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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
* apiGetMedia
*/
class MediaLoader {
constructor() {
this._token = {};
this._mediaCache = new Map();
this._loadMediaData = [];
}
async loadMedia(path, dictionaryName, onLoad, onUnload) {
const token = this.token;
const data = {onUnload, loaded: false};
this._loadMediaData.push(data);
const media = await this.getMedia(path, dictionaryName);
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, dictionaryName) {
let cachedData;
let dictionaryCache = this._mediaCache.get(dictionaryName);
if (typeof dictionaryCache !== 'undefined') {
cachedData = dictionaryCache.get(path);
} else {
dictionaryCache = new Map();
this._mediaCache.set(dictionaryName, dictionaryCache);
}
if (typeof cachedData === 'undefined') {
cachedData = {
promise: null,
data: null,
url: null
};
dictionaryCache.set(path, cachedData);
cachedData.promise = this._getMediaData(path, dictionaryName, cachedData);
}
return cachedData.promise;
}
async _getMediaData(path, dictionaryName, cachedData) {
const token = this._token;
const data = (await apiGetMedia([{path, dictionaryName}]))[0];
if (token === this._token && data !== null) {
const sourceArrayBuffer = this._base64ToArrayBuffer(data.source);
const blob = new Blob([sourceArrayBuffer], {type: data.mediaType});
const url = URL.createObjectURL(blob);
cachedData.data = data;
cachedData.url = url;
}
return cachedData;
}
_base64ToArrayBuffer(source) {
const binarySource = window.atob(source);
const length = binarySource.length;
const array = new Uint8Array(length);
for (let i = 0; i < length; ++i) {
array[i] = binarySource.charCodeAt(i);
}
return array.buffer;
}
}
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