eub@google.com
e0c3b45219
Review URL: https://chromiumcodereview.appspot.com//10539164 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@8686 260f80e4-7a28-3924-810f-c04153c831b5
90 lines
2.7 KiB
Dart
90 lines
2.7 KiB
Dart
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#library('json');
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#import('dart:coreimpl');
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// TODO(jmesserly): this needs cleanup
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// Ideally JS objects could be treated as Dart Maps directly, and then we can
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// really use native JSON.parse and JSON.stringify.
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typedef Object _NativeJsonConvert(Object key, Object value);
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class _JSON native 'JSON' {
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static Object parse(String jsonString, _NativeJsonConvert fn) native;
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static String stringify(Object value, _NativeJsonConvert fn) native;
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}
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Object _getValue(obj, key) native 'return obj[key]';
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void _setValue(obj, key, value) native 'obj[key] = value';
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// This is a guard against general Dart objects getting through to
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// JSON.stringify. We restrict to JS primitives and JS Array.
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bool _directToJson(obj) native
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"return typeof obj != 'object' || obj == null || obj instanceof Array";
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ListFactory<String> _jsKeys(Object obj) native '''
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if (obj != null && typeof obj == 'object' && !(obj instanceof Array)) {
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return Object.keys(obj);
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}
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return null;
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''';
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/**
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* Dart interface to JavaScript objects and JSON.
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*/
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class JSON {
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/**
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* Takes a string in JSON notation and returns the value it
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* represents. The resulting value is one of the following:
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* * null
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* * a bool
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* * a double
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* * a String
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* * an Array of values (recursively)
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* * a Map from property names to values (recursively)
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*/
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static Object parse(String str) {
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return _JSON.parse(str, (_, obj) {
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final keys = _jsKeys(obj);
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if (keys == null) return obj;
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// Note: only need to shallow convert here--JSON.parse handles the rest.
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final map = {};
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for (String key in keys) {
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map[key] = _getValue(obj, key);
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}
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return map;
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});
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}
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/**
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* Takes a value and returns a string in JSON notation
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* representing its value, or returns null if the value is not representable
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* in JSON. A representable value is one of the following:
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* * null
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* * a bool
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* * a double
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* * a String
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* * an Array of values (recursively)
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* * a Map from property names to values (recursively)
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*/
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// TODO(jmesserly): handle any List subtype? Right now it's converted as
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// something like:
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// {"0":1,"1":2}
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static String stringify(Object value) {
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return _JSON.stringify(value, (_, obj) {
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if (_directToJson(obj)) return obj;
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if (obj is Map<String, Dynamic>) {
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Map<String, Dynamic> map = obj;
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obj = new Object();
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map.forEach((k, v) => _setValue(obj, k, v));
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return obj;
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}
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throw new IllegalArgumentException('cannot convert "$value" to JSON');
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});
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}
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}
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