blob: 3e7496419317b203d578383b8d444d41011c2da7 [file] [log] [blame]
// Copyright (C) 1999 and onwards Google, Inc.
// Author: Ray Sidney
// This file contains #include information about logging-related stuff.
// Pretty much everybody needs to #include this file so that they can
// log various happenings.
#ifndef _LOGGING_H_
#define _LOGGING_H_
#include <errno.h>
#include <string.h>
#include <time.h>
#include <string>
#include <unistd.h>
// Make GCC quiet.
# undef __DEPRECATED
# include <strstream>
# define __DEPRECATED
# include <strstream>
#include <vector>
// We care a lot about number of bits things take up. Unfortunately,
// systems define their bit-specific ints in a lot of different ways.
// We use our own way, and have a typedef to get there.
// Note: these commands below may look like "#if 1" or "#if 0", but
// that's because they were constructed that way at ./configure time.
// Look at to see how they're calculated (based on your config).
#if @ac_cv_have_stdint_h@
#include <stdint.h> // the normal place uint16_t is defined
#if @ac_cv_have_systypes_h@
#include <sys/types.h> // the normal place u_int16_t is defined
#if @ac_cv_have_inttypes_h@
#include <inttypes.h> // a third place for uint16_t or u_int16_t
#if @ac_cv_have_libgflags@
#include <gflags/gflags.h>
#if @ac_cv_have_uint16_t@ // the C99 format
typedef int32_t int32;
typedef uint32_t uint32;
typedef int64_t int64;
typedef uint64_t uint64;
#elif @ac_cv_have_u_int16_t@ // the BSD format
typedef int32_t int32;
typedef u_int32_t uint32;
typedef int64_t int64;
typedef u_int64_t uint64;
#elif @ac_cv_have___uint16@ // the windows (vc7) format
typedef __int32 int32;
typedef __uint32 uint32;
typedef __int64 int64;
typedef __uint64 uint64;
#error Do not know how to define a 32-bit integer quantity on your system
// The global value of GOOGLE_STRIP_LOG. All the messages logged to
// LOG(XXX) with severity less than GOOGLE_STRIP_LOG will not be displayed.
// If it can be determined at compile time that the message will not be
// printed, the statement will be compiled out.
// Example: to strip out all INFO and WARNING messages, use the value
// of 2 below. To make an exception for WARNING messages from a single
// file, add "#define GOOGLE_STRIP_LOG 1" to that file _before_ including
// base/logging.h
// GCC can be told that a certain branch is not likely to be taken (for
// instance, a CHECK failure), and use that information in static analysis.
// Giving it this information can help it optimize for the common case in
// the absence of better information (ie. -fprofile-arcs).
#if @ac_cv_have___builtin_expect@
#define GOOGLE_PREDICT_BRANCH_NOT_TAKEN(x) (__builtin_expect(x, 0))
// A macro to disallow the evil copy constructor and operator= functions
// This should be used in the private: declarations for a class
TypeName(const TypeName&); \
void operator=(const TypeName&)
// 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 capture log messages in a string, rather than reporting them
// immediately:
// vector<string> errors;
// LOG_STRING(ERROR, &errors) << "Couldn't parse cookie #" << cookie_num;
// This pushes back the new error onto 'errors'; if given a NULL pointer,
// it reports the error via LOG(ERROR).
// You can also do conditional logging:
// LOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
// You can also do occasional logging (log every n'th occurrence of an
// event):
// LOG_EVERY_N(INFO, 10) << "Got the " << COUNTER << "th cookie";
// The above will cause log messages to be output on the 1st, 11th, 21st, ...
// times it is executed. Note that the special COUNTER value is used to
// identify which repetition is happening.
// You can also do occasional conditional logging (log every n'th
// occurrence of an event, when condition is satisfied):
// LOG_IF_EVERY_N(INFO, (size > 1024), 10) << "Got the " << COUNTER
// << "th big cookie";
// You can log messages the first N times your code executes a line. E.g.
// LOG_FIRST_N(INFO, 20) << "Got the " << COUNTER << "th cookie";
// Outputs log messages for the first 20 times it is executed.
// Analogous SYSLOG, SYSLOG_IF, and SYSLOG_EVERY_N macros are available.
// These log to syslog as well as to the normal logs. If you use these at
// all, you need to be aware that syslog can drastically reduce performance,
// especially if it is configured for remote logging! Don't use these
// unless you fully understand this and have a concrete need to use them.
// Even then, try to minimize your use of them.
// 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";
// DLOG_EVERY_N(INFO, 10) << "Got the " << COUNTER << "th cookie";
// All "debug mode" logging is compiled away to nothing for non-debug mode
// compiles.
// 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=mapreduce=2,file=1,gfs*=3 --v=0
// will cause:
// a. VLOG(2) and lower messages to be printed from mapreduce.{h,cc}
// b. VLOG(1) and lower messages to be printed from file.{h,cc}
// c. VLOG(3) and lower messages to be printed from files prefixed with "gfs"
// d. 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.
