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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 | |
3 // BSD-style license that can be found in the LICENSE file. | |
4 | |
5 part of _js_helper; | |
6 | |
7 | |
8 // TODO(ngeoffray): stop using this method once our optimizers can | |
9 // change str1.contains(str2) into str1.indexOf(str2) != -1. | |
10 bool contains(String userAgent, String name) { | |
11 return JS('int', '#.indexOf(#)', userAgent, name) != -1; | |
12 } | |
13 | |
14 int arrayLength(List array) { | |
15 return JS('int', '#.length', array); | |
16 } | |
17 | |
18 arrayGet(List array, int index) { | |
19 return JS('var', '#[#]', array, index); | |
20 } | |
21 | |
22 void arraySet(List array, int index, var value) { | |
23 JS('var', '#[#] = #', array, index, value); | |
24 } | |
25 | |
26 propertyGet(var object, String property) { | |
27 return JS('var', '#[#]', object, property); | |
28 } | |
29 | |
30 bool callHasOwnProperty(var function, var object, String property) { | |
31 return JS('bool', '#.call(#, #)', function, object, property); | |
32 } | |
33 | |
34 void propertySet(var object, String property, var value) { | |
35 JS('var', '#[#] = #', object, property, value); | |
36 } | |
37 | |
38 getPropertyFromPrototype(var object, String name) { | |
39 return JS('var', 'Object.getPrototypeOf(#)[#]', object, name); | |
40 } | |
41 | |
42 /** | |
43 * Returns a String tag identifying the type of the native object, or `null`. | |
44 * The tag is not the name of the type, but usually the name of the JavaScript | |
45 * constructor function. Initialized by [initHooks]. | |
46 */ | |
47 Function getTagFunction; | |
48 | |
49 /** | |
50 * If a lookup via [getTagFunction] on an object [object] that has [tag] fails, | |
51 * this function is called to provide an alternate tag. This allows us to fail | |
52 * gracefully if we can make a good guess, for example, when browsers add novel | |
53 * kinds of HTMLElement that we have never heard of. Initialized by | |
54 * [initHooks]. | |
55 */ | |
56 Function alternateTagFunction; | |
57 | |
58 /** | |
59 * Returns the prototype for the JavaScript constructor named by an input tag. | |
60 * Returns `null` if there is no such constructor, or if pre-patching of the | |
61 * constructor is to be avoided. Initialized by [initHooks]. | |
62 */ | |
63 Function prototypeForTagFunction; | |
64 | |
65 | |
66 String toStringForNativeObject(var obj) { | |
67 // TODO(sra): Is this code dead? | |
68 // [getTagFunction] might be uninitialized, but in usual usage, toString has | |
69 // been called via an interceptor and initialized it. | |
70 String name = getTagFunction == null | |
71 ? '<Unknown>' | |
72 : JS('String', '#', getTagFunction(obj)); | |
73 return 'Instance of $name'; | |
74 } | |
75 | |
76 int hashCodeForNativeObject(object) => Primitives.objectHashCode(object); | |
77 | |
78 /** | |
79 * Sets a JavaScript property on an object. | |
80 */ | |
81 void defineProperty(var obj, String property, var value) { | |
82 JS('void', | |
83 'Object.defineProperty(#, #, ' | |
84 '{value: #, enumerable: false, writable: true, configurable: true})', | |
85 obj, | |
86 property, | |
87 value); | |
88 } | |
89 | |
90 | |
91 // Is [obj] an instance of a Dart-defined class? | |
92 bool isDartObject(obj) { | |
93 // Some of the extra parens here are necessary. | |
94 return JS('bool', '((#) instanceof (#))', | |
95 obj, | |
96 JS_BUILTIN('depends:none;effects:none;', | |
97 JsBuiltin.dartObjectConstructor)); | |
98 } | |
99 | |
100 /** | |
101 * A JavaScript object mapping tags to the constructors of interceptors. | |
