blob: 3b89853881a579a758ddf8168cd1b78c29d1c963 [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_LOGGING_H_
#define BASE_LOGGING_H_
#include <stddef.h>
#include <cassert>
#include <cstring>
#include <sstream>
#include <string>
#include <typeinfo>
#include <type_traits>
#include <utility>
#include "base/base_export.h"
#include "base/macros.h"
#include "base/template_util.h"
#include "build/build_config.h"
//
// Optional message capabilities
// -----------------------------
// Assertion failed messages and fatal errors are displayed in a dialog box
// before the application exits. However, running this UI creates a message
// loop, which causes application messages to be processed and potentially
// dispatched to existing application windows. Since the application is in a
// bad state when this assertion dialog is displayed, these messages may not
// get processed and hang the dialog, or the application might go crazy.
//
// Therefore, it can be beneficial to display the error dialog in a separate
// process from the main application. When the logging system needs to display
// a fatal error dialog box, it will look for a program called
// "DebugMessage.exe" in the same directory as the application executable. It
// will run this application with the message as the command line, and will
// not include the name of the application as is traditional for easier
// parsing.
//
// The code for DebugMessage.exe is only one line. In WinMain, do:
// MessageBox(NULL, GetCommandLineW(), L"Fatal Error", 0);
//
// If DebugMessage.exe is not found, the logging code will use a normal
// MessageBox, potentially causing the problems discussed above.
// Instructions
// ------------
//
// Make a bunch of macros for logging. The way to log things is to stream
// things to LOG(<a particular severity level>). E.g.,
//
// LOG(INFO) << "Found " << num_cookies << " cookies";
//
// You can also do conditional logging:
//
// LOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
//
// The CHECK(condition) macro is active in both debug and release builds and
// effectively performs a LOG(FATAL) which terminates the process and
// generates a crashdump unless a debugger is attached.
//
// There are also "debug mode" logging macros like the ones above:
//
// DLOG(INFO) << "Found cookies";
//
// DLOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
//
// All "debug mode" logging is compiled away to nothing for non-debug mode
// compiles. LOG_IF and development flags also work well together
// because the code can be compiled away sometimes.
//
// We also have
//
// LOG_ASSERT(assertion);
// DLOG_ASSERT(assertion);
//
// which is syntactic sugar for {,D}LOG_IF(FATAL, assert fails) << assertion;
//
// There are "verbose level" logging macros. They look like
//
// VLOG(1) << "I'm printed when you run the program with --v=1 or more";
// VLOG(2) << "I'm printed when you run the program with --v=2 or more";
//
// These always log at the INFO log level (when they log at all).
// The verbose logging can also be turned on module-by-module. For instance,
// --vmodule=profile=2,icon_loader=1,browser_*=3,*/chromeos/*=4 --v=0
// will cause:
// a. VLOG(2) and lower messages to be printed from profile.{h,cc}
// b. VLOG(1) and lower messages to be printed from icon_loader.{h,cc}
// c. VLOG(3) and lower messages to be printed from files prefixed with
// "browser"
// d. VLOG(4) and lower messages to be printed from files under a
// "chromeos" directory.
// e. VLOG(0) and lower messages to be printed from elsewhere
//
// The wildcarding functionality shown by (c) supports both '*' (match
// 0 or more characters) and '?' (match any single character)
// wildcards. Any pattern containing a forward or backward slash will
// be tested against the whole pathname and not just the module.
// E.g., "*/foo/bar/*=2" would change the logging level for all code
// in source files under a "foo/bar" directory.
//
// There's also VLOG_IS_ON(n) "verbose level" condition macro. To be used as
//
// if (VLOG_IS_ON(2)) {
// // do some logging preparation and logging
// // that can't be accomplished with just VLOG(2) << ...;
// }
//
// There is also a VLOG_IF "verbose level" condition macro for sample
// cases, when some extra computation and preparation for logs is not
// needed.
//
// VLOG_IF(1, (size > 1024))
// << "I'm printed when size is more than 1024 and when you run the "
// "program with --v=1 or more";
//
// We also override the standard 'assert' to use 'DLOG_ASSERT'.
//
// The supported severity levels for macros that allow you to specify one
// are (in increasing order of severity) INFO, WARNING, ERROR, and FATAL.
//
// Very important: logging a message at the FATAL severity level causes
// the program to terminate (after the message is logged).