// 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 are also VLOG_IF, VLOG_EVERY_N and VLOG_IF_EVERY_N "verbose level"
// condition macros 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";
// VLOG_EVERY_N(1, 10)
// << "I'm printed every 10th occurrence, and when you run the program "
// "with --v=1 or more. Present occurence is " << COUNTER;
// VLOG_IF_EVERY_N(1, (size > 1024), 10)
// << "I'm printed on every 10th occurence of case when size is more "
// " than 1024, when you run the program with --v=1 or more. ";
// "Present occurence is " << COUNTER;
// The supported severity levels for macros that allow you to specify one
// are (in increasing order of severity) INFO, WARNING, ERROR, and FATAL.
// Note that messages of a given severity are logged not only in the
// logfile for that severity, but also in all logfiles of lower severity.
// E.g., a message of severity FATAL will be logged to the logfiles of
// severity FATAL, ERROR, WARNING, and INFO.
// There is also the special severity of DFATAL, which logs FATAL in
// debug mode, ERROR in normal mode.
// Very important: logging a message at the FATAL severity level causes
// the program to terminate (after the message is logged).
// Unless otherwise specified, logs will be written to the filename
// "<program name>.<hostname>.<user name>.log.<severity level>.", followed
// by the date, time, and pid (you can't prevent the date, time, and pid
// from being in the filename).
// The logging code takes two flags:
// --v=# set the verbose level
// --logtostderr log all the messages to stderr instead of to logfiles
#define DECLARE_VARIABLE(type, name, tn) \
namespace FLAG__namespace_do_not_use_directly_use_DECLARE_##tn##_instead { \
extern type FLAGS_##name; \
} \
using FLAG__namespace_do_not_use_directly_use_DECLARE_##tn##_instead::FLAGS_##name
// bool specialization
#define DECLARE_bool(name) \
DECLARE_VARIABLE(bool, name, bool)
// int32 specialization
#define DECLARE_int32(name) \
DECLARE_VARIABLE(@ac_google_namespace@::int32, name, int32)
// Special case for string, because we have to specify the namespace
// std::string, which doesn't play nicely with our FLAG__namespace hackery.
#define DECLARE_string(name) \
namespace FLAG__namespace_do_not_use_directly_use_DECLARE_string_instead { \
extern std::string FLAGS_##name; \
} \
using FLAG__namespace_do_not_use_directly_use_DECLARE_string_instead::FLAGS_##name
// Set whether log messages go to stderr instead of logfiles
// Set how important a log message should be to avoid buffering
// Log suppression level: messages logged at a lower level than this
// are suppressed.
// If specified, logfiles are written into this directory instead of the
// default logging directory.
DECLARE_int32(v); // in
#undef DECLARE_bool
#undef DECLARE_int32
#undef DECLARE_string
// Log messages below the GOOGLE_STRIP_LOG level will be compiled away for
// security reasons. See LOG(severtiy) below.
// A few definitions of macros that don't generate much code. Since
// LOG(INFO) and its ilk are used all over our code, it's
// better to have compact code for these operations.
#define COMPACT_GOOGLE_LOG_INFO @ac_google_namespace@::LogMessage(__FILE__, __LINE__)
#define COMPACT_GOOGLE_LOG_INFO @ac_google_namespace@::NullStream()
#define COMPACT_GOOGLE_LOG_WARNING @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::WARNING)
#define COMPACT_GOOGLE_LOG_WARNING @ac_google_namespace@::NullStream()
#define COMPACT_GOOGLE_LOG_ERROR @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::ERROR)
#define COMPACT_GOOGLE_LOG_ERROR @ac_google_namespace@::NullStream()
#define COMPACT_GOOGLE_LOG_FATAL @ac_google_namespace@::LogMessageFatal(__FILE__, __LINE__)
#define COMPACT_GOOGLE_LOG_FATAL @ac_google_namespace@::NullStreamFatal()
// For DFATAL, we want to use LogMessage (as opposed to
// LogMessageFatal), to be consistent with the original behavior.
#ifdef NDEBUG
#define COMPACT_GOOGLE_LOG_DFATAL @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::FATAL)
#define COMPACT_GOOGLE_LOG_DFATAL @ac_google_namespace@::NullStreamFatal()
#define GOOGLE_LOG_INFO(counter) @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::INFO, counter, &@ac_google_namespace@::LogMessage::SendToLog)
#define SYSLOG_INFO(counter) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::INFO, counter, \
#define GOOGLE_LOG_WARNING(counter) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::WARNING, counter, \
#define SYSLOG_WARNING(counter) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::WARNING, counter, \
#define GOOGLE_LOG_ERROR(counter) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::ERROR, counter, \
#define SYSLOG_ERROR(counter) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::ERROR, counter, \
#define GOOGLE_LOG_FATAL(counter) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::FATAL, counter, \
#define SYSLOG_FATAL(counter) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::FATAL, counter, \
#define GOOGLE_LOG_DFATAL(counter) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::DFATAL_LEVEL, counter, \
#define SYSLOG_DFATAL(counter) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::DFATAL_LEVEL, counter, \
#if defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__CYGWIN__) || defined(__CYGWIN32__)
// A very useful logging macro to log windows errors:
#define LOG_SYSRESULT(result) \
if (FAILED(result)) { \
LPTSTR message = NULL; \
LPTSTR msg = reinterpret_cast<LPTSTR>(&message); \
DWORD message_length = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | \
0, result, 0, msg, 100, NULL); \
if (message_length > 0) { \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, ERROR, 0, \
&@ac_google_namespace@::LogMessage::SendToLog).stream() << message; \
LocalFree(message); \
} \
// We use the preprocessor's merging operator, "##", so that, e.g.,
// LOG(INFO) becomes the token 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(severity) COMPACT_GOOGLE_LOG_ ##
#define SYSLOG(severity) SYSLOG_ ## severity(0).stream()
// They need the definitions of integer types.