102 * This is a JavaScript object with no prototype. | |
103 * | |
104 * Example: 'HTMLImageElement' maps to the ImageElement class constructor. | |
105 */ | |
106 get interceptorsByTag => JS_EMBEDDED_GLOBAL('=Object', INTERCEPTORS_BY_TAG); | |
107 | |
108 /** | |
109 * A JavaScript object mapping tags to `true` or `false`. | |
110 * | |
111 * Example: 'HTMLImageElement' maps to `true` since, as there are no subclasses | |
112 * of ImageElement, it is a leaf class in the native class hierarchy. | |
113 */ | |
114 get leafTags => JS_EMBEDDED_GLOBAL('=Object', LEAF_TAGS); | |
115 | |
116 String findDispatchTagForInterceptorClass(interceptorClassConstructor) { | |
117 return JS('', r'#.#', | |
118 interceptorClassConstructor, NATIVE_SUPERCLASS_TAG_NAME); | |
119 } | |
120 | |
121 /** | |
122 * Cache of dispatch records for instances. This is a JavaScript object used as | |
123 * a map. Keys are instance tags, e.g. "!SomeThing". The cache permits the | |
124 * sharing of one dispatch record between multiple instances. | |
125 */ | |
126 var dispatchRecordsForInstanceTags; | |
127 | |
128 /** | |
129 * Cache of interceptors indexed by uncacheable tags, e.g. "~SomeThing". | |
130 * This is a JavaScript object used as a map. | |
131 */ | |
132 var interceptorsForUncacheableTags; | |
133 | |
134 | |
135 lookupInterceptor(String tag) { | |
136 return propertyGet(interceptorsByTag, tag); | |
137 } | |
138 | |
139 | |
140 // Dispatch tag marks are optional prefixes for a dispatch tag that direct how | |
141 // the interceptor for the tag may be cached. | |
142 | |
143 /// No caching permitted. | |
144 const UNCACHED_MARK = '~'; | |
145 | |
146 /// Dispatch record must be cached per instance | |
147 const INSTANCE_CACHED_MARK = '!'; | |
148 | |
149 /// Dispatch record is cached on immediate prototype. | |
150 const LEAF_MARK = '-'; | |
151 | |
152 /// Dispatch record is cached on immediate prototype with a prototype | |
153 /// verification to prevent the interceptor being associated with a subclass | |
154 /// before a dispatch record is cached on the subclass. | |
155 const INTERIOR_MARK = '+'; | |
156 | |
157 /// A 'discriminator' function is to be used. TBD. | |
158 const DISCRIMINATED_MARK = '*'; | |
159 | |
160 | |
161 /** | |
162 * Returns the interceptor for a native object, or returns `null` if not found. | |
163 * | |
164 * A dispatch record is cached according to the specification of the dispatch | |
165 * tag for [obj]. | |
166 */ | |
167 lookupAndCacheInterceptor(obj) { | |
168 assert(!isDartObject(obj)); | |
169 String tag = getTagFunction(obj); | |
170 | |
171 // Fast path for instance (and uncached) tags because the lookup is repeated | |
172 // for each instance (or getInterceptor call). | |
173 var record = propertyGet(dispatchRecordsForInstanceTags, tag); | |
174 if (record != null) return patchInstance(obj, record); | |
175 var interceptor = propertyGet(interceptorsForUncacheableTags, tag); | |
176 if (interceptor != null) return interceptor; | |
177 | |
178 // This lookup works for derived dispatch tags because we add them all in | |
179 // [initNativeDispatch]. | |
180 var interceptorClass = lookupInterceptor(tag); | |
181 if (interceptorClass == null) { | |
182 tag = alternateTagFunction(obj, tag); | |
183 if (tag != null) { | |
184 // Fast path for instance and uncached tags again. | |
185 record = propertyGet(dispatchRecordsForInstanceTags, tag); | |
186 if (record != null) return patchInstance(obj, record); | |
187 interceptor = propertyGet(interceptorsForUncacheableTags, tag); | |
188 if (interceptor != null) return interceptor; | |
189 | |
