From 80abb55903b1152df988bb72d4bdb6479b6b1ff3 Mon Sep 17 00:00:00 2001 From: Weston Ruter Date: Tue, 27 Jun 2023 17:24:25 +0000 Subject: [PATCH] Emoji: Optimize emoji loader with `sessionStorage`, `willReadFrequently`, and `OffscreenCanvas`. * Use `sessionStorage` to remember the previous results of calls to `browserSupportsEmoji()` for 1 week. * Optimize reading from canvas by supplying the `willReadFrequently` option for the 2D context. * When `OffscreenCanvas` is available, offload `browserSupportsEmoji()` to a web worker to prevent blocking the main thread. This is of primary benefit to Safari which does not yet support `willReadFrequently`. * Remove obsolete support for IE11 since promises are now utilized. Nevertheless, ES3 syntax is maintained and IE11 will simply short-circuit. Props westonruter, dmsnell, peterwilsoncc, valterlorran, flixos90, spacedmonkey, joemcgill. Fixes #58472. Built from https://develop.svn.wordpress.org/trunk@56074 git-svn-id: http://core.svn.wordpress.org/trunk@55586 1a063a9b-81f0-0310-95a4-ce76da25c4cd --- wp-includes/js/wp-emoji-loader.js | 364 ++++++++++++++++++++------ wp-includes/js/wp-emoji-loader.min.js | 2 +- wp-includes/version.php | 2 +- 3 files changed, 289 insertions(+), 79 deletions(-) diff --git a/wp-includes/js/wp-emoji-loader.js b/wp-includes/js/wp-emoji-loader.js index 536b839f0e..f32fbaa384 100644 --- a/wp-includes/js/wp-emoji-loader.js +++ b/wp-includes/js/wp-emoji-loader.js @@ -2,65 +2,189 @@ * @output wp-includes/js/wp-emoji-loader.js */ -( function( window, document, settings ) { - var src, ready, ii, tests; +/** + * Emoji Settings as exported in PHP via _print_emoji_detection_script(). + * @typedef WPEmojiSettings + * @type {object} + * @property {?object} source + * @property {?string} source.concatemoji + * @property {?string} source.twemoji + * @property {?string} source.wpemoji + * @property {?boolean} DOMReady + * @property {?Function} readyCallback + */ - // Create a canvas element for testing native browser support of emoji. - var canvas = document.createElement( 'canvas' ); - var context = canvas.getContext && canvas.getContext( '2d' ); +/** + * Support tests. + * @typedef SupportTests + * @type {object} + * @property {?boolean} flag + * @property {?boolean} emoji + */ + +/** + * IIFE to detect emoji support and load Twemoji if needed. + * + * @param {Window} window + * @param {Document} document + * @param {WPEmojiSettings} settings + */ +( function wpEmojiLoader( window, document, settings ) { + if ( typeof Promise === 'undefined' ) { + return; + } + + var sessionStorageKey = 'wpEmojiSettingsSupports'; + var tests = [ 'flag', 'emoji' ]; + + /** + * Checks whether the browser supports offloading to a Worker. + * + * @since 6.3.0 + * + * @private + * + * @returns {boolean} + */ + function supportsWorkerOffloading() { + return ( + typeof Worker !== 'undefined' && + typeof OffscreenCanvas !== 'undefined' && + typeof URL !== 'undefined' && + URL.createObjectURL && + typeof Blob !== 'undefined' + ); + } + + /** + * @typedef SessionSupportTests + * @type {object} + * @property {number} timestamp + * @property {SupportTests} supportTests + */ + + /** + * Get support tests from session. + * + * @since 6.3.0 + * + * @private + * + * @returns {?SupportTests} Support tests, or null if not set or older than 1 week. + */ + function getSessionSupportTests() { + if ( + typeof sessionStorage !== 'undefined' && + sessionStorageKey in sessionStorage + ) { + try { + /** @type {SessionSupportTests} */ + var item = JSON.parse( + sessionStorage.getItem( sessionStorageKey ) + ); + if ( + typeof item === 'object' && + typeof item.timestamp === 'number' && + new Date().valueOf() < item.timestamp + 604800 && // Note: Number is a week in seconds. + typeof item.supportTests === 'object' + ) { + return item.supportTests; + } + } catch ( e ) {} + } + return null; + } + + /** + * Persist the supports in session storage. + * + * @since 6.3.0 + * + * @private + * + * @param {SupportTests} supportTests Support tests. + */ + function setSessionSupportTests( supportTests ) { + if ( typeof sessionStorage !== 'undefined' ) { + try { + /** @type {SessionSupportTests} */ + var item = { + supportTests: supportTests, + timestamp: new Date().valueOf() + }; + + sessionStorage.setItem( + sessionStorageKey, + JSON.stringify( item ) + ); + } catch ( e ) {} + } + } /** * Checks if two sets of Emoji characters render the same visually. * + * This function may be serialized to run in a Worker. Therefore, it cannot refer to variables from the containing + * scope. Everything must be passed by parameters. + * * @since 4.9.0 * * @private * + * @param {CanvasRenderingContext2D} context 2D Context. * @param {string} set1 Set of Emoji to test. * @param {string} set2 Set of Emoji to test. * * @return {boolean} True if the two sets render the same. */ - function emojiSetsRenderIdentically( set1, set2 ) { + function emojiSetsRenderIdentically( context, set1, set2 ) { // Cleanup from previous test. - context.clearRect( 0, 0, canvas.width, canvas.height ); + context.clearRect( 0, 0, context.canvas.width, context.canvas.height ); context.fillText( set1, 0, 0 ); - var rendered1 = canvas.toDataURL(); + var rendered1 = new Uint32Array( + context.getImageData( + 0, + 0, + context.canvas.width, + context.canvas.height + ).data + ); // Cleanup from previous test. - context.clearRect( 0, 0, canvas.width, canvas.height ); + context.clearRect( 0, 0, context.canvas.width, context.canvas.height ); context.fillText( set2, 0, 0 ); - var rendered2 = canvas.toDataURL(); + var rendered2 = new Uint32Array( + context.getImageData( + 0, + 0, + context.canvas.width, + context.canvas.height + ).data + ); - return rendered1 === rendered2; + return rendered1.every( function ( rendered2Data, index ) { + return rendered2Data === rendered2[ index ]; + } ); } /** * Determines if the browser properly renders Emoji that Twemoji can supplement. * + * This function may be serialized to run in a Worker. Therefore, it cannot refer to variables from the containing + * scope. Everything must be passed by parameters. + * * @since 4.2.0 * * @private * + * @param {CanvasRenderingContext2D} context 2D Context. * @param {string} type Whether to test for support of "flag" or "emoji". * * @return {boolean} True if the browser can render emoji, false if it cannot. */ - function browserSupportsEmoji( type ) { + function browserSupportsEmoji( context, type ) { var isIdentical; - if ( ! context || ! context.fillText ) { - return false; - } - - /* - * Chrome on OS X added native emoji rendering in M41. Unfortunately, - * it doesn't work when the font is bolder than 500 weight. So, we - * check for bold rendering support to avoid invisible emoji in Chrome. - */ - context.textBaseline = 'top'; - context.font = '600 32px Arial'; - switch ( type ) { case 'flag': /* @@ -70,8 +194,9 @@ * the browser doesn't render it correctly (white flag emoji + transgender symbol). */ isIdentical = emojiSetsRenderIdentically( + context, '\uD83C\uDFF3\uFE0F\u200D\u26A7\uFE0F', // as a zero-width joiner sequence - '\uD83C\uDFF3\uFE0F\u200B\u26A7\uFE0F' // separated by a zero-width space + '\uD83C\uDFF3\uFE0F\u200B\u26A7\uFE0F' // separated by a zero-width space ); if ( isIdentical ) { @@ -86,8 +211,9 @@ * the browser doesn't render it correctly ([U] + [N]). */ isIdentical = emojiSetsRenderIdentically( - '\uD83C\uDDFA\uD83C\uDDF3', // as the sequence of two code points - '\uD83C\uDDFA\u200B\uD83C\uDDF3' // as the two code points separated by a zero-width space + context, + '\uD83C\uDDFA\uD83C\uDDF3', // as the sequence of two code points + '\uD83C\uDDFA\u200B\uD83C\uDDF3' // as the two code points separated by a zero-width space ); if ( isIdentical ) { @@ -102,6 +228,7 @@ * the browser doesn't render it correctly (black flag