#include "glog/log_severity.h"
#include "glog/vlog_is_on.h"
// Initialize google's logging library. You will see the program name
// specified by argv0 in log outputs.
void InitGoogleLogging(const char* argv0);
// Install a function which will be called after LOG(FATAL).
void InstallFailureFunction(void (*fail_func)());
class LogSink; // defined below
// If a non-NULL sink pointer is given, we push this message to that sink.
// We then do normal LOG(severity) logging as well.
// This is useful for capturing messages and passing/storing them
// somewhere more specific than the global log of the process.
// Argument types:
// LogSink* sink;
// LogSeverity severity;
// The cast is to disambiguate NULL arguments.
#define LOG_TO_SINK(sink, severity) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::severity, \
// If a non-NULL pointer is given, we push the message onto the end
// of a vector of strings; otherwise, we report it with LOG(severity).
// This is handy for capturing messages and perhaps passing them back
// to the caller, rather than reporting them immediately.
// Argument types:
// LogSeverity severity;
// vector<string> *outvec;
// The cast is to disambiguate NULL arguments.
#define LOG_STRING(severity, outvec) \
@ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::severity, \
#define LOG_IF(severity, condition) \
!(condition) ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(severity)
#define SYSLOG_IF(severity, condition) \
!(condition) ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & SYSLOG(severity)
#define LOG_ASSERT(condition) \
LOG_IF(FATAL, !(condition)) << "Assert failed: " #condition
#define SYSLOG_ASSERT(condition) \
SYSLOG_IF(FATAL, !(condition)) << "Assert failed: " #condition
// 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. Therefore, it is safe to do things like:
// CHECK(fp->Write(x) == 4)
#define CHECK(condition) \
<< "Check failed: " #condition " "
// A container for a string pointer which can be evaluated to a bool -
// true iff the pointer is NULL.
struct CheckOpString {
CheckOpString(std::string* str) : str_(str) { }
// No destructor: if str_ is non-NULL, we're about to LOG(FATAL),
// so there's no point in cleaning up str_.
operator bool() const {
std::string* str_;
// Function is overloaded for integral types to allow static const
// integrals declared in classes and not defined to be used as arguments to
// CHECK* macros. It's not encouraged though.
template <class T>
inline const T& GetReferenceableValue(const T& t) { return t; }
inline char GetReferenceableValue(char t) { return t; }
inline unsigned char GetReferenceableValue(unsigned char t) { return t; }
inline signed char GetReferenceableValue(signed char t) { return t; }
inline short GetReferenceableValue(short t) { return t; }
inline unsigned short GetReferenceableValue(unsigned short t) { return t; }
inline int GetReferenceableValue(int t) { return t; }
inline unsigned int GetReferenceableValue(unsigned int t) { return t; }
inline long GetReferenceableValue(long t) { return t; }
inline unsigned long GetReferenceableValue(unsigned long t) { return t; }
inline long long GetReferenceableValue(long long t) { return t; }
inline unsigned long long GetReferenceableValue(unsigned long long t) {
return t;
// This is a dummy class to define the following operator.
struct DummyClassToDefineOperator {};
// Define global operator<< to declare using ::operator<<.
// This declaration will allow use to use CHECK macros for user
// defined classes which have operator<< (e.g., stl_logging.h).
inline std::ostream& operator<<(
std::ostream& out, const google::DummyClassToDefineOperator& dummy) {
return out;
// Build the error message string.
template<class t1, class t2>
std::string* MakeCheckOpString(const t1& v1, const t2& v2, const char* names) {
// It means that we cannot use stl_logging if compiler doesn't
// support using expression for operator.
// TODO(hamaji): Figure out a way to fix.
#if @ac_cv_cxx_using_operator@
using ::operator<<;
std::strstream ss;
ss << names << " (" << v1 << " vs. " << v2 << ")";
return new std::string(ss.str(), ss.pcount());
// 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) { \
return Check##name##Impl<int, int>(v1, v2, names); \
// Use _EQ, _NE, _LE, etc. in case the file including base/logging.h
// provides its own #defines for the simpler names EQ, NE, LE, etc.
// This happens if, for example, those are used as token names in a
// yacc grammar.
// Helper macro for binary operators.
// Don't use this macro directly in your code, use CHECK_EQ et al below.
#if defined(STATIC_ANALYSIS)
// Only for static analysis tool to know that it is equivalent to assert
#define CHECK_OP_LOG(name, op, val1, val2, log) CHECK((val1) op (val2))
#elif !defined(NDEBUG)
// In debug mode, avoid constructing CheckOpStrings if possible,
// to reduce the overhead of CHECK statments by 2x.
