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//
// Copyright (C) 2017 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.
//
#ifndef UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_READER_H_
#define UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_READER_H_
#include <vector>
#include "update_engine/payload_consumer/file_descriptor.h"
#include "update_engine/update_metadata.pb.h"
namespace chromeos_update_engine {
// ExtentReader is an abstract class with reads from a given file descriptor at
// the extents given.
class ExtentReader {
public:
virtual ~ExtentReader() = default;
// Initializes |ExtentReader|
virtual bool Init(FileDescriptorPtr fd,
const google::protobuf::RepeatedPtrField<Extent>& extents,
uint32_t block_size) = 0;
// Seeks to the given |offset| assuming all extents are concatenated together.
virtual bool Seek(uint64_t offset) = 0;
// Returns true on success.
virtual bool Read(void* buffer, size_t count) = 0;
};
// DirectExtentReader is probably the simplest ExtentReader implementation.
// It reads the data directly from the extents.
class DirectExtentReader : public ExtentReader {
public:
DirectExtentReader() = default;
~DirectExtentReader() override = default;
bool Init(FileDescriptorPtr fd,
const google::protobuf::RepeatedPtrField<Extent>& extents,
uint32_t block_size) override;
bool Seek(uint64_t offset) override;
bool Read(void* bytes, size_t count) override;
private:
FileDescriptorPtr fd_{nullptr};
google::protobuf::RepeatedPtrField<Extent> extents_;
size_t block_size_{0};
// Current extent being read from |fd_|.
google::protobuf::RepeatedPtrField<Extent>::iterator cur_extent_;
// Bytes read from |cur_extent_| thus far.
uint64_t cur_extent_bytes_read_{0};
// Offset assuming all extents are concatenated.
uint64_t offset_{0};
// The accelaring upper bounds for |extents_| if we assume all extents are
// concatenated.
std::vector<uint64_t> extents_upper_bounds_;
uint64_t total_size_{0};
DISALLOW_COPY_AND_ASSIGN(DirectExtentReader);
};
} // namespace chromeos_update_engine
#endif // UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_READER_H_
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