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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 .
*/
/*
* This file is part of LibreOffice published API.
*/
#pragma once
#include <sal/config.h>
#include <com/sun/star/uno/Reference.hxx>
#include <com/sun/star/uno/XInterface.hpp>
#include <cppuhelper/weakref.hxx>
#include <cppuhelper/weak.hxx>
#include <rtl/ref.hxx>
#include <type_traits>
namespace unotools
{
/** The WeakReference<> holds a weak reference to an object.
That object must implement the css::uno::XWeak interface.
The WeakReference itself is *not* thread safe, just as
Reference itself isn't, but the implementation of the listeners etc.
behind it *is* thread-safe, so multiple threads can have their own
WeakReferences to the same XWeak object.
@tparam interface_type Must be a C++ implementation class type, not a UNO interface type. (See
the C++20 requires-clause on the get member. That clause is not put on the class as a whole to
avoid overly tight requirements on when interface_type needs to be complete.)
*/
template <class interface_type>
class SAL_WARN_UNUSED WeakReference : public com::sun::star::uno::WeakReferenceHelper
{
public:
/** Default ctor. Creates an empty weak reference.
*/
WeakReference()
: WeakReferenceHelper()
{
}
/** Copy ctor. Initialize this reference with a hard reference.
@param rRef another hard ref
*/
WeakReference(const rtl::Reference<interface_type>& rRef)
: WeakReferenceHelper(css::uno::Reference<css::uno::XWeak>(rRef))
{
}
/** Copy ctor. Initialize this reference with a hard reference.
@param rRef another hard ref
*/
WeakReference(interface_type& rRef)
: WeakReferenceHelper(&rRef)
{
}
/** Copy ctor. Initialize this reference with a hard reference.
@param rRef another hard ref
*/
WeakReference(interface_type* pRef)
: WeakReferenceHelper(
css::uno::Reference<css::uno::XWeak>(static_cast<cppu::OWeakObject*>(pRef)))
{
}
/** Releases this reference and takes over hard reference xInt.
If the implementation behind xInt does not support XWeak
or XInt is null, then this reference is null.
@param xInt another hard reference
*/
WeakReference& operator=(const rtl::Reference<interface_type>& xInt)
{
WeakReferenceHelper::operator=(xInt);
return *this;
}
WeakReference& operator=(rtl::Reference<interface_type>&& xInt)
{
WeakReferenceHelper::operator=(std::move(xInt));
return *this;
}
WeakReference& operator=(interface_type* pInt)
{
WeakReferenceHelper::operator=(
css::uno::Reference<css::uno::XWeak>(static_cast<::cppu::OWeakObject*>(pInt)));
return *this;
}
/** Gets a hard reference to the object.
@return hard reference or null, if the weakly referenced interface has gone
*/
rtl::Reference<interface_type> SAL_CALL get() const
#if __cplusplus >= 202002L
requires(!cppu::detail::isUnoInterfaceType<interface_type>)
#endif
{
css::uno::Reference<css::uno::XInterface> xInterface = WeakReferenceHelper::get();
// If XInterface is an ambiguous base of interface_type, we have to use dynamic_cast,
// otherwise we can use the faster static_cast.
if constexpr (std::is_convertible_v<interface_type*, css::uno::XInterface*>)
return static_cast<interface_type*>(xInterface.get());
else
return dynamic_cast<interface_type*>(xInterface.get());
}
/** Gets a hard reference to the object.
@return hard reference or null, if the weakly referenced interface has gone
*/
operator ::rtl::Reference<interface_type>() const { return get(); }
};
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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