Issue #2230, #3391 - Load filters on "download begin" event

src/plugin/PluginTabBase.cpp

Index: src/plugin/PluginTabBase.cpp
===================================================================
--- a/src/plugin/PluginTabBase.cpp
+++ b/src/plugin/PluginTabBase.cpp
@@ -29,8 +29,6 @@
   : m_isActivated(false)
   , m_continueThreadRunning(true)
 {
-  m_filter.hideFiltersLoadedEvent = CreateEvent(NULL, true, false, NULL);
-
   CPluginClient* client = CPluginClient::GetInstance();
   if (AdblockPlus::IE::InstalledMajorVersion() < 10)
   {
@@ -79,38 +77,29 @@
   m_isActivated = true;
 }
 
-namespace
+void CPluginTab::OnNavigate(const std::wstring& url)
 {
-  // Entry Point
-  void FilterLoader(CPluginFilter* filter, const std::wstring& domain)
+  SetDocumentUrl(url);
+}
+
+void CPluginTab::OnDownloadBegin()
+{
+  std::wstring domain = GetDocumentDomain();
+  ClearFrameCache(domain);
+  if (!filter)
   {
     try
     {
-      filter->LoadHideFilters(CPluginClient::GetInstance()->GetElementHidingSelectors(domain));
-      SetEvent(filter->hideFiltersLoadedEvent);
+      filter.reset(new CPluginFilter(domain));
     }
-    catch (...)
+    catch (const std::exception& e)
     {
-      // As a thread-main function, we truncate any C++ exception.
+      DEBUG_EXCEPTION(e);
     }
   }
-}
-
-void CPluginTab::OnNavigate(const std::wstring& url)
-{
-  SetDocumentUrl(url);
-  ClearFrameCache(GetDocumentDomain());
-  std::wstring domainString = GetDocumentDomain();
-  ResetEvent(m_filter.hideFiltersLoadedEvent);
-  try
+  else
   {
-    std::thread filterLoaderThread(&FilterLoader, &m_filter, GetDocumentDomain());
-    filterLoaderThread.detach(); // TODO: but actually we should wait for the thread in the dtr.
-  }
-  catch (const std::system_error& ex)
-  {
-    DEBUG_SYSTEM_EXCEPTION(ex, PLUGIN_ERROR_THREAD, PLUGIN_ERROR_MAIN_THREAD_CREATE_PROCESS,
-      "Class::Thread - Failed to start filter loader thread");
+    DEBUG_GENERAL("Suspicious: Reached CPluginTab::OnDownloadBegin with a non-null filter")
   }
 }
 
@@ -261,9 +250,15 @@
   std::wstring url = GetDocumentUrl();
   if (!client->IsWhitelistedUrl(url) && !client->IsElemhideWhitelistedOnDomain(url))
   {
-    CPluginDomTraverser traversal(&m_filter);
-    traversal.TraverseDocumentRoot(browser, GetDocumentDomain(), GetDocumentUrl());
+    CPluginFilter* f = filter.get();
+    if (f)
+    {
+      f->EnsureInitialized();
+      CPluginDomTraverser traversal(f);
+      traversal.TraverseDocumentRoot(browser, GetDocumentDomain(), GetDocumentUrl());
+    }
   }
+  filter.reset();
   InjectABP(browser);
 }