//
// There is the special severity of DFATAL, which logs FATAL in debug mode,
// ERROR in normal mode.
// Note that "The behavior of a C++ program is undefined if it adds declarations
// or definitions to namespace std or to a namespace within namespace std unless
// otherwise specified." --C++11[namespace.std]
//
// We've checked that this particular definition has the intended behavior on
// our implementations, but it's prone to breaking in the future, and please
// don't imitate this in your own definitions without checking with some
// standard library experts.
namespace std {
// These functions are provided as a convenience for logging, which is where we
// use streams (it is against Google style to use streams in other places). It
// is designed to allow you to emit non-ASCII Unicode strings to the log file,
// which is normally ASCII. It is relatively slow, so try not to use it for
// common cases. Non-ASCII characters will be converted to UTF-8 by these
// operators.
BASE_EXPORT std::ostream& operator<<(std::ostream& out, const wchar_t* wstr);
inline std::ostream& operator<<(std::ostream& out, const std::wstring& wstr) {
return out << wstr.c_str();
}
template<typename T>
typename std::enable_if<std::is_enum<T>::value, std::ostream&>::type operator<<(
std::ostream& out, T value) {
return out << static_cast<typename std::underlying_type<T>::type>(value);
}
} // namespace std
namespace logging {
// Where to record logging output? A flat file and/or system debug log
// via OutputDebugString.
enum LoggingDestination {
LOG_NONE = 0,
LOG_TO_SYSTEM_DEBUG_LOG = 1 << 1,
LOG_TO_ALL = LOG_TO_SYSTEM_DEBUG_LOG,
LOG_DEFAULT = LOG_TO_SYSTEM_DEBUG_LOG,
};
struct BASE_EXPORT LoggingSettings {
// The defaults values are:
//
// logging_dest: LOG_DEFAULT
LoggingSettings();
LoggingDestination logging_dest;
};
// Define different names for the BaseInitLoggingImpl() function depending on
// whether NDEBUG is defined or not so that we'll fail to link if someone tries
// to compile logging.cc with NDEBUG but includes logging.h without defining it,
// or vice versa.
#if NDEBUG
#define BaseInitLoggingImpl BaseInitLoggingImpl_built_with_NDEBUG
#else
#define BaseInitLoggingImpl BaseInitLoggingImpl_built_without_NDEBUG
#endif
// Implementation of the InitLogging() method declared below. We use a
// more-specific name so we can #define it above without affecting other code
// that has named stuff "InitLogging".
BASE_EXPORT bool BaseInitLoggingImpl(const LoggingSettings& settings);
// Sets the log file name and other global logging state. Calling this function
// is recommended, and is normally done at the beginning of application init.
// If you don't call it, all the flags will be initialized to their default
// values, and there is a race condition that may leak a critical section
// object if two threads try to do the first log at the same time.
// See the definition of the enums above for descriptions and default values.
//
// The default log file is initialized to "debug.log" in the application
// directory. You probably don't want this, especially since the program
// directory may not be writable on an enduser's system.
//
// This function may be called a second time to re-direct logging (e.g after
// loging in to a user partition), however it should never be called more than
// twice.
inline bool InitLogging(const LoggingSettings& settings) {
return BaseInitLoggingImpl(settings);
}
// Sets the log level. Anything at or above this level will be written to the
// log file/displayed to the user (if applicable). Anything below this level
// will be silently ignored. The log level defaults to 0 (everything is logged
// up to level INFO) if this function is not called.
// Note that log messages for VLOG(x) are logged at level -x, so setting
// the min log level to negative values enables verbose logging.
BASE_EXPORT void SetMinLogLevel(int level);
// Gets the current log level.
BASE_EXPORT int GetMinLogLevel();
// Used by LOG_IS_ON to lazy-evaluate stream arguments.
BASE_EXPORT bool ShouldCreateLogMessage(int severity);
// Gets the VLOG default verbosity level.
BASE_EXPORT int GetVlogVerbosity();
// Gets the current vlog level for the given file (usually taken from
// __FILE__).
// Note that |N| is the size *with* the null terminator.
inline int GetVlogLevelHelper(const char* file_start, size_t N) {
return GetVlogVerbosity();
}
template <size_t N>
int GetVlogLevel(const char (&file)[N]) {
return GetVlogLevelHelper(file, N);
}
// Sets the common items you want to be prepended to each log message.