// Real DCHECK-heavy tests have seen 1.5x speedups.
// The meaning of "string" might be different between now and
// when this macro gets invoked (e.g., if someone is experimenting
// with other string implementations that get defined after this
// file is included). Save the current meaning now and use it
// in the macro.
typedef std::string _Check_string;
#define CHECK_OP_LOG(name, op, val1, val2, log) \
while (@ac_google_namespace@::_Check_string* _result = \
@ac_google_namespace@::Check##name##Impl((val1), (val2), #val1 " " #op " " #val2)) \
log(__FILE__, __LINE__, @ac_google_namespace@::CheckOpString(_result)).stream()
// In optimized mode, use CheckOpString to hint to compiler that
// the while condition is unlikely.
#define CHECK_OP_LOG(name, op, val1, val2, log) \
while (@ac_google_namespace@::CheckOpString _result = \
@ac_google_namespace@::Check##name##Impl(GetReferenceableValue(val1), \
GetReferenceableValue(val2), \
#val1 " " #op " " #val2)) \
log(__FILE__, __LINE__, _result).stream()
#define CHECK_OP(name, op, val1, val2) \
CHECK_OP_LOG(name, op, val1, val2, @ac_google_namespace@::LogMessageFatal)
// Equality/Inequality checks - compare two values, and log a FATAL 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:
// CHECK_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:
// CHECK_EQ(string("abc")[1], 'b');
// WARNING: These don't 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 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)
// Check that the input is non NULL. This very useful in constructor
// initializer lists.
#define CHECK_NOTNULL(val) \
@ac_google_namespace@::CheckNotNull(__FILE__, __LINE__, "'" #val "' Must be non NULL", (val))
// Helper functions for string comparisons.
// To avoid bloat, the definitions are in
#define DECLARE_CHECK_STROP_IMPL(func, expected) \
std::string* Check##func##expected##Impl(const char* s1, const char* s2, \
const char* names);
DECLARE_CHECK_STROP_IMPL(strcasecmp, true)
DECLARE_CHECK_STROP_IMPL(strcasecmp, false)
// Helper macro for string comparisons.
// Don't use this macro directly in your code, use CHECK_STREQ et al below.
#define CHECK_STROP(func, op, expected, s1, s2) \
while (@ac_google_namespace@::CheckOpString _result = \
@ac_google_namespace@::Check##func##expected##Impl((s1), (s2), \
#s1 " " #op " " #s2)) \
LOG(FATAL) << *_result.str_
// String (char*) equality/inequality checks.
// CASE versions are case-insensitive.
// Note that "s1" and "s2" may be temporary strings which are destroyed
// by the compiler at the end of the current "full expression"
// (e.g. CHECK_STREQ(Foo().c_str(), Bar().c_str())).
#define CHECK_STREQ(s1, s2) CHECK_STROP(strcmp, ==, true, s1, s2)
#define CHECK_STRNE(s1, s2) CHECK_STROP(strcmp, !=, false, s1, s2)
#define CHECK_STRCASEEQ(s1, s2) CHECK_STROP(strcasecmp, ==, true, s1, s2)
#define CHECK_STRCASENE(s1, s2) CHECK_STROP(strcasecmp, !=, false, s1, s2)
#define CHECK_INDEX(I,A) CHECK(I < (sizeof(A)/sizeof(A[0])))
#define CHECK_BOUND(B,A) CHECK(B <= (sizeof(A)/sizeof(A[0])))
#define CHECK_DOUBLE_EQ(val1, val2) \
do { \
CHECK_LE((val1), (val2)+0.000000000000001L); \
CHECK_GE((val1), (val2)-0.000000000000001L); \
} while (0)
#define CHECK_NEAR(val1, val2, margin) \
do { \
CHECK_LE((val1), (val2)+(margin)); \
CHECK_GE((val1), (val2)-(margin)); \
} while (0)
// perror()..googly style!
// PLOG() and PLOG_IF() and PCHECK() behave exactly like their LOG* and
// CHECK equivalents with the addition that they postpend a description
// of the current state of errno to their output lines.
#define PLOG(severity) GOOGLE_PLOG(severity, 0).stream()
#define GOOGLE_PLOG(severity, counter) \
@ac_google_namespace@::ErrnoLogMessage( \
__FILE__, __LINE__, @ac_google_namespace@::severity, counter, \
#define PLOG_IF(severity, condition) \
!(condition) ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & PLOG(severity)
// A CHECK() macro that postpends errno if the condition is false. E.g.
// if (poll(fds, nfds, timeout) == -1) { PCHECK(errno == EINTR); ... }
#define PCHECK(condition) \
<< "Check failed: " #condition " "
// A CHECK() macro that lets you assert the success of a function that
// returns -1 and sets errno in case of an error. E.g.
// CHECK_ERR(mkdir(path, 0700));
// or
// int fd = open(filename, flags); CHECK_ERR(fd) << ": open " << filename;
#define CHECK_ERR(invocation) \
<< #invocation
// Use macro expansion to create, for each use of LOG_EVERY_N(), static
// variables with the __LINE__ expansion as part of the variable name.
