blob: 5cd4f72f2278cdc645fda23384596cd5963a7d6a [file] [log] [blame]
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
// RTC_LOG(...) an ostream target that can be used to send formatted
// output to a variety of logging targets, such as debugger console, stderr,
// or any LogSink.
// The severity level passed as the first argument to the logging
// functions is used as a filter, to limit the verbosity of the logging.
// Static members of LogMessage documented below are used to control the
// verbosity and target of the output.
// There are several variations on the RTC_LOG macro which facilitate logging
// of common error conditions, detailed below.
// RTC_LOG(sev) logs the given stream at severity "sev", which must be a
// compile-time constant of the LoggingSeverity type, without the namespace
// prefix.
// RTC_LOG_V(sev) Like RTC_LOG(), but sev is a run-time variable of the
// LoggingSeverity type (basically, it just doesn't prepend the namespace).
// RTC_LOG_F(sev) Like RTC_LOG(), but includes the name of the current function.
// RTC_LOG_T(sev) Like RTC_LOG(), but includes the this pointer.
// RTC_LOG_T_F(sev) Like RTC_LOG_F(), but includes the this pointer.
// RTC_LOG_GLE(sev [, mod]) attempt to add a string description of the
// HRESULT returned by GetLastError.
// RTC_LOG_ERRNO(sev) attempts to add a string description of an errno-derived
// error. errno and associated facilities exist on both Windows and POSIX,
// but on Windows they only apply to the C/C++ runtime.
// RTC_LOG_ERR(sev) is an alias for the platform's normal error system, i.e.
// _GLE on Windows and _ERRNO on POSIX.
// (The above three also all have _EX versions that let you specify the error
// code, rather than using the last one.)
// RTC_LOG_E(sev, ctx, err, ...) logs a detailed error interpreted using the
// specified context.
// RTC_LOG_CHECK_LEVEL(sev) (and RTC_LOG_CHECK_LEVEL_V(sev)) can be used as a
// test before performing expensive or sensitive operations whose sole
// purpose is to output logging data at the desired level.
#include <errno.h>
#include <list>
#include <sstream> // no-presubmit-check TODO(webrtc:8982)
#include <string>
#include <utility>
#include "absl/strings/string_view.h"
#include "rtc_base/constructor_magic.h"
#include "rtc_base/deprecation.h"
#include "rtc_base/strings/string_builder.h"
#include "rtc_base/system/inline.h"
#if defined(WEBRTC_MAC) && !defined(WEBRTC_IOS)
#include "rtc_base/logging_mac.h"
#endif // WEBRTC_MAC
#if !defined(NDEBUG) || defined(DLOG_ALWAYS_ON)
#define RTC_DLOG_IS_ON 1
#define RTC_DLOG_IS_ON 0
namespace rtc {
// Note that the non-standard LoggingSeverity aliases exist because they are
// still in broad use. The meanings of the levels are:
// LS_VERBOSE: This level is for data which we do not want to appear in the
// normal debug log, but should appear in diagnostic logs.
// LS_INFO: Chatty level used in debugging for all sorts of things, the default
// in debug builds.
// LS_WARNING: Something that may warrant investigation.
// LS_ERROR: Something that should not have occurred.
// LS_NONE: Don't log.
enum LoggingSeverity {
// LogErrorContext assists in interpreting the meaning of an error value.
enum LogErrorContext {
ERRCTX_ERRNO, // System-local errno
// Abbreviations for LOG_E macro
// Virtual sink interface that can receive log messages.
class LogSink {
LogSink() {}
virtual ~LogSink() {}
virtual void OnLogMessage(const std::string& msg,
LoggingSeverity severity,
const char* tag);
virtual void OnLogMessage(const std::string& message,
LoggingSeverity severity);
virtual void OnLogMessage(const std::string& message) = 0;
namespace webrtc_logging_impl {
class LogMetadata {
LogMetadata(const char* file, int line, LoggingSeverity severity)
: file_(file),
line_and_sev_(static_cast<uint32_t>(line) << 3 | severity) {}
LogMetadata() = default;
const char* File() const { return file_; }
int Line() const { return line_and_sev_ >> 3; }
LoggingSeverity Severity() const {
return static_cast<LoggingSeverity>(line_and_sev_ & 0x7);
const char* file_;
// Line number and severity, the former in the most significant 29 bits, the
// latter in the least significant 3 bits. (This is an optimization; since
// both numbers are usually compile-time constants, this way we can load them
// both with a single instruction.)
uint32_t line_and_sev_;
static_assert(std::is_trivial<LogMetadata>::value, "");
struct LogMetadataErr {
LogMetadata meta;
LogErrorContext err_ctx;
int err;
struct LogMetadataTag {
LoggingSeverity severity;
const char* tag;
enum class LogArgType : int8_t {
kEnd = 0,
// Wrapper for log arguments. Only ever make values of this type with the
// MakeVal() functions.