// process and thread IDs default to off, the timestamp defaults to on.
// If this function is not called, logging defaults to writing the timestamp
// only.
BASE_EXPORT void SetLogItems(bool enable_process_id,
bool enable_thread_id,
bool enable_timestamp,
bool enable_tickcount);
// Sets whether or not you'd like to see fatal debug messages popped up in
// a dialog box or not.
// Dialogs are not shown by default.
void SetShowErrorDialogs(bool enable_dialogs);
// Sets the Log Assert Handler that will be used to notify of check failures.
// The default handler shows a dialog box and then terminate the process,
// however clients can use this function to override with their own handling
// (e.g. a silent one for Unit Tests)
typedef void (*LogAssertHandlerFunction)(const std::string& str);
BASE_EXPORT void SetLogAssertHandler(LogAssertHandlerFunction handler);
// Sets the Log Message Handler that gets passed every log message before
// it's sent to other log destinations (if any).
// Returns true to signal that it handled the message and the message
// should not be sent to other log destinations.
typedef bool (*LogMessageHandlerFunction)(int severity,
const char* file, int line, size_t message_start, const std::string& str);
BASE_EXPORT void SetLogMessageHandler(LogMessageHandlerFunction handler);
BASE_EXPORT LogMessageHandlerFunction GetLogMessageHandler();
typedef int LogSeverity;
const LogSeverity LOG_VERBOSE = -1; // This is level 1 verbosity
// Note: the log severities are used to index into the array of names,
// see log_severity_names.
const LogSeverity LOG_INFO = 0;
const LogSeverity LOG_WARNING = 1;
const LogSeverity LOG_ERROR = 2;
const LogSeverity LOG_FATAL = 3;
const LogSeverity LOG_NUM_SEVERITIES = 4;
// LOG_DFATAL is LOG_FATAL in debug mode, ERROR in normal mode
#ifdef NDEBUG
const LogSeverity LOG_DFATAL = LOG_ERROR;
#else
const LogSeverity LOG_DFATAL = LOG_FATAL;
#endif
// A few definitions of macros that don't generate much code. These are used
// by LOG() and LOG_IF, etc. Since these are used all over our code, it's
// better to have compact code for these operations.
#define COMPACT_GOOGLE_LOG_EX_INFO(ClassName, ...) \
logging::ClassName(__FILE__, __LINE__, logging::LOG_INFO , ##__VA_ARGS__)
#define COMPACT_GOOGLE_LOG_EX_WARNING(ClassName, ...) \
logging::ClassName(__FILE__, __LINE__, logging::LOG_WARNING , ##__VA_ARGS__)
#define COMPACT_GOOGLE_LOG_EX_ERROR(ClassName, ...) \
logging::ClassName(__FILE__, __LINE__, logging::LOG_ERROR , ##__VA_ARGS__)
#define COMPACT_GOOGLE_LOG_EX_FATAL(ClassName, ...) \
logging::ClassName(__FILE__, __LINE__, logging::LOG_FATAL , ##__VA_ARGS__)
#define COMPACT_GOOGLE_LOG_EX_DFATAL(ClassName, ...) \
logging::ClassName(__FILE__, __LINE__, logging::LOG_DFATAL , ##__VA_ARGS__)
#define COMPACT_GOOGLE_LOG_INFO \
COMPACT_GOOGLE_LOG_EX_INFO(LogMessage)
#define COMPACT_GOOGLE_LOG_WARNING \
COMPACT_GOOGLE_LOG_EX_WARNING(LogMessage)
#define COMPACT_GOOGLE_LOG_ERROR \
COMPACT_GOOGLE_LOG_EX_ERROR(LogMessage)
#define COMPACT_GOOGLE_LOG_FATAL \
COMPACT_GOOGLE_LOG_EX_FATAL(LogMessage)
#define COMPACT_GOOGLE_LOG_DFATAL \
COMPACT_GOOGLE_LOG_EX_DFATAL(LogMessage)
// As special cases, we can assume that LOG_IS_ON(FATAL) always holds. Also,
// LOG_IS_ON(DFATAL) always holds in debug mode. In particular, CHECK()s will
// always fire if they fail.
