Made sure to enable acceptable ads and to open the first-run page

lib/adblockplus_compat.js

Index: lib/adblockplus_compat.js
===================================================================
--- a/lib/adblockplus_compat.js
+++ b/lib/adblockplus_compat.js
@@ -88,17 +88,17 @@ var XPCOMUtils =
 //
 
 require.scopes.info =
 {
   get addonID()
   {
     return chrome.i18n.getMessage("@@extension_id");
   },
-  addonVersion: "2.0.3", // Hardcoded for now
+  addonVersion: "2.1", // Hardcoded for now
   addonRoot: "",
   get addonName()
   {
     return chrome.i18n.getMessage("name");
   },
   application: "chrome"
 };
 
@@ -356,27 +356,67 @@ require.scopes.utils =
     {
       // We cannot calculate MD5 checksums yet :-(
       return null;
     },
     makeURI: function(url)
     {
       return Services.io.newURI(url);
     },
+
     checkLocalePrefixMatch: function(prefixes)
     {
       if (!prefixes)
         return null;
 
       var list = prefixes.split(",");
       for (var i = 0; i < list.length; i++)
         if (new RegExp("^" + list[i] + "\\b").test(this.appLocale))
           return list[i];
 
       return null;
+    },
+
+    chooseFilterSubscription: function(subscriptions)
+    {
+      var selectedItem = null;
+      var selectedPrefix = null;
+      var matchCount = 0;
+      for (var i = 0; i < subscriptions.length; i++)
+      {
+        var subscription = subscriptions[i];
+        if (!selectedItem)
+          selectedItem = subscription;
+
+        var prefix = require("utils").Utils.checkLocalePrefixMatch(subscription.getAttribute("prefixes"));
+        if (prefix)
+        {
+          if (!selectedPrefix || selectedPrefix.length < prefix.length)
+          {
+            selectedItem = subscription;
+            selectedPrefix = prefix;
+            matchCount = 1;
+          }
+          else if (selectedPrefix && selectedPrefix.length == prefix.length)
+          {
+            matchCount++;
+
+            // If multiple items have a matching prefix of the same length:
+            // Select one of the items randomly, probability should be the same
+            // for all items. So we replace the previous match here with
+            // probability 1/N (N being the number of matches).
+            if (Math.random() * matchCount < 1)
+            {
+              selectedItem = subscription;
+              selectedPrefix = prefix;
+            }
+          }
+        }
+      }
+      return selectedItem;
     }
   }
 };
 
 //
 // ElemHideHitRegistration dummy implementation
 //