xref: /third_party/gn/src/base/json/json_writer.h (revision 6d528ed9) 
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
12namespace base {
13
14class Value;
15
16class JSONWriter {
17 public:
18  enum Options {
19    // This option instructs the writer that if a Binary value is encountered,
20    // the value (and key if within a dictionary) will be omitted from the
21    // output, and success will be returned. Otherwise, if a binary value is
22    // encountered, failure will be returned.
23    OPTIONS_OMIT_BINARY_VALUES = 1 << 0,
24
25    // Return a slightly nicer formatted json string (pads with whitespace to
26    // help with readability).
27    OPTIONS_PRETTY_PRINT = 1 << 2,
28  };
29
30  // Given a root node, generates a JSON string and puts it into |json|.
31  // The output string is overwritten and not appended.
32  //
33  // TODO(tc): Should we generate json if it would be invalid json (e.g.,
34  // |node| is not a DictionaryValue/ListValue or if there are inf/-inf float
35  // values)? Return true on success and false on failure.
36  static bool Write(const Value& node, std::string* json);
37
38  // Same as above but with |options| which is a bunch of JSONWriter::Options
39  // bitwise ORed together. Return true on success and false on failure.
40  static bool WriteWithOptions(const Value& node,
41                               int options,
42                               std::string* json);
43
44 private:
45  JSONWriter(int options, std::string* json);
46
47  // Called recursively to build the JSON string. When completed,
48  // |json_string_| will contain the JSON.
49  bool BuildJSONString(const Value& node, size_t depth);
50
51  // Adds space to json_string_ for the indent level.
52  void IndentLine(size_t depth);
53
54  bool omit_binary_values_;
55  bool pretty_print_;
56
57  // Where we write JSON data as we generate it.
58  std::string* json_string_;
59
60  JSONWriter(const JSONWriter&) = delete;
61  JSONWriter& operator=(const JSONWriter&) = delete;
62};
63
64}  // namespace base
65
66#endif  // BASE_JSON_JSON_WRITER_H_
67