The Tor Browser / file comparison
comparison: addon-sdk/source/lib/sdk/lang/weak-set.js
addon-sdk/source/lib/sdk/lang/weak-set.js
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- 6474c204b198
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| -1:000000000000 | 0:240243051189 |
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| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 module.metadata = { | |
| 6 "stability": "experimental" | |
| 7 }; | |
| 8 | |
| 9 "use strict"; | |
| 10 | |
| 11 const { Cu } = require("chrome"); | |
| 12 | |
| 13 function makeGetterFor(Type) { | |
| 14 let cache = new WeakMap(); | |
| 15 | |
| 16 return function getFor(target) { | |
| 17 if (!cache.has(target)) | |
| 18 cache.set(target, new Type()); | |
| 19 | |
| 20 return cache.get(target); | |
| 21 } | |
| 22 } | |
| 23 | |
| 24 let getLookupFor = makeGetterFor(WeakMap); | |
| 25 let getRefsFor = makeGetterFor(Set); | |
| 26 | |
| 27 function add(target, value) { | |
| 28 if (has(target, value)) | |
| 29 return; | |
| 30 | |
| 31 getLookupFor(target).set(value, true); | |
| 32 getRefsFor(target).add(Cu.getWeakReference(value)); | |
| 33 } | |
| 34 exports.add = add; | |
| 35 | |
| 36 function remove(target, value) { | |
| 37 getLookupFor(target).delete(value); | |
| 38 } | |
| 39 exports.remove = remove; | |
| 40 | |
| 41 function has(target, value) { | |
| 42 return getLookupFor(target).has(value); | |
| 43 } | |
| 44 exports.has = has; | |
| 45 | |
| 46 function clear(target) { | |
| 47 getLookupFor(target).clear(); | |
| 48 getRefsFor(target).clear(); | |
| 49 } | |
| 50 exports.clear = clear; | |
| 51 | |
| 52 function iterator(target) { | |
| 53 let refs = getRefsFor(target); | |
| 54 | |
| 55 for (let ref of refs) { | |
| 56 let value = ref.get(); | |
| 57 | |
| 58 // If `value` is already gc'ed, it would be `null`. | |
| 59 // The `has` function is using a WeakMap as lookup table, so passing `null` | |
| 60 // would raise an exception because WeakMap accepts as value only non-null | |
| 61 // object. | |
| 62 // Plus, if `value` is already gc'ed, we do not have to take it in account | |
| 63 // during the iteration, and remove it from the references. | |
| 64 if (value !== null && has(target, value)) | |
| 65 yield value; | |
| 66 else | |
| 67 refs.delete(ref); | |
| 68 } | |
| 69 } | |
| 70 exports.iterator = iterator; |
