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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/macros.h"
13 
14 namespace base {
15 
16 class Value;
17 
18 class JSONWriter {
19  public:
20   enum Options {
21     // This option instructs the writer that if a Binary value is encountered,
22     // the value (and key if within a dictionary) will be omitted from the
23     // output, and success will be returned. Otherwise, if a binary value is
24     // encountered, failure will be returned.
25     OPTIONS_OMIT_BINARY_VALUES = 1 << 0,
26 
27     // Return a slightly nicer formatted json string (pads with whitespace to
28     // help with readability).
29     OPTIONS_PRETTY_PRINT = 1 << 2,
30   };
31 
32   // Given a root node, generates a JSON string and puts it into |json|.
33   // The output string is overwritten and not appended.
34   //
35   // TODO(tc): Should we generate json if it would be invalid json (e.g.,
36   // |node| is not a DictionaryValue/ListValue or if there are inf/-inf float
37   // values)? Return true on success and false on failure.
38   static bool Write(const Value& node, std::string* json);
39 
40   // Same as above but with |options| which is a bunch of JSONWriter::Options
41   // bitwise ORed together. Return true on success and false on failure.
42   static bool WriteWithOptions(const Value& node,
43                                int options,
44                                std::string* json);
45 
46  private:
47   JSONWriter(int options, std::string* json);
48 
49   // Called recursively to build the JSON string. When completed,
50   // |json_string_| will contain the JSON.
51   bool BuildJSONString(const Value& node, size_t depth);
52 
53   // Adds space to json_string_ for the indent level.
54   void IndentLine(size_t depth);
55 
56   bool omit_binary_values_;
57   bool pretty_print_;
58 
59   // Where we write JSON data as we generate it.
60   std::string* json_string_;
61 
62   DISALLOW_COPY_AND_ASSIGN(JSONWriter);
63 };
64 
65 }  // namespace base
66 
67 #endif  // BASE_JSON_JSON_WRITER_H_
68