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