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//
// Copyright (C) 2021 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#include <cstdint>
#include <memory>
#include <libsnapshot/snapshot_writer.h>
#include "update_engine/payload_consumer/file_descriptor.h"
namespace chromeos_update_engine {
// A Readable/Writable FileDescriptor class. This is a simple wrapper around
// CowWriter. Only intended to be used by FileSystemVerifierAction for writing
// FEC. Writes must be block aligned(4096) or write will fail.
class CowWriterFileDescriptor final : public FileDescriptor {
public:
explicit CowWriterFileDescriptor(
std::unique_ptr<android::snapshot::ISnapshotWriter> cow_writer);
~CowWriterFileDescriptor();
bool Open(const char* path, int flags, mode_t mode) override;
bool Open(const char* path, int flags) override;
ssize_t Read(void* buf, size_t count) override;
// |count| must be block aligned, current offset of this fd must also be block
// aligned.
ssize_t Write(const void* buf, size_t count) override;
off64_t Seek(off64_t offset, int whence) override;
uint64_t BlockDevSize() override;
bool BlkIoctl(int request,
uint64_t start,
uint64_t length,
int* result) override;
bool Flush() override;
bool Close() override;
bool IsSettingErrno() override;
bool IsOpen() override;
private:
std::unique_ptr<android::snapshot::ISnapshotWriter> cow_writer_;
FileDescriptorPtr cow_reader_;
bool dirty_ = false;
};
} // namespace chromeos_update_engine
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