chromium/net/shared_dictionary/shared_dictionary_header_checker_source_stream.h

// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_SHARED_DICTIONARY_SHARED_DICTIONARY_HEADER_CHECKER_SOURCE_STREAM_H_
#define NET_SHARED_DICTIONARY_SHARED_DICTIONARY_HEADER_CHECKER_SOURCE_STREAM_H_

#include <memory>
#include <string>

#include "net/base/completion_once_callback.h"
#include "net/base/hash_value.h"
#include "net/base/net_export.h"
#include "net/filter/source_stream.h"

namespace net {
class IOBuffer;
class GrowableIOBuffer;

// This class is used to check the header bytes of "Dictionary-Compressed
// Brotli" stream and "Dictionary-Compressed Zstandard" stream.
//
// The "Dictionary-Compressed Brotli" stream's header is 36 bytes containing:
//  - 4 bytes magic number: 0xff, 0x44, 0x43, 0x42
//  - 32 bytes SHA-256 hash digest of the dictionary.
// The "Dictionary-Compressed Zstandard" stream's header is 40 bytes containing:
//  - 8 bytes magic number: 0x5e, 0x2a, 0x4d, 0x18, 0x20, 0x00, 0x00, 0x00
//  - 32 bytes SHA-256 hash digest of the dictionary.
//
// When an error occurred while reading the upstream, this class passes the
// error to the reader of this class. When the header bytes from the upstream
// was different from the expected header, this class passes
// ERR_UNEXPECTED_CONTENT_DICTIONARY_HEADER to the reader.
//
// This class consumes the header bytes from the upstream. So the reader of
// this class can read the bytes after the header bytes.
class NET_EXPORT SharedDictionaryHeaderCheckerSourceStream
    : public SourceStream { … };

}  // namespace net

#endif  // NET_SHARED_DICTIONARY_SHARED_DICTIONARY_HEADER_CHECKER_SOURCE_STREAM_H_