/*
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* Copyright (C) 2019 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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#pragma once
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#include <stdint.h>
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#include <string>
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#include <android-base/unique_fd.h>
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// This is the base class to read data from source and provide the data to FUSE.
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class FuseDataProvider {
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public:
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FuseDataProvider(uint64_t file_size, uint32_t block_size)
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: file_size_(file_size), fuse_block_size_(block_size) {}
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virtual ~FuseDataProvider() = default;
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uint64_t file_size() const {
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return file_size_;
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}
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uint32_t fuse_block_size() const {
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return fuse_block_size_;
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}
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// Reads |fetch_size| bytes data starting from |start_block|. Puts the result in |buffer|.
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virtual bool ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
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uint32_t start_block) const = 0;
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virtual void Close() {}
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protected:
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FuseDataProvider() = default;
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// Size in bytes of the file to read.
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uint64_t file_size_ = 0;
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// Block size passed to the fuse, this is different from the block size of the block device.
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uint32_t fuse_block_size_ = 0;
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};
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// This class reads data from a file.
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class FuseFileDataProvider : public FuseDataProvider {
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public:
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FuseFileDataProvider(const std::string& path, uint32_t block_size);
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bool ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
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uint32_t start_block) const override;
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bool Valid() const {
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return fd_ != -1;
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}
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void Close() override;
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private:
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// The underlying source to read data from.
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android::base::unique_fd fd_;
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};
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