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_WRITER_H_
6#define BASE_JSON_JSON_WRITER_H_
7
8#include <stddef.h>
9
10#include <string>
11
12#include "base/base_export.h"
13#include "base/macros.h"
14
15namespace base {
16
17class Value;
18
19class BASE_EXPORT JSONWriter {
20 public:
21  enum Options {
22    // This option instructs the writer that if a Binary value is encountered,
23    // the value (and key if within a dictionary) will be omitted from the
24    // output, and success will be returned. Otherwise, if a binary value is
25    // encountered, failure will be returned.
26    OPTIONS_OMIT_BINARY_VALUES = 1 << 0,
27
28    // This option instructs the writer to write doubles that have no fractional
29    // part as a normal integer (i.e., without using exponential notation
30    // or appending a '.0') as long as the value is within the range of a
31    // 64-bit int.
32    OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION = 1 << 1,
33
34    // Return a slightly nicer formatted json string (pads with whitespace to
35    // help with readability).
36    OPTIONS_PRETTY_PRINT = 1 << 2,
37  };
38
39  // Given a root node, generates a JSON string and puts it into |json|.
40  // The output string is overwritten and not appended.
41  //
42  // TODO(tc): Should we generate json if it would be invalid json (e.g.,
43  // |node| is not a DictionaryValue/ListValue or if there are inf/-inf float
44  // values)? Return true on success and false on failure.
45  static bool Write(const Value& node, std::string* json);
46
47  // Same as above but with |options| which is a bunch of JSONWriter::Options
48  // bitwise ORed together. Return true on success and false on failure.
49  static bool WriteWithOptions(const Value& node,
50                               int options,
51                               std::string* json);
52
53 private:
54  JSONWriter(int options, std::string* json);
55
56  // Called recursively to build the JSON string. When completed,
57  // |json_string_| will contain the JSON.
58  bool BuildJSONString(const Value& node, size_t depth);
59
60  // Adds space to json_string_ for the indent level.
61  void IndentLine(size_t depth);
62
63  bool omit_binary_values_;
64  bool omit_double_type_preservation_;
65  bool pretty_print_;
66
67  // Where we write JSON data as we generate it.
68  std::string* json_string_;
69
70  DISALLOW_COPY_AND_ASSIGN(JSONWriter);
71};
72
73}  // namespace base
74
75#endif  // BASE_JSON_JSON_WRITER_H_
76