addon-sdk/source/lib/sdk/event/chrome.js@b8a032363ba2 (annotated)
addon-sdk/source/lib/sdk/event/chrome.js
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 2 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 3 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 4 | |
| michael@0 | 5 | "use strict"; |
| michael@0 | 6 | |
| michael@0 | 7 | module.metadata = { |
| michael@0 | 8 | "stability": "unstable" |
| michael@0 | 9 | }; |
| michael@0 | 10 | |
| michael@0 | 11 | const { Cc, Ci, Cr } = require("chrome"); |
| michael@0 | 12 | const { emit, on, off } = require("./core"); |
| michael@0 | 13 | const { addObserver } = Cc['@mozilla.org/observer-service;1']. |
| michael@0 | 14 | getService(Ci.nsIObserverService); |
| michael@0 | 15 | |
| michael@0 | 16 | // Simple class that can be used to instantiate event channel that |
| michael@0 | 17 | // implements `nsIObserver` interface. It's will is used by `observe` |
| michael@0 | 18 | // function as observer + event target. It basically proxies observer |
| michael@0 | 19 | // notifications as to it's registered listeners. |
| michael@0 | 20 | function ObserverChannel() {} |
| michael@0 | 21 | Object.freeze(Object.defineProperties(ObserverChannel.prototype, { |
| michael@0 | 22 | QueryInterface: { |
| michael@0 | 23 | value: function(iid) { |
| michael@0 | 24 | if (!iid.equals(Ci.nsIObserver) && |
| michael@0 | 25 | !iid.equals(Ci.nsISupportsWeakReference) && |
| michael@0 | 26 | !iid.equals(Ci.nsISupports)) |
| michael@0 | 27 | throw Cr.NS_ERROR_NO_INTERFACE; |
| michael@0 | 28 | return this; |
| michael@0 | 29 | } |
| michael@0 | 30 | }, |
| michael@0 | 31 | observe: { |
| michael@0 | 32 | value: function(subject, topic, data) { |
| michael@0 | 33 | emit(this, "data", { |
| michael@0 | 34 | type: topic, |
| michael@0 | 35 | target: subject, |
| michael@0 | 36 | data: data |
| michael@0 | 37 | }); |
| michael@0 | 38 | } |
| michael@0 | 39 | } |
| michael@0 | 40 | })); |
| michael@0 | 41 | |
| michael@0 | 42 | function observe(topic) { |
| michael@0 | 43 | let observerChannel = new ObserverChannel(); |
| michael@0 | 44 | |
| michael@0 | 45 | // Note: `nsIObserverService` will not hold a weak reference to a |
| michael@0 | 46 | // observerChannel (since third argument is `true`). There for if it |
| michael@0 | 47 | // will be GC-ed with all it's event listeners once no other references |
| michael@0 | 48 | // will be held. |
| michael@0 | 49 | addObserver(observerChannel, topic, true); |
| michael@0 | 50 | |
| michael@0 | 51 | return observerChannel; |
| michael@0 | 52 | } |
| michael@0 | 53 | |
| michael@0 | 54 | exports.observe = observe; |
