diff options
Diffstat (limited to 'tools/addon-sdk-1.12/lib/sdk/system/unload.js')
-rw-r--r-- | tools/addon-sdk-1.12/lib/sdk/system/unload.js | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/tools/addon-sdk-1.12/lib/sdk/system/unload.js b/tools/addon-sdk-1.12/lib/sdk/system/unload.js new file mode 100644 index 0000000..4d2575b --- /dev/null +++ b/tools/addon-sdk-1.12/lib/sdk/system/unload.js @@ -0,0 +1,82 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +// Parts of this module were taken from narwhal: +// +// http://narwhaljs.org + +module.metadata = { + "stability": "experimental" +}; + +const { on, off } = require('./events'); +const unloadSubject = require('@loader/unload'); + +const observers = []; +const unloaders = []; + +var when = exports.when = function when(observer) { + if (observers.indexOf(observer) != -1) + return; + observers.unshift(observer); +}; + +var ensure = exports.ensure = function ensure(obj, destructorName) { + if (!destructorName) + destructorName = "unload"; + if (!(destructorName in obj)) + throw new Error("object has no '" + destructorName + "' property"); + + let called = false; + let originalDestructor = obj[destructorName]; + + function unloadWrapper(reason) { + if (!called) { + called = true; + let index = unloaders.indexOf(unloadWrapper); + if (index == -1) + throw new Error("internal error: unloader not found"); + unloaders.splice(index, 1); + originalDestructor.call(obj, reason); + originalDestructor = null; + destructorName = null; + obj = null; + } + }; + + // TODO: Find out why the order is inverted here. It seems that + // it may be causing issues! + unloaders.push(unloadWrapper); + + obj[destructorName] = unloadWrapper; +}; + +function unload(reason) { + observers.forEach(function(observer) { + try { + observer(reason); + } + catch (error) { + console.exception(error); + } + }); +} + +when(function(reason) { + unloaders.slice().forEach(function(unloadWrapper) { + unloadWrapper(reason); + }); +}); + +on('sdk:loader:destroy', function onunload({ subject, data: reason }) { + // If this loader is unload then `subject.wrappedJSObject` will be + // `destructor`. + if (subject.wrappedJSObject === unloadSubject) { + off('sdk:loader:destroy', onunload); + unload(reason); + } +// Note that we use strong reference to listener here to make sure it's not +// GC-ed, which may happen otherwise since nothing keeps reference to `onunolad` +// function. +}, true); |