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 <stddef.h> 9 10 #include <cassert> 11 #include <cstring> 12 #include <sstream> 13 #include <string> 14 #include <type_traits> 15 #include <utility> 16 17 #include "base/base_export.h" 18 #include "base/debug/debugger.h" 19 #include "base/macros.h" 20 #include "base/template_util.h" 21 #include "build/build_config.h" 22 23 // 24 // Optional message capabilities 25 // ----------------------------- 26 // Assertion failed messages and fatal errors are displayed in a dialog box 27 // before the application exits. However, running this UI creates a message 28 // loop, which causes application messages to be processed and potentially 29 // dispatched to existing application windows. Since the application is in a 30 // bad state when this assertion dialog is displayed, these messages may not 31 // get processed and hang the dialog, or the application might go crazy. 32 // 33 // Therefore, it can be beneficial to display the error dialog in a separate 34 // process from the main application. When the logging system needs to display 35 // a fatal error dialog box, it will look for a program called 36 // "DebugMessage.exe" in the same directory as the application executable. It 37 // will run this application with the message as the command line, and will 38 // not include the name of the application as is traditional for easier 39 // parsing. 40 // 41 // The code for DebugMessage.exe is only one line. In WinMain, do: 42 // MessageBox(NULL, GetCommandLineW(), L"Fatal Error", 0); 43 // 44 // If DebugMessage.exe is not found, the logging code will use a normal 45 // MessageBox, potentially causing the problems discussed above. 46 47 48 // Instructions 49 // ------------ 50 // 51 // Make a bunch of macros for logging. The way to log things is to stream 52 // things to LOG(<a particular severity level>). E.g., 53 // 54 // LOG(INFO) << "Found " << num_cookies << " cookies"; 55 // 56 // You can also do conditional logging: 57 // 58 // LOG_IF(INFO, num_cookies > 10) << "Got lots of cookies"; 59 // 60 // The CHECK(condition) macro is active in both debug and release builds and 61 // effectively performs a LOG(FATAL) which terminates the process and 62 // generates a crashdump unless a debugger is attached. 63 // 64 // There are also "debug mode" logging macros like the ones above: 65 // 66 // DLOG(INFO) << "Found cookies"; 67 // 68 // DLOG_IF(INFO, num_cookies > 10) << "Got lots of cookies"; 69 // 70 // All "debug mode" logging is compiled away to nothing for non-debug mode 71 // compiles. LOG_IF and development flags also work well together 72 // because the code can be compiled away sometimes. 73 // 74 // We also have 75 // 76 // LOG_ASSERT(assertion); 77 // DLOG_ASSERT(assertion); 78 // 79 // which is syntactic sugar for {,D}LOG_IF(FATAL, assert fails) << assertion; 80 // 81 // There are "verbose level" logging macros. They look like 82 // 83 // VLOG(1) << "I'm printed when you run the program with --v=1 or more"; 84 // VLOG(2) << "I'm printed when you run the program with --v=2 or more"; 85 // 86 // These always log at the INFO log level (when they log at all). 87 // The verbose logging can also be turned on module-by-module. For instance, 88 // --vmodule=profile=2,icon_loader=1,browser_*=3,*/chromeos/*=4 --v=0 89 // will cause: 90 // a. VLOG(2) and lower messages to be printed from profile.{h,cc} 91 // b. VLOG(1) and lower messages to be printed from icon_loader.{h,cc} 92 // c. VLOG(3) and lower messages to be printed from files prefixed with 93 // "browser" 94 // d. VLOG(4) and lower messages to be printed from files under a 95 // "chromeos" directory. 96 // e. VLOG(0) and lower messages to be printed from elsewhere 97 // 98 // The wildcarding functionality shown by (c) supports both '*' (match 99 // 0 or more characters) and '?' (match any single character) 100 // wildcards. Any pattern containing a forward or backward slash will 101 // be tested against the whole pathname and not just the module. 102 // E.g., "*/foo/bar/*=2" would change the logging level for all code 103 // in source files under a "foo/bar" directory. 104 // 105 // There's also VLOG_IS_ON(n) "verbose level" condition macro. To be used as 106 // 107 // if (VLOG_IS_ON(2)) { 108 // // do some logging preparation and logging 109 // // that can't be accomplished with just VLOG(2) << ...; 110 // } 111 // 112 // There is also a VLOG_IF "verbose level" condition macro for sample 113 // cases, when some extra computation and preparation for logs is not 114 // needed. 115 // 116 // VLOG_IF(1, (size > 1024)) 117 // << "I'm printed when size is more than 1024 and when you run the " 118 // "program with --v=1 or more"; 119 // 120 // We also override the standard 'assert' to use 'DLOG_ASSERT'. 121 // 122 // Lastly, there is: 123 // 124 // PLOG(ERROR) << "Couldn't do foo"; 125 // DPLOG(ERROR) << "Couldn't do foo"; 126 // PLOG_IF(ERROR, cond) << "Couldn't do foo"; 127 // DPLOG_IF(ERROR, cond) << "Couldn't do foo"; 128 // PCHECK(condition) << "Couldn't do foo"; 129 // DPCHECK(condition) << "Couldn't do foo"; 130 // 131 // which append the last system error to the message in string form (taken from 132 // GetLastError() on Windows and errno on POSIX). 