190 interceptorClass = lookupInterceptor(tag); | |
191 } | |
192 } | |
193 | |
194 if (interceptorClass == null) { | |
195 // This object is not known to Dart. There could be several reasons for | |
196 // that, including (but not limited to): | |
197 // | |
198 // * A bug in native code (hopefully this is caught during development). | |
199 // * An unknown DOM object encountered. | |
200 // * JavaScript code running in an unexpected context. For example, on | |
201 // node.js. | |
202 return null; | |
203 } | |
204 | |
205 interceptor = JS('', '#.prototype', interceptorClass); | |
206 | |
207 var mark = JS('String|Null', '#[0]', tag); | |
208 | |
209 if (mark == INSTANCE_CACHED_MARK) { | |
210 record = makeLeafDispatchRecord(interceptor); | |
211 propertySet(dispatchRecordsForInstanceTags, tag, record); | |
212 return patchInstance(obj, record); | |
213 } | |
214 | |
215 if (mark == UNCACHED_MARK) { | |
216 propertySet(interceptorsForUncacheableTags, tag, interceptor); | |
217 return interceptor; | |
218 } | |
219 | |
220 if (mark == LEAF_MARK) { | |
221 return patchProto(obj, makeLeafDispatchRecord(interceptor)); | |
222 } | |
223 | |
224 if (mark == INTERIOR_MARK) { | |
225 return patchInteriorProto(obj, interceptor); | |
226 } | |
227 | |
228 if (mark == DISCRIMINATED_MARK) { | |
229 // TODO(sra): Use discriminator of tag. | |
230 throw new UnimplementedError(tag); | |
231 } | |
232 | |
233 // [tag] was not explicitly an interior or leaf tag, so | |
234 var isLeaf = JS('bool', '(#[#]) === true', leafTags, tag); | |
235 if (isLeaf) { | |
236 return patchProto(obj, makeLeafDispatchRecord(interceptor)); | |
237 } else { | |
238 return patchInteriorProto(obj, interceptor); | |
239 } | |
240 } | |
241 | |
242 patchInstance(obj, record) { | |
243 setDispatchProperty(obj, record); | |
244 return dispatchRecordInterceptor(record); | |
245 } | |
246 | |
247 patchProto(obj, record) { | |
248 setDispatchProperty(JS('', 'Object.getPrototypeOf(#)', obj), record); | |
249 return dispatchRecordInterceptor(record); | |
250 } | |
251 | |
252 patchInteriorProto(obj, interceptor) { | |
253 var proto = JS('', 'Object.getPrototypeOf(#)', obj); | |
254 var record = makeDispatchRecord(interceptor, proto, null, null); | |
255 setDispatchProperty(proto, record); | |
256 return interceptor; | |
257 } | |
258 | |
259 | |
260 makeLeafDispatchRecord(interceptor) { | |
261 var fieldName = JS_GET_NAME(JsGetName.IS_INDEXABLE_FIELD_NAME); | |
262 bool indexability = JS('bool', r'!!#[#]', interceptor, fieldName); | |
263 return makeDispatchRecord(interceptor, false, null, indexability); | |
264 } | |
265 | |
266 makeDefaultDispatchRecord(tag, interceptorClass, proto) { | |
267 var interceptor = JS('', '#.prototype', interceptorClass); | |
268 var isLeaf = JS('bool', '(#[#]) === true', leafTags, tag); | |
269 if (isLeaf) { | |
270 return makeLeafDispatchRecord(interceptor); | |
271 } else { | |
272 return makeDispatchRecord(interceptor, proto, null, null); | |
273 } | |
274 } | |
275 | |
276 /** | |
277 * [proto] should have no shadowing prototypes that are not also assigned a | |
278 * dispatch rescord. | |
279 */ | |
280 setNativeSubclassDispatchRecord(proto, interceptor) { | |
281 setDispatchProperty(proto, makeLeafDispatchRecord(interceptor)); | |
282 } | |
283 | |
284 String constructorNameFallback(object) { | |
285 return JS('String', '#(#)', _constructorNameFallback, object); | |
286 } | |
287 | |
288 | |
289 var initNativeDispatchFlag; // null or true | |
290 | |
291 void initNativeDispatch() { | |
292 if (true == initNativeDispatchFlag) return; | |
293 initNativeDispatchFlag = true; | |
