gecko/devtools/server/performance/framerate.js

100 lines
2.8 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";
const { on, once, off, emit } = require("sdk/event/core");
const { Class } = require("sdk/core/heritage");
/**
* A very simple utility for monitoring framerate. Takes a `tabActor`
* and monitors framerate over time. The actor wrapper around this
* can be found at devtools/server/actors/framerate.js
*/
var Framerate = exports.Framerate = Class({
initialize: function (tabActor) {
this.tabActor = tabActor;
this._contentWin = tabActor.window;
this._onRefreshDriverTick = this._onRefreshDriverTick.bind(this);
this._onGlobalCreated = this._onGlobalCreated.bind(this);
on(this.tabActor, "window-ready", this._onGlobalCreated);
},
destroy: function(conn) {
off(this.tabActor, "window-ready", this._onGlobalCreated);
this.stopRecording();
},
/**
* Starts monitoring framerate, storing the frames per second.
*/
startRecording: function () {
if (this._recording) {
return;
}
this._recording = true;
this._ticks = [];
this._startTime = this.tabActor.docShell.now();
this._rafID = this._contentWin.requestAnimationFrame(this._onRefreshDriverTick);
},
/**
* Stops monitoring framerate, returning the recorded values.
*/
stopRecording: function (beginAt = 0, endAt = Number.MAX_SAFE_INTEGER) {
if (!this._recording) {
return [];
}
let ticks = this.getPendingTicks(beginAt, endAt);
this.cancelRecording();
return ticks;
},
/**
* Stops monitoring framerate, without returning the recorded values.
*/
cancelRecording: function () {
this._contentWin.cancelAnimationFrame(this._rafID);
this._recording = false;
this._ticks = null;
this._rafID = -1;
},
/**
* Returns whether this instance is currently recording.
*/
isRecording: function () {
return !!this._recording;
},
/**
* Gets the refresh driver ticks recorded so far.
*/
getPendingTicks: function (beginAt = 0, endAt = Number.MAX_SAFE_INTEGER) {
if (!this._ticks) {
return [];
}
return this._ticks.filter(e => e >= beginAt && e <= endAt);
},
/**
* Function invoked along with the refresh driver.
*/
_onRefreshDriverTick: function () {
if (!this._recording) {
return;
}
this._rafID = this._contentWin.requestAnimationFrame(this._onRefreshDriverTick);
this._ticks.push(this.tabActor.docShell.now() - this._startTime);
},
/**
* When the content window for the tab actor is created.
*/
_onGlobalCreated: function (win) {
if (this._recording) {
this._contentWin.cancelAnimationFrame(this._rafID);
this._rafID = this._contentWin.requestAnimationFrame(this._onRefreshDriverTick);
}
}
});