Xavier Morel
a7e58993cd
shim necessary for browsers supporting old mutation events but not new mutation observers bzr revid: xmo@openerp.com-20130828084945-yfqrs0v9v8iecwjm
36 lines
1.1 KiB
JavaScript
36 lines
1.1 KiB
JavaScript
/*
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* Copyright 2012 The Polymer Authors. All rights reserved.
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* Use of this source code is goverened by a BSD-style
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* license that can be found in the LICENSE file.
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*/
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// SideTable is a weak map where possible. If WeakMap is not available the
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// association is stored as an expando property.
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var SideTable;
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// TODO(arv): WeakMap does not allow for Node etc to be keys in Firefox
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if (typeof WeakMap !== 'undefined' && navigator.userAgent.indexOf('Firefox/') < 0) {
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SideTable = WeakMap;
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} else {
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(function() {
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var defineProperty = Object.defineProperty;
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var hasOwnProperty = Object.hasOwnProperty;
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var counter = new Date().getTime() % 1e9;
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SideTable = function() {
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this.name = '__st' + (Math.random() * 1e9 >>> 0) + (counter++ + '__');
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};
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SideTable.prototype = {
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set: function(key, value) {
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defineProperty(key, this.name, {value: value, writable: true});
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},
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get: function(key) {
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return hasOwnProperty.call(key, this.name) ? key[this.name] : undefined;
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},
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delete: function(key) {
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this.set(key, undefined);
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}
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}
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})();
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}
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