The Tor Browser / file diff

     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/addon-sdk/source/lib/sdk/lang/weak-set.js	Wed Dec 31 06:09:35 2014 +0100
     1.3 @@ -0,0 +1,70 @@
     1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
     1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
     1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
     1.7 +
     1.8 +module.metadata = {
     1.9 +  "stability": "experimental"
    1.10 +};
    1.11 +
    1.12 +"use strict";
    1.13 +
    1.14 +const { Cu } = require("chrome");
    1.15 +
    1.16 +function makeGetterFor(Type) {
    1.17 +  let cache = new WeakMap();
    1.18 +
    1.19 +  return function getFor(target) {
    1.20 +    if (!cache.has(target))
    1.21 +      cache.set(target, new Type());
    1.22 +
    1.23 +    return cache.get(target);
    1.24 +  }
    1.25 +}
    1.26 +
    1.27 +let getLookupFor = makeGetterFor(WeakMap);
    1.28 +let getRefsFor = makeGetterFor(Set);
    1.29 +
    1.30 +function add(target, value) {
    1.31 +  if (has(target, value))
    1.32 +    return;
    1.33 +
    1.34 +  getLookupFor(target).set(value, true);
    1.35 +  getRefsFor(target).add(Cu.getWeakReference(value));
    1.36 +}
    1.37 +exports.add = add;
    1.38 +
    1.39 +function remove(target, value) {
    1.40 +  getLookupFor(target).delete(value);
    1.41 +}
    1.42 +exports.remove = remove;
    1.43 +
    1.44 +function has(target, value) {
    1.45 +  return getLookupFor(target).has(value);
    1.46 +}
    1.47 +exports.has = has;
    1.48 +
    1.49 +function clear(target) {
    1.50 +  getLookupFor(target).clear();
    1.51 +  getRefsFor(target).clear();
    1.52 +}
    1.53 +exports.clear = clear;
    1.54 +
    1.55 +function iterator(target) {
    1.56 +  let refs = getRefsFor(target);
    1.57 +
    1.58 +  for (let ref of refs) {
    1.59 +    let value = ref.get();
    1.60 +
    1.61 +    // If `value` is already gc'ed, it would be `null`.
    1.62 +    // The `has` function is using a WeakMap as lookup table, so passing `null`
    1.63 +    // would raise an exception because WeakMap accepts as value only non-null
    1.64 +    // object.
    1.65 +    // Plus, if `value` is already gc'ed, we do not have to take it in account
    1.66 +    // during the iteration, and remove it from the references.
    1.67 +    if (value !== null && has(target, value))
    1.68 +      yield value;
    1.69 +    else
    1.70 +      refs.delete(ref);
    1.71 +  }
    1.72 +}
    1.73 +exports.iterator = iterator;