157 lines
3.5 KiB
C++
157 lines
3.5 KiB
C++
/**
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* @file _refcounted.h
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* @brief Atomic, thread-safe ref counting and destruction mixin class
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*
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* $LicenseInfo:firstyear=2012&license=viewerlgpl$
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* Second Life Viewer Source Code
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* Copyright (C) 2012, Linden Research, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License only.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
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* $/LicenseInfo$
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*/
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#ifndef LLCOREINT__REFCOUNTED_H_
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#define LLCOREINT__REFCOUNTED_H_
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#include "linden_common.h"
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#include "fix_macros.h"
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#include <boost/thread.hpp>
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#include <boost/intrusive_ptr.hpp>
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#include "llatomic.h"
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namespace LLCoreInt
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{
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class RefCounted
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{
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private:
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RefCounted(); // Not defined - may not be default constructed
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void operator=(const RefCounted &); // Not defined
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public:
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explicit RefCounted(bool const implicit)
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: mRefCount(implicit)
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{}
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// ref-count interface
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void addRef() const;
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void release() const;
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bool isLastRef() const;
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S32 getRefCount() const;
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void noRef() const;
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static const S32 NOT_REF_COUNTED = -1;
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protected:
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virtual ~RefCounted();
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virtual void destroySelf();
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private:
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mutable LLAtomicS32 mRefCount;
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}; // end class RefCounted
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inline void RefCounted::addRef() const
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{
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S32 count(++mRefCount);
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llassert_always(count >= 0);
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}
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inline void RefCounted::release() const
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{
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S32 count(mRefCount);
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llassert_always(count != NOT_REF_COUNTED);
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llassert_always(count > 0);
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count = --mRefCount;
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// clean ourselves up if that was the last reference
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if (0 == count)
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{
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const_cast<RefCounted *>(this)->destroySelf();
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}
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}
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inline bool RefCounted::isLastRef() const
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{
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const S32 count(mRefCount);
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llassert_always(count != NOT_REF_COUNTED);
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llassert_always(count >= 1);
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return (1 == count);
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}
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inline S32 RefCounted::getRefCount() const
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{
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const S32 result(mRefCount);
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return result;
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}
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inline void RefCounted::noRef() const
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{
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llassert_always(mRefCount <= 1);
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mRefCount = NOT_REF_COUNTED;
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}
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inline void RefCounted::destroySelf()
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{
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delete this;
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}
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/**
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* boost::intrusive_ptr may be used to manage RefCounted classes.
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* Unfortunately RefCounted and boost::intrusive_ptr use different conventions
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* for the initial refcount value. To avoid leaky (immortal) objects, you
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* should really construct boost::intrusive_ptr<RefCounted*>(rawptr, false).
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* IntrusivePtr<T> encapsulates that for you.
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*/
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template <typename T>
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struct IntrusivePtr: public boost::intrusive_ptr<T>
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{
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IntrusivePtr():
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boost::intrusive_ptr<T>()
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{}
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IntrusivePtr(T* p):
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boost::intrusive_ptr<T>(p, false)
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{}
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};
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inline void intrusive_ptr_add_ref(RefCounted* p)
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{
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p->addRef();
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}
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inline void intrusive_ptr_release(RefCounted* p)
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{
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p->release();
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}
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} // end namespace LLCoreInt
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#endif // LLCOREINT__REFCOUNTED_H_
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