ClickHouse/base/poco/Foundation/include/Poco/RefCountedObject.h
2024-02-09 21:39:35 +03:00

101 lines
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C++

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