xref: /aosp_15_r20/external/bsdiff/buffer_file.h (revision a3a45f308bd90ef1a6e6a5e8fb92fe449b895909)
1*a3a45f30SXin Li // Copyright 2016 The Chromium OS Authors. All rights reserved.
2*a3a45f30SXin Li // Use of this source code is governed by a BSD-style license that can be
3*a3a45f30SXin Li // found in the LICENSE file.
4*a3a45f30SXin Li 
5*a3a45f30SXin Li #ifndef _BSDIFF_BUFFER_FILE_H_
6*a3a45f30SXin Li #define _BSDIFF_BUFFER_FILE_H_
7*a3a45f30SXin Li 
8*a3a45f30SXin Li #include <memory>
9*a3a45f30SXin Li #include <vector>
10*a3a45f30SXin Li 
11*a3a45f30SXin Li #include "bsdiff/file_interface.h"
12*a3a45f30SXin Li 
13*a3a45f30SXin Li namespace bsdiff {
14*a3a45f30SXin Li 
15*a3a45f30SXin Li class BufferFile : public FileInterface {
16*a3a45f30SXin Li  public:
17*a3a45f30SXin Li   // Creates a write only BufferFile based on the underlying |file| passed.
18*a3a45f30SXin Li   // The BufferFile will cache all the write in a buffer and write everything
19*a3a45f30SXin Li   // to |file| at once upon closing. Read and Seek are not supported.
20*a3a45f30SXin Li   // |size| should be the estimated total file size, it is used to reserve
21*a3a45f30SXin Li   // buffer space.
22*a3a45f30SXin Li   BufferFile(std::unique_ptr<FileInterface> file, size_t size);
23*a3a45f30SXin Li 
24*a3a45f30SXin Li   ~BufferFile() override;
25*a3a45f30SXin Li 
26*a3a45f30SXin Li   // FileInterface overrides.
27*a3a45f30SXin Li   bool Read(void* buf, size_t count, size_t* bytes_read) override;
28*a3a45f30SXin Li   bool Write(const void* buf, size_t count, size_t* bytes_written) override;
29*a3a45f30SXin Li   bool Seek(off_t pos) override;
30*a3a45f30SXin Li   bool Close() override;
31*a3a45f30SXin Li   bool GetSize(uint64_t* size) override;
32*a3a45f30SXin Li 
33*a3a45f30SXin Li  private:
34*a3a45f30SXin Li   // The underlying FileInterace instance.
35*a3a45f30SXin Li   std::unique_ptr<FileInterface> file_ = nullptr;
36*a3a45f30SXin Li   std::vector<uint8_t> buffer_;
37*a3a45f30SXin Li };
38*a3a45f30SXin Li 
39*a3a45f30SXin Li }  // namespace bsdiff
40*a3a45f30SXin Li 
41*a3a45f30SXin Li #endif  // _BSDIFF_BUFFER_FILE_H_
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