294 initNativeDispatchContinue(); | |
295 } | |
296 | |
297 void initNativeDispatchContinue() { | |
298 | |
299 dispatchRecordsForInstanceTags = JS('', 'Object.create(null)'); | |
300 interceptorsForUncacheableTags = JS('', 'Object.create(null)'); | |
301 | |
302 initHooks(); | |
303 | |
304 // Try to pro-actively patch prototypes of DOM objects. For each of our known | |
305 // tags `TAG`, if `window.TAG` is a (constructor) function, set the dispatch | |
306 // property if the function's prototype to a dispatch record. | |
307 var map = interceptorsByTag; | |
308 var tags = JS('JSMutableArray', 'Object.getOwnPropertyNames(#)', map); | |
309 | |
310 if (JS('bool', 'typeof window != "undefined"')) { | |
311 var context = JS('=Object', 'window'); | |
312 var fun = JS('=Object', 'function () {}'); | |
313 for (int i = 0; i < tags.length; i++) { | |
314 var tag = tags[i]; | |
315 var proto = prototypeForTagFunction(tag); | |
316 if (proto != null) { | |
317 var interceptorClass = JS('', '#[#]', map, tag); | |
318 var record = makeDefaultDispatchRecord(tag, interceptorClass, proto); | |
319 if (record != null) { | |
320 setDispatchProperty(proto, record); | |
321 // Ensure the modified prototype is still fast by assigning it to | |
322 // the prototype property of a function object. | |
323 JS('', '#.prototype = #', fun, proto); | |
324 } | |
325 } | |
326 } | |
327 } | |
328 | |
329 // [interceptorsByTag] maps 'plain' dispatch tags. Add all the derived | |
330 // dispatch tags to simplify lookup of derived tags. | |
331 for (int i = 0; i < tags.length; i++) { | |
332 var tag = JS('String', '#[#]', tags, i); | |
333 if (JS('bool', '/^[A-Za-z_]/.test(#)', tag)) { | |
334 var interceptorClass = propertyGet(map, tag); | |
335 propertySet(map, INSTANCE_CACHED_MARK + tag, interceptorClass); | |
336 propertySet(map, UNCACHED_MARK + tag, interceptorClass); | |
337 propertySet(map, LEAF_MARK + tag, interceptorClass); | |
338 propertySet(map, INTERIOR_MARK + tag, interceptorClass); | |
339 propertySet(map, DISCRIMINATED_MARK + tag, interceptorClass); | |
340 } | |
341 } | |
342 } | |
343 | |
344 | |
345 /** | |
346 * Initializes [getTagFunction] and [alternateTagFunction]. | |
347 * | |
348 * These functions are 'hook functions', collectively 'hooks'. They initialized | |
349 * by applying a series of hooks transformers. Built-in hooks transformers deal | |
350 * with various known browser behaviours. | |
351 * | |
352 * Each hook tranformer takes a 'hooks' input which is a JavaScript object | |
353 * containing the hook functions, and returns the same or a new object with | |
354 * replacements. The replacements can wrap the originals to provide alternate | |
355 * or modified behaviour. | |
356 * | |
357 * { getTag: function(obj) {...}, | |
358 * getUnknownTag: function(obj, tag) {...}, | |
359 * prototypeForTag: function(tag) {...}, | |
360 * discriminator: function(tag) {...}, | |
361 * } | |
362 * | |
363 * * getTag(obj) returns the dispatch tag, or `null`. | |
364 * * getUnknownTag(obj, tag) returns a tag when [getTag] fails. | |
365 * * prototypeForTag(tag) returns the prototype of the constructor for tag, | |
366 * or `null` if not available or prepatching is undesirable. | |
367 * * discriminator(tag) returns a function TBD. | |
368 * | |
369 * The web site can adapt a dart2js application by loading code ahead of the | |
370 * dart2js application that defines hook transformers to be after the built in | |
371 * ones. Code defining a transformer HT should use the following pattern to | |
372 * ensure multiple transformers can be composed: | |
373 * | |
