poco/Foundation/include/Poco/AutoPtr.h

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2012-04-29 20:52:25 +02:00
//
// AutoPtr.h
//
// Library: Foundation
// Package: Core
// Module: AutoPtr
//
// Definition of the AutoPtr template class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
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//
#ifndef Foundation_AutoPtr_INCLUDED
#define Foundation_AutoPtr_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/Exception.h"
#include <algorithm>
namespace Poco {
template <class C>
class AutoPtr
/// AutoPtr is a "smart" pointer for classes implementing
/// reference counting based garbage collection.
/// To be usable with the AutoPtr template, a class must
/// implement the following behaviour:
/// A class must maintain a reference count.
/// The constructors of the object initialize the reference
/// count to one.
/// The class must implement a public duplicate() method:
/// void duplicate();
/// that increments the reference count by one.
/// The class must implement a public release() method:
/// void release()
/// that decrements the reference count by one, and,
/// if the reference count reaches zero, deletes the
/// object.
///
/// AutoPtr works in the following way:
/// If an AutoPtr is assigned an ordinary pointer to
/// an object (via the constructor or the assignment operator),
/// it takes ownership of the object and the object's reference
/// count remains unchanged.
/// If the AutoPtr is assigned another AutoPtr, the
/// object's reference count is incremented by one by
/// calling duplicate() on its object.
/// The destructor of AutoPtr calls release() on its
/// object.
/// AutoPtr supports dereferencing with both the ->
/// and the * operator. An attempt to dereference a null
/// AutoPtr results in a NullPointerException being thrown.
/// AutoPtr also implements all relational operators.
/// Note that AutoPtr allows casting of its encapsulated data types.
{
public:
AutoPtr(): _ptr(0)
{
}
AutoPtr(C* ptr): _ptr(ptr)
{
}
AutoPtr(C* ptr, bool shared): _ptr(ptr)
{
if (shared && _ptr) _ptr->duplicate();
}
AutoPtr(const AutoPtr& ptr): _ptr(ptr._ptr)
{
if (_ptr) _ptr->duplicate();
}
template <class Other>
AutoPtr(const AutoPtr<Other>& ptr): _ptr(const_cast<Other*>(ptr.get()))
{
if (_ptr) _ptr->duplicate();
}
~AutoPtr()
{
if (_ptr) _ptr->release();
}
AutoPtr& assign(C* ptr)
{
if (_ptr != ptr)
{
if (_ptr) _ptr->release();
_ptr = ptr;
}
return *this;
}
AutoPtr& assign(C* ptr, bool shared)
{
if (_ptr != ptr)
{
if (_ptr) _ptr->release();
_ptr = ptr;
if (shared && _ptr) _ptr->duplicate();
}
return *this;
}
AutoPtr& assign(const AutoPtr& ptr)
{
if (&ptr != this)
{
if (_ptr) _ptr->release();
_ptr = ptr._ptr;
if (_ptr) _ptr->duplicate();
}
return *this;
}
template <class Other>
AutoPtr& assign(const AutoPtr<Other>& ptr)
{
if (ptr.get() != _ptr)
{
if (_ptr) _ptr->release();
_ptr = const_cast<Other*>(ptr.get());
if (_ptr) _ptr->duplicate();
}
return *this;
}
void reset()
{
if (_ptr)
{
_ptr->release();
_ptr = 0;
}
}
void reset(C* ptr)
{
assign(ptr);
}
void reset(C* ptr, bool shared)
{
assign(ptr, shared);
}
void reset(const AutoPtr& ptr)
{
assign(ptr);
}
template <class Other>
void reset(const AutoPtr<Other>& ptr)
{
assign<Other>(ptr);
}
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AutoPtr& operator = (C* ptr)
{
return assign(ptr);
}
AutoPtr& operator = (const AutoPtr& ptr)
{
return assign(ptr);
}
template <class Other>
AutoPtr& operator = (const AutoPtr<Other>& ptr)
{
return assign<Other>(ptr);
}
void swap(AutoPtr& ptr)
{
std::swap(_ptr, ptr._ptr);
}
template <class Other>
AutoPtr<Other> cast() const
/// Casts the AutoPtr via a dynamic cast to the given type.
/// Returns an AutoPtr containing NULL if the cast fails.
/// Example: (assume class Sub: public Super)
/// AutoPtr<Super> super(new Sub());
/// AutoPtr<Sub> sub = super.cast<Sub>();
/// poco_assert (sub.get());
{
Other* pOther = dynamic_cast<Other*>(_ptr);
return AutoPtr<Other>(pOther, true);
}
template <class Other>
AutoPtr<Other> unsafeCast() const
/// Casts the AutoPtr via a static cast to the given type.
/// Example: (assume class Sub: public Super)
/// AutoPtr<Super> super(new Sub());
/// AutoPtr<Sub> sub = super.unsafeCast<Sub>();
/// poco_assert (sub.get());
{
Other* pOther = static_cast<Other*>(_ptr);
return AutoPtr<Other>(pOther, true);
}
C* operator -> ()
{
if (_ptr)
return _ptr;
else
throw NullPointerException();
}
const C* operator -> () const
{
if (_ptr)
return _ptr;
else
throw NullPointerException();
}
C& operator * ()
{
if (_ptr)
return *_ptr;
else
throw NullPointerException();
}
const C& operator * () const
{
if (_ptr)
return *_ptr;
else
throw NullPointerException();
}
C* get()
{
return _ptr;
}
const C* get() const
{
return _ptr;
}
operator C* ()
{
return _ptr;
}
operator const C* () const
{
return _ptr;
}
bool operator ! () const
{
return _ptr == 0;
}
bool isNull() const
{
return _ptr == 0;
}
C* duplicate()
{
if (_ptr) _ptr->duplicate();
return _ptr;
}
bool operator == (const AutoPtr& ptr) const
{
return _ptr == ptr._ptr;
}
bool operator == (const C* ptr) const
{
return _ptr == ptr;
}
bool operator == (C* ptr) const
{
return _ptr == ptr;
}
bool operator != (const AutoPtr& ptr) const
{
return _ptr != ptr._ptr;
}
bool operator != (const C* ptr) const
{
return _ptr != ptr;
}
bool operator != (C* ptr) const
{
return _ptr != ptr;
}
bool operator < (const AutoPtr& ptr) const
{
return _ptr < ptr._ptr;
}
bool operator < (const C* ptr) const
{
return _ptr < ptr;
}
bool operator < (C* ptr) const
{
return _ptr < ptr;
}
bool operator <= (const AutoPtr& ptr) const
{
return _ptr <= ptr._ptr;
}
bool operator <= (const C* ptr) const
{
return _ptr <= ptr;
}
bool operator <= (C* ptr) const
{
return _ptr <= ptr;
}
bool operator > (const AutoPtr& ptr) const
{
return _ptr > ptr._ptr;
}
bool operator > (const C* ptr) const
{
return _ptr > ptr;
}
bool operator > (C* ptr) const
{
return _ptr > ptr;
}
bool operator >= (const AutoPtr& ptr) const
{
return _ptr >= ptr._ptr;
}
bool operator >= (const C* ptr) const
{
return _ptr >= ptr;
}
bool operator >= (C* ptr) const
{
return _ptr >= ptr;
}
private:
C* _ptr;
};
template <class C>
inline void swap(AutoPtr<C>& p1, AutoPtr<C>& p2)
{
p1.swap(p2);
}
} // namespace Poco
#endif // Foundation_AutoPtr_INCLUDED