1 | // Copyright 2006 The Closure Library Authors. All Rights Reserved. |
2 | // |
3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
4 | // you may not use this file except in compliance with the License. |
5 | // You may obtain a copy of the License at |
6 | // |
7 | // http://www.apache.org/licenses/LICENSE-2.0 |
8 | // |
9 | // Unless required by applicable law or agreed to in writing, software |
10 | // distributed under the License is distributed on an "AS-IS" BASIS, |
11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
12 | // See the License for the specific language governing permissions and |
13 | // limitations under the License. |
14 | |
15 | /** |
16 | * @fileoverview JSON utility functions. |
17 | * @author arv@google.com (Erik Arvidsson) |
18 | */ |
19 | |
20 | |
21 | goog.provide('goog.json'); |
22 | goog.provide('goog.json.Replacer'); |
23 | goog.provide('goog.json.Reviver'); |
24 | goog.provide('goog.json.Serializer'); |
25 | |
26 | |
27 | /** |
28 | * @define {boolean} If true, use the native JSON parsing API. |
29 | * NOTE(user): EXPERIMENTAL, handle with care. Setting this to true might |
30 | * break your code. The default {@code goog.json.parse} implementation is able |
31 | * to handle invalid JSON, such as JSPB. |
32 | */ |
33 | goog.define('goog.json.USE_NATIVE_JSON', false); |
34 | |
35 | |
36 | /** |
37 | * Tests if a string is an invalid JSON string. This only ensures that we are |
38 | * not using any invalid characters |
39 | * @param {string} s The string to test. |
40 | * @return {boolean} True if the input is a valid JSON string. |
41 | * @private |
42 | */ |
43 | goog.json.isValid_ = function(s) { |
44 | // All empty whitespace is not valid. |
45 | if (/^\s*$/.test(s)) { |
46 | return false; |
47 | } |
48 | |
49 | // This is taken from http://www.json.org/json2.js which is released to the |
50 | // public domain. |
51 | // Changes: We dissallow \u2028 Line separator and \u2029 Paragraph separator |
52 | // inside strings. We also treat \u2028 and \u2029 as whitespace which they |
53 | // are in the RFC but IE and Safari does not match \s to these so we need to |
54 | // include them in the reg exps in all places where whitespace is allowed. |
55 | // We allowed \x7f inside strings because some tools don't escape it, |
56 | // e.g. http://www.json.org/java/org/json/JSONObject.java |
57 | |
58 | // Parsing happens in three stages. In the first stage, we run the text |
59 | // against regular expressions that look for non-JSON patterns. We are |
60 | // especially concerned with '()' and 'new' because they can cause invocation, |
61 | // and '=' because it can cause mutation. But just to be safe, we want to |
62 | // reject all unexpected forms. |
63 | |
64 | // We split the first stage into 4 regexp operations in order to work around |
65 | // crippling inefficiencies in IE's and Safari's regexp engines. First we |
66 | // replace all backslash pairs with '@' (a non-JSON character). Second, we |
67 | // replace all simple value tokens with ']' characters. Third, we delete all |
68 | // open brackets that follow a colon or comma or that begin the text. Finally, |
69 | // we look to see that the remaining characters are only whitespace or ']' or |
70 | // ',' or ':' or '{' or '}'. If that is so, then the text is safe for eval. |
71 | |
72 | // Don't make these static since they have the global flag. |
73 | var backslashesRe = /\\["\\\/bfnrtu]/g; |
74 | var simpleValuesRe = |
75 | /"[^"\\\n\r\u2028\u2029\x00-\x08\x0a-\x1f]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g; |
76 | var openBracketsRe = /(?:^|:|,)(?:[\s\u2028\u2029]*\[)+/g; |
77 | var remainderRe = /^[\],:{}\s\u2028\u2029]*$/; |
78 | |
79 | return remainderRe.test(s.replace(backslashesRe, '@'). |
80 | replace(simpleValuesRe, ']'). |
81 | replace(openBracketsRe, '')); |
82 | }; |
83 | |
84 | |
85 | /** |
86 | * Parses a JSON string and returns the result. This throws an exception if |
87 | * the string is an invalid JSON string. |
88 | * |
89 | * Note that this is very slow on large strings. If you trust the source of |
90 | * the string then you should use unsafeParse instead. |
91 | * |
92 | * @param {*} s The JSON string to parse. |
93 | * @throws Error if s is invalid JSON. |
94 | * @return {Object} The object generated from the JSON string, or null. |
95 | */ |
96 | goog.json.parse = goog.json.USE_NATIVE_JSON ? |
97 | /** @type {function(*):Object} */ (goog.global['JSON']['parse']) : |
98 | function(s) { |
99 | var o = String(s); |