374 * (dartNativeDispatchHooksTransformer = | |
375 * window.dartNativeDispatchHooksTransformer || []).push(HT); | |
376 * | |
377 * | |
378 * TODO: Implement and describe dispatch tags and their caching methods. | |
379 */ | |
380 void initHooks() { | |
381 // The initial simple hooks: | |
382 var hooks = JS('', '#()', _baseHooks); | |
383 | |
384 // Customize for browsers where `object.constructor.name` fails: | |
385 var _fallbackConstructorHooksTransformer = | |
386 JS('', '#(#)', _fallbackConstructorHooksTransformerGenerator, | |
387 _constructorNameFallback); | |
388 hooks = applyHooksTransformer(_fallbackConstructorHooksTransformer, hooks); | |
389 | |
390 // Customize for browsers: | |
391 hooks = applyHooksTransformer(_firefoxHooksTransformer, hooks); | |
392 hooks = applyHooksTransformer(_ieHooksTransformer, hooks); | |
393 hooks = applyHooksTransformer(_operaHooksTransformer, hooks); | |
394 hooks = applyHooksTransformer(_safariHooksTransformer, hooks); | |
395 | |
396 hooks = applyHooksTransformer(_fixDocumentHooksTransformer, hooks); | |
397 | |
398 // TODO(sra): Update ShadowDOM polyfil to use | |
399 // [dartNativeDispatchHooksTransformer] and remove this hook. | |
400 hooks = applyHooksTransformer(_dartExperimentalFixupGetTagHooksTransformer, | |
401 hooks); | |
402 | |
403 // Apply global hooks. | |
404 // | |
405 // If defined, dartNativeDispatchHookdTransformer should be a single function | |
406 // of a JavaScript Array of functions. | |
407 | |
408 if (JS('bool', 'typeof dartNativeDispatchHooksTransformer != "undefined"')) { | |
409 var transformers = JS('', 'dartNativeDispatchHooksTransformer'); | |
410 if (JS('bool', 'typeof # == "function"', transformers)) { | |
411 transformers = [transformers]; | |
412 } | |
413 if (JS('bool', '#.constructor == Array', transformers)) { | |
414 for (int i = 0; i < JS('int', '#.length', transformers); i++) { | |
415 var transformer = JS('', '#[#]', transformers, i); | |
416 if (JS('bool', 'typeof # == "function"', transformer)) { | |
417 hooks = applyHooksTransformer(transformer, hooks); | |
418 } | |
419 } | |
420 } | |
421 } | |
422 | |
423 var getTag = JS('', '#.getTag', hooks); | |
424 var getUnknownTag = JS('', '#.getUnknownTag', hooks); | |
425 var prototypeForTag = JS('', '#.prototypeForTag', hooks); | |
426 | |
427 getTagFunction = (o) => JS('String|Null', '#(#)', getTag, o); | |
428 alternateTagFunction = | |
429 (o, String tag) => JS('String|Null', '#(#, #)', getUnknownTag, o, tag); | |
430 prototypeForTagFunction = | |
431 (String tag) => JS('', '#(#)', prototypeForTag, tag); | |
432 } | |
433 | |
434 applyHooksTransformer(transformer, hooks) { | |
435 var newHooks = JS('=Object|Null', '#(#)', transformer, hooks); | |
436 return JS('', '# || #', newHooks, hooks); | |
437 } | |
438 | |
439 // JavaScript code fragments. | |
440 // | |
441 // This is a temporary place for the JavaScript code. | |
442 // | |
443 // TODO(sra): These code fragments are not minified. They could be generated by | |
444 // the code emitter, or JS_CONST could be improved to parse entire functions and | |
445 // take care of the minification. | |
446 | |
447 const _baseHooks = const JS_CONST(r''' | |
448 function() { | |
449 function typeNameInChrome(o) { | |
450 var constructor = o.constructor; | |
451 if (constructor) { | |
452 var name = constructor.name; | |
453 if (name) return name; | |
454 } | |
455 var s = Object.prototype.toString.call(o); | |
456 return s.substring(8, s.length - 1); | |
457 } | |
458 function getUnknownTag(object, tag) { | |
459 // This code really belongs in [getUnknownTagGenericBrowser] but having it | |