133 // 134 // The supported severity levels for macros that allow you to specify one 135 // are (in increasing order of severity) INFO, WARNING, ERROR, 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 // There is the special severity of DFATAL, which logs FATAL in debug mode, 141 // ERROR in normal mode. 142 143 // Note that "The behavior of a C++ program is undefined if it adds declarations 144 // or definitions to namespace std or to a namespace within namespace std unless 145 // otherwise specified." --C++11[namespace.std] 146 // 147 // We've checked that this particular definition has the intended behavior on 148 // our implementations, but it's prone to breaking in the future, and please 149 // don't imitate this in your own definitions without checking with some 150 // standard library experts. 151 namespace std { 152 // These functions are provided as a convenience for logging, which is where we 153 // use streams (it is against Google style to use streams in other places). It 154 // is designed to allow you to emit non-ASCII Unicode strings to the log file, 155 // which is normally ASCII. It is relatively slow, so try not to use it for 156 // common cases. Non-ASCII characters will be converted to UTF-8 by these 157 // operators. 158 BASE_EXPORT std::ostream& operator<<(std::ostream& out, const wchar_t* wstr); 159 inline std::ostream& operator<<(std::ostream& out, const std::wstring& wstr) { 160 return out << wstr.c_str(); 161 } 162 163 template<typename T> 164 typename std::enable_if<std::is_enum<T>::value, std::ostream&>::type operator<<( 165 std::ostream& out, T value) { 166 return out << static_cast<typename std::underlying_type<T>::type>(value); 167 } 168 169 } // namespace std 170 171 namespace logging { 172 173 // TODO(avi): do we want to do a unification of character types here? 174 #if defined(OS_WIN) 175 typedef wchar_t PathChar; 176 #else 177 typedef char PathChar; 178 #endif 179 180 // Where to record logging output? A flat file and/or system debug log 181 // via OutputDebugString. 182 enum LoggingDestination { 183 LOG_NONE = 0, 184 LOG_TO_FILE = 1 << 0, 185 LOG_TO_SYSTEM_DEBUG_LOG = 1 << 1, 186 187 LOG_TO_ALL = LOG_TO_FILE | LOG_TO_SYSTEM_DEBUG_LOG, 188 189 // On Windows, use a file next to the exe; on POSIX platforms, where 190 // it may not even be possible to locate the executable on disk, use 191 // stderr. 192 #if defined(OS_WIN) 193 LOG_DEFAULT = LOG_TO_FILE, 194 #elif defined(OS_POSIX) 195 LOG_DEFAULT = LOG_TO_SYSTEM_DEBUG_LOG, 196 #endif 197 }; 198 199 // Indicates that the log file should be locked when being written to. 200 // Unless there is only one single-threaded process that is logging to 201 // the log file, the file should be locked during writes to make each 202 // log output atomic. Other writers will block. 203 // 204 // All processes writing to the log file must have their locking set for it to 205 // work properly. Defaults to LOCK_LOG_FILE. 206 enum LogLockingState { LOCK_LOG_FILE, DONT_LOCK_LOG_FILE }; 207 208 // On startup, should we delete or append to an existing log file (if any)? 209 // Defaults to APPEND_TO_OLD_LOG_FILE. 210 enum OldFileDeletionState { DELETE_OLD_LOG_FILE, APPEND_TO_OLD_LOG_FILE }; 211 212 struct BASE_EXPORT LoggingSettings { 213 // The defaults values are: 214 // 215 // logging_dest: LOG_DEFAULT 216 // log_file: NULL 217 // lock_log: LOCK_LOG_FILE 218 // delete_old: APPEND_TO_OLD_LOG_FILE 219 LoggingSettings(); 220 221 LoggingDestination logging_dest; 222 223 // The three settings below have an effect only when LOG_TO_FILE is 224 // set in |logging_dest|. 225 const PathChar* log_file; 226 LogLockingState lock_log; 227 OldFileDeletionState delete_old; 228 }; 229 230 // Define different names for the BaseInitLoggingImpl() function depending on 231 // whether NDEBUG is defined or not so that we'll fail to link if someone tries 232 // to compile logging.cc with NDEBUG but includes logging.h without defining it, 233 // or vice versa. 234 #if NDEBUG 235 #define BaseInitLoggingImpl BaseInitLoggingImpl_built_with_NDEBUG 236 #else 237 #define BaseInitLoggingImpl BaseInitLoggingImpl_built_without_NDEBUG 238 #endif 239 240 // Implementation of the InitLogging() method declared below. We use a 241 // more-specific name so we can #define it above without affecting other code 242 // that has named stuff "InitLogging". 243 BASE_EXPORT bool BaseInitLoggingImpl(const LoggingSettings& settings); 244 245 // Sets the log file name and other global logging state. Calling this function 246 // is recommended, and is normally done at the beginning of application init. 247 // If you don't call it, all the flags will be initialized to their default 248 // values, and there is a race condition that may leak a critical section 249 // object if two threads try to do the first log at the same time. 250 // See the definition of the enums above for descriptions and default values. 