blob: 4840dfe462d9af161f6f5518781faf5996ca5d86 [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.
// 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 LOG macro which facilitate logging
// of common error conditions, detailed below.
// LOG(sev) logs the given stream at severity "sev", which must be a
// compile-time constant of the LoggingSeverity type, without the namespace
// prefix.
// LOG_V(sev) Like LOG(), but sev is a run-time variable of the LoggingSeverity
// type (basically, it just doesn't prepend the namespace).
// LOG_F(sev) Like LOG(), but includes the name of the current function.
// LOG_T(sev) Like LOG(), but includes the this pointer.
// LOG_T_F(sev) Like LOG_F(), but includes the this pointer.
// LOG_GLE(M)(sev [, mod]) attempt to add a string description of the
// HRESULT returned by GetLastError. The "M" variant allows searching of a
// DLL's string table for the error description.
// 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.
// 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.)
// LOG_E(sev, ctx, err, ...) logs a detailed error interpreted using the
// specified context.
// LOG_CHECK_LEVEL(sev) (and 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.
// Lastly, PLOG(sev, err) is an alias for LOG_ERR_EX.
#include "config.h" // NOLINT
#include <list>
#include <sstream>
#include <string>
#include <utility>
#include "webrtc/base/basictypes.h"
#include "webrtc/base/criticalsection.h"
#include "webrtc/base/thread_annotations.h"
namespace rtc {
// ConstantLabel can be used to easily generate string names from constant
// values. This can be useful for logging descriptive names of error messages.
// Usage:
// const ConstantLabel LIBRARY_ERRORS[] = {
// ...
// }
// int err = LibraryFunc();
// LOG(LS_ERROR) << "LibraryFunc returned: "
// << ErrorName(err, LIBRARY_ERRORS);
struct ConstantLabel { int value; const char * label; };
#define KLABEL(x) { x, #x }
#define TLABEL(x, y) { x, y }
#define LASTLABEL { 0, 0 }
const char* FindLabel(int value, const ConstantLabel entries[]);
std::string ErrorName(int err, const ConstantLabel* err_table);
// Note that the non-standard LoggingSeverity aliases exist because they are
// still in broad use. The meanings of the levels are:
// LS_SENSITIVE: Information which should only be logged with the consent
// of the user, due to privacy concerns.
// 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& message) = 0;
class LogMessage {
static const uint32 WARN_SLOW_LOGS_DELAY = 50; // ms
LogMessage(const char* file, int line, LoggingSeverity sev,
LogErrorContext err_ctx = ERRCTX_NONE, int err = 0,
const char* module = NULL);
static inline bool Loggable(LoggingSeverity sev) { return (sev >= min_sev_); }
std::ostream& stream() { return print_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 uint32 LogStartTime();
// Returns the wall clock equivalent of |LogStartTime|, in seconds from the
// epoch.
static uint32 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() { return dbg_sev_; }
// 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 = NULL);
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() { return min_sev_; }
// Parses the provided parameter stream to configure the options above.
// Useful for configuring logging from the command line.
static void ConfigureLogging(const char* params);
typedef std::pair<LogSink*, LoggingSeverity> StreamAndSeverity;
typedef std::list<StreamAndSeverity> StreamList;
// Updates min_sev_ appropriately when debug sinks change.
static void UpdateMinLogSeverity() EXCLUSIVE_LOCKS_REQUIRED(crit_);
// These write out the actual log messages.
static void OutputToDebug(const std::string& msg, LoggingSeverity severity_);
// The ostream that buffers the formatted message before output
std::ostringstream print_stream_;
// The severity level of this message
LoggingSeverity severity_;
// String data generated in the constructor, that should be appended to
// the message before output.
std::string extra_;
// If time it takes to write to stream is more than this, log one
// additional warning about it.
uint32 warn_slow_logs_delay_;
// Global lock for the logging subsystem
static CriticalSection crit_;
// dbg_sev_ is the thresholds for those output targets
// min_sev_ is the minimum (most verbose) of those levels, and is used
// as a short-circuit in the logging macros to identify messages that won't
// be logged.
// ctx_sev_ is the minimum level at which file context is displayed
static LoggingSeverity min_sev_, dbg_sev_, ctx_sev_;
// 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
class LogMultilineState {
size_t unprintable_count_[2];
LogMultilineState() {
unprintable_count_[0] = unprintable_count_[1] = 0;
// When possible, pass optional state variable to track various data across
// multiple calls to LogMultiline. Otherwise, pass NULL.
void LogMultiline(LoggingSeverity level, const char* label, bool input,
const void* data, size_t len, bool hex_mode,
LogMultilineState* state);
#ifndef LOG
// The following non-obvious technique for implementation of a
// conditional log stream was stolen from google3/base/logging.h.
// 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&) { }
!(rtc::LogMessage::Loggable(sev)) \
? (void) 0 \
: rtc::LogMessageVoidify() &
#define LOG(sev) \
rtc::LogMessage(__FILE__, __LINE__, rtc::sev).stream()
// The _V version is for when a variable is passed in. It doesn't do the
// namespace concatination.
#define LOG_V(sev) \
rtc::LogMessage(__FILE__, __LINE__, sev).stream()
// The _F version prefixes the message with the current function name.
#if (defined(__GNUC__) && defined(_DEBUG)) || defined(WANT_PRETTY_LOG_F)
#define LOG_F(sev) LOG(sev) << __PRETTY_FUNCTION__ << ": "
#define LOG_T_F(sev) LOG(sev) << this << ": " << __PRETTY_FUNCTION__ << ": "
#define LOG_F(sev) LOG(sev) << __FUNCTION__ << ": "
#define LOG_T_F(sev) LOG(sev) << this << ": " << __FUNCTION__ << ": "
#define LOG_CHECK_LEVEL(sev) \
#define LOG_CHECK_LEVEL_V(sev) \
inline bool LogCheckLevel(LoggingSeverity sev) {
return (LogMessage::GetMinLogSeverity() <= sev);
#define LOG_E(sev, ctx, err, ...) \
rtc::LogMessage(__FILE__, __LINE__, rtc::sev, \
rtc::ERRCTX_ ## ctx, err , ##__VA_ARGS__) \
#define LOG_T(sev) LOG(sev) << this << ": "
#define LOG_ERRNO_EX(sev, err) \
LOG_E(sev, ERRNO, err)
#define LOG_ERRNO(sev) \
LOG_ERRNO_EX(sev, errno)
#if defined(WEBRTC_WIN)
#define LOG_GLE_EX(sev, err) \
LOG_E(sev, HRESULT, err)
#define LOG_GLE(sev) \
LOG_GLE_EX(sev, GetLastError())
#define LOG_GLEM(sev, mod) \
LOG_E(sev, HRESULT, GetLastError(), mod)
#define LOG_ERR_EX(sev, err) \
LOG_GLE_EX(sev, err)
#define LOG_ERR(sev) \
#elif __native_client__
#define LOG_ERR_EX(sev, err) \
#define LOG_ERR(sev) \
#elif defined(WEBRTC_POSIX)
#define LOG_ERR_EX(sev, err) \
LOG_ERRNO_EX(sev, err)
#define LOG_ERR(sev) \
#endif // WEBRTC_WIN
#define PLOG(sev, err) \
LOG_ERR_EX(sev, err)
// TODO(?): Add an "assert" wrapper that logs in the same manner.
#endif // LOG
} // namespace rtc