Add new logging category qt.quick.window.transient

to monitor the increasing number of places from which the transient
parent relationship can be detected; and a debug operator for
QQuickWindow so that these log messages are more useful.

[ChangeLog][QtQuick][QQuickWindow] added logging category
qt.quick.window.transient to check detection of transient windows
declared inside other Items and Windows

Change-Id: Ic899af648765fcdc59b8da7dd1f1bed20db300f2
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

6 files changed, 58 insertions, 3 deletions

diff --git a/src/quick/items/qquickitem.cpp b/src/quick/items/qquickitem.cpp
index bd37323ef9..4a44b1531a 100644
--- a/src/quick/items/qquickitem.cpp
+++ b/src/quick/items/qquickitem.cpp
@@ -86,6 +86,7 @@ QT_BEGIN_NAMESPACE
 
 Q_DECLARE_LOGGING_CATEGORY(DBG_MOUSE_TARGET)
 Q_DECLARE_LOGGING_CATEGORY(DBG_HOVER_TRACE)
+Q_DECLARE_LOGGING_CATEGORY(lcTransient)
 
 void debugFocusTree(QQuickItem *item, QQuickItem *scope = 0, int depth = 1)
 {
@@ -3248,11 +3249,13 @@ void QQuickItemPrivate::data_append(QQmlListProperty<QObject> *prop, QObject *o)
             }
 
             if (thisWindow) {
-                if (itemWindow)
+                if (itemWindow) {
+                    qCDebug(lcTransient) << thisWindow << "is transient for" << itemWindow;
                     thisWindow->setTransientParent(itemWindow);
-                else
+                } else {
                     QObject::connect(item, SIGNAL(windowChanged(QQuickWindow*)),
                                      thisWindow, SLOT(setTransientParent_helper(QQuickWindow*)));
+                }
             }
             o->setParent(that);
         }
diff --git a/src/quick/items/qquickitemsmodule.cpp b/src/quick/items/qquickitemsmodule.cpp
index 489b1cbd03..b411e676c2 100644
--- a/src/quick/items/qquickitemsmodule.cpp
+++ b/src/quick/items/qquickitemsmodule.cpp
@@ -111,6 +111,10 @@
 #include <private/qqmlmetatype_p.h>
 #include <QtQuick/private/qquickaccessibleattached_p.h>
 
+QT_BEGIN_NAMESPACE
+Q_DECLARE_LOGGING_CATEGORY(lcTransient)
+QT_END_NAMESPACE
+
 static QQmlPrivate::AutoParentResult qquickitem_autoParent(QObject *obj, QObject *parent)
 {
     // When setting a parent (especially during dynamic object creation) in QML,
@@ -125,6 +129,7 @@ static QQmlPrivate::AutoParentResult qquickitem_autoParent(QObject *obj, QObject
             QQuickWindow *win = qmlobject_cast<QQuickWindow *>(obj);
             if (win) {
                 // A Window inside an Item should be transient for that item's window
+                qCDebug(lcTransient) << win << "is transient for" << parentItem->window();
                 win->setTransientParent(parentItem->window());
                 return QQmlPrivate::Parented;
             }
@@ -134,6 +139,7 @@ static QQmlPrivate::AutoParentResult qquickitem_autoParent(QObject *obj, QObject
         QQuickWindow *win = qmlobject_cast<QQuickWindow *>(obj);
         if (win) {
             // A Window inside a Window should be transient for it
+            qCDebug(lcTransient) << win << "is transient for" << parentWindow;
             win->setTransientParent(parentWindow);
             return QQmlPrivate::Parented;
         } else {
diff --git a/src/quick/items/qquickloader.cpp b/src/quick/items/qquickloader.cpp
index 27afe5a5db..414103c63e 100644
--- a/src/quick/items/qquickloader.cpp
+++ b/src/quick/items/qquickloader.cpp
@@ -48,6 +48,8 @@
 
 QT_BEGIN_NAMESPACE
 
+Q_DECLARE_LOGGING_CATEGORY(lcTransient)
+
 static const QQuickItemPrivate::ChangeTypes watchedChanges
     = QQuickItemPrivate::Geometry | QQuickItemPrivate::ImplicitWidth | QQuickItemPrivate::ImplicitHeight;
 
diff --git a/src/quick/items/qquickwindow.cpp b/src/quick/items/qquickwindow.cpp
index a483020439..15ade6767c 100644
--- a/src/quick/items/qquickwindow.cpp
+++ b/src/quick/items/qquickwindow.cpp
@@ -77,6 +77,9 @@
 # include <private/qopenglvertexarrayobject_p.h>
 # include <private/qsgdefaultrendercontext_p.h>
 #endif
+#ifndef QT_NO_DEBUG_STREAM
+#include <private/qdebug_p.h>
+#endif
 