251 // 252 // The default log file is initialized to "debug.log" in the application 253 // directory. You probably don't want this, especially since the program 254 // directory may not be writable on an enduser's system. 255 // 256 // This function may be called a second time to re-direct logging (e.g after 257 // loging in to a user partition), however it should never be called more than 258 // twice. 259 inline bool InitLogging(const LoggingSettings& settings) { 260 return BaseInitLoggingImpl(settings); 261 } 262 263 // Sets the log level. Anything at or above this level will be written to the 264 // log file/displayed to the user (if applicable). Anything below this level 265 // will be silently ignored. The log level defaults to 0 (everything is logged 266 // up to level INFO) if this function is not called. 267 // Note that log messages for VLOG(x) are logged at level -x, so setting 268 // the min log level to negative values enables verbose logging. 269 BASE_EXPORT void SetMinLogLevel(int level); 270 271 // Gets the current log level. 272 BASE_EXPORT int GetMinLogLevel(); 273 274 // Used by LOG_IS_ON to lazy-evaluate stream arguments. 275 BASE_EXPORT bool ShouldCreateLogMessage(int severity); 276 277 // Gets the VLOG default verbosity level. 278 BASE_EXPORT int GetVlogVerbosity(); 279 280 // Gets the current vlog level for the given file (usually taken from 281 // __FILE__). 282 283 // Note that |N| is the size *with* the null terminator. 284 BASE_EXPORT int GetVlogLevelHelper(const char* file_start, size_t N); 285 286 template <size_t N> 287 int GetVlogLevel(const char (&file)[N]) { 288 return GetVlogLevelHelper(file, N); 289 } 290 291 // Sets the common items you want to be prepended to each log message. 292 // process and thread IDs default to off, the timestamp defaults to on. 293 // If this function is not called, logging defaults to writing the timestamp 294 // only. 295 BASE_EXPORT void SetLogItems(bool enable_process_id, bool enable_thread_id, 296 bool enable_timestamp, bool enable_tickcount); 297 298 // Sets whether or not you'd like to see fatal debug messages popped up in 299 // a dialog box or not. 300 // Dialogs are not shown by default. 301 BASE_EXPORT void SetShowErrorDialogs(bool enable_dialogs); 302 303 // Sets the Log Assert Handler that will be used to notify of check failures. 304 // The default handler shows a dialog box and then terminate the process, 305 // however clients can use this function to override with their own handling 306 // (e.g. a silent one for Unit Tests) 307 typedef void (*LogAssertHandlerFunction)(const std::string& str); 308 BASE_EXPORT void SetLogAssertHandler(LogAssertHandlerFunction handler); 309 310 // Sets the Log Message Handler that gets passed every log message before 311 // it's sent to other log destinations (if any). 312 // Returns true to signal that it handled the message and the message 313 // should not be sent to other log destinations. 314 typedef bool (*LogMessageHandlerFunction)(int severity, 315 const char* file, int line, size_t message_start, const std::string& str); 316 BASE_EXPORT void SetLogMessageHandler(LogMessageHandlerFunction handler); 317 BASE_EXPORT LogMessageHandlerFunction GetLogMessageHandler(); 318 319 typedef int LogSeverity; 320 const LogSeverity LOG_VERBOSE = -1; // This is level 1 verbosity 321 // Note: the log severities are used to index into the array of names, 322 // see log_severity_names. 323 const LogSeverity LOG_INFO = 0; 324 const LogSeverity LOG_WARNING = 1; 325 const LogSeverity LOG_ERROR = 2; 326 const LogSeverity LOG_FATAL = 3; 327 const LogSeverity LOG_NUM_SEVERITIES = 4; 328 329 // LOG_DFATAL is LOG_FATAL in debug mode, ERROR in normal mode 330 #ifdef NDEBUG 331 const LogSeverity LOG_DFATAL = LOG_ERROR; 332 #else 333 const LogSeverity LOG_DFATAL = LOG_FATAL; 334 #endif 335 336 // A few definitions of macros that don't generate much code. These are used 337 // by LOG() and LOG_IF, etc. Since these are used all over our code, it's 338 // better to have compact code for these operations. 339 #define COMPACT_GOOGLE_LOG_EX_INFO(ClassName, ...) \ 340 logging::ClassName(__FILE__, __LINE__, logging::LOG_INFO , ##__VA_ARGS__) 341 #define COMPACT_GOOGLE_LOG_EX_WARNING(ClassName, ...) \ 342 logging::ClassName(__FILE__, __LINE__, logging::LOG_WARNING , ##__VA_ARGS__) 343 #define COMPACT_GOOGLE_LOG_EX_ERROR(ClassName, ...) \ 344 logging::ClassName(__FILE__, __LINE__, logging::LOG_ERROR , ##__VA_ARGS__) 345 #define COMPACT_GOOGLE_LOG_EX_FATAL(ClassName, ...) \ 346 logging::ClassName(__FILE__, __LINE__, logging::LOG_FATAL , ##__VA_ARGS__) 347 #define COMPACT_GOOGLE_LOG_EX_DFATAL(ClassName, ...) \ 348 logging::ClassName(__FILE__, __LINE__, logging::LOG_DFATAL , ##__VA_ARGS__) 349 350 #define COMPACT_GOOGLE_LOG_INFO \ 351 COMPACT_GOOGLE_LOG_EX_INFO(LogMessage) 352 #define COMPACT_GOOGLE_LOG_WARNING \ 353 COMPACT_GOOGLE_LOG_EX_WARNING(LogMessage) 354 #define COMPACT_GOOGLE_LOG_ERROR \ 355 COMPACT_GOOGLE_LOG_EX_ERROR(LogMessage) 356 #define COMPACT_GOOGLE_LOG_FATAL \ 357 COMPACT_GOOGLE_LOG_EX_FATAL(LogMessage) 358 #define COMPACT_GOOGLE_LOG_DFATAL \ 359 COMPACT_GOOGLE_LOG_EX_DFATAL(LogMessage) 360 361 #if defined(OS_WIN) 362 // wingdi.h defines ERROR to be 0. When we call LOG(ERROR), it gets 363 // substituted with 0, and it expands to COMPACT_GOOGLE_LOG_0. To allow us 364 // to keep using this syntax, we define this macro to do the same thing 365 // as COMPACT_GOOGLE_LOG_ERROR, and also define ERROR the same way that 366 // the Windows SDK does for consistency. 