file_rotating_stream.h | Explore in Territory

/*
 *  Copyright 2015 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.
 */

#ifndef RTC_BASE_FILE_ROTATING_STREAM_H_
#define RTC_BASE_FILE_ROTATING_STREAM_H_

#include <stddef.h>

#include <memory>
#include <string>
#include <vector>

#include "absl/strings/string_view.h"
#include "rtc_base/system/file_wrapper.h"

namespace rtc {

// FileRotatingStream writes to a file in the directory specified in the
// constructor. It rotates the files once the current file is full. The
// individual file size and the number of files used is configurable in the
// constructor. Open() must be called before using this stream.
class FileRotatingStream { … };

// CallSessionFileRotatingStream is meant to be used in situations where we will
// have limited disk space. Its purpose is to write logs up to a
// maximum size. Once the maximum size is exceeded, logs from the middle are
// deleted whereas logs from the beginning and end are preserved. The reason for
// this is because we anticipate that in WebRTC the beginning and end of the
// logs are most useful for call diagnostics.
//
// This implementation simply writes to a single file until
// `max_total_log_size` / 2 bytes are written to it, and subsequently writes to
// a set of rotating files. We do this by inheriting FileRotatingStream and
// setting the appropriate internal variables so that we don't delete the last
// (earliest) file on rotate, and that that file's size is bigger.
//
// Open() must be called before using this stream.

// To read the logs produced by this class, one can use the companion class
// CallSessionFileRotatingStreamReader.
class CallSessionFileRotatingStream : public FileRotatingStream { … };

// This is a convenience class, to read all files produced by a
// FileRotatingStream, all in one go. Typical use calls GetSize and ReadData
// only once. The list of file names to read is based on the contents of the log
// directory at construction time.
class FileRotatingStreamReader { … };

class CallSessionFileRotatingStreamReader : public FileRotatingStreamReader { … };

}  // namespace rtc

#endif  // RTC_BASE_FILE_ROTATING_STREAM_H_
chromium/third_party/webrtc/rtc_base/file_rotating_stream.h
