Implement window modality in QtGui

QWindow already has windowModality() and setWindowModality() as part of
its API from commit 516f4e283ba4626d7239630397ef867ab0366071. Platform
plugins can use this already to setup modality hints on windows that
they create, but it's not enough to implement modality fully.

QGuiApplication gets a modalWindow() static method, which is similar to
QApplication::activeModalWidget() in that it returns the last modal
window to be shown.

The modal window "stack" moves from QApplicationPrivate to
QGuiApplicationPrivate. The enterModal*() and leaveModal*() functions in
QApplicationPrivate are removed and replaced by
QGuiApplicationPrivate::showModalWindow() and hideModalWindow(), which
are called by QWindow::setVisible() just before calling
QPlatformWindow::setVisible().

The virtual QGuiApplicationPrivate::isWindowBlocked() will tell us if a
window is blocked by a modal window (and tell which modal window for any
interested callers). The default implementation works on the QWindow
level. QApplicationPrivate reimplements isWindowBlocked() and adds popup
and WA_GroupLeader support.

QGuiApplication uses the state set from isWindowBlocked() to block
user-input events: mouse press, mouse move, mouse release, wheel, key
presses, key releases, enter/leave events, close events, and touch
begin, update, and end events.

Note also that the modality helper functions in QtWidgets and
QApplicationPrivate are left in place and working as they always have.
The behavior of QWidget in the presence of modal windows/dialogs should
not change.

Change-Id: I2c89e6026d40160387787a6e009ae1fdc12dfd69
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@nokia.com>

1 files changed, 76 insertions, 95 deletions

diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp
index a8b1fa6d1c..c560dba1b7 100644
--- a/src/widgets/kernel/qapplication.cpp
+++ b/src/widgets/kernel/qapplication.cpp
@@ -440,8 +440,6 @@ FontHash *qt_app_fonts_hash()
 QWidgetList *QApplicationPrivate::popupWidgets = 0;        // has keyboard input focus
 
 QDesktopWidget *qt_desktopWidget = 0;                // root window widgets
-QWidgetList * qt_modal_stack = 0;                // stack of modal widgets
-bool app_do_modal = false;
 
 /*!
     \internal
@@ -755,7 +753,8 @@ QWidget *QApplication::activePopupWidget()
 
 QWidget *QApplication::activeModalWidget()
 {
-    return qt_modal_stack && !qt_modal_stack->isEmpty() ? qt_modal_stack->first() : 0;
+    QWidgetWindow *widgetWindow = qobject_cast<QWidgetWindow *>(modalWindow());
+    return widgetWindow ? widgetWindow->widget() : 0;
 }
 
 /*!
@@ -2315,31 +2314,52 @@ Q_WIDGETS_EXPORT bool qt_tryModalHelper(QWidget *widget, QWidget **rettop)
 bool QApplicationPrivate::isBlockedByModal(QWidget *widget)
 {
     widget = widget->window();
-    if (!modalState())
+    return self->isWindowBlocked(widget->windowHandle());
+}
+
+bool QApplicationPrivate::isWindowBlocked(QWindow *window, QWindow **blockingWindow) const
+{
+    QWindow *unused = 0;
+    if (!blockingWindow)
+        blockingWindow = &unused;
+
+    if (modalWindowList.isEmpty()) {
+        *blockingWindow = 0;
         return false;
-    if (QApplication::activePopupWidget() == widget)
+    }
+    QWidget *popupWidget = QApplication::activePopupWidget();
+    QWindow *popupWindow = popupWidget ? popupWidget->windowHandle() : 0;
+    if (popupWindow == window) {
+        *blockingWindow = 0;
         return false;
+    }
 
-    for (int i = 0; i < qt_modal_stack->size(); ++i) {
-        QWidget *modalWidget = qt_modal_stack->at(i);
+    for (int i = 0; i < modalWindowList.count(); ++i) {
+        QWindow *modalWindow = modalWindowList.at(i);
 
         {
-            // check if the active modal widget is our widget or a parent of our widget
-            QWidget *w = widget;
+            // check if the modal window is our window or a (transient) parent of our window
+            QWindow *w = window;
             while (w) {
-                if (w == modalWidget)
+                if (w == modalWindow) {
+                    *blockingWindow = 0;
                     return false;
-                w = w->parentWidget();
+                }
+                QWindow *p = w->parent();
+                if (!p)
+                    p = w->transientParent();
+                w = p;
             }
         }
 