367 #define ERROR 0 368 #define COMPACT_GOOGLE_LOG_EX_0(ClassName, ...) \ 369 COMPACT_GOOGLE_LOG_EX_ERROR(ClassName , ##__VA_ARGS__) 370 #define COMPACT_GOOGLE_LOG_0 COMPACT_GOOGLE_LOG_ERROR 371 // Needed for LOG_IS_ON(ERROR). 372 const LogSeverity LOG_0 = LOG_ERROR; 373 #endif 374 375 // As special cases, we can assume that LOG_IS_ON(FATAL) always holds. Also, 376 // LOG_IS_ON(DFATAL) always holds in debug mode. In particular, CHECK()s will 377 // always fire if they fail. 378 #define LOG_IS_ON(severity) \ 379 (::logging::ShouldCreateLogMessage(::logging::LOG_##severity)) 380 381 // We can't do any caching tricks with VLOG_IS_ON() like the 382 // google-glog version since it requires GCC extensions. This means 383 // that using the v-logging functions in conjunction with --vmodule 384 // may be slow. 385 #define VLOG_IS_ON(verboselevel) \ 386 ((verboselevel) <= ::logging::GetVlogLevel(__FILE__)) 387 388 // Helper macro which avoids evaluating the arguments to a stream if 389 // the condition doesn't hold. Condition is evaluated once and only once. 390 #define LAZY_STREAM(stream, condition) \ 391 !(condition) ? (void) 0 : ::logging::LogMessageVoidify() & (stream) 392 393 // We use the preprocessor's merging operator, "##", so that, e.g., 394 // LOG(INFO) becomes the token COMPACT_GOOGLE_LOG_INFO. There's some funny 395 // subtle difference between ostream member streaming functions (e.g., 396 // ostream::operator<<(int) and ostream non-member streaming functions 397 // (e.g., ::operator<<(ostream&, string&): it turns out that it's 398 // impossible to stream something like a string directly to an unnamed 399 // ostream. We employ a neat hack by calling the stream() member 400 // function of LogMessage which seems to avoid the problem. 401 #define LOG_STREAM(severity) COMPACT_GOOGLE_LOG_ ## severity.stream() 402 403 #define LOG(severity) LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity)) 404 #define LOG_IF(severity, condition) \ 405 LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity) && (condition)) 406 407 // The VLOG macros log with negative verbosities. 408 #define VLOG_STREAM(verbose_level) \ 409 logging::LogMessage(__FILE__, __LINE__, -verbose_level).stream() 410 411 #define VLOG(verbose_level) \ 412 LAZY_STREAM(VLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level)) 413 414 #define VLOG_IF(verbose_level, condition) \ 415 LAZY_STREAM(VLOG_STREAM(verbose_level), \ 416 VLOG_IS_ON(verbose_level) && (condition)) 417 418 #if defined (OS_WIN) 419 #define VPLOG_STREAM(verbose_level) \ 420 logging::Win32ErrorLogMessage(__FILE__, __LINE__, -verbose_level, \ 421 ::logging::GetLastSystemErrorCode()).stream() 422 #elif defined(OS_POSIX) 423 #define VPLOG_STREAM(verbose_level) \ 424 logging::ErrnoLogMessage(__FILE__, __LINE__, -verbose_level, \ 425 ::logging::GetLastSystemErrorCode()).stream() 426 #endif 427 428 #define VPLOG(verbose_level) \ 429 LAZY_STREAM(VPLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level)) 430 431 #define VPLOG_IF(verbose_level, condition) \ 432 LAZY_STREAM(VPLOG_STREAM(verbose_level), \ 433 VLOG_IS_ON(verbose_level) && (condition)) 434 435 // TODO(akalin): Add more VLOG variants, e.g. VPLOG. 436 437 #define LOG_ASSERT(condition) \ 438 LOG_IF(FATAL, !(condition)) << "Assert failed: " #condition ". " 439 440 #if defined(OS_WIN) 441 #define PLOG_STREAM(severity) \ 442 COMPACT_GOOGLE_LOG_EX_ ## severity(Win32ErrorLogMessage, \ 443 ::logging::GetLastSystemErrorCode()).stream() 444 #elif defined(OS_POSIX) 445 #define PLOG_STREAM(severity) \ 446 COMPACT_GOOGLE_LOG_EX_ ## severity(ErrnoLogMessage, \ 447 ::logging::GetLastSystemErrorCode()).stream() 448 #endif 449 450 #define PLOG(severity) \ 451 LAZY_STREAM(PLOG_STREAM(severity), LOG_IS_ON(severity)) 452 453 #define PLOG_IF(severity, condition) \ 454 LAZY_STREAM(PLOG_STREAM(severity), LOG_IS_ON(severity) && (condition)) 455 456 // The actual stream used isn't important. 457 #define EAT_STREAM_PARAMETERS \ 458 true ? (void) 0 : ::logging::LogMessageVoidify() & LOG_STREAM(FATAL) 459 460 // Captures the result of a CHECK_EQ (for example) and facilitates testing as a 461 // boolean. 462 class CheckOpResult { 463 public: 464 // |message| must be non-null if and only if the check failed. 465 CheckOpResult(std::string* message) : message_(message) {} 466 // Returns true if the check succeeded. 467 operator bool() const { return !message_; } 468 // Returns the message. 