Issue 2444 - Configure default prefs in JSON

lib/prefs.js

Index: lib/prefs.js
===================================================================
--- a/lib/prefs.js
+++ b/lib/prefs.js
@@ -16,31 +16,28 @@
 {
   // Load default preferences and set up properties for them
   let defaultBranch = Services.prefs.getDefaultBranch(branchName);
-  let scope =
+
+  let request = new XMLHttpRequest();
+  request.open("GET", addonRoot + "defaults/prefs.json", false);

[Felix Dahlke, 2015/05/01 20:36:52]

Not really happy with using a sync request here - those are deprecated
(particularly in combination with responseType). However, I haven't found
another way to read this file synchronously yet so far, and the only alternative
I see would be to have some kind of pref initialisation event and wit for that
wherever we want to work with prefs - not brilliant.

+  request.responseType = "json";
+  request.send();
+
+  let defaults = request.response.defaults;
+  for (let pref in defaults)
   {
-    pref: function(pref, value, preconfigurable)
+    let value = defaults[pref];
+    let [getter, setter] = typeMap[typeof value];
+    if (request.response.preconfigurable.indexOf(pref) != -1)
     {
-      if (pref.substr(0, branchName.length) != branchName)
+      try
       {
-        Cu.reportError(new Error("Ignoring default preference " + pref + ", wrong branch."));
-        return;
+        value = getter(preconfiguredBranch, pref);
       }
-      pref = pref.substr(branchName.length);
-
-      let [getter, setter] = typeMap[typeof value];
-      if (preconfigurable)
-      {
-        try
-        {
-          value = getter(preconfiguredBranch, pref);
-        }
-        catch (e) {}
-      }
-      setter(defaultBranch, pref, value);
-      defineProperty(pref, false, getter, setter);
+      catch (e) {}
     }
-  };
-  Services.scriptloader.loadSubScript(addonRoot + "defaults/prefs.js", scope);
+    setter(defaultBranch, pref, value);
+    defineProperty(pref, false, getter, setter);
+  }
 
   // Add preference change observer
   try