-        Qt::WindowModality windowModality = modalWidget->windowModality();
+        Qt::WindowModality windowModality = modalWindow->windowModality();
+        QWidgetWindow *modalWidgetWindow = qobject_cast<QWidgetWindow *>(modalWindow);
         if (windowModality == Qt::NonModal) {
             // determine the modality type if it hasn't been set on the
-            // modalWidget, this normally happens when waiting for a
-            // native dialog. use WindowModal if we are the child of a
-            // group leader; otherwise use ApplicationModal.
-            QWidget *m = modalWidget;
+            // modalWindow's widget, this normally happens when waiting for a
+            // native dialog. use WindowModal if we are the child of a group
+            // leader; otherwise use ApplicationModal.
+            QWidget *m = modalWidgetWindow ? modalWidgetWindow->widget() : 0;
             while (m && !m->testAttribute(Qt::WA_GroupLeader)) {
                 m = m->parentWidget();
                 if (m)
@@ -2352,98 +2372,59 @@ bool QApplicationPrivate::isBlockedByModal(QWidget *widget)
 
         switch (windowModality) {
         case Qt::ApplicationModal:
-            {
-                QWidget *groupLeaderForWidget = widget;
-                while (groupLeaderForWidget && !groupLeaderForWidget->testAttribute(Qt::WA_GroupLeader))
-                    groupLeaderForWidget = groupLeaderForWidget->parentWidget();
-
-                if (groupLeaderForWidget) {
-                    // if \a widget has WA_GroupLeader, it can only be blocked by ApplicationModal children
-                    QWidget *m = modalWidget;
-                    while (m && m != groupLeaderForWidget && !m->testAttribute(Qt::WA_GroupLeader))
-                        m = m->parentWidget();
-                    if (m == groupLeaderForWidget)
-                        return true;
-                } else if (modalWidget != widget) {
+        {
+            QWidgetWindow *widgetWindow = qobject_cast<QWidgetWindow *>(window);
+            QWidget *groupLeaderForWidget = widgetWindow ? widgetWindow->widget() : 0;
+            while (groupLeaderForWidget && !groupLeaderForWidget->testAttribute(Qt::WA_GroupLeader))
+                groupLeaderForWidget = groupLeaderForWidget->parentWidget();
+
+            if (groupLeaderForWidget) {
+                // if \a widget has WA_GroupLeader, it can only be blocked by ApplicationModal children
+                QWidget *m = modalWidgetWindow ? modalWidgetWindow->widget() : 0;
+                while (m && m != groupLeaderForWidget && !m->testAttribute(Qt::WA_GroupLeader))
+                    m = m->parentWidget();
+                if (m == groupLeaderForWidget) {
+                    *blockingWindow = m->windowHandle();
                     return true;
                 }
-                break;
+            } else if (modalWindow != window) {
+                *blockingWindow = modalWindow;
+                return true;
             }
+            break;
+        }
         case Qt::WindowModal:
-            {
-                QWidget *w = widget;
+        {
+            QWindow *w = window;
+            do {
+                QWindow *m = modalWindow;
                 do {
-                    QWidget *m = modalWidget;
-                    do {
-                        if (m == w)
-                            return true;
-                        m = m->parentWidget();
-                        if (m)
-                            m = m->window();
-                    } while (m);
-                    w = w->parentWidget();
-                    if (w)
-                        w = w->window();
-                } while (w);
-                break;
-            }
+                    if (m == w) {
+                        *blockingWindow = m;
+                        return true;
+                    }
+                    QWindow *p = m->parent();
+                    if (!p)
+                        p = m->transientParent();
+                    m = p;
+                } while (m);
+                QWindow *p = w->parent();
+                if (!p)
+                    p = w->transientParent();
+                w = p;
+            } while (w);
+            break;
+        }
         default:
-            Q_ASSERT_X(false, "QApplication", "internal error, a modal widget cannot be modeless");
+            Q_ASSERT_X(false, "QApplication", "internal error, a modal window cannot be modeless");
             break;
         }
     }
+    *blockingWindow = 0;
     return false;
 }
 
 /*!\internal
- */
-void QApplicationPrivate::enterModal(QWidget *widget)
-{
-    QSet<QWidget*> blocked;
-    QList<QWidget*> windows = QApplication::topLevelWidgets();
-    for (int i = 0; i < windows.count(); ++i) {
-        QWidget *window = windows.at(i);
-        if (window->windowType() != Qt::Tool && isBlockedByModal(window))
-            blocked.insert(window);
-    }
-
-    enterModal_sys(widget);
-
-    windows = QApplication::topLevelWidgets();
-    QEvent e(QEvent::WindowBlocked);
-    for (int i = 0; i < windows.count(); ++i) {
-        QWidget *window = windows.at(i);
-        if (!blocked.contains(window) && window->windowType() != Qt::Tool && isBlockedByModal(window))
-            QApplication::sendEvent(window, &e);
-    }
-}
-
-/*!\internal
- */
-void QApplicationPrivate::leaveModal(QWidget *widget)
-{
-    QSet<QWidget*> blocked;
-    QList<QWidget*> windows = QApplication::topLevelWidgets();
-    for (int i = 0; i < windows.count(); ++i) {
-        QWidget *window = windows.at(i);
-        if (window->windowType() != Qt::Tool && isBlockedByModal(window))
-            blocked.insert(window);
-    }
-
-    leaveModal_sys(widget);
-
-    windows = QApplication::topLevelWidgets();
-    QEvent e(QEvent::WindowUnblocked);
-    for (int i = 0; i < windows.count(); ++i) {
-        QWidget *window = windows.at(i);
-        if(blocked.contains(window) && window->windowType() != Qt::Tool && !isBlockedByModal(window))
-            QApplication::sendEvent(window, &e);
-    }
-}
-
-
-
-/*!\internal
 
   Called from qapplication_\e{platform}.cpp, returns true
   if the widget should accept the event.