/* -*- 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
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 css::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;
}
@return hard reference or null, if the weakly referenced interface has gone
*/
rtl::Reference<interface_type> SAL_CALL get() const #if !(defined __clang__ && __clang_major__ <= 15)
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*>) returnstatic_cast<interface_type*>(xInterface.get()); else returndynamic_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(); }
};
}
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