Make JavaScript sources compile into the library; convert JavaScript files on the fly

lib/utils.js

+var Utils = exports.Utils = {
+  systemPrincipal: null,
+  getString: function(id)
+  {
+    return id;
+  },
+  runAsync: function(callback, thisPtr)
+  {
+    var params = Array.prototype.slice.call(arguments, 2);
+    window.setTimeout(function()
+    {
+      callback.apply(thisPtr, params);
+    }, 0);
+  },
+  get appLocale()
+  {
+    var locale = chrome.i18n.getMessage("@@ui_locale").replace(/_/g, "-");
+    this.__defineGetter__("appLocale", function() {return locale});
+    return this.appLocale;
+  },
+  generateChecksum: function(lines)
+  {
+    // 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;
+  }
+};