Added clear interval

Also ensures that the persistent data is loaded correctly in ESR.

Fixes #139 and #143

lib/persistentRndStorage.js

@@ -0,0 +1,111 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+(function(){
+	"use strict";
+
+	var scope;
+	if ((typeof exports) !== "undefined"){
+		scope = exports;
+	}
+	else {
+		scope = {};
+		window.scope.persistentRndStorage = scope;
+	}
+
+
+	const settings = require("./settings");
+	const logging = require("./logging");
+	
+	scope.persistentRnd = Object.create(null);
+	scope.init = function init(){
+		logging.message("initializing persistent rng storage");
+
+		logging.notice("build persistent storage");
+
+		if (settings.storePersistentRnd){
+			try {
+				let storedData = JSON.parse(settings.persistentRndStorage);
+				for (var domain in storedData){
+					var value = storedData[domain];
+					if (
+						Array.isArray(value) &&
+						value.length === 128 &&
+						value.every(function(value){
+							return typeof value === "number" && value >= 0 && value < 256;
+						})
+					){
+						scope.persistentRnd[domain] = value;
+					}
+				}
+			}
+			catch (e){
+				// JSON is not valid -> ignore it
+			}
+		}
+		else {
+			settings.persistentRndStorage = "";
+			settings.lastPersistentRndClearing = Date.now();
+		}
+
+		registerTimeout();
+
+		logging.notice("register settings change event listener");
+		settings.on(["persistentRndClearIntervalValue", "persistentRndClearIntervalUnit"], function(){
+			window.clearTimeout(clearTimeout);
+			registerTimeout();
+		});
+		settings.on("storePersistentRnd", function({newValue}){
+			settings.persistentRndStorage = newValue? JSON.stringify(scope.persistentRnd): "";
+		});
+	};
+
+	const getInterval = function(){
+		var units = {
+			seconds: 1000,
+			minutes: 60 * 1000,
+			hours: 60 * 60 * 1000,
+			days: 24 * 60 * 60 * 1000,
+			weeks: 7 * 24 * 60 * 60 * 1000,
+			months: 30 * 24 * 60 * 60 * 1000,
+			years: 365 * 24 * 60 * 60 * 1000,
+		};
+		return function getInterval(){
+			return settings.persistentRndClearIntervalValue * units[settings.persistentRndClearIntervalUnit] || 0;
+		};
+	}();
+
+	let clearTimeout;
+	function registerTimeout(){
+		var interval = getInterval();
+		if (interval > 0){
+			var timeout =  settings.lastPersistentRndClearing + interval - Date.now();
+			logging.message("registering persistent rng data clearing timeout. Clearing in ", timeout, "ms");
+			clearTimeout = window.setTimeout(clear, timeout);
+		}
+	}
+	function broadcast(data){
+		browser.tabs.query({}).then(function(tabs){
+			tabs.forEach(function(tab){
+				browser.tabs.sendMessage(tab.id, data);
+			});
+		});
+	}
+	function clear(){
+		logging.verbose("domain rnd cleared");
+		scope.persistentRnd = Object.create(null);
+		settings.persistentRndStorage = JSON.stringify(scope.persistentRnd);
+		settings.lastPersistentRndClearing = Date.now();
+		registerTimeout();
+		broadcast({"canvasBlocker-clear-domain-rnd": true});
+	}
+	function setDomainData(domain, rnd){
+		logging.verbose("got new domain rnd for ", domain, ":", rnd);
+		scope.persistentRnd[domain] = rnd;
+		settings.persistentRndStorage = JSON.stringify(scope.persistentRnd);
+		broadcast({"canvasBlocker-set-domain-rnd": {domain, rnd}});
+	}
+
+	scope.clear = clear;
+	scope.setDomainData = setDomainData;
+}());