template <LogArgType N, typename T>
struct Val {
static constexpr LogArgType Type() { return N; }
T GetVal() const { return val; }
T val;
// TODO( Get rid of this specialization when callers
// don't need it anymore. No in-tree caller does, but some external callers
// still do.
template <>
struct Val<LogArgType::kStdString, std::string> {
static constexpr LogArgType Type() { return LogArgType::kStdString; }
const std::string* GetVal() const { return &val; }
std::string val;
inline Val<LogArgType::kInt, int> MakeVal(int x) {
return {x};
inline Val<LogArgType::kLong, long> MakeVal(long x) {
return {x};
inline Val<LogArgType::kLongLong, long long> MakeVal(long long x) {
return {x};
inline Val<LogArgType::kUInt, unsigned int> MakeVal(unsigned int x) {
return {x};
inline Val<LogArgType::kULong, unsigned long> MakeVal(unsigned long x) {
return {x};
inline Val<LogArgType::kULongLong, unsigned long long> MakeVal(
unsigned long long x) {
return {x};
inline Val<LogArgType::kDouble, double> MakeVal(double x) {
return {x};
inline Val<LogArgType::kLongDouble, long double> MakeVal(long double x) {
return {x};
inline Val<LogArgType::kCharP, const char*> MakeVal(const char* x) {
return {x};
inline Val<LogArgType::kStdString, const std::string*> MakeVal(
const std::string& x) {
return {&x};
inline Val<LogArgType::kStringView, const absl::string_view*> MakeVal(
const absl::string_view& x) {
return {&x};
inline Val<LogArgType::kVoidP, const void*> MakeVal(const void* x) {
return {x};
inline Val<LogArgType::kLogMetadata, LogMetadata> MakeVal(
const LogMetadata& x) {
return {x};
inline Val<LogArgType::kLogMetadataErr, LogMetadataErr> MakeVal(
const LogMetadataErr& x) {
return {x};
inline Val<LogArgType::kLogMetadataTag, LogMetadataTag> MakeVal(
const LogMetadataTag& x) {
return {x};
// Handle arbitrary types other than the above by falling back to stringstream.
// TODO( Get rid of this overload when callers don't need
// it anymore. No in-tree caller does, but some external callers still do.
template <
typename T,
typename T1 =
typename std::remove_cv<typename std::remove_reference<T>::type>::type,
typename std::enable_if<
std::is_class<T1>::value && !std::is_same<T1, std::string>::value &&
!std::is_same<T1, LogMetadata>::value &&
!std::is_same<T1, LogMetadataTag>::value &&
!std::is_same<T1, LogMetadataErr>::value>::type* = nullptr>
Val<LogArgType::kStdString, std::string> MakeVal(const T& x) {
std::ostringstream os; // no-presubmit-check TODO(webrtc:8982)
os << x;
return {os.str()};
void Log(const LogArgType* fmt, ...);
// Ephemeral type that represents the result of the logging << operator.
template <typename... Ts>
class LogStreamer;
// Base case: Before the first << argument.
template <>
class LogStreamer<> final {
template <
typename U,
typename std::enable_if<std::is_arithmetic<U>::value>::type* = nullptr>
RTC_FORCE_INLINE LogStreamer<decltype(MakeVal(std::declval<U>()))> operator<<(
U arg) const {
return LogStreamer<decltype(MakeVal(std::declval<U>()))>(MakeVal(arg),
template <
typename U,
typename std::enable_if<!std::is_arithmetic<U>::value>::type* = nullptr>
RTC_FORCE_INLINE LogStreamer<decltype(MakeVal(std::declval<U>()))> operator<<(
const U& arg) const {
return LogStreamer<decltype(MakeVal(std::declval<U>()))>(MakeVal(arg),
template <typename... Us>
RTC_FORCE_INLINE static void Call(const Us&... args) {
static constexpr LogArgType t[] = {Us::Type()..., LogArgType::kEnd};
Log(t, args.GetVal()...);
// Inductive case: We've already seen at least one << argument. The most recent
// one had type `T`, and the earlier ones had types `Ts`.
template <typename T, typename... Ts>
class LogStreamer<T, Ts...> final {
RTC_FORCE_INLINE LogStreamer(T arg, const LogStreamer<Ts...>* prior)
: arg_(arg), prior_(prior) {}
template <
typename U,
typename std::enable_if<std::is_arithmetic<U>::value>::type* = nullptr>
RTC_FORCE_INLINE LogStreamer<decltype(MakeVal(std::declval<U>())), T, Ts...>
operator<<(U arg) const {
return LogStreamer<decltype(MakeVal(std::declval<U>())), T, Ts...>(
MakeVal(arg), this);
template <
typename U,
typename std::enable_if<!std::is_arithmetic<U>::value>::type* = nullptr>
RTC_FORCE_INLINE LogStreamer<decltype(MakeVal(std::declval<U>())), T, Ts...>
operator<<(const U& arg) const {
return LogStreamer<decltype(MakeVal(std::declval<U>())), T, Ts...>(
MakeVal(arg), this);
template <typename... Us>
RTC_FORCE_INLINE void Call(const Us&... args) const {
prior_->Call(arg_, args...);
// The most recent argument.
