chromium/components/update_client/unpacker.h

// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_UPDATE_CLIENT_UNPACKER_H_
#define COMPONENTS_UPDATE_CLIENT_UNPACKER_H_

#include <stdint.h>

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

#include "base/files/file_path.h"
#include "base/functional/callback.h"
#include "base/memory/ref_counted.h"
#include "base/sequence_checker.h"
#include "components/update_client/update_client_errors.h"

namespace crx_file {
enum class VerifierFormat;
}

namespace update_client {

class Unzipper;

// Unpacks the component CRX package and verifies that it is
// well formed and the cryptographic signature is correct.
//
// This class is only used by the component updater. It is inspired by
// and overlaps with code in the extension's SandboxedUnpacker.
// The main differences are:
// - The public key hash is SHA256.
// - Does not use a sandboxed unpacker. A valid component is fully trusted.
// - The manifest can have different attributes and resources are not
//   transcoded.
//
// This is an updated version of Unpacker that leverages the new
// Puffin-based puffpatch CRX-diff format, rather than the legacy
// courgette/bsdiff per-file CRXD format. Puffin patches the CRX before
// unpacking, changing the order of operations such that patching needs to occur
// before verifying and unpacking. Unlike the original implementation, by the
// time we unpack, the patching has already occurred.
//
// Note: During unzip step we also check for verified_contents.json in the
// header of crx file and unpack it to metadata_ folder if it doesn't already
// contain verified_contents file.
class Unpacker : public base::RefCountedThreadSafe<Unpacker> { … };

}  // namespace update_client

#endif  // COMPONENTS_UPDATE_CLIENT_UNPACKER_H_