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