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# 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/.
// A couple of classes to simplify creating observers.
//
// Example1:
//
// function doSomething() { ... }
// var observer = new G_ObserverWrapper(topic, doSomething);
// someObj.addObserver(topic, observer);
//
// Example2:
//
// function doSomething() { ... }
// new G_ObserverServiceObserver("profile-after-change",
// doSomething,
// true /* run only once */);
/**
* This class abstracts the admittedly simple boilerplate required of
* an nsIObserver. It saves you the trouble of implementing the
* indirection of your own observe() function.
*
* @param topic String containing the topic the observer will filter for
*
* @param observeFunction Reference to the function to call when the
* observer fires
*
* @constructor
*/
this.G_ObserverWrapper = function G_ObserverWrapper(topic, observeFunction) {
this.debugZone = "observer";
this.topic_ = topic;
this.observeFunction_ = observeFunction;
}
/**
* XPCOM
*/
G_ObserverWrapper.prototype.QueryInterface = function(iid) {
if (iid.equals(Ci.nsISupports) || iid.equals(Ci.nsIObserver))
return this;
throw Components.results.NS_ERROR_NO_INTERFACE;
}
/**
* Invoked by the thingy being observed
*/
G_ObserverWrapper.prototype.observe = function(subject, topic, data) {
if (topic == this.topic_)
this.observeFunction_(subject, topic, data);
}
/**
* This class abstracts the admittedly simple boilerplate required of
* observing an observerservice topic. It implements the indirection
* required, and automatically registers to hear the topic.
*
* @param topic String containing the topic the observer will filter for
*
* @param observeFunction Reference to the function to call when the
* observer fires
*
* @param opt_onlyOnce Boolean indicating if the observer should unregister
* after it has fired
*
* @constructor
*/
this.G_ObserverServiceObserver =
function G_ObserverServiceObserver(topic, observeFunction, opt_onlyOnce) {
this.debugZone = "observerserviceobserver";
this.topic_ = topic;
this.observeFunction_ = observeFunction;
this.onlyOnce_ = !!opt_onlyOnce;
this.observer_ = new G_ObserverWrapper(this.topic_,
BindToObject(this.observe_, this));
this.observerService_ = Cc["@mozilla.org/observer-service;1"]
.getService(Ci.nsIObserverService);
this.observerService_.addObserver(this.observer_, this.topic_, false);
}
/**
* Unregister the observer from the observerservice
*/
G_ObserverServiceObserver.prototype.unregister = function() {
this.observerService_.removeObserver(this.observer_, this.topic_);
this.observerService_ = null;
}
/**
* Invoked by the observerservice
*/
G_ObserverServiceObserver.prototype.observe_ = function(subject, topic, data) {
this.observeFunction_(subject, topic, data);
if (this.onlyOnce_)
this.unregister();
}
#ifdef DEBUG
this.TEST_G_Observer = function TEST_G_Observer() {
if (G_GDEBUG) {
var z = "observer UNITTEST";
G_debugService.enableZone(z);
G_Debug(z, "Starting");
var regularObserverRan = 0;
var observerServiceObserverRan = 0;
let regularObserver = function () {
regularObserverRan++;
};
let observerServiceObserver = function () {
observerServiceObserverRan++;
};
var service = Cc["@mozilla.org/observer-service;1"]
.getService(Ci.nsIObserverService);
var topic = "google-observer-test";
var o1 = new G_ObserverWrapper(topic, regularObserver);
service.addObserver(o1, topic, false);
new G_ObserverServiceObserver(topic,
observerServiceObserver, true /* once */);
// Notifications happen synchronously, so this is easy
service.notifyObservers(null, topic, null);
service.notifyObservers(null, topic, null);
G_Assert(z, regularObserverRan == 2, "Regular observer broken");
G_Assert(z, observerServiceObserverRan == 1, "ObsServObs broken");
service.removeObserver(o1, topic);
G_Debug(z, "PASSED");
}
}
#endif
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