
 905                        int line,
 906                        LogSeverity severity,
 907                        SystemErrorCode err);
 908
 909   // Appends the error message before destructing the encapsulated class.
 910   ~Win32ErrorLogMessage();
 911
 912   std::ostream& stream() { return log_message_.stream(); }
 913
 914  private:
 915   SystemErrorCode err_;
 916   // Optional name of the module defining the error.
 917   const char* module_;
 918   LogMessage log_message_;
 919
 920   DISALLOW_COPY_AND_ASSIGN(Win32ErrorLogMessage);
 921 };
 922 #elif defined(OS_POSIX)
 923 // Appends a formatted system message of the errno type
 924 class BASE_EXPORT ErrnoLogMessage {
 925  public:
 926   ErrnoLogMessage(const char* file,
 927                   int line,
 928                   LogSeverity severity,
 929                   SystemErrorCode err);
 930
 931   // Appends the error message before destructing the encapsulated class.
 932   ~ErrnoLogMessage();
 933
 934   std::ostream& stream() { return log_message_.stream(); }
 935
 936  private:
 937   SystemErrorCode err_;
 938   LogMessage log_message_;
 939
 940   DISALLOW_COPY_AND_ASSIGN(ErrnoLogMessage);
 941 };
 942 #endif  // OS_WIN
 943
 944 // Closes the log file explicitly if open.
 945 // NOTE: Since the log file is opened as necessary by the action of logging
 946 //       statements, there's no guarantee that it will stay closed
 947 //       after this call.
 948 BASE_EXPORT void CloseLogFile();
 949
 950 // Async signal safe logging mechanism.
 951 BASE_EXPORT void RawLog(int level, const char* message);
 952
 953 #define RAW_LOG(level, message) logging::RawLog(logging::LOG_ ## level, message)
 954
 955 #define RAW_CHECK(condition)                                                   \
 956   do {                                                                         \
 957     if (!(condition))                                                          \
 958       logging::RawLog(logging::LOG_FATAL, "Check failed: " #condition "\n");   \
 959   } while (0)
 960
 961 #if defined(OS_WIN)
 962 // Returns the default log file path.
 963 BASE_EXPORT std::wstring GetLogFileFullPath();
 964 #endif
 965
 966 }  // namespace logging
 967
 968 // These functions are provided as a convenience for logging, which is where we
 969 // use streams (it is against Google style to use streams in other places). It
 970 // is designed to allow you to emit non-ASCII Unicode strings to the log file,
 971 // which is normally ASCII. It is relatively slow, so try not to use it for
 972 // common cases. Non-ASCII characters will be converted to UTF-8 by these
 973 // operators.
 974 BASE_EXPORT std::ostream& operator<<(std::ostream& out, const wchar_t* wstr);
 975 inline std::ostream& operator<<(std::ostream& out, const std::wstring& wstr) {
 976   return out << wstr.c_str();
 977 }
 978
 979 // The NOTIMPLEMENTED() macro annotates codepaths which have
 980 // not been implemented yet.
 981 //
 982 // The implementation of this macro is controlled by NOTIMPLEMENTED_POLICY:
 983 //   0 -- Do nothing (stripped by compiler)
 984 //   1 -- Warn at compile time
 985 //   2 -- Fail at compile time
 986 //   3 -- Fail at runtime (DCHECK)
 987 //   4 -- [default] LOG(ERROR) at runtime
 988 //   5 -- LOG(ERROR) at runtime, only once per call-site
 989
 990 #ifndef NOTIMPLEMENTED_POLICY
 991 #if defined(OS_ANDROID) && defined(OFFICIAL_BUILD)
 992 #define NOTIMPLEMENTED_POLICY 0
 993 #else
 994 // Select default policy: LOG(ERROR)
 995 #define NOTIMPLEMENTED_POLICY 4
 996 #endif
 997 #endif
 998
 999 #if defined(COMPILER_GCC)
1000 // On Linux, with GCC, we can use __PRETTY_FUNCTION__ to get the demangled name
1001 // of the current function in the NOTIMPLEMENTED message.
1002 #define NOTIMPLEMENTED_MSG "Not implemented reached in " << __PRETTY_FUNCTION__
1003 #else
1004 #define NOTIMPLEMENTED_MSG "NOT IMPLEMENTED"
1005 #endif
1006
1007 #if NOTIMPLEMENTED_POLICY == 0
1008 #define NOTIMPLEMENTED() EAT_STREAM_PARAMETERS
1009 #elif NOTIMPLEMENTED_POLICY == 1
1010 // TODO, figure out how to generate a warning
1011 #define NOTIMPLEMENTED() COMPILE_ASSERT(false, NOT_IMPLEMENTED)
1012 #elif NOTIMPLEMENTED_POLICY == 2
1013 #define NOTIMPLEMENTED() COMPILE_ASSERT(false, NOT_IMPLEMENTED)
1014 #elif NOTIMPLEMENTED_POLICY == 3
1015 #define NOTIMPLEMENTED() NOTREACHED()
1016 #elif NOTIMPLEMENTED_POLICY == 4
1017 #define NOTIMPLEMENTED() LOG(ERROR) << NOTIMPLEMENTED_MSG
1018 #elif NOTIMPLEMENTED_POLICY == 5
1019 #define NOTIMPLEMENTED() do {\
1020   static bool logged_once = false;\
1021   LOG_IF(ERROR, !logged_once) << NOTIMPLEMENTED_MSG;\
1022   logged_once = true;\
1023 } while(0);\
1024 EAT_STREAM_PARAMETERS
1025 #endif
1026
1027 #endif  // BASE_LOGGING_H_