#define LOG_EVERY_N_VARNAME(base, line) LOG_EVERY_N_VARNAME_CONCAT(base, line)
#define LOG_EVERY_N_VARNAME_CONCAT(base, line) base ## line
#define LOG_OCCURRENCES_MOD_N LOG_EVERY_N_VARNAME(occurrences_mod_n_, __LINE__)
#define SOME_KIND_OF_LOG_EVERY_N(severity, n, what_to_do) \
@ac_google_namespace@::LogMessage( \
__FILE__, __LINE__, @ac_google_namespace@::severity, LOG_OCCURRENCES, \
#define SOME_KIND_OF_LOG_IF_EVERY_N(severity, condition, n, what_to_do) \
if (condition && \
@ac_google_namespace@::LogMessage( \
__FILE__, __LINE__, @ac_google_namespace@::severity, LOG_OCCURRENCES, \
#define SOME_KIND_OF_PLOG_EVERY_N(severity, n, what_to_do) \
@ac_google_namespace@::ErrnoLogMessage( \
__FILE__, __LINE__, @ac_google_namespace@::severity, LOG_OCCURRENCES, \
#define SOME_KIND_OF_LOG_FIRST_N(severity, n, what_to_do) \
static int LOG_OCCURRENCES = 0; \
@ac_google_namespace@::LogMessage( \
__FILE__, __LINE__, @ac_google_namespace@::severity, LOG_OCCURRENCES, \
#define LOG_EVERY_N(severity, n) \
SOME_KIND_OF_LOG_EVERY_N(severity, (n), @ac_google_namespace@::LogMessage::SendToLog)
#define SYSLOG_EVERY_N(severity, n) \
SOME_KIND_OF_LOG_EVERY_N(severity, (n), @ac_google_namespace@::LogMessage::SendToSyslogAndLog)
#define PLOG_EVERY_N(severity, n) \
SOME_KIND_OF_PLOG_EVERY_N(severity, (n), @ac_google_namespace@::LogMessage::SendToLog)
#define LOG_FIRST_N(severity, n) \
SOME_KIND_OF_LOG_FIRST_N(severity, (n), @ac_google_namespace@::LogMessage::SendToLog)
#define LOG_IF_EVERY_N(severity, condition, n) \
SOME_KIND_OF_LOG_IF_EVERY_N(severity, (condition), (n), @ac_google_namespace@::LogMessage::SendToLog)
// We want the special COUNTER value available for LOG_EVERY_X()'ed messages
enum PRIVATE_Counter {COUNTER};
// Plus some debug-logging macros that get compiled to nothing for production
#ifndef NDEBUG
#define DLOG(severity) LOG(severity)
#define DLOG_IF(severity, condition) LOG_IF(severity, condition)
#define DLOG_EVERY_N(severity, n) LOG_EVERY_N(severity, n)
#define DLOG_IF_EVERY_N(severity, condition, n) \
LOG_IF_EVERY_N(severity, condition, n)
#define DLOG_ASSERT(condition) LOG_ASSERT(condition)
// debug-only checking. not executed in NDEBUG mode.
#define DCHECK(condition) CHECK(condition)
#define DCHECK_EQ(val1, val2) CHECK_EQ(val1, val2)
#define DCHECK_NE(val1, val2) CHECK_NE(val1, val2)
#define DCHECK_LE(val1, val2) CHECK_LE(val1, val2)
#define DCHECK_LT(val1, val2) CHECK_LT(val1, val2)
#define DCHECK_GE(val1, val2) CHECK_GE(val1, val2)
#define DCHECK_GT(val1, val2) CHECK_GT(val1, val2)
#define DCHECK_STREQ(str1, str2) CHECK_STREQ(str1, str2)
#define DCHECK_STRCASEEQ(str1, str2) CHECK_STRCASEEQ(str1, str2)
#define DCHECK_STRNE(str1, str2) CHECK_STRNE(str1, str2)
#define DCHECK_STRCASENE(str1, str2) CHECK_STRCASENE(str1, str2)
#else // NDEBUG
#define DLOG(severity) \
true ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(severity)
#define DLOG_IF(severity, condition) \
(true || !(condition)) ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(severity)
#define DLOG_EVERY_N(severity, n) \
true ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(severity)
#define DLOG_IF_EVERY_N(severity, condition, n) \
(true || !(condition))? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(severity)
#define DLOG_ASSERT(condition) \
true ? (void) 0 : LOG_ASSERT(condition)
#define DCHECK(condition) \
while (false) \
#define DCHECK_EQ(val1, val2) \
while (false) \
CHECK_EQ(val1, val2)
#define DCHECK_NE(val1, val2) \
while (false) \
CHECK_NE(val1, val2)
#define DCHECK_LE(val1, val2) \
while (false) \
CHECK_LE(val1, val2)
#define DCHECK_LT(val1, val2) \
while (false) \
CHECK_LT(val1, val2)
#define DCHECK_GE(val1, val2) \
while (false) \
CHECK_GE(val1, val2)
#define DCHECK_GT(val1, val2) \
while (false) \
CHECK_GT(val1, val2)
#define DCHECK_STREQ(str1, str2) \
while (false) \
CHECK_STREQ(str1, str2)
#define DCHECK_STRCASEEQ(str1, str2) \
while (false) \
#define DCHECK_STRNE(str1, str2) \
while (false) \
CHECK_STRNE(str1, str2)
#define DCHECK_STRCASENE(str1, str2) \
while (false) \
#endif // NDEBUG
// Log only in verbose mode.