#define LOG_IS_ON(severity) \
(::logging::ShouldCreateLogMessage(::logging::LOG_##severity))
// We can't do any caching tricks with VLOG_IS_ON() like the
// google-glog version since it requires GCC extensions. This means
// that using the v-logging functions in conjunction with --vmodule
// may be slow.
#define VLOG_IS_ON(verboselevel) \
((verboselevel) <= ::logging::GetVlogLevel(__FILE__))
// Helper macro which avoids evaluating the arguments to a stream if
// the condition doesn't hold. Condition is evaluated once and only once.
#define LAZY_STREAM(stream, condition) \
!(condition) ? (void) 0 : ::logging::LogMessageVoidify() & (stream)
// We use the preprocessor's merging operator, "##", so that, e.g.,
// LOG(INFO) becomes the token COMPACT_GOOGLE_LOG_INFO. There's some funny
// subtle difference between ostream member streaming functions (e.g.,
// ostream::operator<<(int) and ostream non-member streaming functions
// (e.g., ::operator<<(ostream&, string&): it turns out that it's
// impossible to stream something like a string directly to an unnamed
// ostream. We employ a neat hack by calling the stream() member
// function of LogMessage which seems to avoid the problem.
#define LOG_STREAM(severity) COMPACT_GOOGLE_LOG_ ## severity.stream()
#define LOG(severity) LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity))
#define LOG_IF(severity, condition) \
LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity) && (condition))
// The VLOG macros log with negative verbosities.
#define VLOG_STREAM(verbose_level) \
logging::LogMessage(__FILE__, __LINE__, -verbose_level).stream()
#define VLOG(verbose_level) \
LAZY_STREAM(VLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level))
#define VLOG_IF(verbose_level, condition) \
LAZY_STREAM(VLOG_STREAM(verbose_level), \
VLOG_IS_ON(verbose_level) && (condition))
#define LOG_ASSERT(condition) \
LOG_IF(FATAL, !(condition)) << "Assert failed: " #condition ". "
// The actual stream used isn't important.
#define EAT_STREAM_PARAMETERS \
true ? (void) 0 : ::logging::LogMessageVoidify() & LOG_STREAM(FATAL)
// Captures the result of a CHECK_EQ (for example) and facilitates testing as a
// boolean.
class CheckOpResult {
public:
// |message| must be null if and only if the check failed.
CheckOpResult(std::string* message) : message_(message) {}
// Returns true if the check succeeded.
operator bool() const { return !message_; }
// Returns the message.
std::string* message() { return message_; }
private:
std::string* message_;
};
// CHECK dies with a fatal error if condition is not true. It is *not*
// controlled by NDEBUG, so the check will be executed regardless of
// compilation mode.
//
// We make sure CHECK et al. always evaluates their arguments, as
// doing CHECK(FunctionWithSideEffect()) is a common idiom.
#if defined(OFFICIAL_BUILD) && defined(NDEBUG) && !defined(OS_ANDROID)
// Make all CHECK functions discard their log strings to reduce code
// bloat for official release builds (except Android).
// TODO(akalin): This would be more valuable if there were some way to
// remove BreakDebugger() from the backtrace, perhaps by turning it
// into a macro (like __debugbreak() on Windows).
#define CHECK(condition) \
!(condition) ? ::base::debug::BreakDebugger() : EAT_STREAM_PARAMETERS
#define PCHECK(condition) CHECK(condition)
#define CHECK_OP(name, op, val1, val2) CHECK((val1) op (val2))
#else
// Do as much work as possible out of line to reduce inline code size.
#define CHECK(condition) \
LAZY_STREAM(logging::LogMessage(__FILE__, __LINE__, #condition).stream(), \
!(condition))
// Helper macro for binary operators.
// Don't use this macro directly in your code, use CHECK_EQ et al below.
// The 'switch' is used to prevent the 'else' from being ambiguous when the
// macro is used in an 'if' clause such as:
// if (a == 1)
// CHECK_EQ(2, a);
#define CHECK_OP(name, op, val1, val2) \
switch (0) case 0: default: \
if (logging::CheckOpResult true_if_passed = \
logging::Check##name##Impl((val1), (val2), \
#val1 " " #op " " #val2)) \
; \
else \
logging::LogMessage(__FILE__, __LINE__, true_if_passed.message()).stream()
#endif
// This formats a value for a failing CHECK_XX statement. Ordinarily,
// it uses the definition for operator<<, with a few special cases below.
template <typename T>
inline typename std::enable_if<
base::internal::SupportsOstreamOperator<const T&>::value,
void>::type
MakeCheckOpValueString(std::ostream* os, const T& v) {
(*os) << v;
}
// We need overloads for enums that don't support operator<<.
