Split QPlatformWindow::isEmbedded into isAncestorOf to separate concerns

The function was doing two things, both checking window ancestry and
whether or the window was a direct child of non-Qt window. The former
has now been split of in a QPlatformWindow::isAncestorOf(), which
simplifies the code in e.g. QApplicationPrivate::isWindowBlocked().

Change-Id: I259a190e03ef8def23356005474eeeee74c9ae89
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

src/gui/kernel/qplatformwindow.cpp

@@ -192,15 +192,30 @@ bool QPlatformWindow::isActive() const
 }
 
 /*!
-    Returns \c true if the window is a descendant of an embedded non-Qt window.
-    Example of an embedded non-Qt window is the parent window of an in-process QAxServer.
+    Returns \c true if the window is an ancestor of the given \a child.
 
-    If \a parentWindow is nonzero, only check if the window is embedded in the
-    specified \a parentWindow.
+    Platform overrides should iterate the native window hierarchy of the child,
+    to ensure that ancestary is reflected even with native windows in the window
+    hierarchy.
 */
-bool QPlatformWindow::isEmbedded(const QPlatformWindow *parentWindow) const
+bool QPlatformWindow::isAncestorOf(const QPlatformWindow *child) const
+{
+    for (const QPlatformWindow *parent = child->parent(); parent; parent = child->parent()) {
+        if (parent == this)
+            return true;
+    }
+
+    return false;
+}
+
+/*!
+    Returns \c true if the window is a child of a non-Qt window.
+
+    A embedded window has no parent platform window as reflected
+    though parent(), but will have a native parent window.
+*/
+bool QPlatformWindow::isEmbedded() const
 {
-    Q_UNUSED(parentWindow);
     return false;
 }
 

src/gui/kernel/qplatformwindow.h

@@ -102,7 +102,8 @@ public:
 
     virtual bool isExposed() const;
     virtual bool isActive() const;
-    virtual bool isEmbedded(const QPlatformWindow *parentWindow = 0) const;
+    virtual bool isAncestorOf(const QPlatformWindow *child) const;
+    virtual bool isEmbedded() const;
     virtual QPoint mapToGlobal(const QPoint &pos) const;
     virtual QPoint mapFromGlobal(const QPoint &pos) const;
 

src/gui/kernel/qwindow.cpp

@@ -1300,8 +1300,13 @@ bool QWindow::isAncestorOf(const QWindow *child, AncestorMode mode) const
     if (child->parent() == this || (mode == IncludeTransients && child->transientParent() == this))
         return true;
 
-    if (child->parent(mode) && isAncestorOf(child->parent(mode), mode))
-        return true;
+    if (QWindow *parent = child->parent(mode)) {
+        if (isAncestorOf(parent, mode))
+            return true;
+    } else if (handle() && child->handle()) {
+        if (handle()->isAncestorOf(child->handle()))
+            return true;
+    }
 
     return false;
 }

src/plugins/platforms/windows/qwindowswindow.cpp

@@ -1243,18 +1243,14 @@ bool QWindowsWindow::isActive() const
     return false;
 }
 
-bool QWindowsWindow::isEmbedded(const QPlatformWindow *parentWindow) const
+bool QWindowsWindow::isAncestorOf(const QPlatformWindow *child) const
 {
-    if (parentWindow) {
-        const QWindowsWindow *ww = static_cast<const QWindowsWindow *>(parentWindow);
-        const HWND hwnd = ww->handle();
-        if (!IsChild(hwnd, m_data.hwnd))
-            return false;
-    }
-
-    if (!m_data.embedded && parent())
-        return parent()->isEmbedded();
+    const QWindowsWindow *childWindow = static_cast<const QWindowsWindow *>(child);
+    return IsChild(m_data.hwnd, childWindow->handle());
+}
 
+bool QWindowsWindow::isEmbedded() const
+{
     return m_data.embedded;
 }
 

src/plugins/platforms/windows/qwindowswindow.h

@@ -222,7 +222,8 @@ public:
     bool isVisible() const;
     bool isExposed() const override { return testFlag(Exposed); }
     bool isActive() const override;
-    bool isEmbedded(const QPlatformWindow *parentWindow = 0) const override;
+    bool isAncestorOf(const QPlatformWindow *child) const override;
+    bool isEmbedded() const override;
     QPoint mapToGlobal(const QPoint &pos) const override;
     QPoint mapFromGlobal(const QPoint &pos) const override;
 

src/plugins/platforms/xcb/qxcbwindow.cpp

@@ -2154,12 +2154,9 @@ bool QXcbWindow::isExposed() const
     return m_mapped;
 }
 
-bool QXcbWindow::isEmbedded(const QPlatformWindow *parentWindow) const
+bool QXcbWindow::isEmbedded() const
 {
-    if (!m_embedded)
-        return false;
-
-    return parentWindow ? (parentWindow == parent()) : true;
+    return m_embedded;
 }
 
 QPoint QXcbWindow::mapToGlobal(const QPoint &pos) const

src/plugins/platforms/xcb/qxcbwindow.h

@@ -87,7 +87,7 @@ public:
     void setParent(const QPlatformWindow *window) override;
 
     bool isExposed() const override;
-    bool isEmbedded(const QPlatformWindow *parentWindow = 0) const override;
+    bool isEmbedded() const override;
     QPoint mapToGlobal(const QPoint &pos) const override;
     QPoint mapFromGlobal(const QPoint &pos) const override;
 

src/widgets/kernel/qapplication.cpp

@@ -2462,13 +2462,6 @@ bool QApplicationPrivate::isWindowBlocked(QWindow *window, QWindow **blockingWin
             return false;
         }
 
-        // Embedded windows are not visible in normal parent-child chain,
-        // so check the native parent chain, too.
-        const QPlatformWindow *platWin = window->handle();
-        const QPlatformWindow *modalPlatWin = modalWindow->handle();
-        if (platWin && modalPlatWin && platWin->isEmbedded(modalPlatWin))
-            return false;
-
         Qt::WindowModality windowModality = modalWindow->modality();
         QWidgetWindow *modalWidgetWindow = qobject_cast<QWidgetWindow *>(modalWindow);
         if (windowModality == Qt::NonModal) {