T arg_;
// Earlier arguments.
const LogStreamer<Ts...>* prior_;
class LogCall final {
// This can be any binary operator with precedence lower than <<.
template <typename... Ts>
RTC_FORCE_INLINE void operator&(const LogStreamer<Ts...>& streamer) {
} // namespace webrtc_logging_impl
// Direct use of this class is deprecated; please use the logging macros
// instead.
// TODO( Move this class to an unnamed namespace in the
// .cc file.
class LogMessage {
LogMessage(const char* file, int line, LoggingSeverity sev);
// Same as the above, but using a compile-time constant for the logging
// severity. This saves space at the call site, since passing an empty struct
// is generally the same as not passing an argument at all.
template <LoggingSeverity S>
RTC_NO_INLINE LogMessage(const char* file,
int line,
std::integral_constant<LoggingSeverity, S>)
: LogMessage(file, line, S) {}
LogMessage(const char* file,
int line,
LoggingSeverity sev,
LogErrorContext err_ctx,
int err);
#if defined(WEBRTC_ANDROID)
LogMessage(const char* file, int line, LoggingSeverity sev, const char* tag);
// Android code should use the 'const char*' version since tags are static
// and we want to avoid allocating a std::string copy per log line.
LogMessage(const char* file,
int line,
LoggingSeverity sev,
const std::string& tag);
void AddTag(const char* tag);
rtc::StringBuilder& stream();
// Returns the time at which this function was called for the first time.
// The time will be used as the logging start time.
// If this is not called externally, the LogMessage ctor also calls it, in
// which case the logging start time will be the time of the first LogMessage
// instance is created.
static int64_t LogStartTime();
// Returns the wall clock equivalent of |LogStartTime|, in seconds from the
// epoch.
static uint32_t WallClockStartTime();
// LogThreads: Display the thread identifier of the current thread
static void LogThreads(bool on = true);
// LogTimestamps: Display the elapsed time of the program
static void LogTimestamps(bool on = true);
// These are the available logging channels
// Debug: Debug console on Windows, otherwise stderr
static void LogToDebug(LoggingSeverity min_sev);
static LoggingSeverity GetLogToDebug();
// Sets whether logs will be directed to stderr in debug mode.
static void SetLogToStderr(bool log_to_stderr);
// Stream: Any non-blocking stream interface. LogMessage takes ownership of
// the stream. Multiple streams may be specified by using AddLogToStream.
// LogToStream is retained for backwards compatibility; when invoked, it
// will discard any previously set streams and install the specified stream.
// GetLogToStream gets the severity for the specified stream, of if none
// is specified, the minimum stream severity.
// RemoveLogToStream removes the specified stream, without destroying it.
static int GetLogToStream(LogSink* stream = nullptr);
static void AddLogToStream(LogSink* stream, LoggingSeverity min_sev);
static void RemoveLogToStream(LogSink* stream);
// Testing against MinLogSeverity allows code to avoid potentially expensive
// logging operations by pre-checking the logging level.
static int GetMinLogSeverity();
// Parses the provided parameter stream to configure the options above.
// Useful for configuring logging from the command line.
static void ConfigureLogging(const char* params);
// Checks the current global debug severity and if the |streams_| collection
// is empty. If |severity| is smaller than the global severity and if the
// |streams_| collection is empty, the LogMessage will be considered a noop
// LogMessage.
static bool IsNoop(LoggingSeverity severity);
friend class LogMessageForTesting;
typedef std::pair<LogSink*, LoggingSeverity> StreamAndSeverity;
typedef std::list<StreamAndSeverity> StreamList;
// Updates min_sev_ appropriately when debug sinks change.
static void UpdateMinLogSeverity();
// These write out the actual log messages.
