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| 1 // Copyright (c) 2014, 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 // Updates document.registerElement so Dart can see when Javascript custom |
| 6 // elements are created, and wrap them to provide a Dart friendly API. |
| 7 (function (doc) { |
| 8 if (window._dart_register_element_interop_support) return; |
| 9 window._dart_register_element_interop_support = true; |
| 10 |
| 11 var upgraders = {}; // upgrader associated with a custom-tag. |
| 12 var unpatchableTags = {}; // set of custom-tags that can't be patched. |
| 13 var pendingElements = {}; // will upgrade when/if an upgrader is installed. |
| 14 var upgradeOldElements = true; |
| 15 |
| 16 var originalRegisterElement = doc.registerElement; |
| 17 if (!originalRegisterElement) { |
| 18 throw new Error('document.registerElement is not present.'); |
| 19 } |
| 20 |
| 21 function reportError(name) { |
| 22 console.error("Couldn't patch prototype to notify Dart when " + name + |
| 23 " elements are created. This can be fixed by making the " + |
| 24 "createdCallback in " + name + " a configurable property."); |
| 25 } |
| 26 |
| 27 function registerElement(name, options) { |
| 28 var proto, extendsOption; |
| 29 if (options !== undefined) { |
| 30 proto = options.prototype; |
| 31 } else { |
| 32 proto = Object.create(HTMLElement.prototype); |
| 33 options = {protoptype: proto}; |
| 34 } |
| 35 |
| 36 var original = proto.createdCallback; |
| 37 var newCallback = function() { |
| 38 original.call(this); |
| 39 var name = (this.getAttribute('is') || this.localName).toLowerCase(); |
| 40 var upgrader = upgraders[name]; |
| 41 if (upgrader) { |
| 42 upgrader(this); |
| 43 } else if (upgradeOldElements) { |
| 44 // Save this element in case we can upgrade it later when an upgrader is |
| 45 // registered. |
| 46 var list = pendingElements[name]; |
| 47 if (!list) { |
| 48 list = pendingElements[name] = []; |
| 49 } |
| 50 list.push(this); |
| 51 } |
| 52 }; |
| 53 |
| 54 var descriptor = Object.getOwnPropertyDescriptor(proto, 'createdCallback'); |
| 55 if (!descriptor || descriptor.writable) { |
| 56 proto.createdCallback = newCallback; |
| 57 } else if (descriptor.configurable) { |
| 58 descriptor['value'] = newCallback; |
| 59 Object.defineProperty(proto, 'createdCallback', descriptor); |
| 60 } else { |
| 61 unpatchableTags[name] = true; |
| 62 if (upgraders[name]) reportError(name); |
| 63 } |
| 64 return originalRegisterElement.call(this, name, options); |
| 65 } |
| 66 |
| 67 function registerDartTypeUpgrader(name, upgrader) { |
| 68 if (!upgrader) return; |
| 69 name = name.toLowerCase(); |
| 70 var existing = upgraders[name]; |
| 71 if (existing) { |
| 72 console.error('Already have a Dart type associated with ' + name); |
| 73 return; |
| 74 } |
| 75 upgraders[name] = upgrader; |
| 76 if (unpatchableTags[name]) reportError(name); |
| 77 if (upgradeOldElements) { |
| 78 // Upgrade elements that were created before the upgrader was registered. |
| 79 var list = pendingElements[name]; |
| 80 if (list) { |
| 81 for (var i = 0; i < list.length; i++) { |
| 82 upgrader(list[i]); |
| 83 } |
| 84 } |
| 85 delete pendingElements[name]; |
| 86 } else { |
| 87 console.warn("Didn't expect more Dart types to be registered. '" + name |
| 88 + "' elements that already exist in the page might not be wrapped."); |
| 89 } |
| 90 } |
| 91 |
| 92 function onlyUpgradeNewElements() { |
| 93 upgradeOldElements = false; |
| 94 pendingElements = null; |
| 95 } |
| 96 |
| 97 // Native custom elements outside the app in Chrome have constructor |
| 98 // names like "x-tag", which need to be translated to the DOM |
| 99 // element they extend. When using the shadow dom polyfill this is |
| 100 // taken care of in dart_support.js. |
| 101 var ShadowDOMPolyfill = window.ShadowDOMPolyfill; |
| 102 if (!ShadowDOMPolyfill) { |
| 103 // dartNativeDispatchHooksTransformer is described on initHooks() in |
| 104 // sdk/lib/_internal/lib/native_helper.dart. |
| 105 if (typeof window.dartNativeDispatchHooksTransformer == 'undefined') |
| 106 window.dartNativeDispatchHooksTransformer = []; |
| 107 |
| 108 window.dartNativeDispatchHooksTransformer.push(function(hooks) { |
| 109 var originalGetUnknownTag = hooks.getUnknownTag; |
| 110 hooks.getUnknownTag = function(o, tag) { |
| 111 if (/-/.test(tag)) { // "x-tag" |
| 112 var s = Object.prototype.toString.call(o); |
| 113 var match = s.match(/^\[object ([A-Za-z]*Element)\]$/); |
| 114 if (match) { |
| 115 return match[1]; |
| 116 } |
| 117 return originalGetUnknownTag(o, tag); |
| 118 } |
| 119 }; |
| 120 }); |
| 121 } |
| 122 |
| 123 doc._registerDartTypeUpgrader = registerDartTypeUpgrader; |
| 124 doc._onlyUpgradeNewElements = onlyUpgradeNewElements; |
| 125 doc.registerElement = registerElement; |
| 126 })(document); |
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