Issue #4338, #3391 - Remove registered window class for the status bar

src/plugin/PluginClass.cpp

Index: src/plugin/PluginClass.cpp
===================================================================
--- a/src/plugin/PluginClass.cpp
+++ b/src/plugin/PluginClass.cpp
@@ -40,6 +40,9 @@
 
 extern CComModule _Module;
 
+// Status bar pane number
+#define STATUSBAR_PANE_NUMBER 2
+
 typedef HANDLE (WINAPI *OPENTHEMEDATA)(HWND, LPCWSTR);
 typedef HRESULT (WINAPI *DRAWTHEMEBACKGROUND)(HANDLE, HDC, INT, INT, LPRECT, LPRECT);
 typedef HRESULT (WINAPI *CLOSETHEMEDATA)(HANDLE);
@@ -55,7 +58,6 @@
 DRAWTHEMEBACKGROUND pfnDrawThemeBackground = NULL;
 OPENTHEMEDATA pfnOpenThemeData = NULL;
 
-ATOM CPluginClass::s_atomPaneClass = NULL;
 HINSTANCE CPluginClass::s_hUxtheme = NULL;
 std::set<CPluginClass*> CPluginClass::s_instances;
 
@@ -700,37 +702,6 @@
   }
   s_criticalSectionLocal.Unlock();
 
-  // Register pane class
-  if (!GetAtomPaneClass())
-  {
-    WNDCLASSEX wcex;
-
-    wcex.cbSize = sizeof(wcex);
-    wcex.style = 0;
-    wcex.lpfnWndProc = (WNDPROC)PaneWindowProc;
-    wcex.cbClsExtra = 0;
-    wcex.cbWndExtra = 0;
-    wcex.hInstance = _Module.m_hInst;
-    wcex.hIcon = NULL;
-    wcex.hCursor = NULL;
-    wcex.hbrBackground = NULL;
-    wcex.lpszMenuName = NULL;
-    wcex.lpszClassName = STATUSBAR_PANE_NAME;
-    wcex.hIconSm = NULL;
-
-    s_criticalSectionLocal.Lock();
-    {
-      s_atomPaneClass = ::RegisterClassEx(&wcex);
-    }
-    s_criticalSectionLocal.Unlock();
-
-    if (!GetAtomPaneClass())
-    {
-      DEBUG_ERROR_LOG(::GetLastError(), PLUGIN_ERROR_UI, PLUGIN_ERROR_UI_REGISTER_PANE_CLASS, "Class::InitObject - RegisterClassEx");
-      return false;
-    }
-  }
-
   int ieVersion = AdblockPlus::IE::InstalledMajorVersion();
   // Create status pane
   if (ieVersion > 6 && !CreateStatusBarPane())
@@ -776,6 +747,25 @@
   return true;
 }
 
+namespace
+{
+  /**
+   * Wrapper for Windows API 'SetWindowLongPtr()' to set a new window procedure
+   *
+   * Adds type safety and proper error handling over calling the API function directly.
+   */
+  DWORD SetWindowProc(HWND window, WNDPROC procedure)
+  {
+    /*
+     * Error handling for 'SetWindowLongPtr()' is not standard.
+     * The method below is as specified by its documentation.
+     */
+    SetLastError(0);
+    ::SetWindowLongPtr(window, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(procedure));
+    return ::GetLastError();
+  }
+}
+
 bool CPluginClass::CreateStatusBarPane()
 {
   CriticalSection::Lock lock(m_csStatusBar);
@@ -902,8 +892,8 @@
   // Create pane window
   HWND hWndNewPane = ::CreateWindowEx(
     NULL,
-    MAKEINTATOM(GetAtomPaneClass()),
-    L"",
+    L"Edit", // predefined system class
+    L"ABPStatusBarPane",
     WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN,
     rcStatusBar.Width() - 500, 0, m_nPaneWidth, rcStatusBar.Height(),
     hWndStatusBar,
@@ -917,6 +907,15 @@
     return false;
   }
 
+  // Set window procedure to the one for status bars
+  auto error = SetWindowProc(hWndNewPane, CPluginClass::PaneWindowProc);
+  if (error)
+  {
+    DEBUG_ERROR_LOG(error, PLUGIN_ERROR_UI, PLUGIN_ERROR_UI_CREATE_STATUSBAR_PANE, "Class::SetStatusBarPaneWindowProc - SetWindowProc");
+    ::DestroyWindow(hWndNewPane);
+    return false;
+  }
+
   DEBUG_GENERAL("ABP window created");
   m_hTabWnd = hTabWnd;
   m_hStatusBarWnd = hWndStatusBar;
@@ -1069,8 +1068,8 @@
   // Create menu parent window
   HWND hMenuWnd = ::CreateWindowEx(
     NULL,
-    MAKEINTATOM(GetAtomPaneClass()),
-    L"",
+    L"Edit", // predefined system class
+    L"ABPStatusBarPopupMenu",
     0,
     0,0,0,0,
     NULL,
@@ -1084,6 +1083,15 @@
     return;
   }
 
+  // Set window procedure to the one for status bars.
+  auto error = SetWindowProc(hMenuWnd, CPluginClass::PaneWindowProc);
+  if (error)
+  {
+    DEBUG_ERROR_LOG(error, PLUGIN_ERROR_UI, PLUGIN_ERROR_UI_CREATE_STATUSBAR_PANE, "Class::DisplayPluginMenu - SetWindowProc");
+    ::DestroyWindow(hMenuWnd);
+    return;
+  }
+
   // Display menu
   nMenuFlags |= TPM_NONOTIFY | TPM_RETURNCMD | TPM_LEFTBUTTON;
 
@@ -1729,9 +1737,3 @@
 
   return icon;
 }
-
-ATOM CPluginClass::GetAtomPaneClass()
-{
-  return s_atomPaneClass;
-}
-