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// Copyright 2006-2009 the V8 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.
#ifndef V8_LOGGING_LOG_UTILS_H_
#define V8_LOGGING_LOG_UTILS_H_
#include <stdio.h>
#include <cstdarg>
#include "src/base/compiler-specific.h"
#include "src/base/optional.h"
#include "src/base/platform/mutex.h"
#include "src/flags/flags.h"
#include "src/utils/allocation.h"
#include "src/utils/ostreams.h"
namespace v8 {
namespace internal {
class Logger;
template <typename T>
class Vector;
enum class LogSeparator { kSeparator };
// Functions and data for performing output of log messages.
class Log {
public:
Log(Logger* log, const char* log_file_name);
// Disables logging, but preserves acquired resources.
void stop() { is_stopped_ = true; }
static bool InitLogAtStart() {
return FLAG_log || FLAG_log_api || FLAG_log_code || FLAG_log_handles ||
FLAG_log_suspect || FLAG_ll_prof || FLAG_perf_basic_prof ||
FLAG_perf_prof || FLAG_log_source_code || FLAG_gdbjit ||
FLAG_log_internal_timer_events || FLAG_prof_cpp || FLAG_trace_ic ||
FLAG_log_function_events;
}
// Frees all resources acquired in Initialize and Open... functions.
// When a temporary file is used for the log, returns its stream descriptor,
// leaving the file open.
FILE* Close();
// Returns whether logging is enabled.
bool IsEnabled() { return !is_stopped_ && output_handle_ != nullptr; }
// Size of buffer used for formatting log messages.
static const int kMessageBufferSize = 2048;
// This mode is only used in tests, as temporary files are automatically
// deleted on close and thus can't be accessed afterwards.
V8_EXPORT_PRIVATE static const char* const kLogToTemporaryFile;
static const char* const kLogToConsole;
// Utility class for formatting log messages. It escapes the given messages
// and then appends them to the static buffer in Log.
class MessageBuilder {
public:
// Create a message builder starting from position 0.
// This acquires the mutex in the log as well.
explicit MessageBuilder(Log* log);
~MessageBuilder() = default;
void AppendString(String str,
base::Optional<int> length_limit = base::nullopt);
void AppendString(Vector<const char> str);
void AppendString(const char* str);
void AppendString(const char* str, size_t length);
void PRINTF_FORMAT(2, 3) AppendFormatString(const char* format, ...);
void AppendCharacter(char c);
void AppendSymbolName(Symbol symbol);
// Delegate insertion to the underlying {log_}.
// All appended strings are escaped to maintain one-line log entries.
template <typename T>
MessageBuilder& operator<<(T value) {
log_->os_ << value;
return *this;
}
// Finish the current log line an flush the it to the log file.
void WriteToLogFile();
private:
// Prints the format string into |log_->format_buffer_|. Returns the length
// of the result, or kMessageBufferSize if it was truncated.
int PRINTF_FORMAT(2, 0)
FormatStringIntoBuffer(const char* format, va_list args);
void AppendSymbolNameDetails(String str, bool show_impl_info);
void PRINTF_FORMAT(2, 3) AppendRawFormatString(const char* format, ...);
void AppendRawCharacter(const char character);
Log* log_;
base::MutexGuard lock_guard_;
};
private:
static FILE* CreateOutputHandle(const char* file_name);
// Implementation of writing to a log file.
int WriteToFile(const char* msg, int length) {
DCHECK_NOT_NULL(output_handle_);
os_.write(msg, length);
DCHECK(!os_.bad());
return length;
}
// Whether logging is stopped (e.g. due to insufficient resources).
bool is_stopped_;
// When logging is active output_handle_ is used to store a pointer to log
// destination. mutex_ should be acquired before using output_handle_.
FILE* output_handle_;
OFStream os_;
// mutex_ is a Mutex used for enforcing exclusive
// access to the formatting buffer and the log file or log memory buffer.
base::Mutex mutex_;
// Buffer used for formatting log messages. This is a singleton buffer and
// mutex_ should be acquired before using it.
std::unique_ptr<char[]> format_buffer_;
Logger* logger_;
friend class Logger;
};
template <>
Log::MessageBuilder& Log::MessageBuilder::operator<<<LogSeparator>(
LogSeparator separator);
template <>
Log::MessageBuilder& Log::MessageBuilder::operator<<<void*>(void* pointer);
template <>
Log::MessageBuilder& Log::MessageBuilder::operator<<<const char*>(
const char* string);
template <>
Log::MessageBuilder& Log::MessageBuilder::operator<<<char>(char c);
template <>
Log::MessageBuilder& Log::MessageBuilder::operator<<<String>(String string);
template <>
Log::MessageBuilder& Log::MessageBuilder::operator<<<Symbol>(Symbol symbol);
template <>
Log::MessageBuilder& Log::MessageBuilder::operator<<<Name>(Name name);
} // namespace internal
} // namespace v8
#endif // V8_LOGGING_LOG_UTILS_H_
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