460 // here allows [getUnknownTag] to be tested on d8. | |
461 if (/^HTML[A-Z].*Element$/.test(tag)) { | |
462 // Check that it is not a simple JavaScript object. | |
463 var name = Object.prototype.toString.call(object); | |
464 if (name == "[object Object]") return null; | |
465 return "HTMLElement"; | |
466 } | |
467 } | |
468 function getUnknownTagGenericBrowser(object, tag) { | |
469 if (self.HTMLElement && object instanceof HTMLElement) return "HTMLElement"; | |
470 return getUnknownTag(object, tag); | |
471 } | |
472 function prototypeForTag(tag) { | |
473 if (typeof window == "undefined") return null; | |
474 if (typeof window[tag] == "undefined") return null; | |
475 var constructor = window[tag]; | |
476 if (typeof constructor != "function") return null; | |
477 return constructor.prototype; | |
478 } | |
479 function discriminator(tag) { return null; } | |
480 | |
481 var isBrowser = typeof navigator == "object"; | |
482 | |
483 return { | |
484 getTag: typeNameInChrome, | |
485 getUnknownTag: isBrowser ? getUnknownTagGenericBrowser : getUnknownTag, | |
486 prototypeForTag: prototypeForTag, | |
487 discriminator: discriminator }; | |
488 }'''); | |
489 | |
490 | |
491 /** | |
492 * Returns the name of the constructor function for browsers where | |
493 * `object.constructor.name` is not reliable. | |
494 * | |
495 * This function is split out of [_fallbackConstructorHooksTransformerGenerator] | |
496 * as it is called from both the dispatch hooks and via | |
497 * [constructorNameFallback] from objectToString. | |
498 */ | |
499 const _constructorNameFallback = const JS_CONST(r''' | |
500 function getTagFallback(o) { | |
501 var constructor = o.constructor; | |
502 if (typeof constructor == "function") { | |
503 var name = constructor.name; | |
504 // If the name is a non-empty string, we use that as the type name of this | |
505 // object. There are various cases where that does not work, so we have to | |
506 // detect them and fall through to the toString() based implementation. | |
507 | |
508 if (typeof name == "string" && | |
509 | |
510 // Sometimes the string is empty. This test also catches minified | |
511 // shadow dom polyfil wrapper for Window on Firefox where the faked | |
512 // constructor name does not 'stick'. The shortest real DOM object | |
513 // names have three characters (e.g. URL, CSS). | |
514 name.length > 2 && | |
515 | |
516 // On Firefox we often get "Object" as the constructor name, even for | |
517 // more specialized DOM objects. | |
518 name !== "Object" && | |
519 | |
520 // This can happen in Opera. | |
521 name !== "Function.prototype") { | |
522 return name; | |
523 } | |
524 } | |
525 var s = Object.prototype.toString.call(o); | |
526 return s.substring(8, s.length - 1); | |
527 }'''); | |
528 | |
529 | |
530 const _fallbackConstructorHooksTransformerGenerator = const JS_CONST(r''' | |
531 function(getTagFallback) { | |
532 return function(hooks) { | |
533 // If we are not in a browser, assume we are in d8. | |
534 // TODO(sra): Recognize jsshell. | |
535 if (typeof navigator != "object") return hooks; | |
536 | |
537 var ua = navigator.userAgent; | |
538 // TODO(antonm): remove a reference to DumpRenderTree. | |
539 if (ua.indexOf("DumpRenderTree") >= 0) return hooks; | |
540 if (ua.indexOf("Chrome") >= 0) { | |
541 // Confirm constructor name is usable for dispatch. | |
542 function confirm(p) { | |
543 return typeof window == "object" && window[p] && window[p].name == p; | |
544 } | |
545 if (confirm("Window") && confirm("HTMLElement")) return hooks; | |
546 } | |
547 | |
548 hooks.getTag = getTagFallback; | |
