From c414c76461355c76bfa4044b5836ab260043e504 Mon Sep 17 00:00:00 2001
From: Yury Delendik <ydelendik@mozilla.com>
Date: Fri, 17 Aug 2012 11:05:51 -0500
Subject: [PATCH] Fixes font loading concurency
---
src/fonts.js | 139 +++++++++++++++++++++++++++++++--------------------
1 file changed, 86 insertions(+), 53 deletions(-)
diff --git a/src/fonts.js b/src/fonts.js
index f0e1bd4d3..9a6dc37b5 100644
--- a/src/fonts.js
+++ b/src/fonts.js
@@ -404,28 +404,16 @@ function mapPrivateUseChars(code) {
}
var FontLoader = {
- listeningForFontLoad: false,
+ loadingContext: {
+ pending: 0,
+ requests: [],
+ nextRequestId: 0
+ },
bind: function fontLoaderBind(fonts, callback) {
- function checkFontsLoaded() {
- for (var i = 0, ii = fonts.length; i < ii; i++) {
- var fontObj = fonts[i];
- if (fontObj.loading) {
- return false;
- }
- }
-
- document.documentElement.removeEventListener(
- 'pdfjsFontLoad', checkFontsLoaded, false);
-
- // Use timeout to fix chrome intermittent failures on font loading.
- setTimeout(callback, 0);
- return true;
- }
-
- var rules = [], names = [], fontsToLoad = [];
- var fontCreateTimer = 0;
+ assert(!isWorker, 'bind() shall be called from main thread');
+ var rules = [], fontsToLoad = [];
for (var i = 0, ii = fonts.length; i < ii; i++) {
var font = fonts[i];
@@ -436,8 +424,6 @@ var FontLoader = {
}
font.attached = true;
- fontsToLoad.push(font);
-
var str = '';
var data = font.data;
if (data) {
@@ -448,28 +434,79 @@ var FontLoader = {
var rule = font.bindDOM(str);
if (rule) {
rules.push(rule);
- names.push(font.loadedName);
+ fontsToLoad.push(font);
}
}
}
- this.listeningForFontLoad = false;
- if (!isWorker && rules.length) {
- FontLoader.prepareFontLoadEvent(rules, names, fontsToLoad);
+ var request = FontLoader.queueLoadingCallback(callback);
+ if (rules.length > 0) {
+ FontLoader.prepareFontLoadEvent(rules, fontsToLoad, request);
+ } else {
+ request.complete();
}
+ },
- if (!checkFontsLoaded()) {
- document.documentElement.addEventListener(
- 'pdfjsFontLoad', checkFontsLoaded, false);
+ queueLoadingCallback: function FontLoader_queueLoadingCallback(callback) {
+ function LoadLoader_completeRequest() {
+ assert(!request.end, 'completeRequest() cannot be called twice');
+ request.end = Date.now();
+
+ if (context.pending <= 1) {
+ // it's simple completion for one request
+ context.pending = 0;
+ context.requests.pop();
+ callback();
+ return;
+ }
+
+ // calculating the load delay for all fonts and checking if all loaded
+ var totalTime = 0;
+ for (var i = 0, ii = context.requests.length; i < ii; i++) {
+ var otherRequest = context.requests[i];
+ if (!otherRequest.end)
+ return; // one more font to load, cancel the completion
+ totalTime += otherRequest.end - otherRequest.start;
+ }
+ var now = Date.now();
+ var startTime = context.requests[0].start;
+ var leftToWait = Math.max(totalTime - (now - startTime), 0);
+ context.timeout = setTimeout(function completeAllRequests() {
+ for (var i = 0, ii = context.requests.length; i < ii; i++) {
+ context.requests[i].callback();
+ }
+ context.pending = 0;
+ context.requests = [];
+ delete context.timeout;
+ }, leftToWait);
}
+
+ var context = FontLoader.loadingContext;
+ var requestId = 'pdfjs-font-loading-' + (context.nextRequestId++);
+ context.pending++;
+ var request = {
+ id: requestId,
+ complete: LoadLoader_completeRequest,
+ callback: callback,
+ started: Date.now()
+ };
+ context.requests.push(request);
+ if (context.timeout) {
+ // timeout for callbacks was set, removing that
+ clearTimeout(context.timeout);
+ delete context.timeout;
+ }
+ return request;
},
+
// Set things up so that at least one pdfjsFontLoad event is
- // dispatched when all the @font-face |rules| for |names| have been
+ // dispatched when all the @font-face |rules| for |fonts| have been
// loaded in a subdocument. It's expected that the load of |rules|
// has already started in this (outer) document, so that they should
// be ordered before the load in the subdocument.
- prepareFontLoadEvent: function fontLoaderPrepareFontLoadEvent(rules, names,
- fonts) {
+ prepareFontLoadEvent: function fontLoaderPrepareFontLoadEvent(rules,
+ fonts,
+ request) {
/** Hack begin */
// There's no event when a font has finished downloading so the
// following code is a dirty hack to 'guess' when a font is
@@ -493,6 +530,10 @@ var FontLoader = {
// The postMessage() hackery was added to work around chrome bug
// 82402.
+ var names = [];
+ for (var i = 0, ii = fonts.length; i < ii; i++)
+ names.push(fonts[i].loadedName);
+
// Validate the names parameter -- the values can used to construct HTML.
if (!/^\w+$/.test(names.join(''))) {
error('Invalid font name(s): ' + names.join());
@@ -514,22 +555,19 @@ var FontLoader = {
div.innerHTML = html;
document.body.appendChild(div);
- if (!this.listeningForFontLoad) {
- window.addEventListener(
- 'message',
- function fontLoaderMessage(e) {
- var fontNames = JSON.parse(e.data);
- for (var i = 0, ii = fonts.length; i < ii; ++i) {
- var font = fonts[i];
- font.loading = false;
- }
- var evt = document.createEvent('Events');
- evt.initEvent('pdfjsFontLoad', true, false);
- document.documentElement.dispatchEvent(evt);
- },
- false);
- this.listeningForFontLoad = true;
- }
+ var requestId = request.id;
+ window.addEventListener(
+ 'message',
+ function fontLoaderMessage(e) {
+ if (e.data !== requestId)
+ return;
+ for (var i = 0, ii = fonts.length; i < ii; ++i) {
+ var font = fonts[i];
+ font.loading = false;
+ }
+ request.complete();
+ },
+ false);
// XXX we should have a time-out here too, and maybe fire
// pdfjsFontLoadFailed?
@@ -540,13 +578,8 @@ var FontLoader = {
}
src += '</style>';
src += '<script type="application/javascript">';
- var fontNamesArray = '';
- for (var i = 0, ii = names.length; i < ii; ++i) {
- fontNamesArray += '"' + names[i] + '", ';
- }
- src += ' var fontNames=[' + fontNamesArray + '];\n';
src += ' window.onload = function fontLoaderOnload() {\n';
- src += ' parent.postMessage(JSON.stringify(fontNames), "*");\n';
+ src += ' parent.postMessage("' + requestId + '", "*");\n';
src += ' }';
// Hack so the end script tag isn't counted if this is inline JS.
src += '</scr' + 'ipt></head><body>';