Implement support for global whatsthis on Windows

Task-Number: QTBUG-32835

Change-Id: Ifee10d815ce0037c96eda574ab9e1af67ff6bd78
Reviewed-by: Andy Shaw <andy.shaw@digia.com>

src/gui/kernel/qguiapplication.cpp

@@ -1480,6 +1480,8 @@ void QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePriv
                     static_cast<QWindowSystemInterfacePrivate::ContextMenuEvent *>(e));
         break;
 #endif
+    case QWindowSystemInterfacePrivate::EnterWhatsThisMode:
+        QGuiApplication::postEvent(QGuiApplication::instance(), new QEvent(QEvent::EnterWhatsThisMode));
     default:
         qWarning() << "Unknown user input event type:" << e->type;
         break;

src/gui/kernel/qwindowsysteminterface.cpp

@@ -694,6 +694,15 @@ void QWindowSystemInterface::handleContextMenuEvent(QWindow *w, bool mouseTrigge
 }
 #endif
 
+#ifndef QT_NO_WHATSTHIS
+void QWindowSystemInterface::handleEnterWhatsThisEvent()
+{
+    QWindowSystemInterfacePrivate::WindowSystemEvent *e =
+            new QWindowSystemInterfacePrivate::WindowSystemEvent(QWindowSystemInterfacePrivate::EnterWhatsThisMode);
+    QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
+}
+#endif
+
 #ifndef QT_NO_DEBUG_STREAM
 Q_GUI_EXPORT QDebug operator<<(QDebug dbg, const QWindowSystemInterface::TouchPoint &p) {
     dbg.nospace() << "TouchPoint(" << p.id << " @" << p.normalPosition << " press " << p.pressure << " vel " << p.velocity << " state " << (int)p.state;

src/gui/kernel/qwindowsysteminterface.h

@@ -184,6 +184,9 @@ public:
                                        const QPoint &pos, const QPoint &globalPos,
                                        Qt::KeyboardModifiers modifiers);
 #endif
+#ifndef QT_NO_WHATSTHIS
+    static void handleEnterWhatsThisEvent();
+#endif
 
     // For event dispatcher implementations
     static bool sendWindowSystemEvents(QEventLoop::ProcessEventsFlags flags);

src/gui/kernel/qwindowsysteminterface_p.h

@@ -90,6 +90,7 @@ public:
         TabletLeaveProximity = UserInputEvent | 0x16,
         PlatformPanel = UserInputEvent | 0x17,
         ContextMenu = UserInputEvent | 0x18,
+        EnterWhatsThisMode = UserInputEvent | 0x19,
         ApplicationStateChanged = 0x19,
         FlushEvents = 0x20,
         WindowScreenChanged = 0x21

src/plugins/platforms/windows/qtwindowsglobal.h

@@ -83,6 +83,7 @@ enum WindowsEventType // Simplify event types
     CalculateSize = WindowEventFlag + 16,
     FocusInEvent = WindowEventFlag + 17,
     FocusOutEvent = WindowEventFlag + 18,
+    WhatsThisEvent = WindowEventFlag + 19,
     MouseEvent = MouseEventFlag + 1,
     MouseWheelEvent = MouseEventFlag + 2,
     CursorEvent = MouseEventFlag + 3,
@@ -199,6 +200,12 @@ inline QtWindows::WindowsEventType windowsEventType(UINT message, WPARAM wParamI
     case WM_CONTEXTMENU:
         return QtWindows::ContextMenu;
 #endif
+    case WM_SYSCOMMAND:
+#ifndef Q_OS_WINCE
+        if ((wParamIn & 0xfff0) == SC_CONTEXTHELP)
+            return QtWindows::WhatsThisEvent;
+#endif
+        break;
     default:
         break;
     }

src/plugins/platforms/windows/qwindowscontext.cpp

@@ -887,6 +887,12 @@ bool QWindowsContext::windowsProc(HWND hwnd, UINT message,
     case QtWindows::ContextMenu:
         return handleContextMenuEvent(platformWindow->window(), msg);
 #endif
+    case QtWindows::WhatsThisEvent: {
+#ifndef QT_NO_WHATSTHIS
+        QWindowSystemInterface::handleEnterWhatsThisEvent();
+        return true;
+#endif
+    }   break;
     default:
         break;
     }

src/plugins/platforms/xcb/qxcbwindow.cpp

@@ -1512,8 +1512,7 @@ void QXcbWindow::handleClientMessageEvent(const xcb_client_message_event_t *even
             m_syncValue.hi = event->data.data32[3];
 #ifndef QT_NO_WHATSTHIS
         } else if (event->data.data32[0] == atom(QXcbAtom::_NET_WM_CONTEXT_HELP)) {
-            QEvent *e = new QEvent(QEvent::EnterWhatsThisMode);
-            QGuiApplication::postEvent(QGuiApplication::instance(), e);
+            QWindowSystemInterface::handleEnterWhatsThisEvent();
 #endif
         } else {
             qWarning() << "QXcbWindow: Unhandled WM_PROTOCOLS message:" << connection()->atomName(event->data.data32[0]);