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////////////////////////////////////////////////////////////////////////////////
// The Loki Library
// Copyright (c) 2006 by Guillaume Chatelet
//
// Code covered by the MIT License
//
// Permission to use, copy, modify, distribute and sell this software for any
// purpose is hereby granted without fee, provided that the above copyright
// notice appear in all copies and that both that copyright notice and this
// permission notice appear in supporting documentation.
//
// The authors make no representations about the suitability of this software
// for any purpose. It is provided "as is" without express or implied warranty.
//
// This code DOES NOT accompany the book:
// Alexandrescu, Andrei. "Modern C++ Design: Generic Programming and Design
// Patterns Applied". Copyright (c) 2001. Addison-Wesley.
//
////////////////////////////////////////////////////////////////////////////////
// $Id: SPCachedFactory.h 896 2008-08-08 22:20:05Z syntheticpp $
#ifndef SPCACHEDFACTORY_H_
#define SPCACHEDFACTORY_H_
/**
* This file is intented to be used if you want a CachedFactory with
* a SmartPointer encapsulation policy.
* It as been defined in a separate file because of the many introduced
* dependencies (SmartPtr.h would depend on Functor.h and CachedFactory.h
* would depend on SmartPtr.h). By defining another header you pay for those
* extra dependencies only if you need it.
*
* This file defines FunctionStorage a new SmartPointer storage policy and
* SmartPointer a new CachedFactory encapsulation policy.
*/
#include <loki/Functor.h>
#include <loki/SmartPtr.h>
#include <loki/CachedFactory.h>
namespace Loki
{
////////////////////////////////////////////////////////////////////////////////
/// \class FunctionStorage
///
/// \ingroup SmartPointerStorageGroup
/// \brief Implementation of the StoragePolicy used by SmartPtr.
///
/// This storage policy is used by SmartPointer CachedFactory's encapsulation
/// policy. It's purpose is to call a Functor instead of deleting the
/// underlying pointee object. You have to set the callback functor by calling
/// SetCallBackFunction(const FunctorType &functor).
///
/// Unfortunately, the functor argument is not a reference to the SmartPtr but
/// a void *. Making functor argument a reference to the pointer would require
/// the FunctionStorage template to know the full definition of the SmartPtr.
////////////////////////////////////////////////////////////////////////////////
template <class T>
class FunctionStorage
{
public:
/// the type of the pointee_ object
typedef T* StoredType;
/// type used to declare OwnershipPolicy type.
typedef T* InitPointerType;
/// type returned by operator->
typedef T* PointerType;
/// type returned by operator*
typedef T& ReferenceType;
/// type of the Functor to set
typedef Functor< void , Seq< void* > > FunctorType;
FunctionStorage() : pointee_(Default()), functor_()
{}
// The storage policy doesn't initialize the stored pointer
// which will be initialized by the OwnershipPolicy's Clone fn
FunctionStorage(const FunctionStorage& rsh) : pointee_(0), functor_(rsh.functor_)
{}
template <class U>
FunctionStorage(const FunctionStorage<U>& rsh) : pointee_(0), functor_(rsh.functor_)
{}
FunctionStorage(const StoredType& p) : pointee_(p), functor_() {}
PointerType operator->() const { return pointee_; }
ReferenceType operator*() const { return *pointee_; }
void Swap(FunctionStorage& rhs)
{
std::swap(pointee_, rhs.pointee_);
std::swap(functor_, rhs.functor_);
}
/// Sets the callback function to call. You have to specify it or
/// the smartPtr will throw a bad_function_call exception.
void SetCallBackFunction(const FunctorType& functor)
{
functor_ = functor;
}
// Accessors
template <class F>
friend typename FunctionStorage<F>::PointerType GetImpl(const FunctionStorage<F>& sp);
template <class F>
friend const typename FunctionStorage<F>::StoredType& GetImplRef(const FunctionStorage<F>& sp);
template <class F>
friend typename FunctionStorage<F>::StoredType& GetImplRef(FunctionStorage<F>& sp);
protected:
// Destroys the data stored
// (Destruction might be taken over by the OwnershipPolicy)
void Destroy()
{
functor_(this);
}
// Default value to initialize the pointer
static StoredType Default()
{ return 0; }
private:
// Data
StoredType pointee_;
FunctorType functor_;
};
template <class T>
inline typename FunctionStorage<T>::PointerType GetImpl(const FunctionStorage<T>& sp)
{ return sp.pointee_; }
template <class T>
inline const typename FunctionStorage<T>::StoredType& GetImplRef(const FunctionStorage<T>& sp)
{ return sp.pointee_; }
template <class T>
inline typename FunctionStorage<T>::StoredType& GetImplRef(FunctionStorage<T>& sp)
{ return sp.pointee_; }
/**
* \class SmartPointer
* \ingroup EncapsulationPolicyCachedFactoryGroup
* \brief Encapsulate the object in a SmartPtr with FunctionStorage policy.
*
* The object will come back to the Cache as soon as no more SmartPtr are
* referencing this object. You can customize the SmartPointer with the standard
* SmartPtr policies (OwnershipPolicy, ConversionPolicy, CheckingPolicy,
* ConstnessPolicy) but StoragePolicy is forced to FunctionStorage.
*/
template
<
class AbstractProduct,
template <class> class OwnershipPolicy = RefCounted,
class ConversionPolicy = DisallowConversion,
template <class> class CheckingPolicy = AssertCheck,
template<class> class ConstnessPolicy = LOKI_DEFAULT_CONSTNESS
>
class SmartPointer
{
private:
typedef SmartPtr < AbstractProduct, OwnershipPolicy,
ConversionPolicy, CheckingPolicy,
FunctionStorage, ConstnessPolicy > CallBackSP;
protected:
typedef CallBackSP ProductReturn;
SmartPointer() : fun(this, &SmartPointer::smartPointerCallbackFunction) {}
virtual ~SmartPointer() {}
ProductReturn encapsulate(AbstractProduct* pProduct)
{
CallBackSP SP(pProduct);
SP.SetCallBackFunction(fun);
return SP;
}
AbstractProduct* release(ProductReturn& pProduct)
{
return GetImpl(pProduct);
}
const char* name() {return "smart pointer";}
private:
SmartPointer& operator=(const SmartPointer&);
SmartPointer(const SmartPointer&);
void smartPointerCallbackFunction(void* pSP)
{
CallBackSP& SP(*reinterpret_cast<CallBackSP*>(pSP));
ReleaseObject(SP);
}
virtual void ReleaseObject(ProductReturn& object) = 0;
const typename CallBackSP::FunctorType fun;
};
} // namespace Loki
#endif /*SPCACHEDFACTORY_H_*/
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