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-rw-r--r--ext/js/display/display-content-manager.js97
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diff --git a/ext/js/display/display-content-manager.js b/ext/js/display/display-content-manager.js
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+/*
+ * Copyright (C) 2020-2022 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 DisplayContentManager {
+ 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;
+ }
+}