#if defined(WEBRTC_ANDROID)
static void OutputToDebug(const std::string& msg,
LoggingSeverity severity,
const char* tag);
static void OutputToDebug(const std::string& msg, LoggingSeverity severity);
// Called from the dtor (or from a test) to append optional extra error
// information to the log stream and a newline character.
void FinishPrintStream();
// The stringbuilder that buffers the formatted message before output
rtc::StringBuilder print_stream_;
// The severity level of this message
LoggingSeverity severity_;
#if defined(WEBRTC_ANDROID)
// The default Android debug output tag.
const char* tag_ = "libjingle";
// String data generated in the constructor, that should be appended to
// the message before output.
std::string extra_;
// The output streams and their associated severities
static StreamList streams_;
// Flags for formatting options
static bool thread_, timestamp_;
// Determines if logs will be directed to stderr in debug mode.
static bool log_to_stderr_;
// Logging Helpers
#define RTC_LOG_FILE_LINE(sev, file, line) \
rtc::webrtc_logging_impl::LogCall() & \
rtc::webrtc_logging_impl::LogStreamer<>() \
<< rtc::webrtc_logging_impl::LogMetadata(file, line, sev)
#define RTC_LOG(sev) RTC_LOG_FILE_LINE(rtc::sev, __FILE__, __LINE__)
// The _V version is for when a variable is passed in.
#define RTC_LOG_V(sev) RTC_LOG_FILE_LINE(sev, __FILE__, __LINE__)
// The _F version prefixes the message with the current function name.
#if (defined(__GNUC__) && !defined(NDEBUG)) || defined(WANT_PRETTY_LOG_F)
#define RTC_LOG_F(sev) RTC_LOG(sev) << __PRETTY_FUNCTION__ << ": "
#define RTC_LOG_T_F(sev) \
RTC_LOG(sev) << this << ": " << __PRETTY_FUNCTION__ << ": "
#define RTC_LOG_F(sev) RTC_LOG(sev) << __FUNCTION__ << ": "
#define RTC_LOG_T_F(sev) RTC_LOG(sev) << this << ": " << __FUNCTION__ << ": "
#define RTC_LOG_CHECK_LEVEL(sev) rtc::LogCheckLevel(rtc::sev)
#define RTC_LOG_CHECK_LEVEL_V(sev) rtc::LogCheckLevel(sev)
inline bool LogCheckLevel(LoggingSeverity sev) {
return (LogMessage::GetMinLogSeverity() <= sev);
#define RTC_LOG_E(sev, ctx, err) \
rtc::webrtc_logging_impl::LogCall() & \
rtc::webrtc_logging_impl::LogStreamer<>() \
<< rtc::webrtc_logging_impl::LogMetadataErr { \
{__FILE__, __LINE__, rtc::sev}, rtc::ERRCTX_##ctx, (err) \
#define RTC_LOG_T(sev) RTC_LOG(sev) << this << ": "
#define RTC_LOG_ERRNO_EX(sev, err) RTC_LOG_E(sev, ERRNO, err)
#define RTC_LOG_ERRNO(sev) RTC_LOG_ERRNO_EX(sev, errno)
#if defined(WEBRTC_WIN)
#define RTC_LOG_GLE_EX(sev, err) RTC_LOG_E(sev, HRESULT, err)
#define RTC_LOG_GLE(sev) RTC_LOG_GLE_EX(sev, static_cast<int>(GetLastError()))
#define RTC_LOG_ERR_EX(sev, err) RTC_LOG_GLE_EX(sev, err)
#define RTC_LOG_ERR(sev) RTC_LOG_GLE(sev)
#elif defined(__native_client__) && __native_client__
#define RTC_LOG_ERR_EX(sev, err) RTC_LOG(sev)
#define RTC_LOG_ERR(sev) RTC_LOG(sev)
#elif defined(WEBRTC_POSIX)
#define RTC_LOG_ERR_EX(sev, err) RTC_LOG_ERRNO_EX(sev, err)
#define RTC_LOG_ERR(sev) RTC_LOG_ERRNO(sev)
#endif // WEBRTC_WIN
namespace webrtc_logging_impl {
// TODO(kwiberg): Replace these with absl::string_view.
inline const char* AdaptString(const char* str) {
return str;
inline const char* AdaptString(const std::string& str) {
return str.c_str();
} // namespace webrtc_logging_impl
#define RTC_LOG_TAG(sev, tag) \
rtc::webrtc_logging_impl::LogCall() & \
rtc::webrtc_logging_impl::LogStreamer<>() \
<< rtc::webrtc_logging_impl::LogMetadataTag { \
sev, rtc::webrtc_logging_impl::AdaptString(tag) \
// DEPRECATED. This macro is only intended for Android.
#define RTC_LOG_TAG(sev, tag) RTC_LOG_V(sev)
// The RTC_DLOG macros are equivalent to their RTC_LOG counterparts except that
// they only generate code in debug builds.
#define RTC_DLOG(sev) RTC_LOG(sev)
#define RTC_DLOG_V(sev) RTC_LOG_V(sev)
#define RTC_DLOG_F(sev) RTC_LOG_F(sev)
while (false) \
} // namespace rtc