469 std::string* message() { return message_; } 470 471 private: 472 std::string* message_; 473 }; 474 475 // CHECK dies with a fatal error if condition is not true. It is *not* 476 // controlled by NDEBUG, so the check will be executed regardless of 477 // compilation mode. 478 // 479 // We make sure CHECK et al. always evaluates their arguments, as 480 // doing CHECK(FunctionWithSideEffect()) is a common idiom. 481 482 #if defined(OFFICIAL_BUILD) && defined(NDEBUG) 483 484 // Make all CHECK functions discard their log strings to reduce code 485 // bloat, and improve performance, for official release builds. 486 487 #if defined(COMPILER_GCC) || __clang__ 488 #define LOGGING_CRASH() __builtin_trap() 489 #else 490 #define LOGGING_CRASH() ((void)(*(volatile char*)0 = 0)) 491 #endif 492 493 // This is not calling BreakDebugger since this is called frequently, and 494 // calling an out-of-line function instead of a noreturn inline macro prevents 495 // compiler optimizations. 496 #define CHECK(condition) \ 497 !(condition) ? LOGGING_CRASH() : EAT_STREAM_PARAMETERS 498 499 #define PCHECK(condition) CHECK(condition) 500 501 #define CHECK_OP(name, op, val1, val2) CHECK((val1) op (val2)) 502 503 #else // !(OFFICIAL_BUILD && NDEBUG) 504 505 #if defined(_PREFAST_) && defined(OS_WIN) 506 // Use __analysis_assume to tell the VC++ static analysis engine that 507 // assert conditions are true, to suppress warnings. The LAZY_STREAM 508 // parameter doesn't reference 'condition' in /analyze builds because 509 // this evaluation confuses /analyze. The !! before condition is because 510 // __analysis_assume gets confused on some conditions: 511 // http://randomascii.wordpress.com/2011/09/13/analyze-for-visual-studio-the-ugly-part-5/ 512 513 #define CHECK(condition) \ 514 __analysis_assume(!!(condition)), \ 515 LAZY_STREAM(LOG_STREAM(FATAL), false) \ 516 << "Check failed: " #condition ". " 517 518 #define PCHECK(condition) \ 519 __analysis_assume(!!(condition)), \ 520 LAZY_STREAM(PLOG_STREAM(FATAL), false) \ 521 << "Check failed: " #condition ". " 522 523 #else // _PREFAST_ 524 525 // Do as much work as possible out of line to reduce inline code size. 526 #define CHECK(condition) \ 527 LAZY_STREAM(logging::LogMessage(__FILE__, __LINE__, #condition).stream(), \ 528 !(condition)) 529 530 #define PCHECK(condition) \ 531 LAZY_STREAM(PLOG_STREAM(FATAL), !(condition)) \ 532 << "Check failed: " #condition ". " 533 534 #endif // _PREFAST_ 535 536 // Helper macro for binary operators. 537 // Don't use this macro directly in your code, use CHECK_EQ et al below. 538 // The 'switch' is used to prevent the 'else' from being ambiguous when the 539 // macro is used in an 'if' clause such as: 540 // if (a == 1) 541 // CHECK_EQ(2, a); 542 #define CHECK_OP(name, op, val1, val2) \ 543 switch (0) case 0: default: \ 544 if (logging::CheckOpResult true_if_passed = \ 545 logging::Check##name##Impl((val1), (val2), \ 546 #val1 " " #op " " #val2)) \ 547 ; \ 548 else \ 549 logging::LogMessage(__FILE__, __LINE__, true_if_passed.message()).stream() 550 551 #endif // !(OFFICIAL_BUILD && NDEBUG) 552 553 // This formats a value for a failing CHECK_XX statement. Ordinarily, 554 // it uses the definition for operator<<, with a few special cases below. 555 template <typename T> 556 inline typename std::enable_if< 557 base::internal::SupportsOstreamOperator<const T&>::value, 558 void>::type 559 MakeCheckOpValueString(std::ostream* os, const T& v) { 560 (*os) << v; 561 } 562 563 // We need overloads for enums that don't support operator<<. 564 // (i.e. scoped enums where no operator<< overload was declared). 565 template <typename T> 566 inline typename std::enable_if< 567 !base::internal::SupportsOstreamOperator<const T&>::value && 568 std::is_enum<T>::value, 569 void>::type 570 MakeCheckOpValueString(std::ostream* os, const T& v) { 571 (*os) << static_cast<typename base::underlying_type<T>::type>(v); 572 } 573 574 // We need an explicit overload for std::nullptr_t. 575 BASE_EXPORT void MakeCheckOpValueString(std::ostream* os, std::nullptr_t p); 576 577 // Build the error message string. This is separate from the "Impl" 578 // function template because it is not performance critical and so can 579 // be out of line, while the "Impl" code should be inline. Caller 580 // takes ownership of the returned string. 581 template<class t1, class t2> 582 std::string* MakeCheckOpString(const t1& v1, const t2& v2, const char* names) { 583 std::ostringstream ss; 584 ss << names << " ("; 585 MakeCheckOpValueString(&ss, v1); 586 ss << " vs. "; 587 MakeCheckOpValueString(&ss, v2); 588 ss << ")"; 589 std::string* msg = new std::string(ss.str()); 590 return msg; 591 } 592 593 // Commonly used instantiations of MakeCheckOpString<>. Explicitly instantiated 594 // in logging.cc. 595 extern template BASE_EXPORT std::string* MakeCheckOpString<int, int>( 596 const int&, const int&, const char* names); 597 extern template BASE_EXPORT 598 std::string* MakeCheckOpString<unsigned long, unsigned long>( 599 const unsigned long&, const unsigned long&, const char* names); 600 extern template BASE_EXPORT 601 std::string* MakeCheckOpString<unsigned long, unsigned int>( 602 const unsigned long&, const unsigned int&, const char* names); 603 extern template BASE_EXPORT 604 std::string* MakeCheckOpString<unsigned int, unsigned long>( 605 const unsigned int&, const unsigned long&, const char* names); 606 extern template BASE_EXPORT 607 std::string* MakeCheckOpString<std::string, std::string>( 608 const std::string&, const std::string&, const char* name); 609 610 // Helper functions for CHECK_OP macro. 