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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_TOOLS_REF_HXX
#define INCLUDED_TOOLS_REF_HXX
#include <sal/config.h>
#include <cassert>
#include <tools/toolsdllapi.h>
#include <utility>
/**
This implements similar functionality to boost::intrusive_ptr
*/
namespace tools {
/** T must be a class that extends SvRefBase */
template<typename T> class SAL_DLLPUBLIC_RTTI SvRef final {
public:
constexpr SvRef(): pObj(nullptr) {}
SvRef(SvRef&& rObj) noexcept
{
pObj = rObj.pObj;
rObj.pObj = nullptr;
}
SvRef(SvRef const & rObj): pObj(rObj.pObj)
{
if (pObj != nullptr) pObj->AddNextRef();
}
SvRef(T * pObjP): pObj(pObjP)
{
if (pObj != nullptr) pObj->AddFirstRef();
}
~SvRef()
{
if (pObj != nullptr) pObj->ReleaseRef();
}
void clear()
{
if (pObj != nullptr) {
T * pRefObj = pObj;
pObj = nullptr;
pRefObj->ReleaseRef();
}
}
SvRef & operator =(SvRef const & rObj)
{
if (rObj.pObj != nullptr) {
rObj.pObj->AddNextRef();
}
T * pRefObj = pObj;
pObj = rObj.pObj;
if (pRefObj != nullptr) {
pRefObj->ReleaseRef();
}
return *this;
}
SvRef & operator =(SvRef && rObj)
{
if (pObj != nullptr) {
pObj->ReleaseRef();
}
pObj = rObj.pObj;
rObj.pObj = nullptr;
return *this;
}
bool is() const { return pObj != nullptr; }
explicit operator bool() const { return is(); }
T * get() const { return pObj; }
T * operator ->() const { assert(pObj != nullptr); return pObj; }
T & operator *() const { assert(pObj != nullptr); return *pObj; }
bool operator ==(const SvRef<T> &rhs) const { return pObj == rhs.pObj; }
bool operator !=(const SvRef<T> &rhs) const { return !(*this == rhs); }
private:
T * pObj;
};
/**
* This implements similar functionality to std::make_shared.
*/
template<typename T, typename... Args>
SvRef<T> make_ref(Args&& ... args)
{
return SvRef<T>(new T(std::forward<Args>(args)...));
}
}
/** Classes that want to be referenced-counted via SvRef<T>, should extend this base class */
class TOOLS_DLLPUBLIC SvRefBase
{
// work around a clang 3.5 optimization bug: if the bNoDelete is *first*
// it mis-compiles "if (--nRefCount == 0)" and never deletes any object
unsigned int nRefCount : 31;
// the only reason this is not bool is because MSVC cannot handle mixed type bitfields
unsigned int bNoDelete : 1;
protected:
virtual ~SvRefBase() COVERITY_NOEXCEPT_FALSE;
public:
SvRefBase() : nRefCount(0), bNoDelete(1) {}
SvRefBase(const SvRefBase &) : nRefCount(0), bNoDelete(1) {}
SvRefBase & operator=(const SvRefBase &) { return *this; }
void AddNextRef()
{
assert( nRefCount < (1 << 30) && "Do not add refs to dead objects" );
++nRefCount;
}
void AddFirstRef()
{
assert( nRefCount < (1 << 30) && "Do not add refs to dead objects" );
if( bNoDelete )
bNoDelete = 0;
++nRefCount;
}
void ReleaseRef()
{
assert( nRefCount >= 1);
if( --nRefCount == 0 && !bNoDelete)
{
// I'm not sure about the original purpose of this line, but right now
// it serves the purpose that anything that attempts to do an AddRef()
// after an object is deleted will trip an assert.
nRefCount = 1 << 30;
delete this;
}
}
unsigned int GetRefCount() const
{ return nRefCount; }
};
template<typename T>
class SvCompatWeakBase;
/** SvCompatWeakHdl acts as an intermediary between SvCompatWeakRef<T> and T.
*/
template<typename T>
class SvCompatWeakHdl final : public SvRefBase
{
friend class SvCompatWeakBase<T>;
T* _pObj;
SvCompatWeakHdl( T* pObj ) : _pObj( pObj ) {}
public:
void ResetWeakBase( ) { _pObj = nullptr; }
T* GetObj() { return _pObj; }
};
/** We only have one place that extends this, in include/sfx2/frame.hxx, class SfxFrame.
Its function is to notify the SvCompatWeakHdl when an SfxFrame object is deleted.
*/
template<typename T>
class SvCompatWeakBase
{
tools::SvRef< SvCompatWeakHdl<T> > _xHdl;
public:
/** Does not use initializer due to compiler warnings,
because the lifetime of the _xHdl object can exceed the lifetime of this class.
*/
SvCompatWeakBase( T* pObj ) { _xHdl = new SvCompatWeakHdl<T>( pObj ); }
~SvCompatWeakBase() { _xHdl->ResetWeakBase(); }
SvCompatWeakHdl<T>* GetHdl() { return _xHdl.get(); }
};
/** We only have one weak reference in LO, in include/sfx2/frame.hxx, class SfxFrameWeak.
*/
template<typename T>
class SAL_WARN_UNUSED SvCompatWeakRef
{
tools::SvRef< SvCompatWeakHdl<T> > _xHdl;
public:
SvCompatWeakRef( ) {}
SvCompatWeakRef( T* pObj )
{ if( pObj ) _xHdl = pObj->GetHdl(); }
#if defined(__COVERITY__)
~SvCompatWeakRef() COVERITY_NOEXCEPT_FALSE {}
#endif
SvCompatWeakRef& operator = ( T * pObj )
{ _xHdl = pObj ? pObj->GetHdl() : nullptr; return *this; }
bool is() const
{ return _xHdl.is() && _xHdl->GetObj(); }
explicit operator bool() const { return is(); }
T* operator -> () const
{ return _xHdl.is() ? _xHdl->GetObj() : nullptr; }
operator T* () const
{ return _xHdl.is() ? _xHdl->GetObj() : nullptr; }
};
#endif
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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