#define VLOG(verboselevel) LOG_IF(INFO, VLOG_IS_ON(verboselevel))
#define VLOG_IF(verboselevel, condition) \
LOG_IF(INFO, (condition) && VLOG_IS_ON(verboselevel))
#define VLOG_EVERY_N(verboselevel, n) \
LOG_IF_EVERY_N(INFO, VLOG_IS_ON(verboselevel), n)
#define VLOG_IF_EVERY_N(verboselevel, condition, n) \
LOG_IF_EVERY_N(INFO, (condition) && VLOG_IS_ON(verboselevel), n)
// 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 LogMessage {
enum {
// Passing kNoLogPrefix for the line number disables the
// log-message prefix. Useful for using the LogMessage
// infrastructure as a printing utility. See also the --log_prefix
// flag for controlling the log-message prefix on an
// application-wide basis.
kNoLogPrefix = -1
class LogStream : public std::ostrstream {
LogStream(char *buf, int len, int ctr)
: ostrstream(buf, len),
ctr_(ctr) {
self_ = this;
int ctr() const { return ctr_; }
void set_ctr(int ctr) { ctr_ = ctr; }
LogStream* self() const { return self_; }
int ctr_; // Counter hack (for the LOG_EVERY_X() macro)
LogStream *self_; // Consistency check hack
// icc 8 requires this typedef to avoid an internal compiler error.
typedef void (LogMessage::*SendMethod)();
LogMessage(const char* file, int line, LogSeverity severity, int ctr,
SendMethod send_method);
// Two special constructors that generate reduced amounts of code at
// LOG call sites for common cases.
// Used for LOG(INFO): Implied are:
// severity = INFO, ctr = 0, send_method = &LogMessage::SendToLog.
// Using this constructor instead of the more complex constructor above
// saves 19 bytes per call site.
LogMessage(const char* file, int line);
// Used for LOG(severity) where severity != INFO. Implied
// are: ctr = 0, send_method = &LogMessage::SendToLog
// Using this constructor instead of the more complex constructor above
// saves 17 bytes per call site.
LogMessage(const char* file, int line, LogSeverity severity);
// Constructor to also log this message to a specified sink (if not NULL).
// Implied are: ctr = 0, send_method = &LogMessage::SendToSinkAndLog.
LogMessage(const char* file, int line, LogSeverity severity, LogSink* sink);
// Constructor where we also give a vector<string> pointer
// for storing the messages (if the pointer is not NULL).
// Implied are: ctr = 0, send_method = &LogMessage::SaveOrSendToLog.
LogMessage(const char* file, int line, LogSeverity severity,
std::vector<std::string>* outvec);
// A special constructor used for check failures
LogMessage(const char* file, int line, const CheckOpString& result);
// Flush a buffered message to the sink set in the constructor. Always
// called by the destructor, it may also be called from elsewhere if
// needed. Only the first call is actioned; any later ones are ignored.
void Flush();
// An arbitrary limit on the length of a single log message. This
// is so that streaming can be done more efficiently.
static const size_t kMaxLogMessageLen;
// Theses should not be called directly outside of logging.*,
// only passed as SendMethod arguments to other LogMessage methods:
void SendToLog(); // Actually dispatch to the logs
void SendToSyslogAndLog(); // Actually dispatch to syslog and the logs
// Call abort() or similar to perform LOG(FATAL) crash.
static void Fail() @ac_cv___attribute___noreturn@;
std::ostream& stream() { return data_->stream_; }
int preserved_errno() const { return data_->preserved_errno_; }
// Must be called without the log_mutex held. (L < log_mutex)
static int64 num_messages(int severity);
// Fully internal SendMethod cases:
void SendToSinkAndLog(); // Send to sink if provided and dispatch to the logs
void SaveOrSendToLog(); // Save to stringvec if provided, else to logs
struct LogMessageData;
void Init(const char* file, int line, LogSeverity severity,
void (LogMessage::*send_method)());
LogMessageData* GetMessageData(int preserved_errno, LogSeverity, int ctr);
// Counts of messages sent at each priority:
static int64 num_messages_[NUM_SEVERITIES]; // under log_mutex
static LogMessageData fatal_message_data_;
// We keep the data in a separate struct so that each instance of
// LogMessage uses less stack space.
struct LogMessageData {
// ORDER DEPENDENCY: preserved_errno_ comes before buf_ comes before
// message_text_ comes before stream_
int preserved_errno_; // preserved errno
char* buf_;
char* message_text_; // Complete message text (points to selected buffer)
LogStream stream_;
const char severity_; // What level is this LogMessage logged at?
int line_; // line number where logging call is.
void (LogMessage::*send_method_)(); // Call this in destructor to send
union { // At most one of these is used: union to keep the size low.