611 // The (int, int) specialization works around the issue that the compiler 612 // will not instantiate the template version of the function on values of 613 // unnamed enum type - see comment below. 614 #define DEFINE_CHECK_OP_IMPL(name, op) \ 615 template <class t1, class t2> \ 616 inline std::string* Check##name##Impl(const t1& v1, const t2& v2, \ 617 const char* names) { \ 618 if (v1 op v2) return NULL; \ 619 else return MakeCheckOpString(v1, v2, names); \ 620 } \ 621 inline std::string* Check##name##Impl(int v1, int v2, const char* names) { \ 622 if (v1 op v2) return NULL; \ 623 else return MakeCheckOpString(v1, v2, names); \ 624 } 625 DEFINE_CHECK_OP_IMPL(EQ, ==) 626 DEFINE_CHECK_OP_IMPL(NE, !=) 627 DEFINE_CHECK_OP_IMPL(LE, <=) 628 DEFINE_CHECK_OP_IMPL(LT, < ) 629 DEFINE_CHECK_OP_IMPL(GE, >=) 630 DEFINE_CHECK_OP_IMPL(GT, > ) 631 #undef DEFINE_CHECK_OP_IMPL 632 633 #define CHECK_EQ(val1, val2) CHECK_OP(EQ, ==, val1, val2) 634 #define CHECK_NE(val1, val2) CHECK_OP(NE, !=, val1, val2) 635 #define CHECK_LE(val1, val2) CHECK_OP(LE, <=, val1, val2) 636 #define CHECK_LT(val1, val2) CHECK_OP(LT, < , val1, val2) 637 #define CHECK_GE(val1, val2) CHECK_OP(GE, >=, val1, val2) 638 #define CHECK_GT(val1, val2) CHECK_OP(GT, > , val1, val2) 639 640 #if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON) 641 #define ENABLE_DLOG 0 642 #else 643 #define ENABLE_DLOG 1 644 #endif 645 646 #if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON) 647 #define DCHECK_IS_ON() 0 648 #else 649 #define DCHECK_IS_ON() 1 650 #endif 651 652 // Definitions for DLOG et al. 653 654 #if ENABLE_DLOG 655 656 #define DLOG_IS_ON(severity) LOG_IS_ON(severity) 657 #define DLOG_IF(severity, condition) LOG_IF(severity, condition) 658 #define DLOG_ASSERT(condition) LOG_ASSERT(condition) 659 #define DPLOG_IF(severity, condition) PLOG_IF(severity, condition) 660 #define DVLOG_IF(verboselevel, condition) VLOG_IF(verboselevel, condition) 661 #define DVPLOG_IF(verboselevel, condition) VPLOG_IF(verboselevel, condition) 662 663 #else // ENABLE_DLOG 664 665 // If ENABLE_DLOG is off, we want to avoid emitting any references to 666 // |condition| (which may reference a variable defined only if NDEBUG 667 // is not defined). Contrast this with DCHECK et al., which has 668 // different behavior. 669 670 #define DLOG_IS_ON(severity) false 671 #define DLOG_IF(severity, condition) EAT_STREAM_PARAMETERS 672 #define DLOG_ASSERT(condition) EAT_STREAM_PARAMETERS 673 #define DPLOG_IF(severity, condition) EAT_STREAM_PARAMETERS 674 #define DVLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS 675 #define DVPLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS 676 677 #endif // ENABLE_DLOG 678 679 // DEBUG_MODE is for uses like 680 // if (DEBUG_MODE) foo.CheckThatFoo(); 681 // instead of 682 // #ifndef NDEBUG 683 // foo.CheckThatFoo(); 684 // #endif 685 // 686 // We tie its state to ENABLE_DLOG. 687 enum { DEBUG_MODE = ENABLE_DLOG }; 688 689 #undef ENABLE_DLOG 690 691 #define DLOG(severity) \ 692 LAZY_STREAM(LOG_STREAM(severity), DLOG_IS_ON(severity)) 693 694 #define DPLOG(severity) \ 695 LAZY_STREAM(PLOG_STREAM(severity), DLOG_IS_ON(severity)) 696 697 #define DVLOG(verboselevel) DVLOG_IF(verboselevel, VLOG_IS_ON(verboselevel)) 698 699 #define DVPLOG(verboselevel) DVPLOG_IF(verboselevel, VLOG_IS_ON(verboselevel)) 700 701 // Definitions for DCHECK et al. 702 703 #if DCHECK_IS_ON() 704 705 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \ 706 COMPACT_GOOGLE_LOG_EX_FATAL(ClassName , ##__VA_ARGS__) 707 #define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_FATAL 708 const LogSeverity LOG_DCHECK = LOG_FATAL; 709 710 #else // DCHECK_IS_ON() 711 712 // These are just dummy values. 713 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \ 714 COMPACT_GOOGLE_LOG_EX_INFO(ClassName , ##__VA_ARGS__) 715 #define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_INFO 716 const LogSeverity LOG_DCHECK = LOG_INFO; 717 718 #endif // DCHECK_IS_ON() 719 720 // DCHECK et al. make sure to reference |condition| regardless of 721 // whether DCHECKs are enabled; this is so that we don't get unused 722 // variable warnings if the only use of a variable is in a DCHECK. 723 // This behavior is different from DLOG_IF et al. 724 725 #if defined(_PREFAST_) && defined(OS_WIN) 726 // See comments on the previous use of __analysis_assume. 727 728 #define DCHECK(condition) \ 729 __analysis_assume(!!