/* * Copyright (C) 2020 Alex Yatskov <alex@foosoft.net> * Author: Alex Yatskov <alex@foosoft.net> * * 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 jpIsStringPartiallyJapanese*/ class ClipboardMonitor extends EventDispatcher { constructor({getClipboard}) { super(); this._timerId = null; this._timerToken = null; this._interval = 250; this._previousText = null; this._getClipboard = getClipboard; } start() { this.stop(); // The token below is used as a unique identifier to ensure that a new clipboard monitor // hasn't been started during the await call. The check below the await this._getClipboard() // call will exit early if the reference has changed. const token = {}; const intervalCallback = async () => { this._timerId = null; let text = null; try { text = await this._getClipboard(); } catch (e) { // NOP } if (this._timerToken !== token) { return; } if ( typeof text === 'string' && (text = text.trim()).length > 0 && text !== this._previousText ) { this._previousText = text; if (jpIsStringPartiallyJapanese(text)) { this.trigger('change', {text}); } } this._timerId = setTimeout(intervalCallback, this._interval); }; this._timerToken = token; intervalCallback(); } stop() { this._timerToken = null; if (this._timerId !== null) { clearTimeout(this._timerId); this._timerId = null; } } setPreviousText(text) { this._previousText = text; } }