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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 /** | 5 /** |
6 * Utilities for encoding and decoding JSON (JavaScript Object Notation) data. | 6 * Utilities for encoding and decoding JSON (JavaScript Object Notation) data. |
7 */ | 7 */ |
8 | 8 |
9 library dart.json; | 9 library dart.json; |
10 | 10 |
| 11 import "dart:convert"; |
| 12 export "dart:convert" show JsonUnsupportedObjectError, JsonCyclicError; |
| 13 |
11 // JSON parsing and serialization. | 14 // JSON parsing and serialization. |
12 | 15 |
13 /** | 16 /** |
14 * Error thrown by JSON serialization if an object cannot be serialized. | |
15 * | |
16 * The [unsupportedObject] field holds that object that failed to be serialized. | |
17 * | |
18 * If an object isn't directly serializable, the serializer calls the 'toJson' | |
19 * method on the object. If that call fails, the error will be stored in the | |
20 * [cause] field. If the call returns an object that isn't directly | |
21 * serializable, the [cause] will be null. | |
22 */ | |
23 class JsonUnsupportedObjectError extends Error { | |
24 /** The object that could not be serialized. */ | |
25 final unsupportedObject; | |
26 /** The exception thrown by object's [:toJson:] method, if any. */ | |
27 final cause; | |
28 | |
29 JsonUnsupportedObjectError(this.unsupportedObject, { this.cause }); | |
30 | |
31 String toString() { | |
32 if (cause != null) { | |
33 return "Calling toJson method on object failed."; | |
34 } else { | |
35 return "Object toJson method returns non-serializable value."; | |
36 } | |
37 } | |
38 } | |
39 | |
40 | |
41 /** | |
42 * Reports that an object could not be stringified due to cyclic references. | |
43 * | |
44 * An object that references itself cannot be serialized by [stringify]. | |
45 * When the cycle is detected, a [JsonCyclicError] is thrown. | |
46 */ | |
47 class JsonCyclicError extends JsonUnsupportedObjectError { | |
48 /** The first object that was detected as part of a cycle. */ | |
49 JsonCyclicError(Object object): super(object); | |
50 String toString() => "Cyclic error in JSON stringify"; | |
51 } | |
52 | |
53 | |
54 /** | |
55 * Parses [json] and build the corresponding parsed JSON value. | 17 * Parses [json] and build the corresponding parsed JSON value. |
56 * | 18 * |
57 * Parsed JSON values are of the types [num], [String], [bool], [Null], | 19 * Parsed JSON values are of the types [num], [String], [bool], [Null], |
58 * [List]s of parsed JSON values or [Map]s from [String] to parsed | 20 * [List]s of parsed JSON values or [Map]s from [String] to parsed |
59 * JSON values. | 21 * JSON values. |
60 * | 22 * |
61 * The optional [reviver] function, if provided, is called once for each | 23 * The optional [reviver] function, if provided, is called once for each |
62 * object or list property parsed. The arguments are the property name | 24 * object or list property parsed. The arguments are the property name |
63 * ([String]) or list index ([int]), and the value is the parsed value. | 25 * ([String]) or list index ([int]), and the value is the parsed value. |
64 * The return value of the reviver will be used as the value of that property | 26 * The return value of the reviver will be used as the value of that property |
65 * instead the parsed value. | 27 * instead the parsed value. |
66 * | 28 * |
67 * Throws [FormatException] if the input is not valid JSON text. | 29 * Throws [FormatException] if the input is not valid JSON text. |
68 */ | 30 */ |
69 external parse(String json, [reviver(var key, var value)]); | 31 parse(String json, [reviver(var key, var value)]) { |
70 | 32 return JSON.decode(json, reviver: reviver); |
71 _parse(String json, reviver(var key, var value)) { | |
72 BuildJsonListener listener; | |
73 if (reviver == null) { | |
74 listener = new BuildJsonListener(); | |
75 } else { | |
76 listener = new ReviverJsonListener(reviver); | |
77 } | |
78 new JsonParser(json, listener).parse(); | |
79 return listener.result; | |
80 } | 33 } |
81 | 34 |
82 /** | 35 /** |
83 * Serializes [object] into a JSON string. | 36 * Serializes [object] into a JSON string. |
84 * | 37 * |
85 * Directly serializable values are [num], [String], [bool], and [Null], as well | 38 * Directly serializable values are [num], [String], [bool], and [Null], as well |
86 * as some [List] and [Map] values. | 39 * as some [List] and [Map] values. |
87 * For [List], the elements must all be serializable. | 40 * For [List], the elements must all be serializable. |
88 * For [Map], the keys must be [String] and the values must be serializable. | 41 * For [Map], the keys must be [String] and the values must be serializable. |
89 * | 42 * |
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821 first = false; | 774 first = false; |
822 }); | 775 }); |
823 sink.write('}'); | 776 sink.write('}'); |
824 seen.removeLast(); | 777 seen.removeLast(); |
825 return true; | 778 return true; |
826 } else { | 779 } else { |
827 return false; | 780 return false; |
828 } | 781 } |
829 } | 782 } |
830 } | 783 } |
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