Add the event loop quitlock feature to QtCore.

A feature of a ref-counted quit (managed by a quit-lock class)
is added to both QEventLoop and QCoreApplication.

This allows, for example, an event loop to quit() when there is
no more work for it to do.

quitOnLastWindowClosed is implemented in terms of the refcount in
QCoreApplication so that jobs can be completed before the
application quits.

Change-Id: I14c8f4e7ee12bbf81a6e5849290d4c8ff37fa110
Reviewed-by: David Faure <faure@kde.org>
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index e85d8379fa..4436884359 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -165,6 +165,14 @@ void QWindow::setVisible(bool visible)
         return;
     d->visible = visible;
     emit visibleChanged(visible);
+    if (QCoreApplication::instance() && !transientParent()) {
+        QCoreApplicationPrivate *applicationPrivate = static_cast<QCoreApplicationPrivate*>(QObjectPrivate::get(QCoreApplication::instance()));
+        if (visible) {
+            applicationPrivate->ref();
+        } else {
+            applicationPrivate->deref();
+        }
+    }
 
     if (!d->platformWindow)
         create();
@@ -499,7 +507,19 @@ void QWindow::setWindowState(Qt::WindowState state)
 void QWindow::setTransientParent(QWindow *parent)
 {
     Q_D(QWindow);
+
+    QWindow *previousParent = d->transientParent;
+
     d->transientParent = parent;
+
+    if (QCoreApplication::instance() && d->visible) {
+        QCoreApplicationPrivate *applicationPrivate = static_cast<QCoreApplicationPrivate*>(QObjectPrivate::get(QCoreApplication::instance()));
+        if (parent && !previousParent) {
+            applicationPrivate->deref();
+        } else if (!parent && previousParent) {
+            applicationPrivate->ref();
+        }
+    }
 }
 
 QWindow *QWindow::transientParent() const