зеркало из https://github.com/mozilla/gecko-dev.git
86 строки
2.7 KiB
JavaScript
86 строки
2.7 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* ManifestObtainer is an implementation of:
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* http://w3c.github.io/manifest/#obtaining
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*
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* Exposes public method `.obtainManifest(browserWindow)`, which returns
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* a promise. If successful, you get back a manifest (string).
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*
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* For e10s compat, this JSM relies on the following to do
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* the nessesary IPC:
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* dom/ipc/manifestMessages.js
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*
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* whose internal URL is:
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* 'chrome://global/content/manifestMessages.js'
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*
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* Which is injected into every browser instance via browser.js.
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*
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* BUG: https://bugzilla.mozilla.org/show_bug.cgi?id=1083410
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* exported ManifestObtainer
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*/
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'use strict';
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this.EXPORTED_SYMBOLS = ['ManifestObtainer'];
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const MSG_KEY = 'DOM:ManifestObtainer:Obtain';
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let messageCounter = 0;
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// FIXME: Ideally, we would store a reference to the
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// message manager in a weakmap instead of needing a
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// browserMap. However, trying to store a messageManager
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// results in a TypeError because of:
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// https://bugzilla.mozilla.org/show_bug.cgi?id=888600
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const browsersMap = new WeakMap();
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function ManifestObtainer() {}
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ManifestObtainer.prototype = {
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obtainManifest(aBrowserWindow) {
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if (!aBrowserWindow) {
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const err = new TypeError('Invalid input. Expected xul browser.');
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return Promise.reject(err);
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}
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const mm = aBrowserWindow.messageManager;
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const onMessage = function(aMsg) {
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const msgId = aMsg.data.msgId;
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const {
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resolve, reject
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} = browsersMap.get(aBrowserWindow).get(msgId);
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browsersMap.get(aBrowserWindow).delete(msgId);
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// If we we've processed all messages,
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// stop listening.
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if (!browsersMap.get(aBrowserWindow).size) {
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browsersMap.delete(aBrowserWindow);
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mm.removeMessageListener(MSG_KEY, onMessage);
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}
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if (aMsg.data.success) {
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return resolve(aMsg.data.result);
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}
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reject(toError(aMsg.data.result));
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};
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// If we are not already listening for messages
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// start listening.
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if (!browsersMap.has(aBrowserWindow)) {
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browsersMap.set(aBrowserWindow, new Map());
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mm.addMessageListener(MSG_KEY, onMessage);
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}
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return new Promise((resolve, reject) => {
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const msgId = messageCounter++;
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browsersMap.get(aBrowserWindow).set(msgId, {
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resolve: resolve,
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reject: reject
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});
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mm.sendAsyncMessage(MSG_KEY, {
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msgId: msgId
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});
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});
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function toError(aErrorClone) {
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const error = new Error();
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Object.getOwnPropertyNames(aErrorClone)
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.forEach(name => error[name] = aErrorClone[name]);
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return error;
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}
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}
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};
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