(condition)), \ 730 LAZY_STREAM(LOG_STREAM(DCHECK), false) \ 731 << "Check failed: " #condition ". " 732 733 #define DPCHECK(condition) \ 734 __analysis_assume(!!(condition)), \ 735 LAZY_STREAM(PLOG_STREAM(DCHECK), false) \ 736 << "Check failed: " #condition ". " 737 738 #else // _PREFAST_ 739 740 #define DCHECK(condition) \ 741 LAZY_STREAM(LOG_STREAM(DCHECK), DCHECK_IS_ON() ? !(condition) : false) \ 742 << "Check failed: " #condition ". " 743 744 #define DPCHECK(condition) \ 745 LAZY_STREAM(PLOG_STREAM(DCHECK), DCHECK_IS_ON() ? !(condition) : false) \ 746 << "Check failed: " #condition ". " 747 748 #endif // _PREFAST_ 749 750 // Helper macro for binary operators. 751 // Don't use this macro directly in your code, use DCHECK_EQ et al below. 752 // The 'switch' is used to prevent the 'else' from being ambiguous when the 753 // macro is used in an 'if' clause such as: 754 // if (a == 1) 755 // DCHECK_EQ(2, a); 756 #define DCHECK_OP(name, op, val1, val2) \ 757 switch (0) case 0: default: \ 758 if (logging::CheckOpResult true_if_passed = \ 759 DCHECK_IS_ON() ? \ 760 logging::Check##name##Impl((val1), (val2), \ 761 #val1 " " #op " " #val2) : nullptr) \ 762 ; \ 763 else \ 764 logging::LogMessage(__FILE__, __LINE__, ::logging::LOG_DCHECK, \ 765 true_if_passed.message()).stream() 766 767 // Equality/Inequality checks - compare two values, and log a 768 // LOG_DCHECK message including the two values when the result is not 769 // as expected. The values must have operator<<(ostream, ...) 770 // defined. 771 // 772 // You may append to the error message like so: 773 // DCHECK_NE(1, 2) << ": The world must be ending!"; 774 // 775 // We are very careful to ensure that each argument is evaluated exactly 776 // once, and that anything which is legal to pass as a function argument is 777 // legal here. In particular, the arguments may be temporary expressions 778 // which will end up being destroyed at the end of the apparent statement, 779 // for example: 780 // DCHECK_EQ(string("abc")[1], 'b'); 781 // 782 // WARNING: These don't compile correctly if one of the arguments is a pointer 783 // and the other is NULL. In new code, prefer nullptr instead. To 784 // work around this for C++98, simply static_cast NULL to the type of the 785 // desired pointer. 786 787 #define DCHECK_EQ(val1, val2) DCHECK_OP(EQ, ==, val1, val2) 788 #define DCHECK_NE(val1, val2) DCHECK_OP(NE, !=, val1, val2) 789 #define DCHECK_LE(val1, val2) DCHECK_OP(LE, <=, val1, val2) 790 #define DCHECK_LT(val1, val2) DCHECK_OP(LT, < , val1, val2) 791 #define DCHECK_GE(val1, val2) DCHECK_OP(GE, >=, val1, val2) 792 #define DCHECK_GT(val1, val2) DCHECK_OP(GT, > , val1, val2) 793 794 #if !DCHECK_IS_ON() && defined(OS_CHROMEOS) 795 // Implement logging of NOTREACHED() as a dedicated function to get function 796 // call overhead down to a minimum. 797 void LogErrorNotReached(const char* file, int line); 798 #define NOTREACHED() \ 799 true ? ::logging::LogErrorNotReached(__FILE__, __LINE__) \ 800 : EAT_STREAM_PARAMETERS 801 #else 802 #define NOTREACHED() DCHECK(false) 803 #endif 804 805 // Redefine the standard assert to use our nice log files 806 #undef assert 807 #define assert(x) DLOG_ASSERT(x) 808 809 // This class more or less represents a particular log message. You 810 // create an instance of LogMessage and then stream stuff to it. 811 // When you finish streaming to it, ~LogMessage is called and the 812 // full message gets streamed to the appropriate destination. 813 // 814 // You shouldn't actually use LogMessage's constructor to log things, 815 // though. You should use the LOG() macro (and variants thereof) 816 // above. 817 class BASE_EXPORT LogMessage { 818 public: 819 // Used for LOG(severity). 820 LogMessage(const char* file, int line, LogSeverity severity); 821 822 // Used for CHECK(). Implied severity = LOG_FATAL. 823 LogMessage(const char* file, int line, const char* condition); 824 825 // Used for CHECK_EQ(), etc. Takes ownership of the given string. 826 // Implied severity = LOG_FATAL. 827 LogMessage(const char* file, int line, std::string* result); 828 829 // Used for DCHECK_EQ(), etc. Takes ownership of the given string. 830 LogMessage(const char* file, int line, LogSeverity severity, 831 std::string* result); 832 833 ~LogMessage(); 834 835 std::ostream& stream() { return stream_; } 836 837 private: 838 void Init(const char* file, int line); 839 840 LogSeverity severity_; 841 std::ostringstream stream_; 842 size_t message_start_; // Offset of the start of the message (past prefix 843 // info). 844 // The file and line information passed in to the constructor. 845 const char* file_; 846 const int line_; 847 848 #if defined(OS_WIN) 849 // Stores the current value of GetLastError in the constructor and restores 850 // it in the destructor by calling SetLastError. 851 // This is useful since the LogMessage class uses a lot of Win32 calls 852 // that will lose the value of GLE and the code that called the log function 853 // will have lost the thread error value when the log call returns. 