1// Copyright (c) 2012 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 BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_
6#define BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_
7
8#include <stddef.h>
9
10#include <string>
11
12#include "base/base_export.h"
13#include "base/files/file_path.h"
14#include "base/macros.h"
15#include "base/values.h"
16
17class BASE_EXPORT JSONFileValueSerializer : public base::ValueSerializer {
18 public:
19  // |json_file_path_| is the path of a file that will be destination of the
20  // serialization. The serializer will attempt to create the file at the
21  // specified location.
22  explicit JSONFileValueSerializer(const base::FilePath& json_file_path);
23
24  ~JSONFileValueSerializer() override;
25
26  // DO NOT USE except in unit tests to verify the file was written properly.
27  // We should never serialize directly to a file since this will block the
28  // thread. Instead, serialize to a string and write to the file you want on
29  // the file thread.
30  //
31  // Attempt to serialize the data structure represented by Value into
32  // JSON.  If the return value is true, the result will have been written
33  // into the file whose name was passed into the constructor.
34  bool Serialize(const base::Value& root) override;
35
36  // Equivalent to Serialize(root) except binary values are omitted from the
37  // output.
38  bool SerializeAndOmitBinaryValues(const base::Value& root);
39
40 private:
41  bool SerializeInternal(const base::Value& root, bool omit_binary_values);
42
43  const base::FilePath json_file_path_;
44
45  DISALLOW_IMPLICIT_CONSTRUCTORS(JSONFileValueSerializer);
46};
47
48class BASE_EXPORT JSONFileValueDeserializer : public base::ValueDeserializer {
49 public:
50  // |json_file_path_| is the path of a file that will be source of the
51  // deserialization.
52  explicit JSONFileValueDeserializer(const base::FilePath& json_file_path);
53
54  ~JSONFileValueDeserializer() override;
55
56  // Attempt to deserialize the data structure encoded in the file passed
57  // in to the constructor into a structure of Value objects.  If the return
58  // value is NULL, and if |error_code| is non-null, |error_code| will
59  // contain an integer error code (either JsonFileError or JsonParseError).
60  // If |error_message| is non-null, it will be filled in with a formatted
61  // error message including the location of the error if appropriate.
62  // The caller takes ownership of the returned value.
63  std::unique_ptr<base::Value> Deserialize(int* error_code,
64                                           std::string* error_message) override;
65
66  // This enum is designed to safely overlap with JSONReader::JsonParseError.
67  enum JsonFileError {
68    JSON_NO_ERROR = 0,
69    JSON_ACCESS_DENIED = 1000,
70    JSON_CANNOT_READ_FILE,
71    JSON_FILE_LOCKED,
72    JSON_NO_SUCH_FILE
73  };
74
75  // File-specific error messages that can be returned.
76  static const char kAccessDenied[];
77  static const char kCannotReadFile[];
78  static const char kFileLocked[];
79  static const char kNoSuchFile[];
80
81  // Convert an error code into an error message.  |error_code| is assumed to
82  // be a JsonFileError.
83  static const char* GetErrorMessageForCode(int error_code);
84
85  void set_allow_trailing_comma(bool new_value) {
86    allow_trailing_comma_ = new_value;
87  }
88
89  // Returns the size (in bytes) of JSON string read from disk in the last
90  // successful |Deserialize()| call.
91  size_t get_last_read_size() const { return last_read_size_; }
92
93 private:
94  // A wrapper for ReadFileToString which returns a non-zero JsonFileError if
95  // there were file errors.
96  int ReadFileToString(std::string* json_string);
97
98  const base::FilePath json_file_path_;
99  bool allow_trailing_comma_;
100  size_t last_read_size_;
101
102  DISALLOW_IMPLICIT_CONSTRUCTORS(JSONFileValueDeserializer);
103};
104
105#endif  // BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_
106
107