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