854 class SaveLastError { 855 public: 856 SaveLastError(); 857 ~SaveLastError(); 858 859 unsigned long get_error() const { return last_error_; } 860 861 protected: 862 unsigned long last_error_; 863 }; 864 865 SaveLastError last_error_; 866 #endif 867 868 DISALLOW_COPY_AND_ASSIGN(LogMessage); 869 }; 870 871 // This class is used to explicitly ignore values in the conditional 872 // logging macros. This avoids compiler warnings like "value computed 873 // is not used" and "statement has no effect". 874 class LogMessageVoidify { 875 public: 876 LogMessageVoidify() { } 877 // This has to be an operator with a precedence lower than << but 878 // higher than ?: 879 void operator&(std::ostream&) { } 880 }; 881 882 #if defined(OS_WIN) 883 typedef unsigned long SystemErrorCode; 884 #elif defined(OS_POSIX) 885 typedef int SystemErrorCode; 886 #endif 887 888 // Alias for ::GetLastError() on Windows and errno on POSIX. Avoids having to 889 // pull in windows.h just for GetLastError() and DWORD. 890 BASE_EXPORT SystemErrorCode GetLastSystemErrorCode(); 891 BASE_EXPORT std::string SystemErrorCodeToString(SystemErrorCode error_code); 892 893 #if defined(OS_WIN) 894 // Appends a formatted system message of the GetLastError() type. 895 class BASE_EXPORT Win32ErrorLogMessage { 896 public: 897 Win32ErrorLogMessage(const char* file, 898 int line, 899 LogSeverity severity, 900 SystemErrorCode err); 901 902 // Appends the error message before destructing the encapsulated class. 903 ~Win32ErrorLogMessage(); 904 905 std::ostream& stream() { return log_message_.stream(); } 906 907 private: 908 SystemErrorCode err_; 909 LogMessage log_message_; 910 911 DISALLOW_COPY_AND_ASSIGN(Win32ErrorLogMessage); 912 }; 913 #elif defined(OS_POSIX) 914 // Appends a formatted system message of the errno type 915 class BASE_EXPORT ErrnoLogMessage { 916 public: 917 ErrnoLogMessage(const char* file, 918 int line, 919 LogSeverity severity, 920 SystemErrorCode err); 921 922 // Appends the error message before destructing the encapsulated class. 923 ~ErrnoLogMessage(); 924 925 std::ostream& stream() { return log_message_.stream(); } 926 927 private: 928 SystemErrorCode err_; 929 LogMessage log_message_; 930 931 DISALLOW_COPY_AND_ASSIGN(ErrnoLogMessage); 932 }; 933 #endif // OS_WIN 934 935 // Closes the log file explicitly if open. 936 // NOTE: Since the log file is opened as necessary by the action of logging 937 // statements, there's no guarantee that it will stay closed 938 // after this call. 939 BASE_EXPORT void CloseLogFile(); 940 941 // Async signal safe logging mechanism. 942 BASE_EXPORT void RawLog(int level, const char* message); 943 944 #define RAW_LOG(level, message) logging::RawLog(logging::LOG_ ## level, message) 945 946 #define RAW_CHECK(condition) \ 947 do { \ 948 if (!(condition)) \ 949 logging::RawLog(logging::LOG_FATAL, "Check failed: " #condition "\n"); \ 950 } while (0) 951 952 #if defined(OS_WIN) 953 // Returns true if logging to file is enabled. 954 BASE_EXPORT bool IsLoggingToFileEnabled(); 955 956 // Returns the default log file path. 957 BASE_EXPORT std::wstring GetLogFileFullPath(); 958 #endif 959 960 } // namespace logging 961 962 // The NOTIMPLEMENTED() macro annotates codepaths which have 963 // not been implemented yet. 964 // 965 // The implementation of this macro is controlled by NOTIMPLEMENTED_POLICY: 966 // 0 -- Do nothing (stripped by compiler) 967 // 1 -- Warn at compile time 968 // 2 -- Fail at compile time 969 // 3 -- Fail at runtime (DCHECK) 970 // 4 -- [default] LOG(ERROR) at runtime 971 // 5 -- LOG(ERROR) at runtime, only once per call-site 972 973 #ifndef NOTIMPLEMENTED_POLICY 974 #if defined(OS_ANDROID) && defined(OFFICIAL_BUILD) 975 #define NOTIMPLEMENTED_POLICY 0 976 #else 977 // Select default policy: LOG(ERROR) 978 #define NOTIMPLEMENTED_POLICY 4 979 #endif 980 #endif 981 982 #if defined(COMPILER_GCC) 983 // On Linux, with GCC, we can use __PRETTY_FUNCTION__ to get the demangled name 984 // of the current function in the NOTIMPLEMENTED message. 985 #define NOTIMPLEMENTED_MSG "Not implemented reached in " << __PRETTY_FUNCTION__ 986 #else 987 #define NOTIMPLEMENTED_MSG "NOT IMPLEMENTED" 988 #endif 989 990 #if NOTIMPLEMENTED_POLICY == 0 991 #define NOTIMPLEMENTED() EAT_STREAM_PARAMETERS 992 #elif NOTIMPLEMENTED_POLICY == 1 993 // TODO, figure out how to generate a warning 994 #define NOTIMPLEMENTED() static_assert(false, "NOT_IMPLEMENTED") 995 #elif NOTIMPLEMENTED_POLICY == 2 996 #define NOTIMPLEMENTED() static_assert(false, "NOT_IMPLEMENTED") 997 #elif NOTIMPLEMENTED_POLICY == 3 998 #define NOTIMPLEMENTED() NOTREACHED() 999 #elif NOTIMPLEMENTED_POLICY == 4 1000 #define NOTIMPLEMENTED() LOG(ERROR) << NOTIMPLEMENTED_MSG 1001 #elif NOTIMPLEMENTED_POLICY == 5 1002 #define NOTIMPLEMENTED() do {\ 1003 static bool logged_once = false;\ 1004 LOG_IF(ERROR, !logged_once) << NOTIMPLEMENTED_MSG;\ 1005 logged_once = true;\ 1006 } while(0);\ 1007 EAT_STREAM_PARAMETERS 1008 #endif 1009 1010 #endif // BASE_LOGGING_H_ 1011