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/* /////////////////////////////////////////////////////////////////////////
* File: stlsoft/smartptr/ref_ptr.hpp (originally MLRelItf.h, ::SynesisStd) * * Purpose: Contains the ref_ptr template class. * * Created: 2nd November 1994 * Updated: 14th May 2010 * * Home: http://stlsoft.org/
* * Copyright (c) 1994-2010, Matthew Wilson and Synesis Software * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * - Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * - Neither the name(s) of Matthew Wilson and Synesis Software nor the names of * any contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * ////////////////////////////////////////////////////////////////////// */
/** \file stlsoft/smartptr/ref_ptr.hpp
* * \brief [C++ only] Definition of the stlsoft::ref_ptr smart * pointer class template * (\ref group__library__smart_pointers "Smart Pointers" Library). */
#ifndef STLSOFT_INCL_STLSOFT_SMARTPTR_HPP_REF_PTR
#define STLSOFT_INCL_STLSOFT_SMARTPTR_HPP_REF_PTR
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
# define STLSOFT_VER_STLSOFT_SMARTPTR_HPP_REF_PTR_MAJOR 5
# define STLSOFT_VER_STLSOFT_SMARTPTR_HPP_REF_PTR_MINOR 3
# define STLSOFT_VER_STLSOFT_SMARTPTR_HPP_REF_PTR_REVISION 2
# define STLSOFT_VER_STLSOFT_SMARTPTR_HPP_REF_PTR_EDIT 489
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
/* /////////////////////////////////////////////////////////////////////////
* Includes */
#ifndef STLSOFT_INCL_STLSOFT_H_STLSOFT
# include <stlsoft/stlsoft.h>
#endif /* !STLSOFT_INCL_STLSOFT_H_STLSOFT */
/* /////////////////////////////////////////////////////////////////////////
* Namespace */
#ifndef _STLSOFT_NO_NAMESPACE
namespace stlsoft { #endif /* _STLSOFT_NO_NAMESPACE */
/* /////////////////////////////////////////////////////////////////////////
* Helper shims */
/** \brief Control shim for adding a reference on a reference-counted
* interface (RCI) * * \ingroup group__library__smart_pointers * * \note The generic shim expects the RCI to have a method named AddRef(), which * has either no parameters, or has all default parameters * * \note The behaviour of the ref_ptr is undefined if this method throws an * exception */ template<ss_typename_param_k I> inline void add_reference(I* pi) { STLSOFT_ASSERT(NULL != pi);
pi->AddRef(); }
/** \brief Control shim for releasing a reference on a reference-counted
* interface (RCI) * * \ingroup group__library__smart_pointers * * \note The generic shim expects the RCI to have a method named Release(), which * has either no parameters, or has all default parameters * * \note The behaviour of the ref_ptr is undefined if this method throws an * exception */ template<ss_typename_param_k I> inline void release_reference(I* pi) { STLSOFT_ASSERT(NULL != pi);
pi->Release(); }
/* /////////////////////////////////////////////////////////////////////////
* Classes */
/** \brief This class provides RAII-safe handling of reference-counted
* interfaces (RCIs). Its notable feature is that it supports forward * declaration of the leaf interface so long as the base counting * interface is visible in the scope of the template parameterisation. * * \ingroup group__library__smart_pointers * * \param T The counted type (i.e. a concrete class) * \param I The interface type * \param U The upcast intermediate type */ template< ss_typename_param_k T , ss_typename_param_k I = T , ss_typename_param_k U = I > class ref_ptr { /// \name Types
/// @{
public: /// \brief The Boolean type
typedef bool_t bool_type; /// \brief The interface type: the type of the RCI (Reference-Counted Interface)
typedef I interface_type; /// \brief The counted type: the concrete type of the objects whose instances will be managed
typedef T counted_type; /// \brief The up-cast type: the type used to disambiguate upcasts between T and I
typedef U upcast_type; /// \brief The current instantiation of the type
typedef ref_ptr<T, I, U> class_type;
/// \brief This to be member-type-compatible with std::auto_ptr
typedef I element_type; /// \brief This is to be compatible with the get_invoker component
typedef counted_type* resource_type; typedef counted_type const* const_resource_type; /// @}
/// \name Implementation
/// @{
private: /// \brief Helper function to effect downcast from interface type to counted type
static counted_type* c_from_i(interface_type* i) { return static_cast<counted_type*>(static_cast<upcast_type*>(i)); } /// \brief Helper function to effect downcast from interface type to counted type
static counted_type const* c_from_i(interface_type const* i) { return static_cast<counted_type const*>(static_cast<upcast_type const*>(i)); } /// \brief Helper function to effect upcast from counted type to interface type
static interface_type* i_from_c(counted_type* c) { return static_cast<upcast_type*>(c); }
#if defined(STLSOFT_COMPILER_IS_MSVC) && \
_MSC_VER == 1300 /// \brief Helper function to effect upcast from const counted type to interface type
static interface_type* i_from_const_c(counted_type const* cc) { counted_type* c = const_cast<counted_type*>(cc);
return i_from_c(c); } #endif /* compiler */
/// @}
/// \name Construction
/// @{
public: /// \brief Default constructor
///
/// Constructs and empty instance
ref_ptr() : m_pi(NULL) {} /// \brief Construct from a raw pointer to the counted type, and a boolean that
/// indicates whether a reference should be taken on the instance.