549 }; | |
550 }'''); | |
551 | |
552 | |
553 const _ieHooksTransformer = const JS_CONST(r''' | |
554 function(hooks) { | |
555 var userAgent = typeof navigator == "object" ? navigator.userAgent : ""; | |
556 if (userAgent.indexOf("Trident/") == -1) return hooks; | |
557 | |
558 var getTag = hooks.getTag; | |
559 | |
560 var quickMap = { | |
561 "BeforeUnloadEvent": "Event", | |
562 "DataTransfer": "Clipboard", | |
563 "HTMLDDElement": "HTMLElement", | |
564 "HTMLDTElement": "HTMLElement", | |
565 "HTMLPhraseElement": "HTMLElement", | |
566 "Position": "Geoposition" | |
567 }; | |
568 | |
569 function getTagIE(o) { | |
570 var tag = getTag(o); | |
571 var newTag = quickMap[tag]; | |
572 if (newTag) return newTag; | |
573 // Patches for types which report themselves as Objects. | |
574 if (tag == "Object") { | |
575 if (window.DataView && (o instanceof window.DataView)) return "DataView"; | |
576 } | |
577 return tag; | |
578 } | |
579 | |
580 function prototypeForTagIE(tag) { | |
581 var constructor = window[tag]; | |
582 if (constructor == null) return null; | |
583 return constructor.prototype; | |
584 } | |
585 | |
586 hooks.getTag = getTagIE; | |
587 hooks.prototypeForTag = prototypeForTagIE; | |
588 }'''); | |
589 | |
590 const _fixDocumentHooksTransformer = const JS_CONST(r''' | |
591 function(hooks) { | |
592 var getTag = hooks.getTag; | |
593 var prototypeForTag = hooks.prototypeForTag; | |
594 function getTagFixed(o) { | |
595 var tag = getTag(o); | |
596 if (tag == "Document") { | |
597 // Some browsers and the polymer polyfill call both HTML and XML documents | |
598 // "Document", so we check for the xmlVersion property, which is the empty | |
599 // string on HTML documents. Since both dart:html classes Document and | |
600 // HtmlDocument share the same type, we must patch the instances and not | |
601 // the prototype. | |
602 if (!!o.xmlVersion) return "!Document"; | |
603 return "!HTMLDocument"; | |
604 } | |
605 return tag; | |
606 } | |
607 | |
608 function prototypeForTagFixed(tag) { | |
609 if (tag == "Document") return null; // Do not pre-patch Document. | |
610 return prototypeForTag(tag); | |
611 } | |
612 | |
613 hooks.getTag = getTagFixed; | |
614 hooks.prototypeForTag = prototypeForTagFixed; | |
615 }'''); | |
616 | |
617 const _firefoxHooksTransformer = const JS_CONST(r''' | |
618 function(hooks) { | |
619 var userAgent = typeof navigator == "object" ? navigator.userAgent : ""; | |
620 if (userAgent.indexOf("Firefox") == -1) return hooks; | |
621 | |
622 var getTag = hooks.getTag; | |
623 | |
624 var quickMap = { | |
625 "BeforeUnloadEvent": "Event", | |
626 "DataTransfer": "Clipboard", | |
627 "GeoGeolocation": "Geolocation", | |
628 "Location": "!Location", // Fixes issue 18151 | |
629 "WorkerMessageEvent": "MessageEvent", | |
630 "XMLDocument": "!Document"}; | |
631 | |
632 function getTagFirefox(o) { | |
633 var tag = getTag(o); | |
634 return quickMap[tag] || tag; | |
635 } | |
636 | |
637 hooks.getTag = getTagFirefox; | |
638 }'''); | |
639 | |
640 | |
641 const _operaHooksTransformer = const JS_CONST(r''' | |
642 function(hooks) { return hooks; } | |
643 '''); | |
644 | |
645 | |
646 const _safariHooksTransformer = const JS_CONST(r''' | |
647 function(hooks) { return hooks; } | |
648 '''); | |
649 | |
650 | |
651 const _dartExperimentalFixupGetTagHooksTransformer = const JS_CONST(r''' | |
652 function(hooks) { | |
653 if (typeof dartExperimentalFixupGetTag != "function") return hooks; | |
654 hooks.getTag = dartExperimentalFixupGetTag(hooks.getTag); | |
655 }'''); | |
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