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. 151namespace 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. 158BASE_EXPORT std::ostream& operator<<(std::ostream& out, const wchar_t* wstr); 159inline std::ostream& operator<<(std::ostream& out, const std::wstring& wstr) { 160 return out << wstr.c_str(); 161} 162 163template<typename T> 164typename 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 171namespace logging { 172 173// TODO(avi): do we want to do a unification of character types here? 174#if defined(OS_WIN) 175typedef wchar_t PathChar; 176#else 177typedef char PathChar; 178#endif 179 180// Where to record logging output? A flat file and/or system debug log 181// via OutputDebugString. 182enum 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. 206enum 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. 210enum OldFileDeletionState { DELETE_OLD_LOG_FILE, APPEND_TO_OLD_LOG_FILE }; 211 212struct 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". 243BASE_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. 259inline 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. 269BASE_EXPORT void SetMinLogLevel(int level); 270 271// Gets the current log level. 272BASE_EXPORT int GetMinLogLevel(); 273 274// Used by LOG_IS_ON to lazy-evaluate stream arguments. 275BASE_EXPORT bool ShouldCreateLogMessage(int severity); 276 277// Gets the VLOG default verbosity level. 278BASE_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. 284BASE_EXPORT int GetVlogLevelHelper(const char* file_start, size_t N); 285 286template <size_t N> 287int 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. 295BASE_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. 301BASE_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) 307typedef void (*LogAssertHandlerFunction)(const std::string& str); 308BASE_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. 314typedef bool (*LogMessageHandlerFunction)(int severity, 315 const char* file, int line, size_t message_start, const std::string& str); 316BASE_EXPORT void SetLogMessageHandler(LogMessageHandlerFunction handler); 317BASE_EXPORT LogMessageHandlerFunction GetLogMessageHandler(); 318 319typedef int LogSeverity; 320const 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. 323const LogSeverity LOG_INFO = 0; 324const LogSeverity LOG_WARNING = 1; 325const LogSeverity LOG_ERROR = 2; 326const LogSeverity LOG_FATAL = 3; 327const LogSeverity LOG_NUM_SEVERITIES = 4; 328 329// LOG_DFATAL is LOG_FATAL in debug mode, ERROR in normal mode 330#ifdef NDEBUG 331const LogSeverity LOG_DFATAL = LOG_ERROR; 332#else 333const 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). 372const 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. 462class 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. 555template <typename T> 556inline typename std::enable_if< 557 base::internal::SupportsOstreamOperator<const T&>::value, 558 void>::type 559MakeCheckOpValueString(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). 565template <typename T> 566inline typename std::enable_if< 567 !base::internal::SupportsOstreamOperator<const T&>::value && 568 std::is_enum<T>::value, 569 void>::type 570MakeCheckOpValueString(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. 575BASE_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. 581template<class t1, class t2> 582std::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. 595extern template BASE_EXPORT std::string* MakeCheckOpString<int, int>( 596 const int&, const int&, const char* names); 597extern template BASE_EXPORT 598std::string* MakeCheckOpString<unsigned long, unsigned long>( 599 const unsigned long&, const unsigned long&, const char* names); 600extern template BASE_EXPORT 601std::string* MakeCheckOpString<unsigned long, unsigned int>( 602 const unsigned long&, const unsigned int&, const char* names); 603extern template BASE_EXPORT 604std::string* MakeCheckOpString<unsigned int, unsigned long>( 605 const unsigned int&, const unsigned long&, const char* names); 606extern template BASE_EXPORT 607std::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 } 625DEFINE_CHECK_OP_IMPL(EQ, ==) 626DEFINE_CHECK_OP_IMPL(NE, !=) 627DEFINE_CHECK_OP_IMPL(LE, <=) 628DEFINE_CHECK_OP_IMPL(LT, < ) 629DEFINE_CHECK_OP_IMPL(GE, >=) 630DEFINE_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. 687enum { 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 708const 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 716const 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. 797void 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. 817class 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". 874class 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) 883typedef unsigned long SystemErrorCode; 884#elif defined(OS_POSIX) 885typedef 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. 890BASE_EXPORT SystemErrorCode GetLastSystemErrorCode(); 891BASE_EXPORT std::string SystemErrorCodeToString(SystemErrorCode error_code); 892 893#if defined(OS_WIN) 894// Appends a formatted system message of the GetLastError() type. 895class 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 915class 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. 939BASE_EXPORT void CloseLogFile(); 940 941// Async signal safe logging mechanism. 942BASE_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. 954BASE_EXPORT bool IsLoggingToFileEnabled(); 955 956// Returns the default log file path. 957BASE_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);\ 1007EAT_STREAM_PARAMETERS 1008#endif 1009 1010#endif // BASE_LOGGING_H_ 1011