// (i.e. scoped enums where no operator<< overload was declared).
template <typename T>
inline typename std::enable_if<
!base::internal::SupportsOstreamOperator<const T&>::value &&
std::is_enum<T>::value,
void>::type
MakeCheckOpValueString(std::ostream* os, const T& v) {
(*os) << static_cast<typename base::underlying_type<T>::type>(v);
}
// We need an explicit overload for std::nullptr_t.
BASE_EXPORT void MakeCheckOpValueString(std::ostream* os, std::nullptr_t p);
// Build the error message string. This is separate from the "Impl"
// function template because it is not performance critical and so can
// be out of line, while the "Impl" code should be inline. Caller
// takes ownership of the returned string.
template<class t1, class t2>
std::string* MakeCheckOpString(const t1& v1, const t2& v2, const char* names) {
std::ostringstream ss;
ss << names << " (";
MakeCheckOpValueString(&ss, v1);
ss << " vs. ";
MakeCheckOpValueString(&ss, v2);
ss << ")";
std::string* msg = new std::string(ss.str());
return msg;
}
// Commonly used instantiations of MakeCheckOpString<>. Explicitly instantiated
// in logging.cc.
extern template BASE_EXPORT std::string*
MakeCheckOpString<int, int>(const int&, const int&, const char* names);
extern template BASE_EXPORT
std::string* MakeCheckOpString<unsigned long, unsigned long>(
const unsigned long&, const unsigned long&, const char* names);
extern template BASE_EXPORT
std::string* MakeCheckOpString<unsigned long, unsigned int>(
const unsigned long&, const unsigned int&, const char* names);
extern template BASE_EXPORT
std::string* MakeCheckOpString<unsigned int, unsigned long>(
const unsigned int&, const unsigned long&, const char* names);
extern template BASE_EXPORT
std::string* MakeCheckOpString<std::string, std::string>(
const std::string&, const std::string&, const char* name);
// Helper functions for CHECK_OP macro.
// The (int, int) specialization works around the issue that the compiler
// will not instantiate the template version of the function on values of
// unnamed enum type - see comment below.
#define DEFINE_CHECK_OP_IMPL(name, op) \
template <class t1, class t2> \
inline std::string* Check##name##Impl(const t1& v1, const t2& v2, \
const char* names) { \
if (v1 op v2) return NULL; \
else return MakeCheckOpString(v1, v2, names); \
} \
inline std::string* Check##name##Impl(int v1, int v2, const char* names) { \
if (v1 op v2) return NULL; \
else return MakeCheckOpString(v1, v2, names); \
}
DEFINE_CHECK_OP_IMPL(EQ, ==)
DEFINE_CHECK_OP_IMPL(NE, !=)
DEFINE_CHECK_OP_IMPL(LE, <=)
DEFINE_CHECK_OP_IMPL(LT, < )
DEFINE_CHECK_OP_IMPL(GE, >=)
DEFINE_CHECK_OP_IMPL(GT, > )
#undef DEFINE_CHECK_OP_IMPL
#define CHECK_EQ(val1, val2) CHECK_OP(EQ, ==, val1, val2)
#define CHECK_NE(val1, val2) CHECK_OP(NE, !=, val1, val2)
#define CHECK_LE(val1, val2) CHECK_OP(LE, <=, val1, val2)
#define CHECK_LT(val1, val2) CHECK_OP(LT, < , val1, val2)
#define CHECK_GE(val1, val2) CHECK_OP(GE, >=, val1, val2)
#define CHECK_GT(val1, val2) CHECK_OP(GT, > , val1, val2)
#if defined(NDEBUG)
#define ENABLE_DLOG 0
#else
#define ENABLE_DLOG 1
#endif
#if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON)
#define DCHECK_IS_ON() 0
#else
#define DCHECK_IS_ON() 1
#endif
// Definitions for DLOG et al.
