108 lines
3.3 KiB
JavaScript
108 lines
3.3 KiB
JavaScript
/*
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* Copyright (C) 2020-2021 Yomichan Authors
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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/* global
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* api
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*/
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class MediaLoader {
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constructor() {
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this._token = {};
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this._mediaCache = new Map();
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this._loadMediaData = [];
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}
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async loadMedia(path, dictionaryName, onLoad, onUnload) {
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const token = this._token;
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const data = {onUnload, loaded: false};
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this._loadMediaData.push(data);
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const media = await this.getMedia(path, dictionaryName);
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if (token !== this._token) { return; }
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onLoad(media.url);
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data.loaded = true;
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}
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unloadAll() {
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for (const {onUnload, loaded} of this._loadMediaData) {
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if (typeof onUnload === 'function') {
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onUnload(loaded);
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}
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}
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this._loadMediaData = [];
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for (const map of this._mediaCache.values()) {
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for (const {url} of map.values()) {
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if (url !== null) {
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URL.revokeObjectURL(url);
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}
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}
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}
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this._mediaCache.clear();
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this._token = {};
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}
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async getMedia(path, dictionaryName) {
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let cachedData;
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let dictionaryCache = this._mediaCache.get(dictionaryName);
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if (typeof dictionaryCache !== 'undefined') {
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cachedData = dictionaryCache.get(path);
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} else {
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dictionaryCache = new Map();
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this._mediaCache.set(dictionaryName, dictionaryCache);
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}
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if (typeof cachedData === 'undefined') {
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cachedData = {
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promise: null,
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data: null,
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url: null
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};
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dictionaryCache.set(path, cachedData);
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cachedData.promise = this._getMediaData(path, dictionaryName, cachedData);
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}
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return cachedData.promise;
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}
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async _getMediaData(path, dictionaryName, cachedData) {
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const token = this._token;
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const data = (await api.getMedia([{path, dictionaryName}]))[0];
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if (token === this._token && data !== null) {
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const contentArrayBuffer = this._base64ToArrayBuffer(data.content);
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const blob = new Blob([contentArrayBuffer], {type: data.mediaType});
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const url = URL.createObjectURL(blob);
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cachedData.data = data;
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cachedData.url = url;
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}
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return cachedData;
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}
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_base64ToArrayBuffer(content) {
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const binaryContent = window.atob(content);
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const length = binaryContent.length;
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const array = new Uint8Array(length);
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for (let i = 0; i < length; ++i) {
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array[i] = binaryContent.charCodeAt(i);
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}
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return array.buffer;
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}
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}
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