emoji + [G] + [B] + [E] + [N] + [G]). */ isIdentical = emojiSetsRenderIdentically( + context, // as the flag sequence '\uD83C\uDFF4\uDB40\uDC67\uDB40\uDC62\uDB40\uDC65\uDB40\uDC6E\uDB40\uDC67\uDB40\uDC7F', // with each code point separated by a zero-width space @@ -129,8 +256,9 @@ * sequence come from older emoji standards. */ isIdentical = emojiSetsRenderIdentically( + context, '\uD83E\uDEF1\uD83C\uDFFB\u200D\uD83E\uDEF2\uD83C\uDFFF', // as the zero-width joiner sequence - '\uD83E\uDEF1\uD83C\uDFFB\u200B\uD83E\uDEF2\uD83C\uDFFF' // separated by a zero-width space + '\uD83E\uDEF1\uD83C\uDFFB\u200B\uD83E\uDEF2\uD83C\uDFFF' // separated by a zero-width space ); return ! isIdentical; @@ -139,6 +267,48 @@ return false; } + /** + * Checks emoji support tests. + * + * This function may be serialized to run in a Worker. Therefore, it cannot refer to variables from the containing + * scope. Everything must be passed by parameters. + * + * @since 6.3.0 + * + * @private + * + * @param {string[]} tests Tests. + * + * @return {SupportTests} Support tests. + */ + function testEmojiSupports( tests ) { + var canvas; + if ( + typeof WorkerGlobalScope !== 'undefined' && + self instanceof WorkerGlobalScope + ) { + canvas = new OffscreenCanvas( 300, 150 ); // Dimensions are default for HTMLCanvasElement. + } else { + canvas = document.createElement( 'canvas' ); + } + + var context = canvas.getContext( '2d', { willReadFrequently: true } ); + + /* + * Chrome on OS X added native emoji rendering in M41. Unfortunately, + * it doesn't work when the font is bolder than 500 weight. So, we + * check for bold rendering support to avoid invisible emoji in Chrome. + */ + context.textBaseline = 'top'; + context.font = '600 32px Arial'; + + var supports = {}; + tests.forEach( function ( test ) { + supports[ test ] = browserSupportsEmoji( context, test ); + } ); + return supports; + } + /** * Adds a script to the head of the document. * @@ -146,75 +316,115 @@ * * @since 4.2.0 * - * @param {Object} src The url where the script is located. + * @param {string} src The url where the script is located. + * * @return {void} */ function addScript( src ) { var script = document.createElement( 'script' ); - script.src = src; - script.defer = script.type = 'text/javascript'; - document.getElementsByTagName( 'head' )[0].appendChild( script ); + script.defer = true; + document.head.appendChild( script ); } - tests = Array( 'flag', 'emoji' ); - settings.supports = { everything: true, everythingExceptFlag: true }; - /* - * Tests the browser support for flag emojis and other emojis, and adjusts the - * support settings accordingly. - */ - for( ii = 0; ii < tests.length; ii++ ) { - settings.supports[ tests[ ii ] ] = browserSupportsEmoji( tests[ ii ] ); + // Create a promise for DOMContentLoaded since the worker logic may finish after the event has fired. + var domReadyPromise = new Promise( function ( resolve ) { + document.addEventListener( 'DOMContentLoaded', resolve, { + once: true + } ); + } ); - settings.supports.everything = settings.supports.everything && settings.supports[ tests[ ii ] ]; - - if ( 'flag' !== tests[ ii ] ) { - settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && settings.supports[ tests[ ii ] ]; + // Obtain the emoji support from the browser, asynchronously when possible. + new Promise( function ( resolve ) { + var supportTests = getSessionSupportTests(); + if ( supportTests ) { + resolve( supportTests ); + return; } - } - settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && ! settings.supports.flag; + if ( supportsWorkerOffloading() ) { + try { + /* + * Note that this string contains the real source code for the + * copied functions, _not_ a string representation of them. This + * is because it's not possible to transfer a Function across + * threads. The lack of quotes is intentional. The function names + * are copied to variable names since