#if ENABLE_DLOG
#define DLOG_IS_ON(severity) LOG_IS_ON(severity)
#define DLOG_IF(severity, condition) LOG_IF(severity, condition)
#define DLOG_ASSERT(condition) LOG_ASSERT(condition)
#define DVLOG_IF(verboselevel, condition) VLOG_IF(verboselevel, condition)
#else // ENABLE_DLOG
// If ENABLE_DLOG is off, we want to avoid emitting any references to
// |condition| (which may reference a variable defined only if NDEBUG
// is not defined). Contrast this with DCHECK et al., which has
// different behavior.
#define DLOG_IS_ON(severity) false
#define DLOG_IF(severity, condition) EAT_STREAM_PARAMETERS
#define DLOG_ASSERT(condition) EAT_STREAM_PARAMETERS
#define DVLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS
#endif // ENABLE_DLOG
// DEBUG_MODE is for uses like
// if (DEBUG_MODE) foo.CheckThatFoo();
// instead of
// #ifndef NDEBUG
// foo.CheckThatFoo();
// #endif
//
// We tie its state to ENABLE_DLOG.
enum { DEBUG_MODE = ENABLE_DLOG };
#undef ENABLE_DLOG
#define DLOG(severity) \
LAZY_STREAM(LOG_STREAM(severity), DLOG_IS_ON(severity))
#define DVLOG(verboselevel) DVLOG_IF(verboselevel, VLOG_IS_ON(verboselevel))
// Definitions for DCHECK et al.
#if DCHECK_IS_ON()
#define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
COMPACT_GOOGLE_LOG_EX_FATAL(ClassName , ##__VA_ARGS__)
#define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_FATAL
const LogSeverity LOG_DCHECK = LOG_FATAL;
#else // DCHECK_IS_ON()
// These are just dummy values.
#define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
COMPACT_GOOGLE_LOG_EX_INFO(ClassName , ##__VA_ARGS__)
#define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_INFO
const LogSeverity LOG_DCHECK = LOG_INFO;
#endif // DCHECK_IS_ON()
// DCHECK et al. make sure to reference |condition| regardless of
// whether DCHECKs are enabled; this is so that we don't get unused
// variable warnings if the only use of a variable is in a DCHECK.
// This behavior is different from DLOG_IF et al.
#define DCHECK(condition) \
LAZY_STREAM(LOG_STREAM(DCHECK), DCHECK_IS_ON() ? !(condition) : false) \
<< "Check failed: " #condition ". "
// Helper macro for binary operators.
// Don't use this macro directly in your code, use DCHECK_EQ et al below.
// The 'switch' is used to prevent the 'else' from being ambiguous when the
// macro is used in an 'if' clause such as:
// if (a == 1)
// DCHECK_EQ(2, a);
#define DCHECK_OP(name, op, val1, val2) \
switch (0) case 0: default: \
if (logging::CheckOpResult true_if_passed = \
DCHECK_IS_ON() ? \
logging::Check##name##Impl((val1), (val2), \
#val1 " " #op " " #val2) : nullptr) \
; \
else \
logging::LogMessage(__FILE__, __LINE__, ::logging::LOG_DCHECK, \
true_if_passed.message()).stream()
// Equality/Inequality checks - compare two values, and log a
// LOG_DCHECK message including the two values when the result is not
// as expected. The values must have operator<<(ostream, ...)
// defined.
//
// You may append to the error message like so:
// DCHECK_NE(1, 2) << ": The world must be ending!";
//
// We are very careful to ensure that each argument is evaluated exactly
// once, and that anything which is legal to pass as a function argument is
// legal here. In particular, the arguments may be temporary expressions
// which will end up being destroyed at the end of the apparent statement,
// for example:
// DCHECK_EQ(string("abc")[1], 'b');
//
// WARNING: These may not compile correctly if one of the arguments is a pointer
// and the other is NULL. To work around this, simply static_cast NULL to the
// type of the desired pointer.
#define DCHECK_EQ(val1, val2) DCHECK_OP(EQ, ==, val1, val2)
#define DCHECK_NE(val1, val2) DCHECK_OP(NE, !=, val1, val2)
#define DCHECK_LE(val1, val2) DCHECK_OP(LE, <=, val1, val2)
#define DCHECK_LT(val1, val2) DCHECK_OP(LT, < , val1, val2)
#define DCHECK_GE(val1, val2) DCHECK_OP(GE, >=, val1, val2)
#define DCHECK_GT(val1, val2) DCHECK_OP(GT, > , val1, val2)
#define NOTREACHED() DCHECK(false)
// Redefine the standard assert to use our nice log files
#undef assert
#define assert(x) DLOG_ASSERT(x)
// This class more or less represents a particular log message. You
// create an instance of LogMessage and then stream stuff to it.
