Applied changes from emailed code review

lib/rules.js

Index: lib/rules.js
===================================================================
--- a/lib/rules.js
+++ b/lib/rules.js
@@ -9,6 +9,8 @@
 
 let RULES_VERSION = 2;
 
+let CUSTOM_RULE_PRIORITY = 0x7FFFFFFF;
+
 let rules = {expressions: []};
 
 loadRules();
@@ -46,6 +48,10 @@
       {
         rules = data;
         callback(true);
+
+        // Add user-defined rules after calling the callback - if the callback
+        // saves the rules then the custom rules won't be included.
+        addCustomRules();
       }
       else
         callback(false);
@@ -81,6 +87,101 @@
   return getRuleFile();
 }
 
+function addCustomRules()
+{
+  for (let domain in Prefs.whitelist)
+    onWhitelistEntryAdded(domain);
+}
+
+function onWhitelistEntryAdded(domain)
+{
+  let reverse = domain.split("").reverse().join("");
+  addSuffix(rules.domain, reverse, CUSTOM_RULE_PRIORITY);
+}
+exports.onWhitelistEntryAdded = onWhitelistEntryAdded;
+
+function onWhitelistEntryRemoved(domain)
+{
+  let reverse = domain.split("").reverse().join("");
+  removeSuffix(rules.domain, reverse, CUSTOM_RULE_PRIORITY);
+}
+exports.onWhitelistEntryRemoved = onWhitelistEntryRemoved;
+
+function addSuffix(tree, suffix, priority)
+{
+  if (suffix.length == 0)
+  {
+    // We are at the last character, just put our priority here
+    tree[""] = " " + priority;
+    return;
+  }
+
+  let c = suffix[0];
+  if (c in tree)
+  {
+    let existing = tree[c];
+    if (typeof existing == "string")
+    {
+      // Single choice for this suffix, maybe the same entry?
+      if (existing.substr(0, suffix.length - 1) == suffix.substr(1) && existing[suffix.length - 1] == " ")
+      {
+        // Same entry, simply replace it by new priority
+        tree[c] = suffix.substr(1) + " " + priority;
+      }
+      else
+      {
+        // Different entry, need to add a new branching point and go deeper
+        if (existing[0] == " ")
+          tree[c] = {"": existing};
+        else
+        {
+          tree[c] = {};
+          tree[c][existing[0]] = existing.substr(1);
+        }
+        addSuffix(tree[c], suffix.substr(1), priority);
+      }
+    }
+    else
+    {
+      // Multiple choices for this suffix - go deeper
+      addSuffix(existing, suffix.substr(1), priority);
+    }
+  }
+  else
+  {
+    // No existing entry yet, just add ours
+    tree[c] = suffix.substr(1) + " " + priority;
+  }
+}
+
+function removeSuffix(tree, suffix, priority)
+{
+  if (suffix.length == 0)
+  {
+    // We are at the last character, check whether there is an entry with
+    // matching priority
+    if ("" in tree && tree[""] == " " + priority)
+      delete tree[""];
+    return;
+  }
+
+  let c = suffix[0];
+  if (!(c in tree))
+    return;
+
+  if (typeof tree[c] == "string")
+  {
+    // Single entry - check whether it is the right one
+    if (tree[c] == suffix.substr(1) + " " + priority)
+      delete tree[c];
+  }
+  else
+  {
+    // Multiple entries, need to go deeper
+    removeSuffix(tree[c], suffix.substr(1), priority);
+  }
+}
+
 function onTimer()
 {
   // Next check in 1 hour
@@ -97,12 +198,6 @@
     {
       rules.timestamp = Date.now();
 
-      var dynRules = require("updateRules").updateRules();
-      for(var i in dynRules)
-      {
-        rules[i] = dynRules[i];
-      }
-
       try
       {
         // Save the rules to file.