Issue 3880 - Improve behavior of Safari content blocker option

options.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 689 matching lines @@
     // Advanced tab
     var tweaks = document.querySelectorAll("#tweaks li[data-pref]");
     tweaks = Array.prototype.map.call(tweaks, function(checkbox)
     {
       return checkbox.getAttribute("data-pref");
     });
     tweaks.forEach(function(key)
     {
       getPref(key, function(value)
       {
-        onPrefMessage(key, value);
+        onPrefMessage(key, value, true);
       });
     });
     ext.backgroundPage.sendMessage(
     {
       type: "app.get",
       what: "features"
     },
     function(features)
     {
       hidePref("show_devtools_panel", !features.devToolsPanel);
-      hidePref("safari_contentblocker", !features.safariContentBlocker);
+
+      // Only show option to switch between Safari Content Blockers
+      // and event based blocking if both are available.
+      hidePref("safari_contentblocker", !(
+        features.safariContentBlocker &&
+        "canLoad" in safari.self.tab &&
+        "onbeforeload" in Element.prototype
+      ));
     });
 
     var filterTextbox = document.querySelector("#custom-filters-add input");
     placeholderValue = getMessage("options_customFilters_textbox_placeholder");
     filterTextbox.setAttribute("placeholder", placeholderValue);
     function addCustomFilters()
     {
       var filterText = filterTextbox.value;
       sendMessageHandleErrors(
       {
@@ skipping 282 matching lines @@
   };
 
   getPref.checks =
   {
     notifications_ignoredcategories: function(callback)
     {
       getPref("notifications_showui", callback);
     }
   };
 
-  function onPrefMessage(key, value)
+  function onPrefMessage(key, value, initial)
   {
+    switch (key)
+    {
+      case "notifications_ignoredcategories":
+        value = value.indexOf("*") == -1;
+        break;
+
+      case "notifications_showui":
+        hidePref("notifications_ignoredcategories", !value);
+        break;
+
+      case "safari_contentblocker":
+        E("restart-safari").setAttribute("aria-hidden", value || initial);
+        break;
+    }
+
     var checkbox = document.querySelector("[data-pref='" + key + "'] button[role='checkbox']");
     if (checkbox)
-    {
-      if (key == "notifications_ignoredcategories")
-        value = (value.indexOf("*") == -1);
       checkbox.setAttribute("aria-checked", value);
-    }
-    else if (key == "notifications_showui")
-      hidePref("notifications_ignoredcategories", !value);
   }
 
   function onShareLinkClick(e)
   {
     e.preventDefault();
 
     getDocLink("share-general", function(link)
     {
       openSharePopup(link);
     });
@@ skipping 41 matching lines @@
           var dialog = E("dialog-content-predefined");
           dialog.querySelector("h3").textContent = subscription.title || "";
           dialog.querySelector(".url").textContent = subscription.url;
           openDialog("predefined");
         }
         break;
       case "filters.respond":
         onFilterMessage(message.action, message.args[0]);
         break;
       case "prefs.respond":
-        onPrefMessage(message.action, message.args[0]);
+        onPrefMessage(message.action, message.args[0], false);
         break;
       case "subscriptions.respond":
         onSubscriptionMessage(message.action, message.args[0]);
         break;
     }
   });
 
   ext.backgroundPage.sendMessage(
   {
     type: "app.listen",
@@ skipping 13 matching lines @@
   });
   ext.backgroundPage.sendMessage(
   {
     type: "subscriptions.listen",
     filter: ["added", "disabled", "homepage", "lastDownload", "removed",
         "title"]
   });
 
   window.addEventListener("DOMContentLoaded", onDOMLoaded, false);
 })();