100 | if (goog.json.isValid_(o)) { |
101 | /** @preserveTry */ |
102 | try { |
103 | return /** @type {Object} */ (eval('(' + o + ')')); |
104 | } catch (ex) { |
105 | } |
106 | } |
107 | throw Error('Invalid JSON string: ' + o); |
108 | }; |
109 | |
110 | |
111 | /** |
112 | * Parses a JSON string and returns the result. This uses eval so it is open |
113 | * to security issues and it should only be used if you trust the source. |
114 | * |
115 | * @param {string} s The JSON string to parse. |
116 | * @return {Object} The object generated from the JSON string. |
117 | */ |
118 | goog.json.unsafeParse = goog.json.USE_NATIVE_JSON ? |
119 | /** @type {function(string):Object} */ (goog.global['JSON']['parse']) : |
120 | function(s) { |
121 | return /** @type {Object} */ (eval('(' + s + ')')); |
122 | }; |
123 | |
124 | |
125 | /** |
126 | * JSON replacer, as defined in Section 15.12.3 of the ES5 spec. |
127 | * @see http://ecma-international.org/ecma-262/5.1/#sec-15.12.3 |
128 | * |
129 | * TODO(nicksantos): Array should also be a valid replacer. |
130 | * |
131 | * @typedef {function(this:Object, string, *): *} |
132 | */ |
133 | goog.json.Replacer; |
134 | |
135 | |
136 | /** |
137 | * JSON reviver, as defined in Section 15.12.2 of the ES5 spec. |
138 | * @see http://ecma-international.org/ecma-262/5.1/#sec-15.12.3 |
139 | * |
140 | * @typedef {function(this:Object, string, *): *} |
141 | */ |
142 | goog.json.Reviver; |
143 | |
144 | |
145 | /** |
146 | * Serializes an object or a value to a JSON string. |
147 | * |
148 | * @param {*} object The object to serialize. |
149 | * @param {?goog.json.Replacer=} opt_replacer A replacer function |
150 | * called for each (key, value) pair that determines how the value |
151 | * should be serialized. By defult, this just returns the value |
152 | * and allows default serialization to kick in. |
153 | * @throws Error if there are loops in the object graph. |
154 | * @return {string} A JSON string representation of the input. |
155 | */ |
156 | goog.json.serialize = goog.json.USE_NATIVE_JSON ? |
157 | /** @type {function(*, ?goog.json.Replacer=):string} */ |
158 | (goog.global['JSON']['stringify']) : |
159 | function(object, opt_replacer) { |
160 | // NOTE(nicksantos): Currently, we never use JSON.stringify. |
161 | // |
162 | // The last time I evaluated this, JSON.stringify had subtle bugs and |
163 | // behavior differences on all browsers, and the performance win was not |
164 | // large enough to justify all the issues. This may change in the future |
165 | // as browser implementations get better. |
166 | // |
167 | // assertSerialize in json_test contains if branches for the cases |
168 | // that fail. |
169 | return new goog.json.Serializer(opt_replacer).serialize(object); |
170 | }; |
171 | |
172 | |
173 | |
174 | /** |
175 | * Class that is used to serialize JSON objects to a string. |
176 | * @param {?goog.json.Replacer=} opt_replacer Replacer. |
177 | * @constructor |
178 | */ |
179 | goog.json.Serializer = function(opt_replacer) { |
180 | /** |
181 | * @type {goog.json.Replacer|null|undefined} |
182 | * @private |
183 | */ |
184 | this.replacer_ = opt_replacer; |
185 | }; |
186 | |
187 | |
188 | /** |
189 | * Serializes an object or a value to a JSON string. |
190 | * |
191 | * @param {*} object The object to serialize. |
192 | * @throws Error if there are loops in the object graph. |
193 | * @return {string} A JSON string representation of the input. |
194 | */ |
195 | goog.json.Serializer.prototype.serialize = function(object) { |
196 | var sb = []; |
197 | this.serializeInternal(object, sb); |
198 | return sb.join(''); |
199 | }; |
200 | |
201 | |
202 | /** |
203 | * Serializes a generic value to a JSON string |
204 | * @protected |
205 | * @param {*} object The object to serialize. |
206 | * @param {Array} sb Array used as a string builder. |
207 | * @throws Error if there are loops in the object graph. |
208 | */ |
209 | goog.json.Serializer.prototype.serializeInternal = function(object, sb) { |
210 | switch (typeof object) { |
211 | case 'string': |
212 | this.serializeString_(/** @type {string} */ (object), sb); |
213 | break; |
214 | case 'number': |
215 | this.serializeNumber_(/** @type {number} */ (object), sb); |
216 | break; |
217 | case 'boolean': |
218 | sb.push(object); |
219 | break; |
220 | case 'undefined': |
221 | sb.push('null'); |
222 | break; |
223 | case 'object': |
224 | if (object == null) { |
225 | sb.push('null'); |
226 | break; |
227 | } |
