//
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// Copyright (C) 2017 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#ifndef UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_READER_H_
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#define UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_READER_H_
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#include <vector>
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#include "update_engine/payload_consumer/file_descriptor.h"
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#include "update_engine/update_metadata.pb.h"
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namespace chromeos_update_engine {
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// ExtentReader is an abstract class with reads from a given file descriptor at
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// the extents given.
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class ExtentReader {
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public:
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virtual ~ExtentReader() = default;
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// Initializes |ExtentReader|
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virtual bool Init(FileDescriptorPtr fd,
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const google::protobuf::RepeatedPtrField<Extent>& extents,
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uint32_t block_size) = 0;
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// Seeks to the given |offset| assuming all extents are concatenated together.
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virtual bool Seek(uint64_t offset) = 0;
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// Returns true on success.
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virtual bool Read(void* buffer, size_t count) = 0;
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};
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// DirectExtentReader is probably the simplest ExtentReader implementation.
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// It reads the data directly from the extents.
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class DirectExtentReader : public ExtentReader {
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public:
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DirectExtentReader() = default;
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~DirectExtentReader() override = default;
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bool Init(FileDescriptorPtr fd,
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const google::protobuf::RepeatedPtrField<Extent>& extents,
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uint32_t block_size) override;
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bool Seek(uint64_t offset) override;
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bool Read(void* bytes, size_t count) override;
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private:
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FileDescriptorPtr fd_{nullptr};
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google::protobuf::RepeatedPtrField<Extent> extents_;
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size_t block_size_{0};
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// Current extent being read from |fd_|.
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google::protobuf::RepeatedPtrField<Extent>::iterator cur_extent_;
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// Bytes read from |cur_extent_| thus far.
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uint64_t cur_extent_bytes_read_{0};
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// Offset assuming all extents are concatenated.
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uint64_t offset_{0};
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// The accelaring upper bounds for |extents_| if we assume all extents are
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// concatenated.
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std::vector<uint64_t> extents_upper_bounds_;
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uint64_t total_size_{0};
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DISALLOW_COPY_AND_ASSIGN(DirectExtentReader);
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};
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} // namespace chromeos_update_engine
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#endif // UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_READER_H_
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