From 6db0153cd7e35e4a919a76ae2aadbf2d2510bfb7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B8rn=20Erik=20Nilsen?= Date: Mon, 2 May 2011 12:39:45 +0200 Subject: Fixes crash in QWidget::effectiveWinId. Widgets are left in a transitional (and incosistent) state while being re-parented, which caused QWidget::effectiveWinId() to crash in certain circumstances. See patch for more details. Auto test included. Reviewed-by: ogoffart --- src/gui/kernel/qwidget.cpp | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'src/gui/kernel/qwidget.cpp') diff --git a/src/gui/kernel/qwidget.cpp b/src/gui/kernel/qwidget.cpp index ac35d425d9..fcb098f249 100644 --- a/src/gui/kernel/qwidget.cpp +++ b/src/gui/kernel/qwidget.cpp @@ -292,6 +292,7 @@ QWidgetPrivate::QWidgetPrivate(int version) #ifndef QT_NO_IM , inheritsInputMethodHints(0) #endif + , inSetParent(0) #if defined(Q_WS_X11) , picture(0) #elif defined(Q_WS_WIN) @@ -2563,6 +2564,22 @@ WId QWidget::effectiveWinId() const if (id || !testAttribute(Qt::WA_WState_Created)) return id; QWidget *realParent = nativeParentWidget(); + if (!realParent && d_func()->inSetParent) { + // In transitional state. This is really just a workaround. The real problem + // is that QWidgetPrivate::setParent_sys (platform specific code) first sets + // the window id to 0 (setWinId(0)) before it sets the Qt::WA_WState_Created + // attribute to false. The correct way is to do it the other way around, and + // in that case the Qt::WA_WState_Created logic above will kick in and + // return 0 whenever the widget is in a transitional state. However, changing + // the original logic for all platforms is far more intrusive and might + // break existing applications. + // Note: The widget can only be in a transitional state when changing its + // parent -- everything else is an internal error -- hence explicitly checking + // against 'inSetParent' rather than doing an unconditional return whenever + // 'realParent' is 0 (which may cause strange artifacts and headache later). + return 0; + } + // This widget *must* have a native parent widget. Q_ASSERT(realParent); Q_ASSERT(realParent->internalWinId()); return realParent->internalWinId(); @@ -10041,6 +10058,7 @@ void QWidget::setParent(QWidget *parent) void QWidget::setParent(QWidget *parent, Qt::WindowFlags f) { Q_D(QWidget); + d->inSetParent = true; bool resized = testAttribute(Qt::WA_Resized); bool wasCreated = testAttribute(Qt::WA_WState_Created); QWidget *oldtlw = window(); @@ -10195,6 +10213,8 @@ void QWidget::setParent(QWidget *parent, Qt::WindowFlags f) ancestorProxy->d_func()->embedSubWindow(this); } #endif + + d->inSetParent = false; } /*! -- cgit v1.2.3