minification will munge the + * function names, thus breaking the ability for the functions to + * refer to each other. + */ + var workerScript = + 'var emojiSetsRenderIdentically = ' + emojiSetsRenderIdentically + ';' + + 'var browserSupportsEmoji = ' + browserSupportsEmoji + ';' + + 'var testEmojiSupports = ' + testEmojiSupports + ';' + + 'postMessage(testEmojiSupports(' + JSON.stringify(tests) + '));'; + var blob = new Blob( [ workerScript ], { + type: 'text/javascript' + } ); + var worker = new Worker( URL.createObjectURL( blob ) ); + worker.onmessage = function ( event ) { + supportTests = event.data; + setSessionSupportTests( supportTests ); + resolve( supportTests ); + }; + return; + } catch ( e ) {} + } - // Sets DOMReady to false and assigns a ready function to settings. - settings.DOMReady = false; - settings.readyCallback = function() { - settings.DOMReady = true; - }; + supportTests = testEmojiSupports( tests ); + setSessionSupportTests( supportTests ); + resolve( supportTests ); + } ) + // Once the browser emoji support has been obtained from the session, finalize the settings. + .then( function ( supportTests ) { + /* + * Tests the browser support for flag emojis and other emojis, and adjusts the + * support settings accordingly. + */ + for ( var test in supportTests ) { + settings.supports[ test ] = supportTests[ test ]; - // When the browser can not render everything we need to load a polyfill. - if ( ! settings.supports.everything ) { - ready = function() { - settings.readyCallback(); - }; + settings.supports.everything = + settings.supports.everything && settings.supports[ test ]; - /* - * Cross-browser version of adding a dom ready event. - */ - if ( document.addEventListener ) { - document.addEventListener( 'DOMContentLoaded', ready, false ); - window.addEventListener( 'load', ready, false ); - } else { - window.attachEvent( 'onload', ready ); - document.attachEvent( 'onreadystatechange', function() { - if ( 'complete' === document.readyState ) { - settings.readyCallback(); + if ( 'flag' !== test ) { + settings.supports.everythingExceptFlag = + settings.supports.everythingExceptFlag && + settings.supports[ test ]; } - } ); - } + } - src = settings.source || {}; + settings.supports.everythingExceptFlag = + settings.supports.everythingExceptFlag && + ! settings.supports.flag; - if ( src.concatemoji ) { - addScript( src.concatemoji ); - } else if ( src.wpemoji && src.twemoji ) { - addScript( src.twemoji ); - addScript( src.wpemoji ); - } - } + // Sets DOMReady to false and assigns a ready function to settings. + settings.DOMReady = false; + settings.readyCallback = function () { + settings.DOMReady = true; + }; + } ) + .then( function () { + return domReadyPromise; + } ) + .then( function () { + // When the browser can not render everything we need to load a polyfill. + if ( ! settings.supports.everything ) { + settings.readyCallback(); + var src = settings.source || {}; + + if ( src.concatemoji ) { + addScript( src.concatemoji ); + } else if ( src.wpemoji && src.twemoji ) { + addScript( src.twemoji ); + addScript( src.wpemoji ); + } + } + } ); } )( window, document, window._wpemojiSettings ); diff --git a/wp-includes/js/wp-emoji-loader.min.js b/wp-includes/js/wp-emoji-loader.min.js index 3669dc910d..60629920e1 100644 --- a/wp-includes/js/wp-emoji-loader.min.js +++ b/wp-includes/js/wp-emoji-loader.min.js @@ -1,2 +1,2 @@ /*! This file is auto-generated */ -!function(e,a,t){var n,r,o,i=a.createElement("canvas"),p=i.getContext&&i.getContext("2d");function s(e,t){p.clearRect(0,0,i.width,i.height),p.fillText(e,0,0);e=i.toDataURL();return p.clearRect(0,0,i.width,i.height),p.fillText(t,0,0),e===i.toDataURL()}function c(e){var t=a.createElement("script");t.src=e,t.defer=t.type="text/javascript",a.getElementsByTagName("head")[0].appendChild(t)}for(o=Array("flag","emoji"),t.supports={everything:!0,everythingExceptFlag:!0},r=0;r