Made sure FilterEngine instances are always initialized

src/FilterEngine.cpp

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2013 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 118 matching lines @@
 }
 
 bool Subscription::operator==(const Subscription& subscription) const
 {
   return GetProperty("url")->AsString() == subscription.GetProperty("url")->AsString();
 }
 
 FilterEngine::FilterEngine(JsEnginePtr jsEngine)
     : jsEngine(jsEngine), initialized(false)
 {
-  jsEngine->SetInitCallback(std::tr1::bind(&FilterEngine::InitDone, this));
+  jsEngine->SetEventCallback("init", std::tr1::bind(&FilterEngine::InitDone, this));
   for (int i = 0; !jsSources[i].empty(); i += 2)
     jsEngine->Evaluate(jsSources[i + 1], jsSources[i]);
 
   // TODO: This should really be implemented via a conditional variable
   while (!initialized)
     ::Sleep(10);
 }
 
 void FilterEngine::InitDone()
 {
+  jsEngine->RemoveEventCallback("init");
   initialized = true;
 }
 
 FilterPtr FilterEngine::GetFilter(const std::string& text)
 {
   JsValuePtr func = jsEngine->Evaluate("API.getFilterFromText");
   JsValueList params;
   params.push_back(jsEngine->NewValue(text));
   return FilterPtr(new Filter(func->Call(params)));
 }
@@ skipping 56 matching lines @@
 {
   JsValuePtr func = jsEngine->Evaluate("API.getElementHidingSelectors");
   JsValueList params;
   params.push_back(jsEngine->NewValue(domain));
   JsValueList result = func->Call(params)->AsList();
   std::vector<std::string> selectors;
   for (JsValueList::iterator it = result.begin(); it != result.end(); ++it)
     selectors.push_back((*it)->AsString());
   return selectors;
 }