/* * Copyright (C) 2020-2021 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 * StringUtil */ class MediaLoader { constructor() { this._token = {}; this._mediaCache = new Map(); this._loadMediaData = []; } async loadMedia(path, dictionary, onLoad, onUnload) { const token = this._token; const data = {onUnload, loaded: false}; this._loadMediaData.push(data); const media = await this.getMedia(path, dictionary); if (token !== this._token) { return; } onLoad(media.url); data.loaded = true; } unloadAll() { for (const {onUnload, loaded} of this._loadMediaData) { if (typeof onUnload === 'function') { onUnload(loaded); } } this._loadMediaData = []; for (const map of this._mediaCache.values()) { for (const {url} of map.values()) { if (url !== null) { URL.revokeObjectURL(url); } } } this._mediaCache.clear(); this._token = {}; } async getMedia(path, dictionary) { let cachedData; let dictionaryCache = this._mediaCache.get(dictionary); if (typeof dictionaryCache !== 'undefined') { cachedData = dictionaryCache.get(path); } else { dictionaryCache = new Map(); this._mediaCache.set(dictionary, dictionaryCache); } if (typeof cachedData === 'undefined') { cachedData = { promise: null, data: null, url: null }; dictionaryCache.set(path, cachedData); cachedData.promise = this._getMediaData(path, dictionary, cachedData); } return cachedData.promise; } async _getMediaData(path, dictionary, cachedData) { const token = this._token; const data = (await yomichan.api.getMedia([{path, dictionary}]))[0]; if (token === this._token && data !== null) { const buffer = StringUtil.base64ToArrayBuffer(data.content); const blob = new Blob([buffer], {type: data.mediaType}); const url = URL.createObjectURL(blob); cachedData.data = data; cachedData.url = url; } return cachedData; } }