Ви не можете вибрати більше 25 тем
Теми мають розпочинатися з літери або цифри, можуть містити дефіси (-) і не повинні перевищувати 35 символів.
124 рядки
4.4 KiB
124 рядки
4.4 KiB
// Copyright (c) 2018 The LevelDB Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file. See the AUTHORS file for names of contributors.
|
|
//
|
|
// Logger implementation for the Windows platform.
|
|
|
|
#ifndef STORAGE_LEVELDB_UTIL_WINDOWS_LOGGER_H_
|
|
#define STORAGE_LEVELDB_UTIL_WINDOWS_LOGGER_H_
|
|
|
|
#include <cassert>
|
|
#include <cstdarg>
|
|
#include <cstdio>
|
|
#include <ctime>
|
|
#include <sstream>
|
|
#include <thread>
|
|
|
|
#include "leveldb/env.h"
|
|
|
|
namespace leveldb {
|
|
|
|
class WindowsLogger final : public Logger {
|
|
public:
|
|
// Creates a logger that writes to the given file.
|
|
//
|
|
// The PosixLogger instance takes ownership of the file handle.
|
|
explicit WindowsLogger(std::FILE* fp) : fp_(fp) { assert(fp != nullptr); }
|
|
|
|
~WindowsLogger() override { std::fclose(fp_); }
|
|
|
|
void Logv(const char* format, std::va_list arguments) override {
|
|
// Record the time as close to the Logv() call as possible.
|
|
SYSTEMTIME now_components;
|
|
::GetLocalTime(&now_components);
|
|
|
|
// Record the thread ID.
|
|
constexpr const int kMaxThreadIdSize = 32;
|
|
std::ostringstream thread_stream;
|
|
thread_stream << std::this_thread::get_id();
|
|
std::string thread_id = thread_stream.str();
|
|
if (thread_id.size() > kMaxThreadIdSize) {
|
|
thread_id.resize(kMaxThreadIdSize);
|
|
}
|
|
|
|
// We first attempt to print into a stack-allocated buffer. If this attempt
|
|
// fails, we make a second attempt with a dynamically allocated buffer.
|
|
constexpr const int kStackBufferSize = 512;
|
|
char stack_buffer[kStackBufferSize];
|
|
static_assert(sizeof(stack_buffer) == static_cast<size_t>(kStackBufferSize),
|
|
"sizeof(char) is expected to be 1 in C++");
|
|
|
|
int dynamic_buffer_size = 0; // Computed in the first iteration.
|
|
for (int iteration = 0; iteration < 2; ++iteration) {
|
|
const int buffer_size =
|
|
(iteration == 0) ? kStackBufferSize : dynamic_buffer_size;
|
|
char* const buffer =
|
|
(iteration == 0) ? stack_buffer : new char[dynamic_buffer_size];
|
|
|
|
// Print the header into the buffer.
|
|
int buffer_offset = std::snprintf(
|
|
buffer, buffer_size, "%04d/%02d/%02d-%02d:%02d:%02d.%06d %s ",
|
|
now_components.wYear, now_components.wMonth, now_components.wDay,
|
|
now_components.wHour, now_components.wMinute, now_components.wSecond,
|
|
static_cast<int>(now_components.wMilliseconds * 1000),
|
|
thread_id.c_str());
|
|
|
|
// The header can be at most 28 characters (10 date + 15 time +
|
|
// 3 delimiters) plus the thread ID, which should fit comfortably into the
|
|
// static buffer.
|
|
assert(buffer_offset <= 28 + kMaxThreadIdSize);
|
|
static_assert(28 + kMaxThreadIdSize < kStackBufferSize,
|
|
"stack-allocated buffer may not fit the message header");
|
|
assert(buffer_offset < buffer_size);
|
|
|
|
// Print the message into the buffer.
|
|
std::va_list arguments_copy;
|
|
va_copy(arguments_copy, arguments);
|
|
buffer_offset +=
|
|
std::vsnprintf(buffer + buffer_offset, buffer_size - buffer_offset,
|
|
format, arguments_copy);
|
|
va_end(arguments_copy);
|
|
|
|
// The code below may append a newline at the end of the buffer, which
|
|
// requires an extra character.
|
|
if (buffer_offset >= buffer_size - 1) {
|
|
// The message did not fit into the buffer.
|
|
if (iteration == 0) {
|
|
// Re-run the loop and use a dynamically-allocated buffer. The buffer
|
|
// will be large enough for the log message, an extra newline and a
|
|
// null terminator.
|
|
dynamic_buffer_size = buffer_offset + 2;
|
|
continue;
|
|
}
|
|
|
|
// The dynamically-allocated buffer was incorrectly sized. This should
|
|
// not happen, assuming a correct implementation of std::(v)snprintf.
|
|
// Fail in tests, recover by truncating the log message in production.
|
|
assert(false);
|
|
buffer_offset = buffer_size - 1;
|
|
}
|
|
|
|
// Add a newline if necessary.
|
|
if (buffer[buffer_offset - 1] != '\n') {
|
|
buffer[buffer_offset] = '\n';
|
|
++buffer_offset;
|
|
}
|
|
|
|
assert(buffer_offset <= buffer_size);
|
|
std::fwrite(buffer, 1, buffer_offset, fp_);
|
|
std::fflush(fp_);
|
|
|
|
if (iteration != 0) {
|
|
delete[] buffer;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
private:
|
|
std::FILE* const fp_;
|
|
};
|
|
|
|
} // namespace leveldb
|
|
|
|
#endif // STORAGE_LEVELDB_UTIL_WINDOWS_LOGGER_H_
|