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100 lines
2.0 KiB
C++
100 lines
2.0 KiB
C++
//
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// RefCountedObject.h
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//
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// Library: Foundation
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// Package: Core
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// Module: RefCountedObject
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//
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// Definition of the RefCountedObject class.
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//
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// Copyright (c) 2004-2009, Applied Informatics Software Engineering GmbH.
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// and Contributors.
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//
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// SPDX-License-Identifier: BSL-1.0
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//
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#ifndef Foundation_RefCountedObject_INCLUDED
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#define Foundation_RefCountedObject_INCLUDED
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#include "Poco/AtomicCounter.h"
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#include "Poco/Foundation.h"
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namespace Poco
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{
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class Foundation_API RefCountedObject
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/// A base class for objects that employ
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/// reference counting based garbage collection.
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///
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/// Reference-counted objects inhibit construction
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/// by copying and assignment.
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{
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public:
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RefCountedObject();
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/// Creates the RefCountedObject.
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/// The initial reference count is one.
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size_t duplicate() const;
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/// Increments the object's reference count, returns reference count before call.
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size_t release() const throw();
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/// Decrements the object's reference count
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/// and deletes the object if the count
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/// reaches zero, returns reference count before call.
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size_t referenceCount() const;
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/// Returns the reference count.
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protected:
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virtual ~RefCountedObject();
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/// Destroys the RefCountedObject.
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mutable std::atomic<size_t> _counter;
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private:
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RefCountedObject(const RefCountedObject &);
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RefCountedObject & operator=(const RefCountedObject &);
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};
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//
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// inlines
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//
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inline size_t RefCountedObject::referenceCount() const
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{
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return _counter.load(std::memory_order_acquire);
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}
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inline size_t RefCountedObject::duplicate() const
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{
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return _counter.fetch_add(1, std::memory_order_acq_rel);
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}
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inline size_t RefCountedObject::release() const throw()
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{
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size_t reference_count_before = _counter.fetch_sub(1, std::memory_order_acq_rel);
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try
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{
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if (reference_count_before == 1)
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delete this;
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}
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catch (...)
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{
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poco_unexpected();
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}
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return reference_count_before;
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}
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} // namespace Poco
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#endif // Foundation_RefCountedObject_INCLUDED
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