Start using browser.alarms instead of setTimeout() where applicable

Related documentation:
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Background_scripts#convert_to_non-persistent

platform/chromium/manifest.json

@@ -82,6 +82,7 @@
     "open_in_tab": true
   },
   "permissions": [
+    "alarms",
     "contextMenus",
     "privacy",
     "storage",

platform/common/vapi-background.js

@@ -95,6 +95,61 @@ vAPI.storage = webext.storage.local;
 /******************************************************************************/
 /******************************************************************************/
 
+vAPI.alarms = {
+    create(callback) {
+        this.uniqueIdGenerator += 1;
+        const name = this.uniqueIdGenerator.toString(36);
+        const client = new this.Client(name, callback);
+        this.clientMap.set(name, client);
+        return client;
+    },
+    Client: class {
+        constructor(name, callback) {
+            this.name = name;
+            this.callback = callback;
+        }
+        on(delay) {
+            const delayInMinutes = this.normalizeDelay(delay);
+            browser.alarms.get(this.name, alarm => {
+                if ( alarm ) { return; }
+                return browser.alarms.create(this.name, { delayInMinutes });
+            });
+        }
+        offon(delay) {
+            const delayInMinutes = this.normalizeDelay(delay);
+            return browser.alarms.create(this.name, { delayInMinutes });
+        }
+        off() {
+            return browser.alarms.clear(this.name);
+        }
+        normalizeDelay(delay) {
+            let delayInMinutes = 0;
+            if ( typeof delay === 'number' ) {
+                delayInMinutes = delay;
+            } else if ( typeof delay === 'object' ) {
+                if ( delay.sec !== undefined ) {
+                    delayInMinutes = delay.sec / 60;
+                } else if ( delay.ms !== undefined ) {
+                    delayInMinutes = delay.ms / 60000;
+                }
+            }
+            return Math.max(delayInMinutes, 1);
+        }
+    },
+    onAlarm(alarm) {
+        const client = this.clientMap.get(alarm.name);
+        if ( client === undefined ) { return; }
+        client.callback(alarm);
+    },
+    clientMap: new Map(),
+    uniqueIdGenerator: 1000000,
+};
+
+browser.alarms.onAlarm.addListener(alarm => vAPI.alarms.onAlarm(alarm));
+
+/******************************************************************************/
+/******************************************************************************/
+
 // https://github.com/gorhill/uMatrix/issues/234
 // https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/privacy/network
 

platform/firefox/manifest.json

@@ -90,6 +90,7 @@
     "open_in_tab": true
   },
   "permissions": [
+    "alarms",
     "dns",
     "menus",
     "privacy",

platform/opera/manifest.json

@@ -78,6 +78,7 @@
   "name": "uBlock Origin",
   "options_page": "dashboard.html",
   "permissions": [
+    "alarms",
     "contextMenus",
     "privacy",
     "storage",

src/js/storage.js

@@ -1276,35 +1276,17 @@ self.addEventListener('hiddenSettingsChanged', ( ) => {
         return false;
     };
 
-    let createTimer;
-    let destroyTimer;
-
     const destroy = function() {
+        if ( µb.selfieIsInvalid === false ) {
             io.remove(/^selfie\//);
             µb.selfieIsInvalid = true;
-        createTimer = vAPI.setTimeout(( ) => {
-            createTimer = undefined;
-            create();
-        }, µb.hiddenSettings.selfieAfter * 60000);
-    };
-
-    const destroyAsync = function() {
-        if ( destroyTimer !== undefined ) { return; }
-        if ( createTimer !== undefined ) {
-            clearTimeout(createTimer);
-            createTimer = undefined;
         }
-        destroyTimer = vAPI.setTimeout(
+        createAlarm.offon(µb.hiddenSettings.selfieAfter);
-            ( ) => {
-                destroyTimer = undefined;
-                destroy();
-            },
-            1019
-        );
-        µb.selfieIsInvalid = true;
     };
 
-    µb.selfieManager = { load, destroy: destroyAsync };
+    const createAlarm = vAPI.alarms.create(create);
+
+    µb.selfieManager = { load, destroy };
 }
 
 /******************************************************************************/