gecko-dev/devtools/server/actors/eventlooplag.js

61 lines
1.7 KiB
JavaScript

/* 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/. */
"use strict";
/**
* The eventLoopLag actor emits "event-loop-lag" events when the event
* loop gets unresponsive. The event comes with a "time" property (the
* duration of the lag in milliseconds).
*/
const {Ci} = require("chrome");
const Services = require("Services");
const {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
const {Actor, ActorClassWithSpec} = require("devtools/shared/protocol");
const events = require("sdk/event/core");
const {eventLoopLagSpec} = require("devtools/shared/specs/eventlooplag");
var EventLoopLagActor = exports.EventLoopLagActor = ActorClassWithSpec(eventLoopLagSpec, {
_observerAdded: false,
/**
* Start tracking the event loop lags.
*/
start: function () {
if (!this._observerAdded) {
Services.obs.addObserver(this, "event-loop-lag", false);
this._observerAdded = true;
}
return Services.appShell.startEventLoopLagTracking();
},
/**
* Stop tracking the event loop lags.
*/
stop: function () {
if (this._observerAdded) {
Services.obs.removeObserver(this, "event-loop-lag");
this._observerAdded = false;
}
Services.appShell.stopEventLoopLagTracking();
},
destroy: function () {
this.stop();
Actor.prototype.destroy.call(this);
},
// nsIObserver
observe: function (subject, topic, data) {
if (topic == "event-loop-lag") {
// Forward event loop lag event
events.emit(this, "event-loop-lag", data);
}
},
QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver]),
});