// When you finish streaming to it, ~LogMessage is called and the
// full message gets streamed to the appropriate destination.
//
// You shouldn't actually use LogMessage's constructor to log things,
// though. You should use the LOG() macro (and variants thereof)
// above.
class BASE_EXPORT LogMessage {
public:
// Used for LOG(severity).
LogMessage(const char* file, int line, LogSeverity severity);
// Used for CHECK(). Implied severity = LOG_FATAL.
LogMessage(const char* file, int line, const char* condition);
// Used for CHECK_EQ(), etc. Takes ownership of the given string.
// Implied severity = LOG_FATAL.
LogMessage(const char* file, int line, std::string* result);
// Used for DCHECK_EQ(), etc. Takes ownership of the given string.
LogMessage(const char* file, int line, LogSeverity severity,
std::string* result);
~LogMessage();
std::ostream& stream() { return stream_; }
private:
void Init(const char* file, int line);
LogSeverity severity_;
std::ostringstream stream_;
size_t message_start_; // Offset of the start of the message (past prefix
// info).
// The file and line information passed in to the constructor.
const char* file_;
const int line_;
DISALLOW_COPY_AND_ASSIGN(LogMessage);
};
// This class is used to explicitly ignore values in the conditional
// logging macros. This avoids compiler warnings like "value computed
// is not used" and "statement has no effect".
class LogMessageVoidify {
public:
LogMessageVoidify() { }
// This has to be an operator with a precedence lower than << but
// higher than ?:
void operator&(std::ostream&) { }
};
// Async signal safe logging mechanism.
BASE_EXPORT void RawLog(int level, const char* message);
#define RAW_LOG(level, message) logging::RawLog(logging::LOG_ ## level, message)
#define RAW_CHECK(condition) \
do { \
if (!(condition)) \
logging::RawLog(logging::LOG_FATAL, "Check failed: " #condition "\n"); \
} while (0)
} // namespace logging
// The NOTIMPLEMENTED() macro annotates codepaths which have
// not been implemented yet.
//
// The implementation of this macro is controlled by NOTIMPLEMENTED_POLICY:
// 0 -- Do nothing (stripped by compiler)
// 1 -- Warn at compile time
// 2 -- Fail at compile time
// 3 -- Fail at runtime (DCHECK)
// 4 -- [default] LOG(ERROR) at runtime
// 5 -- LOG(ERROR) at runtime, only once per call-site
#ifndef NOTIMPLEMENTED_POLICY
// Select default policy: LOG(ERROR)
#define NOTIMPLEMENTED_POLICY 4
#endif
#if defined(COMPILER_GCC)
// On Linux, with GCC, we can use __PRETTY_FUNCTION__ to get the demangled name
// of the current function in the NOTIMPLEMENTED message.
#define NOTIMPLEMENTED_MSG "Not implemented reached in " << __PRETTY_FUNCTION__
#else
#define NOTIMPLEMENTED_MSG "NOT IMPLEMENTED"
#endif
#if NOTIMPLEMENTED_POLICY == 0
#define NOTIMPLEMENTED() EAT_STREAM_PARAMETERS
#elif NOTIMPLEMENTED_POLICY == 1
// TODO, figure out how to generate a warning
#define NOTIMPLEMENTED() static_assert(false, "NOT_IMPLEMENTED")
#elif NOTIMPLEMENTED_POLICY == 2
#define NOTIMPLEMENTED() static_assert(false, "NOT_IMPLEMENTED")
#elif NOTIMPLEMENTED_POLICY == 3
#define NOTIMPLEMENTED() NOTREACHED()
#elif NOTIMPLEMENTED_POLICY == 4
#define NOTIMPLEMENTED() LOG(ERROR) << NOTIMPLEMENTED_MSG
#elif NOTIMPLEMENTED_POLICY == 5
#define NOTIMPLEMENTED() do {\
static bool logged_once = false;\
LOG_IF(ERROR, !logged_once) << NOTIMPLEMENTED_MSG;\
logged_once = true;\
} while(0);\
EAT_STREAM_PARAMETERS
#endif
#endif // BASE_LOGGING_H_