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/system/unload.js	Wed Dec 31 06:09:35 2014 +0100
     1.3 @@ -0,0 +1,82 @@
     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 +// Parts of this module were taken from narwhal:
     1.9 +//
    1.10 +// http://narwhaljs.org
    1.11 +
    1.12 +module.metadata = {
    1.13 +  "stability": "experimental"
    1.14 +};
    1.15 +
    1.16 +const { on, off } = require('./events');
    1.17 +const unloadSubject = require('@loader/unload');
    1.18 +
    1.19 +const observers = [];
    1.20 +const unloaders = [];
    1.21 +
    1.22 +var when = exports.when = function when(observer) {
    1.23 +  if (observers.indexOf(observer) != -1)
    1.24 +    return;
    1.25 +  observers.unshift(observer);
    1.26 +};
    1.27 +
    1.28 +var ensure = exports.ensure = function ensure(obj, destructorName) {
    1.29 +  if (!destructorName)
    1.30 +    destructorName = "unload";
    1.31 +  if (!(destructorName in obj))
    1.32 +    throw new Error("object has no '" + destructorName + "' property");
    1.33 +
    1.34 +  let called = false;
    1.35 +  let originalDestructor = obj[destructorName];
    1.36 +
    1.37 +  function unloadWrapper(reason) {
    1.38 +    if (!called) {
    1.39 +      called = true;
    1.40 +      let index = unloaders.indexOf(unloadWrapper);
    1.41 +      if (index == -1)
    1.42 +        throw new Error("internal error: unloader not found");
    1.43 +      unloaders.splice(index, 1);
    1.44 +      originalDestructor.call(obj, reason);
    1.45 +      originalDestructor = null;
    1.46 +      destructorName = null;
    1.47 +      obj = null;
    1.48 +    }
    1.49 +  };
    1.50 +
    1.51 +  // TODO: Find out why the order is inverted here. It seems that
    1.52 +  // it may be causing issues!
    1.53 +  unloaders.push(unloadWrapper);
    1.54 +
    1.55 +  obj[destructorName] = unloadWrapper;
    1.56 +};
    1.57 +
    1.58 +function unload(reason) {
    1.59 +  observers.forEach(function(observer) {
    1.60 +    try {
    1.61 +      observer(reason);
    1.62 +    }
    1.63 +    catch (error) {
    1.64 +      console.exception(error);
    1.65 +    }
    1.66 +  });
    1.67 +}
    1.68 +
    1.69 +when(function(reason) {
    1.70 +  unloaders.slice().forEach(function(unloadWrapper) {
    1.71 +    unloadWrapper(reason);
    1.72 +  });
    1.73 +});
    1.74 +
    1.75 +on('sdk:loader:destroy', function onunload({ subject, data: reason }) {
    1.76 +  // If this loader is unload then `subject.wrappedJSObject` will be
    1.77 +  // `destructor`.
    1.78 +  if (subject.wrappedJSObject === unloadSubject) {
    1.79 +    off('sdk:loader:destroy', onunload);
    1.80 +    unload(reason);
    1.81 +  }
    1.82 +// Note that we use strong reference to listener here to make sure it's not
    1.83 +// GC-ed, which may happen otherwise since nothing keeps reference to `onunolad`
    1.84 +// function.
    1.85 +}, true);