[idd] helper: use CWindow helper to avoid global state

idd/LGIddHelper/CWindow.cpp

@@ -0,0 +1,60 @@
+#include "CWindow.h"
+#include <strsafe.h>
+#include <CDebug.h>
+
+ATOM CWindow::s_atom = 0;
+static HINSTANCE hInstance = (HINSTANCE)GetModuleHandle(NULL);
+
+bool CWindow::registerClass()
+{
+  WNDCLASSEX wx = {};
+  wx.cbSize = sizeof(WNDCLASSEX);
+  wx.lpfnWndProc = wndProc;
+  wx.hInstance = hInstance;
+  wx.lpszClassName = L"LookingGlassIddHelper";
+  wx.hIcon = LoadIcon(NULL, IDI_APPLICATION);
+  wx.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
+  wx.hCursor = LoadCursor(NULL, IDC_ARROW);
+  wx.hbrBackground = (HBRUSH)COLOR_APPWORKSPACE;
+
+  s_atom = RegisterClassEx(&wx);
+  return s_atom;
+}
+
+CWindow::CWindow()
+{
+  CreateWindowEx(0, MAKEINTATOM(s_atom), NULL,
+    0, 0, 0, 0, 0, NULL, NULL, hInstance, this);
+}
+
+LRESULT CWindow::wndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+  CWindow *self;
+  if (uMsg == WM_NCCREATE)
+  {
+    LPCREATESTRUCT lpcs = (LPCREATESTRUCT)lParam;
+    self = (CWindow*)lpcs->lpCreateParams;
+    self->m_hwnd = hwnd;
+    SetWindowLongPtr(hwnd, GWLP_USERDATA, (LPARAM) self);
+  }
+  else
+  {
+    self = (CWindow*)GetWindowLongPtr(hwnd, GWLP_USERDATA);
+  }
+
+  if (self)
+    return self->handleMessage(uMsg, wParam, lParam);
+  else
+    return DefWindowProc(hwnd, uMsg, wParam, lParam);
+}
+
+LRESULT CWindow::handleMessage(UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+  return DefWindowProc(m_hwnd, uMsg, wParam, lParam);  
+}
+
+CWindow::~CWindow()
+{
+  if (m_hwnd)
+    DestroyWindow(m_hwnd);
+}