 QT_BEGIN_NAMESPACE
 
@@ -87,6 +90,7 @@ Q_LOGGING_CATEGORY(DBG_MOUSE_TARGET, "qt.quick.mouse.target")
 Q_LOGGING_CATEGORY(DBG_HOVER_TRACE, "qt.quick.hover.trace")
 Q_LOGGING_CATEGORY(DBG_FOCUS, "qt.quick.focus")
 Q_LOGGING_CATEGORY(DBG_DIRTY, "qt.quick.dirty")
+Q_LOGGING_CATEGORY(lcTransient, "qt.quick.window.transient")
 
 extern Q_GUI_EXPORT QImage qt_gl_read_framebuffer(const QSize &size, bool alpha_format, bool include_alpha);
 
@@ -2738,8 +2742,10 @@ void QQuickWindowPrivate::data_append(QQmlListProperty<QObject> *property, QObje
     if (!o)
         return;
     QQuickWindow *that = static_cast<QQuickWindow *>(property->object);
-    if (QQuickWindow *window = qmlobject_cast<QQuickWindow *>(o))
+    if (QQuickWindow *window = qmlobject_cast<QQuickWindow *>(o)) {
+        qCDebug(lcTransient) << window << "is transient for" << that;
         window->setTransientParent(that);
+    }
     QQmlListProperty<QObject> itemProperty = QQuickItemPrivate::get(that->contentItem())->data();
     itemProperty.append(&itemProperty, o);
 }
@@ -3266,6 +3272,7 @@ void QQuickWindow::cleanupSceneGraph()
 
 void QQuickWindow::setTransientParent_helper(QQuickWindow *window)
 {
+    qCDebug(lcTransient) << this << "is transient for" << window;
     setTransientParent(window);
     disconnect(sender(), SIGNAL(windowChanged(QQuickWindow*)),
                this, SLOT(setTransientParent_helper(QQuickWindow*)));
@@ -4658,6 +4665,37 @@ QSGNinePatchNode *QQuickWindow::createNinePatchNode() const
     return isSceneGraphInitialized() ? d->context->sceneGraphContext()->createNinePatchNode() : nullptr;
 }
 
+#ifndef QT_NO_DEBUG_STREAM
+QDebug operator<<(QDebug debug, const QQuickWindow *win)
+{
+    QDebugStateSaver saver(debug);
+    debug.nospace();
+    if (!win) {
+        debug << "QQuickWindow(0)";
+        return debug;
+    }
+
+    debug << win->metaObject()->className() << '(' << static_cast<const void *>(win);
+    if (win->isActive())
+        debug << " active";
+    if (win->isExposed())
+        debug << " exposed";
+    debug << ", visibility=" << win->visibility() << ", flags=" << win->flags();
+    if (!win->title().isEmpty())
+        debug << ", title=" << win->title();
+    if (!win->objectName().isEmpty())
+        debug << ", name=" << win->objectName();
+    if (win->parent())
+        debug << ", parent=" << static_cast<const void *>(win->parent());
+    if (win->transientParent())
+        debug << ", transientParent=" << static_cast<const void *>(win->transientParent());
+    debug << ", geometry=";
+    QtDebugUtils::formatQRect(debug, win->geometry());
+    debug << ')';
+    return debug;
+}
+#endif
+
 #include "moc_qquickwindow.cpp"
 
 QT_END_NAMESPACE
diff --git a/src/quick/items/qquickwindow.h b/src/quick/items/qquickwindow.h
index cd27d48bc9..cc88300988 100644
--- a/src/quick/items/qquickwindow.h
+++ b/src/quick/items/qquickwindow.h
@@ -230,6 +230,10 @@ private:
     Q_DISABLE_COPY(QQuickWindow)
 };
 
+#ifndef QT_NO_DEBUG_STREAM
+QDebug Q_QUICK_EXPORT operator<<(QDebug debug, const QQuickWindow *item);
+#endif
+
 QT_END_NAMESPACE
 
 Q_DECLARE_METATYPE(QQuickWindow *)
diff --git a/src/quick/items/qquickwindowmodule.cpp b/src/quick/items/qquickwindowmodule.cpp
index c1cc02568c..1981ed2f70 100644
--- a/src/quick/items/qquickwindowmodule.cpp
+++ b/src/quick/items/qquickwindowmodule.cpp
@@ -52,6 +52,8 @@
 
 QT_BEGIN_NAMESPACE
 
+Q_DECLARE_LOGGING_CATEGORY(lcTransient)
+
 class QQuickWindowQmlImplPrivate : public QQuickWindowPrivate
 {
 public: