Add QPlatformWindow::isForeignWindow()

Simplifies code at call sites and allows for refactoring how to decide
if a window is foreign or not at a later point.

Change-Id: Icc51a83bac187f4975535366b53b4990832b6c82
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

3 files changed, 10 insertions, 11 deletions

diff --git a/src/plugins/platforms/windows/qwindowsmousehandler.cpp b/src/plugins/platforms/windows/qwindowsmousehandler.cpp
index 81abf24131..34c34fd28e 100644
--- a/src/plugins/platforms/windows/qwindowsmousehandler.cpp
+++ b/src/plugins/platforms/windows/qwindowsmousehandler.cpp
@@ -414,7 +414,7 @@ static bool isValidWheelReceiver(QWindow *candidate)
 {
     if (candidate) {
         const QWindow *toplevel = QWindowsWindow::topLevelOf(candidate);
-        if (toplevel->type() == Qt::ForeignWindow)
+        if (toplevel->handle() && toplevel->handle()->isForeignWindow())
             return true;
         if (const QWindowsWindow *ww = QWindowsWindow::windowsWindowOf(toplevel))
             return !ww->testFlag(QWindowsWindow::BlockedByModal);
diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index 04db975360..68d69f3765 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -1122,7 +1122,7 @@ void QWindowsWindow::updateDropSite(bool topLevel)
         // if the parent window is a foreign window wrapped via QWindow::fromWinId, we need to enable the drop site
         // on the first child window
         const QWindow *parent = window()->parent();
-        if (parent && (parent->type() == Qt::ForeignWindow))
+        if (parent && parent->handle() && parent->handle()->isForeignWindow())
             parentIsEmbedded = true;
     }
 
diff --git a/src/plugins/platforms/windows/qwindowswindow.h b/src/plugins/platforms/windows/qwindowswindow.h
index 22ba49b0a5..8179280bb3 100644
--- a/src/plugins/platforms/windows/qwindowswindow.h
+++ b/src/plugins/platforms/windows/qwindowswindow.h
@@ -385,15 +385,14 @@ QPoint QWindowsGeometryHint::mapFromGlobal(const QWindow *w, const QPoint &p)
 
 inline QWindowsWindow *QWindowsWindow::windowsWindowOf(const QWindow *w)
 {
-    QWindowsWindow *result = Q_NULLPTR;
-    if (w) {
-        const Qt::WindowType type = w->type();
-        if (type != Qt::Desktop && type != Qt::ForeignWindow) {
-            if (QPlatformWindow *pw = w->handle())
-                result = static_cast<QWindowsWindow *>(pw);
-        }
-    }
-    return result;
+    if (!w || !w->handle())
+        return nullptr;
+
+    const Qt::WindowType type = w->type();
+    if (type == Qt::Desktop || w->handle()->isForeignWindow())
+        return nullptr;
+
+    return static_cast<QWindowsWindow *>(w->handle());
 }
 
 void *QWindowsWindow::userDataOf(HWND hwnd)