228 | if (goog.isArray(object)) { |
229 | this.serializeArray(/** @type {!Array} */ (object), sb); |
230 | break; |
231 | } |
232 | // should we allow new String, new Number and new Boolean to be treated |
233 | // as string, number and boolean? Most implementations do not and the |
234 | // need is not very big |
235 | this.serializeObject_(/** @type {Object} */ (object), sb); |
236 | break; |
237 | case 'function': |
238 | // Skip functions. |
239 | // TODO(user) Should we return something here? |
240 | break; |
241 | default: |
242 | throw Error('Unknown type: ' + typeof object); |
243 | } |
244 | }; |
245 | |
246 | |
247 | /** |
248 | * Character mappings used internally for goog.string.quote |
249 | * @private |
250 | * @type {!Object} |
251 | */ |
252 | goog.json.Serializer.charToJsonCharCache_ = { |
253 | '\"': '\\"', |
254 | '\\': '\\\\', |
255 | '/': '\\/', |
256 | '\b': '\\b', |
257 | '\f': '\\f', |
258 | '\n': '\\n', |
259 | '\r': '\\r', |
260 | '\t': '\\t', |
261 | |
262 | '\x0B': '\\u000b' // '\v' is not supported in JScript |
263 | }; |
264 | |
265 | |
266 | /** |
267 | * Regular expression used to match characters that need to be replaced. |
268 | * The S60 browser has a bug where unicode characters are not matched by |
269 | * regular expressions. The condition below detects such behaviour and |
270 | * adjusts the regular expression accordingly. |
271 | * @private |
272 | * @type {!RegExp} |
273 | */ |
274 | goog.json.Serializer.charsToReplace_ = /\uffff/.test('\uffff') ? |
275 | /[\\\"\x00-\x1f\x7f-\uffff]/g : /[\\\"\x00-\x1f\x7f-\xff]/g; |
276 | |
277 | |
278 | /** |
279 | * Serializes a string to a JSON string |
280 | * @private |
281 | * @param {string} s The string to serialize. |
282 | * @param {Array} sb Array used as a string builder. |
283 | */ |
284 | goog.json.Serializer.prototype.serializeString_ = function(s, sb) { |
285 | // The official JSON implementation does not work with international |
286 | // characters. |
287 | sb.push('"', s.replace(goog.json.Serializer.charsToReplace_, function(c) { |
288 | // caching the result improves performance by a factor 2-3 |
289 | if (c in goog.json.Serializer.charToJsonCharCache_) { |
290 | return goog.json.Serializer.charToJsonCharCache_[c]; |
291 | } |
292 | |
293 | var cc = c.charCodeAt(0); |
294 | var rv = '\\u'; |
295 | if (cc < 16) { |
296 | rv += '000'; |
297 | } else if (cc < 256) { |
298 | rv += '00'; |
299 | } else if (cc < 4096) { // \u1000 |
300 | rv += '0'; |
301 | } |
302 | return goog.json.Serializer.charToJsonCharCache_[c] = rv + cc.toString(16); |
303 | }), '"'); |
304 | }; |
305 | |
306 | |
307 | /** |
308 | * Serializes a number to a JSON string |
309 | * @private |
310 | * @param {number} n The number to serialize. |
311 | * @param {Array} sb Array used as a string builder. |
312 | */ |
313 | goog.json.Serializer.prototype.serializeNumber_ = function(n, sb) { |
314 | sb.push(isFinite(n) && !isNaN(n) ? n : 'null'); |
315 | }; |
316 | |
317 | |
318 | /** |
319 | * Serializes an array to a JSON string |
320 | * @param {Array} arr The array to serialize. |
321 | * @param {Array} sb Array used as a string builder. |
322 | * @protected |
323 | */ |
324 | goog.json.Serializer.prototype.serializeArray = function(arr, sb) { |
325 | var l = arr.length; |
326 | sb.push('['); |
327 | var sep = ''; |
328 | for (var i = 0; i < l; i++) { |
329 | sb.push(sep); |
330 | |
331 | var value = arr[i]; |
332 | this.serializeInternal( |
333 | this.replacer_ ? this.replacer_.call(arr, String(i), value) : value, |
334 | sb); |
335 | |
336 | sep = ','; |
337 | } |
338 | sb.push(']'); |
339 | }; |
340 | |
341 | |
342 | /** |
343 | * Serializes an object to a JSON string |
344 | * @private |
345 | * @param {Object} obj The object to serialize. |
346 | * @param {Array} sb Array used as a string builder. |
347 | */ |
348 | goog.json.Serializer.prototype.serializeObject_ = function(obj, sb) { |
349 | sb.push('{'); |
350 | var sep = ''; |
351 | for (var key in obj) { |
352 | if (Object.prototype.hasOwnProperty.call(obj, key)) { |
353 | var value = obj[key]; |
354 | // Skip functions. |
355 | // TODO(ptucker) Should we return something for function properties? |
356 | if (typeof value != 'function') { |
357 | sb.push(sep); |
358 | this.serializeString_(key, sb); |
359 | sb.push(':'); |
360 | |
361 | this.serializeInternal( |
362 | this.replacer_ ? this.replacer_.call(obj, key, value) : value, |
363 | sb); |
364 | |
365 | sep = ','; |
366 | } |
367 | } |
368 | } |
369 | sb.push('}'); |
370 | }; |