yomichan/ext/mixed/js/dynamic-loader.js

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/*
* Copyright (C) 2020 Yomichan Authors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/* global
* api
*/
const dynamicLoader = (() => {
const injectedStylesheets = new Map();
async function loadStyle(id, type, value, useWebExtensionApi=false) {
if (useWebExtensionApi && yomichan.isExtensionUrl(window.location.href)) {
// Permissions error will occur if trying to use the WebExtension API to inject into an extension page
useWebExtensionApi = false;
}
let styleNode = injectedStylesheets.get(id);
if (typeof styleNode !== 'undefined') {
if (styleNode === null) {
// Previously injected via WebExtension API
throw new Error(`Stylesheet with id ${id} has already been injected using the WebExtension API`);
}
} else {
styleNode = null;
}
if (useWebExtensionApi) {
// Inject via WebExtension API
if (styleNode !== null && styleNode.parentNode !== null) {
styleNode.parentNode.removeChild(styleNode);
}
injectedStylesheets.set(id, null);
await api.injectStylesheet(type, value);
return null;
}
// Create node in document
const parentNode = document.head;
if (parentNode === null) {
throw new Error('No parent node');
}
// Create or reuse node
const isFile = (type === 'file');
const tagName = isFile ? 'link' : 'style';
if (styleNode === null || styleNode.nodeName.toLowerCase() !== tagName) {
if (styleNode !== null && styleNode.parentNode !== null) {
styleNode.parentNode.removeChild(styleNode);
}
styleNode = document.createElement(tagName);
}
// Update node style
if (isFile) {
styleNode.rel = 'stylesheet';
styleNode.href = value;
} else {
styleNode.textContent = value;
}
// Update parent
if (styleNode.parentNode !== parentNode) {
parentNode.appendChild(styleNode);
}
// Add to map
injectedStylesheets.set(id, styleNode);
return styleNode;
}
function loadScripts(urls) {
return new Promise((resolve, reject) => {
const parent = document.body;
if (parent === null) {
reject(new Error('Missing body'));
return;
}
for (const url of urls) {
const node = parent.querySelector(`script[src='${escapeCSSAttribute(url)}']`);
if (node !== null) { continue; }
const script = document.createElement('script');
script.async = false;
script.src = url;
parent.appendChild(script);
}
loadScriptSentinel(parent, resolve, reject);
});
}
function loadScriptSentinel(parent, resolve, reject) {
const script = document.createElement('script');
const sentinelEventName = 'dynamicLoaderSentinel';
const sentinelEventCallback = (e) => {
if (e.script !== script) { return; }
yomichan.off(sentinelEventName, sentinelEventCallback);
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parent.removeChild(script);
resolve();
};
yomichan.on(sentinelEventName, sentinelEventCallback);
try {
script.async = false;
script.src = '/mixed/js/dynamic-loader-sentinel.js';
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parent.appendChild(script);
} catch (e) {
yomichan.off(sentinelEventName, sentinelEventCallback);
reject(e);
}
}
function escapeCSSAttribute(value) {
return value.replace(/['\\]/g, (character) => `\\${character}`);
}
return {
loadStyle,
loadScripts
};
})();