The Tor Browser / file comparison
comparison: addon-sdk/source/lib/sdk/input/system.js
addon-sdk/source/lib/sdk/input/system.js
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
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deleted
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| -1:000000000000 | 0:cba998c4f913 |
|---|---|
| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 "use strict"; | |
| 5 | |
| 6 const { Cc, Ci, Cr, Cu } = require("chrome"); | |
| 7 const { Input, start, stop, end, receive, outputs } = require("../event/utils"); | |
| 8 const { once, off } = require("../event/core"); | |
| 9 const { id: addonID } = require("../self"); | |
| 10 | |
| 11 const unloadMessage = require("@loader/unload"); | |
| 12 const { addObserver, removeObserver } = Cc['@mozilla.org/observer-service;1']. | |
| 13 getService(Ci.nsIObserverService); | |
| 14 | |
| 15 const addonUnloadTopic = "sdk:loader:destroy"; | |
| 16 | |
| 17 const isXrayWrapper = Cu.isXrayWrapper; | |
| 18 // In the past SDK used to double-wrap notifications dispatched, which | |
| 19 // made them awkward to use outside of SDK. At present they no longer | |
| 20 // do that, although we still supported for legacy reasons. | |
| 21 const isLegacyWrapper = x => | |
| 22 x && x.wrappedJSObject && | |
| 23 "observersModuleSubjectWrapper" in x.wrappedJSObject; | |
| 24 | |
| 25 const unwrapLegacy = x => x.wrappedJSObject.object; | |
| 26 | |
| 27 // `InputPort` provides a way to create a signal out of the observer | |
| 28 // notification subject's for the given `topic`. If `options.initial` | |
| 29 // is provided it is used as initial value otherwise `null` is used. | |
| 30 // Constructor can be given `options.id` that will be used to create | |
| 31 // a `topic` which is namespaced to an add-on (this avoids conflicts | |
| 32 // when multiple add-on are used, although in a future host probably | |
| 33 // should just be shared across add-ons). It is also possible to | |
| 34 // specify a specific `topic` via `options.topic` which is used as | |
| 35 // without namespacing. Created signal ends whenever add-on is | |
| 36 // unloaded. | |
| 37 const InputPort = function InputPort({id, topic, initial}) { | |
| 38 this.id = id || topic; | |
| 39 this.topic = topic || "sdk:" + addonID + ":" + id; | |
| 40 this.value = initial === void(0) ? null : initial; | |
| 41 this.observing = false; | |
| 42 this[outputs] = []; | |
| 43 }; | |
| 44 | |
| 45 // InputPort type implements `Input` signal interface. | |
| 46 InputPort.prototype = new Input(); | |
| 47 InputPort.prototype.constructor = InputPort; | |
| 48 | |
| 49 // When port is started (which is when it's subgraph get's | |
| 50 // first subscriber) actual observer is registered. | |
| 51 InputPort.start = input => { | |
| 52 input.addListener(input); | |
| 53 // Also register add-on unload observer to end this signal | |
| 54 // when that happens. | |
| 55 addObserver(input, addonUnloadTopic, false); | |
| 56 }; | |
| 57 InputPort.prototype[start] = InputPort.start; | |
| 58 | |
| 59 InputPort.addListener = input => addObserver(input, input.topic, false); | |
| 60 InputPort.prototype.addListener = InputPort.addListener; | |
| 61 | |
| 62 // When port is stopped (which is when it's subgraph has no | |
| 63 // no subcribers left) an actual observer unregistered. | |
| 64 // Note that port stopped once it ends as well (which is when | |
| 65 // add-on is unloaded). | |
| 66 InputPort.stop = input => { | |
| 67 input.removeListener(input); | |
| 68 removeObserver(input, addonUnloadTopic); | |
| 69 }; | |
| 70 InputPort.prototype[stop] = InputPort.stop; | |
| 71 | |
| 72 InputPort.removeListener = input => removeObserver(input, input.topic); | |
| 73 InputPort.prototype.removeListener = InputPort.removeListener; | |
| 74 | |
| 75 // `InputPort` also implements `nsIObserver` interface and | |
| 76 // `nsISupportsWeakReference` interfaces as it's going to be used as such. | |
| 77 InputPort.prototype.QueryInterface = function(iid) { | |
| 78 if (!iid.equals(Ci.nsIObserver) && !iid.equals(Ci.nsISupportsWeakReference)) | |
| 79 throw Cr.NS_ERROR_NO_INTERFACE; | |
| 80 | |
| 81 return this; | |
| 82 }; | |
| 83 | |
| 84 // `InputPort` instances implement `observe` method, which is invoked when | |
| 85 // observer notifications are dispatched. The `subject` of that notification | |
| 86 // are received on this signal. | |
| 87 InputPort.prototype.observe = function(subject, topic, data) { | |
| 88 // Unwrap message from the subject. SDK used to have it's own version of | |
| 89 // wrappedJSObjects which take precedence, if subject has `wrappedJSObject` | |
| 90 // and it's not an XrayWrapper use it as message. Otherwise use subject as | |
| 91 // is. | |
| 92 const message = subject === null ? null : | |
| 93 isLegacyWrapper(subject) ? unwrapLegacy(subject) : | |
| 94 isXrayWrapper(subject) ? subject : | |
| 95 subject.wrappedJSObject ? subject.wrappedJSObject : | |
| 96 subject; | |
| 97 | |
| 98 // If observer topic matches topic of the input port receive a message. | |
| 99 if (topic === this.topic) { | |
| 100 receive(this, message); | |
| 101 } | |
| 102 | |
| 103 // If observe topic is add-on unload topic we create an end message. | |
| 104 if (topic === addonUnloadTopic && message === unloadMessage) { | |
| 105 end(this); | |
| 106 } | |
| 107 }; | |
| 108 | |
| 109 exports.InputPort = InputPort; |
