// Copyright 2017 The Chromium OS Authors. All rights reserved.
|
// Use of this source code is governed by a BSD-style license that can be
|
// found in the LICENSE file.
|
|
#ifndef SRC_EXTENT_STREAM_H_
|
#define SRC_EXTENT_STREAM_H_
|
|
#include <memory>
|
#include <vector>
|
|
#include "puffin/src/include/puffin/common.h"
|
#include "puffin/src/include/puffin/stream.h"
|
|
namespace puffin {
|
|
// A stream object that allows reading and writing into disk extents. This is
|
// only used in main.cc for puffin binary to allow puffpatch on a actual rootfs
|
// and kernel images.
|
class ExtentStream : public StreamInterface {
|
public:
|
// Creates a stream only for writing.
|
static UniqueStreamPtr CreateForWrite(UniqueStreamPtr stream,
|
const std::vector<ByteExtent>& extents);
|
// Creates a stream only for reading.
|
static UniqueStreamPtr CreateForRead(UniqueStreamPtr stream,
|
const std::vector<ByteExtent>& extents);
|
~ExtentStream() override = default;
|
|
bool GetSize(uint64_t* size) const override;
|
bool GetOffset(uint64_t* offset) const override;
|
bool Seek(uint64_t offset) override;
|
bool Read(void* buffer, size_t length) override;
|
bool Write(const void* buffer, size_t length) override;
|
bool Close() override;
|
|
private:
|
ExtentStream(UniqueStreamPtr stream,
|
const std::vector<ByteExtent>& extents,
|
bool is_for_write);
|
|
// Since both read and write operations are very similar in this class, this
|
// function acts as a common operation that does both write and read based on
|
// the nullability of |read_buffer| or |write_buffer|.
|
bool DoReadOrWrite(void* read_buffer,
|
const void* write_buffer,
|
size_t length);
|
|
// The underlying stream to read from and write into.
|
UniqueStreamPtr stream_;
|
|
std::vector<ByteExtent> extents_;
|
|
// The current |ByteExtent| that is being read from or write into.
|
std::vector<ByteExtent>::iterator cur_extent_;
|
|
// The current offset in the current |ByteExtent| |cur_extent_|.
|
uint64_t cur_extent_offset_;
|
|
// |True| if the stream is write only. |False| if the stream is read only.
|
bool is_for_write_;
|
|
// The size of the stream. It is actually the cumulative size of all the bytes
|
// in |extents_|.
|
uint64_t size_;
|
|
// The current offset.
|
uint64_t offset_;
|
|
// Used for proper and faster seeking.
|
std::vector<uint64_t> extents_upper_bounds_;
|
|
DISALLOW_COPY_AND_ASSIGN(ExtentStream);
|
};
|
|
} // namespace puffin
|
|
#endif // SRC_EXTENT_STREAM_H_
|
