SingleFile/extension/lib/single-file/lazy/bg/lazy-timeout.js

/*
 * Copyright 2010-2020 Gildas Lormeau
 * contact : gildas.lormeau <at> gmail.com
 * 
 * This file is part of SingleFile.
 *
 *   The code in this file is free software: you can redistribute it and/or 
 *   modify it under the terms of the GNU Affero General Public License 
 *   (GNU AGPL) as published by the Free Software Foundation, either version 3
 *   of the License, or (at your option) any later version.
 * 
 *   The code in this file 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 Affero 
 *   General Public License for more details.
 *
 *   As additional permission under GNU AGPL version 3 section 7, you may 
 *   distribute UNMODIFIED VERSIONS OF THIS file without the copy of the GNU 
 *   AGPL normally required by section 4, provided you include this license 
 *   notice and a URL through which recipients can access the Corresponding 
 *   Source.
 */

/* global browser, setTimeout, clearTimeout */

(() => {

	"use strict";

	const timeouts = new Map();

	browser.runtime.onMessage.addListener((message, sender) => {
		if (message.method == "singlefile.lazyTimeout.setTimeout") {
			let tabTimeouts = timeouts.get(sender.tab.id);
			if (tabTimeouts) {
				const previousTimeoutId = tabTimeouts.get(message.type);
				if (previousTimeoutId) {
					clearTimeout(previousTimeoutId);
				}
			}
			const timeoutId = setTimeout(async () => {
				try {
					const tabTimeouts = timeouts.get(sender.tab.id);
					if (tabTimeouts) {
						deleteTimeout(tabTimeouts, sender.tab.id, message.type);
					}
					await browser.tabs.sendMessage(sender.tab.id, { method: "singlefile.lazyTimeout.onTimeout", type: message.type });
				} catch (error) {
					// ignored
				}
			}, message.delay);
			if (!tabTimeouts) {
				tabTimeouts = new Map();
				timeouts.set(sender.tab.id, tabTimeouts);
			}
			tabTimeouts.set(message.type, timeoutId);
			return Promise.resolve({});
		}
		if (message.method == "singlefile.lazyTimeout.clearTimeout") {
			let tabTimeouts = timeouts.get(sender.tab.id);
			if (tabTimeouts) {
				const timeoutId = tabTimeouts.get(message.type);
				if (timeoutId) {
					clearTimeout(timeoutId);
				}
				deleteTimeout(tabTimeouts, sender.tab.id, message.type);
			}
			return Promise.resolve({});
		}
	});

	browser.tabs.onRemoved.addListener(tabId => timeouts.delete(tabId));

	function deleteTimeout(tabTimeouts, tabId, type) {
		tabTimeouts.delete(type);
		if (!tabTimeouts.size) {
			timeouts.delete(tabId);
		}
	}

})();