1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef EXTENSIONS_BROWSER_COMPUTED_HASHES_H_
6#define EXTENSIONS_BROWSER_COMPUTED_HASHES_H_
7
8#include <map>
9#include <string>
10#include <vector>
11
12#include "base/memory/scoped_ptr.h"
13
14namespace base {
15class FilePath;
16class ListValue;
17}
18
19namespace extensions {
20
21// A pair of classes for serialization of a set of SHA256 block hashes computed
22// over the files inside an extension.
23class ComputedHashes {
24 public:
25  class Reader {
26   public:
27    Reader();
28    ~Reader();
29    bool InitFromFile(const base::FilePath& path);
30
31    // The block size and hashes for |relative_path| will be copied into the
32    // out parameters.
33    bool GetHashes(const base::FilePath& relative_path,
34                   int* block_size,
35                   std::vector<std::string>* hashes);
36
37   private:
38    typedef std::pair<int, std::vector<std::string> > HashInfo;
39
40    // This maps a relative path to a pair of (block size, hashes)
41    std::map<base::FilePath, HashInfo> data_;
42  };
43
44  class Writer {
45   public:
46    Writer();
47    ~Writer();
48
49    // Adds hashes for |relative_path|. Should not be called more than once
50    // for a given |relative_path|.
51    void AddHashes(const base::FilePath& relative_path,
52                   int block_size,
53                   const std::vector<std::string>& hashes);
54
55    bool WriteToFile(const base::FilePath& path);
56
57   private:
58    // Each element of this list contains the path and block hashes for one
59    // file.
60    scoped_ptr<base::ListValue> file_list_;
61  };
62
63  // Computes the SHA256 hash of each |block_size| chunk in |contents|, placing
64  // the results into |hashes|.
65  static void ComputeHashesForContent(const std::string& contents,
66                                      size_t block_size,
67                                      std::vector<std::string>* hashes);
68};
69
70}  // namespace extensions
71
72#endif  // EXTENSIONS_BROWSER_COMPUTED_HASHES_H_
73