From 43a97878ce14b72f0981164f87f2e35e14151312 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 11:22:09 +0200 Subject: Adding upstream version 110.0.1. Signed-off-by: Daniel Baumann --- .../newtab/content-src/lib/perf-service.js | 104 +++++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 browser/components/newtab/content-src/lib/perf-service.js (limited to 'browser/components/newtab/content-src/lib/perf-service.js') diff --git a/browser/components/newtab/content-src/lib/perf-service.js b/browser/components/newtab/content-src/lib/perf-service.js new file mode 100644 index 0000000000..6ea99ce877 --- /dev/null +++ b/browser/components/newtab/content-src/lib/perf-service.js @@ -0,0 +1,104 @@ +/* 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"; + +let usablePerfObj = window.performance; + +export function _PerfService(options) { + // For testing, so that we can use a fake Window.performance object with + // known state. + if (options && options.performanceObj) { + this._perf = options.performanceObj; + } else { + this._perf = usablePerfObj; + } +} + +_PerfService.prototype = { + /** + * Calls the underlying mark() method on the appropriate Window.performance + * object to add a mark with the given name to the appropriate performance + * timeline. + * + * @param {String} name the name to give the current mark + * @return {void} + */ + mark: function mark(str) { + this._perf.mark(str); + }, + + /** + * Calls the underlying getEntriesByName on the appropriate Window.performance + * object. + * + * @param {String} name + * @param {String} type eg "mark" + * @return {Array} Performance* objects + */ + getEntriesByName: function getEntriesByName(name, type) { + return this._perf.getEntriesByName(name, type); + }, + + /** + * The timeOrigin property from the appropriate performance object. + * Used to ensure that timestamps from the add-on code and the content code + * are comparable. + * + * @note If this is called from a context without a window + * (eg a JSM in chrome), it will return the timeOrigin of the XUL hidden + * window, which appears to be the first created window (and thus + * timeOrigin) in the browser. Note also, however, there is also a private + * hidden window, presumably for private browsing, which appears to be + * created dynamically later. Exactly how/when that shows up needs to be + * investigated. + * + * @return {Number} A double of milliseconds with a precision of 0.5us. + */ + get timeOrigin() { + return this._perf.timeOrigin; + }, + + /** + * Returns the "absolute" version of performance.now(), i.e. one that + * should ([bug 1401406](https://bugzilla.mozilla.org/show_bug.cgi?id=1401406) + * be comparable across both chrome and content. + * + * @return {Number} + */ + absNow: function absNow() { + return this.timeOrigin + this._perf.now(); + }, + + /** + * This returns the absolute startTime from the most recent performance.mark() + * with the given name. + * + * @param {String} name the name to lookup the start time for + * + * @return {Number} the returned start time, as a DOMHighResTimeStamp + * + * @throws {Error} "No Marks with the name ..." if none are available + * + * @note Always surround calls to this by try/catch. Otherwise your code + * may fail when the `privacy.resistFingerprinting` pref is true. When + * this pref is set, all attempts to get marks will likely fail, which will + * cause this method to throw. + * + * See [bug 1369303](https://bugzilla.mozilla.org/show_bug.cgi?id=1369303) + * for more info. + */ + getMostRecentAbsMarkStartByName(name) { + let entries = this.getEntriesByName(name, "mark"); + + if (!entries.length) { + throw new Error(`No marks with the name ${name}`); + } + + let mostRecentEntry = entries[entries.length - 1]; + return this._perf.timeOrigin + mostRecentEntry.startTime; + }, +}; + +export const perfService = new _PerfService(); -- cgit v1.2.3