LogSink* sink_; // NULL or sink to send message to
std::vector<std::string>* outvec_; // NULL or vector to push message onto
time_t timestamp_; // Time of creation of LogMessage
struct ::tm tm_time_; // Time of creation of LogMessage
size_t num_prefix_chars_; // How many chars of "prefix" for this message?
size_t num_chars_to_log_; // How many chars of msg to send to log?
size_t num_chars_to_syslog_; // How many chars of msg to send to syslog?
const char* basename_; // basename of the file which called LOG.
const char* fullname_; // full name (including directory)
// of the file which called LOG.
bool has_been_flushed_; // False if data has not yet been flushed.
LogMessageData(int preserved_errno, LogSeverity severity, int ctr);
LogMessageData* allocated_;
LogMessageData* data_;
friend class LogDestination;
// This class happens to be thread-hostile because all instances share
// a single data buffer, but since it can only be created just before
// the process dies, we don't worry so much.
class LogMessageFatal : public LogMessage {
LogMessageFatal(const char* file, int line);
LogMessageFatal(const char* file, int line, const CheckOpString& result);
~LogMessageFatal() @ac_cv___attribute___noreturn@;
// A non-macro interface to the log facility; (useful
// when the logging level is not a compile-time constant).
inline void LogAtLevel(int const log_level, std::string const &msg) {
LogMessage(__FILE__, __LINE__, log_level).stream() << msg;
// A small helper for CHECK_NOTNULL().
template <typename T>
T* CheckNotNull(const char *file, int line, const char *names, T* t) {
if (t == NULL) {
LogMessageFatal(file, line, new std::string(names));
return t;
// Allow folks to put a counter in the LOG_EVERY_X()'ed messages. This
// only works if ostream is a LogStream. If the ostream is not a
// LogStream you'll get an assert saying as much at runtime.
std::ostream& operator<<(std::ostream &os, const PRIVATE_Counter&);
// Derived class for PLOG*() above.
class ErrnoLogMessage : public LogMessage {
ErrnoLogMessage(const char* file, int line, LogSeverity severity, int ctr,
void (LogMessage::*send_method)());
// Postpends ": strerror(errno) [errno]".
// 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 {
LogMessageVoidify() { }
// This has to be an operator with a precedence lower than << but
// higher than ?:
void operator&(std::ostream&) { }
// Flushes all log files that contains messages that are at least of
// the specified severity level. Thread-safe.
void FlushLogFiles(LogSeverity min_severity);
// Flushes all log files that contains messages that are at least of
// the specified severity level. Thread-hostile because it ignores
// locking -- used for catastrophic failures.
void FlushLogFilesUnsafe(LogSeverity min_severity);
// Set the destination to which a particular severity level of log
// messages is sent. If base_filename is "", it means "don't log this
// severity". Thread-safe.
void SetLogDestination(LogSeverity severity, const char* base_filename);
// Set the basename of the symlink to the latest log file at a given
// severity. If symlink_basename is empty, do not make a symlink. If
// you don't call this function, the symlink basename is the
// invocation name of the program. Thread-safe.
void SetLogSymlink(LogSeverity severity, const char* symlink_basename);
// Used to send logs to some other kind of destination
// Users should subclass LogSink and override send to do whatever they want.
// Implementations must be thread-safe because a shared instance will
// be called from whichever thread ran the LOG(XXX) line.
class LogSink {
virtual ~LogSink();
// Sink's logging logic (message_len is such as to exclude '\n' at the end).
// This method can't use LOG() or CHECK() as logging system mutex(s) are held
// during this call.
virtual void send(LogSeverity severity, const char* full_filename,
const char* base_filename, int line,
const struct ::tm* tm_time,
const char* message, size_t message_len) = 0;
// Redefine this to implement waiting for
// the sink's logging logic to complete.
// It will be called after each send() returns,
// but before that LogMessage exits or crashes.
// By default this function does nothing.
// Using this function one can implement complex logic for send()
// that itself involves logging; and do all this w/o causing deadlocks and
// inconsistent rearrangement of log messages.
// E.g. if a LogSink has thread-specific actions, the send() method
// can simply add the message to a queue and wake up another thread that
// handles real logging while itself making some LOG() calls;
// WaitTillSent() can be implemented to wait for that logic to complete.
// See our unittest for an example.
virtual void WaitTillSent();
// Returns the normal text output of the log message.
// Can be useful to implement send().
static std::string ToString(LogSeverity severity, const char* file, int line,
const struct ::tm* tm_time,
const char* message, size_t message_len);
// Add or remove a LogSink as a consumer of logging data. Thread-safe.
void AddLogSink(LogSink *destination);
void RemoveLogSink(LogSink *destination);
// Specify an "extension" added to the filename specified via
// SetLogDestination. This applies to all severity levels. It's
// often used to append the port we're listening on to the logfile
// name. Thread-safe.
void SetLogFilenameExtension(const char* filename_extension);
// Make it so that all log messages of at least a particular severity
// are logged to stderr (in addition to logging to the usual log
// file(s)). Thread-safe.
void SetStderrLogging(LogSeverity min_severity);
// Make it so that all log messages go only to stderr. Thread-safe.
void LogToStderr();
// Make it so that all log messages of at least a particular severity are
// logged via email to a list of addresses (in addition to logging to the
// usual log file(s)). The list of addresses is just a string containing
// the email addresses to send to (separated by spaces, say). Thread-safe.
void SetEmailLogging(LogSeverity min_severity, const char* addresses);
// A simple function that sends email. dest is a commma-separated
// list of addressess. Thread-safe.
bool SendEmail(const char*dest, const char *subject, const char*body);
const std::vector<std::string>& GetLoggingDirectories();
// For tests only: Clear the internal [cached] list of logging directories to
// force a refresh the next time GetLoggingDirectories is called.
