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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-15 05:54:39 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-15 05:54:39 +0000
commit267c6f2ac71f92999e969232431ba04678e7437e (patch)
tree358c9467650e1d0a1d7227a21dac2e3d08b622b2 /include/vcl/lazydelete.hxx
parentInitial commit. (diff)
downloadlibreoffice-267c6f2ac71f92999e969232431ba04678e7437e.tar.xz
libreoffice-267c6f2ac71f92999e969232431ba04678e7437e.zip
Adding upstream version 4:24.2.0.upstream/4%24.2.0
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'include/vcl/lazydelete.hxx')
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed
+ * with this work for additional information regarding copyright
+ * ownership. The ASF licenses this file to you under the Apache
+ * License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_VCL_LAZYDELETE_HXX
+#define INCLUDED_VCL_LAZYDELETE_HXX
+
+#include <vcl/dllapi.h>
+
+#include <com/sun/star/lang/XComponent.hpp>
+
+#include <optional>
+#include <utility>
+
+namespace vcl
+{
+ /*
+ You may not access vcl objects after DeInitVCL has been called this includes their destruction
+ therefore disallowing the existence of static vcl object like e.g. a static BitmapEx
+ To work around this use DeleteOnDeinit<BitmapEx> which will allow you to have a static object container,
+ that will have its contents destroyed on DeinitVCL. The single drawback is that you need to check on the
+ container object whether it still contains content before actually accessing it.
+
+ caveat: when constructing a vcl object, you certainly want to ensure that InitVCL has run already.
+ However this is not necessarily the case when using a class static member or a file level static variable.
+ In these cases make judicious use of the set() method of DeleteOnDeinit, but beware of the changing
+ ownership.
+
+ example use case: use a lazy initialized on call BitmapEx in a paint method. Of course a paint method
+ would not normally be called after DeInitVCL anyway, so the check might not be necessary in a
+ Window::Paint implementation, but always checking is a good idea.
+
+ SomeWindow::Paint()
+ {
+ static vcl::DeleteOnDeinit< BitmapEx > aBmp( ... );
+
+ if( aBmp.get() ) // check whether DeInitVCL has been called already
+ DrawBitmapEx( Point( 10, 10 ), *aBmp );
+ }
+ */
+
+ class VCL_DLLPUBLIC DeleteOnDeinitBase
+ {
+ public:
+ static void SAL_DLLPRIVATE ImplDeleteOnDeInit();
+ virtual ~DeleteOnDeinitBase();
+ protected:
+ static void addDeinitContainer( DeleteOnDeinitBase* i_pContainer );
+
+ virtual void doCleanup() = 0;
+ };
+
+ enum class DeleteOnDeinitFlag { Empty };
+
+ template < typename T >
+ class DeleteOnDeinit final : public DeleteOnDeinitBase
+ {
+ std::optional<T> m_pT;
+ virtual void doCleanup() override { m_pT.reset(); }
+ public:
+ template <class... Args >
+ DeleteOnDeinit(Args&&... args )
+ {
+ m_pT.emplace(args...);
+ addDeinitContainer( this );
+ }
+ DeleteOnDeinit(DeleteOnDeinitFlag)
+ {
+ addDeinitContainer( this );
+ }
+
+ // get contents
+ T* get() { return m_pT ? &*m_pT : nullptr; }
+
+ // set contents, returning old contents
+ // ownership is transferred !
+ template <class... Args >
+ std::optional<T> set(Args&&... args)
+ {
+ auto pOld = std::move(m_pT);
+ m_pT.emplace(args...);
+ return pOld;
+ }
+ };
+
+ /** Similar to DeleteOnDeinit, the DeleteUnoReferenceOnDeinit
+ template class makes sure that a static UNO object is disposed
+ and released at the right time.
+
+ Use like
+ static DeleteUnoReferenceOnDeinit<lang::XMultiServiceFactory>
+ xStaticFactory (\<create factory object>);
+ Reference<lang::XMultiServiceFactory> xFactory (xStaticFactory.get());
+ if (xFactory.is())
+ \<do something with xFactory>
+ */
+ template <typename I>
+ class DeleteUnoReferenceOnDeinit final : public vcl::DeleteOnDeinitBase
+ {
+ css::uno::Reference<I> m_xI;
+ virtual void doCleanup() override { set(nullptr); }
+ public:
+ DeleteUnoReferenceOnDeinit(css::uno::Reference<I> _xI ) : m_xI(std::move( _xI )) {
+ addDeinitContainer( this ); }
+
+ css::uno::Reference<I> get() { return m_xI; }
+
+ void set (const css::uno::Reference<I>& r_xNew )
+ {
+ css::uno::Reference< css::lang::XComponent> xComponent (m_xI, css::uno::UNO_QUERY);
+ m_xI = r_xNew;
+ if (xComponent.is()) try
+ {
+ xComponent->dispose();
+ }
+ catch( css::uno::Exception& )
+ {
+ }
+ }
+ };
+}
+
+#endif
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */