hide login screen to make the login on XP faster

svn path=/trunk/; revision=14350

reactos/subsys/system/explorer/explorer.cpp

@@ -705,6 +705,19 @@ int main(int argc, char* argv[])
 #endif	// __MINGW && UNICODE
 
 
+static bool SetShellReadyEvent(LPCTSTR evtName)
+{
+	HANDLE hEvent = OpenEvent(EVENT_MODIFY_STATE, FALSE, evtName);
+	if (!hEvent)
+		return false;
+
+	SetEvent(hEvent);
+	CloseHandle(hEvent);
+
+	return true;
+}
+
+
 int WINAPI _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nShowCmd)
 {
 	CONTEXT("WinMain()");
@@ -758,10 +771,14 @@ int WINAPI _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdL
 		}
 
 		startup_desktop = TRUE;
-	} else
+	} else {
 		 // create desktop window and task bar only, if there is no other shell and we are
 		 // the first explorer instance
+		 // MS Explorer looks additionally into the registry entry HKCU\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\shell,
+		 // to decide wether it is currently configured as shell application.
 		startup_desktop = !any_desktop_running;
+	}
+
 
 	bool autostart = !any_desktop_running;
 
@@ -803,6 +820,15 @@ int WINAPI _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdL
 	}
 #endif
 
+
+	if (startup_desktop) {
+		 // hide the XP login screen (Credit to Nicolas Escuder)
+		 // another undocumented event: "Global\\msgina: ReturnToWelcome"
+		if (!SetShellReadyEvent(TEXT("msgina: ShellReadyEvent")))
+			SetShellReadyEvent(TEXT("Global\\msgina: ShellReadyEvent"));
+	}
+
+
 	bool use_gdb_stub = false;	// !IsDebuggerPresent();
 
 	if (_tcsstr(lpCmdLine,TEXT("-debug")))
@@ -842,6 +868,7 @@ int WINAPI _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdL
 		g_Globals._desktops.get_current_Desktop()->_hwndDesktop = g_Globals._hwndDesktop;
 #endif
 
+		/**TODO launching autostart programs can be moved into a background thread. */
 		if (autostart) {
 			char* argv[] = {"", "s"};	// call startup routine in SESSION_START mode
 			startup(2, argv);