// Thread-hostile.
void TestOnly_ClearLoggingDirectoriesList();
// Returns a set of existing temporary directories, which will be a
// subset of the directories returned by GetLogginDirectories().
// Thread-safe.
void GetExistingTempDirectories(std::vector<std::string>* list);
// Print any fatal message again -- useful to call from signal handler
// so that the last thing in the output is the fatal message.
// Thread-hostile, but a race is unlikely.
void ReprintFatalMessage();
// Truncate a log file that may be the append-only output of multiple
// processes and hence can't simply be renamed/reopened (typically a
// stdout/stderr). If the file "path" is > "limit" bytes, copy the
// last "keep" bytes to offset 0 and truncate the rest. Since we could
// be racing with other writers, this approach has the potential to
// lose very small amounts of data. For security, only follow symlinks
// if the path is /proc/self/fd/*
void TruncateLogFile(const char *path, int64 limit, int64 keep);
// Truncate stdout and stderr if they are over the value specified by
// --max_log_size; keep the final 1MB. This function has the same
// race condition as TruncateLogFile.
void TruncateStdoutStderr();
// Return the string representation of the provided LogSeverity level.
// Thread-safe.
const char* GetLogSeverityName(LogSeverity severity);
// ---------------------------------------------------------------------
// Implementation details that are not useful to most clients
// ---------------------------------------------------------------------
// A Logger is the interface used by logging modules to emit entries
// to a log. A typical implementation will dump formatted data to a
// sequence of files. We also provide interfaces that will forward
// the data to another thread so that the invoker never blocks.
// Implementations should be thread-safe since the logging system
// will write to them from multiple threads.
namespace base {
class Logger {
virtual ~Logger();
// Writes "message[0,message_len-1]" corresponding to an event that
// occurred at "timestamp". If "force_flush" is true, the log file
// is flushed immediately.
// The input message has already been formatted as deemed
// appropriate by the higher level logging facility. For example,
// textual log messages already contain timestamps, and the
// file:linenumber header.
virtual void Write(bool force_flush,
time_t timestamp,
const char* message,
int message_len) = 0;
// Flush any buffered messages
virtual void Flush() = 0;
// Get the current LOG file size.
// The returned value is approximate since some
// logged data may not have been flushed to disk yet.
virtual uint32 LogSize() = 0;
// Get the logger for the specified severity level. The logger
// remains the property of the logging module and should not be
// deleted by the caller. Thread-safe.
extern Logger* GetLogger(LogSeverity level);
// Set the logger for the specified severity level. The logger
// becomes the property of the logging module and should not
// be deleted by the caller. Thread-safe.
extern void SetLogger(LogSeverity level, Logger* logger);
// glibc has traditionally implemented two incompatible versions of
// strerror_r(). There is a poorly defined convention for picking the
// version that we want, but it is not clear whether it even works with
// all versions of glibc.
// So, instead, we provide this wrapper that automatically detects the
// version that is in use, and then implements POSIX semantics.
// N.B. In addition to what POSIX says, we also guarantee that "buf" will
// be set to an empty string, if this function failed. This means, in most
// cases, you do not need to check the error code and you can directly
// use the value of "buf". It will never have an undefined value.
int posix_strerror_r(int err, char *buf, size_t len);
// A class for which we define operator<<, which does nothing.
class NullStream : public LogMessage::LogStream {
// Initialize the LogStream so the messages can be written somewhere
// (they'll never be actually displayed). This will be needed if a
// NullStream& is implicitly converted to LogStream&, in which case
// the overloaded NullStream::operator<< will not be invoked.
NullStream() : LogMessage::LogStream(message_buffer_, 1, 0) { }
NullStream &stream() { return *this; }
// A very short buffer for messages (which we discard anyway). This
// will be needed if NullStream& converted to LogStream& (e.g. as a
// result of a conditional expression).
char message_buffer_[2];
// Do nothing. This operator is inline, allowing the message to be
// compiled away. The message will not be compiled away if we do
// something like (flag ? LOG(INFO) : LOG(ERROR)) << message; when
// SKIP_LOG=WARNING. In those cases, NullStream will be implicitly
// converted to LogStream and the message will be computed and then
// quietly discarded.
template<class T>
inline NullStream& operator<<(NullStream &str, const T &value) { return str; }
// Similar to NullStream, but aborts the program (without stack
// trace), like LogMessageFatal.
class NullStreamFatal : public NullStream {
@ac_cv___attribute___noreturn@ ~NullStreamFatal() { _exit(1); }
// Undefine these macros not to taint namespace.
#endif // _LOGGING_H_