[host] windows: make mousehook.c work on secure desktop

Basically, this creates a separate thread for the mouse events, and this
thread detects that the desktop has changed (say to the secure desktop),
and unhooks, switches to the new desktop, and then rehooks.

This allows the cursor location to be updated while using NvFBC on secure
desktop and the login screen.

host/platform/Windows/src/mousehook.c

@@ -30,62 +30,125 @@ struct mouseHook
   HHOOK       hook;
   MouseHookFn callback;
   int         x, y;
+  HANDLE      event;
+  HANDLE      thread;
 };
 
 static struct mouseHook mouseHook = { 0 };
 
 // forwards
 static LRESULT WINAPI mouseHook_hook(int nCode, WPARAM wParam, LPARAM lParam);
-static LRESULT msg_callback(WPARAM wParam, LPARAM lParam);
+
+static bool switchDesktopAndHook(void)
+{
+  HDESK desk = OpenInputDesktop(0, FALSE, GENERIC_ALL);
+  if (!desk)
+  {
+    DEBUG_WINERROR("Failed to OpenInputDesktop", GetLastError());
+    return false;
+  }
+
+  if (!SetThreadDesktop(desk))
+  {
+    DEBUG_WINERROR("Failed to SetThreadDesktop", GetLastError());
+    CloseDesktop(desk);
+    return false;
+  }
+  CloseDesktop(desk);
+
+  mouseHook.hook = SetWindowsHookEx(WH_MOUSE_LL, mouseHook_hook, NULL, 0);
+  if (!mouseHook.hook)
+  {
+    DEBUG_WINERROR("Failed to install the mouse hook", GetLastError());
+    return false;
+  }
+  return true;
+}
+
+static VOID WINAPI winEventProc(HWINEVENTHOOK hWinEventHook, DWORD event,
+    HWND hwnd, LONG idObject, LONG idChild, DWORD idEventThread, DWORD dwmsEventTime)
+{
+  switch (event)
+  {
+    case EVENT_SYSTEM_DESKTOPSWITCH:
+      UnhookWindowsHookEx(mouseHook.hook);
+      switchDesktopAndHook();
+      break;
+  }
+}
+
+static DWORD WINAPI threadProc(LPVOID lParam) {
+  if (mouseHook.installed)
+  {
+    DEBUG_WARN("Mouse hook already installed");
+    return 0;
+  }
+
+  if (!switchDesktopAndHook())
+    return 0;
+
+  mouseHook.installed = true;
+  mouseHook.callback  = (MouseHookFn)lParam;
+
+  HWINEVENTHOOK eventHook = SetWinEventHook(
+      EVENT_SYSTEM_DESKTOPSWITCH, EVENT_SYSTEM_DESKTOPSWITCH, NULL,
+      winEventProc, 0, 0, WINEVENT_OUTOFCONTEXT
+  );
+  if (!eventHook)
+  {
+    DEBUG_WINERROR("Failed to SetWinEventHook", GetLastError());
+    goto exit;
+  }
+
+  MSG msg;
+  while (true) {
+    switch (MsgWaitForMultipleObjects(1, &mouseHook.event, FALSE, INFINITE, QS_ALLINPUT)) {
+      case WAIT_OBJECT_0:
+        DEBUG_INFO("Mouse hook thread received quit request");
+        PostQuitMessage(0);
+        break;
+      case WAIT_OBJECT_0 + 1:
+        while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
+        {
+          if (msg.message == WM_QUIT)
+            goto exit;
+          TranslateMessage(&msg);
+          DispatchMessage(&msg);
+        }
+        break;
+      default:
+        goto exit;
+    }
+  }
+
+  exit:
+  if (eventHook) UnhookWinEvent(eventHook);
+  UnhookWindowsHookEx(mouseHook.hook);
+  mouseHook.installed = false;
+  return 0;
+}
 
 void mouseHook_install(MouseHookFn callback)
 {
-  struct MSG_CALL_FUNCTION cf;
-  cf.fn     = msg_callback;
-  cf.wParam = 1;
-  cf.lParam = (LPARAM)callback;
-  sendAppMessage(WM_CALL_FUNCTION, 0, (LPARAM)&cf);
+  if (!mouseHook.event)
+  {
+    mouseHook.event = CreateEventA(NULL, FALSE, FALSE, NULL);
+    if (!mouseHook.event)
+    {
+      DEBUG_WINERROR("Failed to create mouse hook uninstall event", GetLastError());
+      return;
+    }
+  }
+  mouseHook.thread = CreateThread(NULL, 0, threadProc, callback, 0, NULL);
 }
 
 void mouseHook_remove(void)
 {
-  struct MSG_CALL_FUNCTION cf;
-  cf.fn     = msg_callback;
-  cf.wParam = 0;
-  cf.lParam = 0;
-  sendAppMessage(WM_CALL_FUNCTION, 0, (LPARAM)&cf);
-}
-
-static LRESULT msg_callback(WPARAM wParam, LPARAM lParam)
-{
-  if (wParam)
-  {
-    if (mouseHook.installed)
-    {
-      DEBUG_WARN("Mouse hook already installed");
-      return 0;
-    }
-
-    mouseHook.hook = SetWindowsHookEx(WH_MOUSE_LL, mouseHook_hook, NULL, 0);
-    if (!mouseHook.hook)
-    {
-      DEBUG_WINERROR("Failed to install the mouse hook", GetLastError());
-      return 0;
-    }
-
-    mouseHook.installed = true;
-    mouseHook.callback  = (MouseHookFn)lParam;
-  }
-  else
-  {
-    if (!mouseHook.installed)
-      return 0;
-
-    UnhookWindowsHookEx(mouseHook.hook);
-    mouseHook.installed = false;
-  }
-
-  return 0;
+  if (!mouseHook.event)
+    return;
+  SetEvent(mouseHook.event);
+  WaitForSingleObject(mouseHook.thread, INFINITE);
+  CloseHandle(mouseHook.thread);
 }
 
 static LRESULT WINAPI mouseHook_hook(int nCode, WPARAM wParam, LPARAM lParam)