///
/// \param c Pointer to a counted_type. May be NULL
/// \param bAddRef parameter that determines whether reference will be
/// <i>consumed</i> (<code>false</code>) or <i>borrowed</i>
/// (<code>true</code>).
///
/// \note It is usual that ref_ptr is used to "sink" an instance, i.e. to take
/// ownership of it. In such a case, \c false should be specified as the second
/// parameter. If, however, a reference is being "borrowed", then \c true should
/// be specified.
ref_ptr(counted_type* c, bool_type bAddRef) : m_pi(i_from_c(c)) { if( bAddRef && NULL != m_pi) { add_reference(m_pi); } }
/// \brief Creates a copy of the given ref_ptr instance, and increments the
/// reference count on its referent object, if any
///
/// \param rhs The instance to copy
ref_ptr(class_type const& rhs) : m_pi(rhs.m_pi) { if(NULL != m_pi) { add_reference(m_pi); } }
#if !defined(STLSOFT_COMPILER_IS_MSVC) || \
_MSC_VER > 1100 /// \brief Copy constructs from an instance with different interface and/or
/// counted type
///
/// \note The interface types of the copying and copied instance must be
/// compatible
template< ss_typename_param_k T2 , ss_typename_param_k I2 , ss_typename_param_k U2 > # if defined(STLSOFT_COMPILER_IS_MSVC) && \
_MSC_VER == 1300 ref_ptr(ref_ptr<T2, I2, U2> const& rhs) # if 0
// We cannot use this form, as it would lead to instances with different
// counted_type being cross cast invisibly. This would be a *very bad thing*
: m_pi(rhs.m_pi) # else /* ? 0 */
: m_pi(i_from_const_c(rhs.get())) # endif /* 0 */
{ if(NULL != m_pi) { add_reference(m_pi); } } # else /* ? compiler */
ref_ptr(ref_ptr<T2, I2, U2>& rhs) # if 0
// We cannot use this form, as it would lead to instances with different
// counted_type being cross cast invisibly. This would be a *very bad thing*
: m_pi(rhs.m_pi) # else /* ? 0 */
: m_pi(i_from_c(rhs.get())) # endif /* 0 */
{ if(NULL != m_pi) { add_reference(m_pi); } } # endif /* compiler */
#endif /* compiler */
#if !defined(STLSOFT_COMPILER_IS_INTEL) && \
!defined(STLSOFT_COMPILER_IS_MWERKS) && \ 0 template< ss_typename_param_k I2 , ss_typename_param_k U2 > explicit ref_ptr(ref_ptr<T, I2, U2>& rhs) : m_pi(rhs.m_pi) { if(NULL != m_pi) { add_reference(m_pi); } } #endif /* compiler */
/// \brief Destructor
///
/// If the ref_ptr instance is still holding a pointer to a managed instance,
/// it will be released.
~ref_ptr() stlsoft_throw_0() { if(NULL != m_pi) { release_reference(m_pi); } }
/// \brief Copy assignment from a ref_ptr instance of the same type
///
/// \note It is strongly exception-safe, as long as the implementations of the
/// add-ref and release functions - as utilised in the \c add_reference() and
/// \c release_reference() control shims - do not throw (which they must not).
class_type& operator =(class_type const& rhs) { class_type t(rhs);
t.swap(*this);
return *this; }
#if !defined(STLSOFT_COMPILER_IS_MSVC) || \
( _MSC_VER > 1100 && \ _MSC_VER != 1300) /// \brief Copy assignment from an instance of ref_ptr with a different counted_type (but
/// the same interface type).
///
/// \note This function template uses the copy constructor template, and has the same
/// instantiation restrictions
///
/// \note It is strongly exception-safe, as long as the implementations of the
/// add-ref and release functions - as utilised in the \c add_reference() and
/// \c release_reference() control shims - do not throw (which they must not).
template< ss_typename_param_k T2 , ss_typename_param_k U2 > class_type& operator =(ref_ptr<T2, I, U2>& rhs) { class_type t(rhs);
t.swap(*this);
return *this; } #endif /* compiler */
#if !defined(STLSOFT_COMPILER_IS_INTEL) && \
!defined(STLSOFT_COMPILER_IS_MWERKS) && \ 0 template< ss_typename_param_k I2 , ss_typename_param_k U2 > class_type& operator =(ref_ptr<T, I2, U2>& rhs) { class_type t(rhs);
t.swap(*this);
return *this; } #endif /* compiler */
/// @}
/// \name Operations
/// @{
public: /// \brief Swaps the managed instance of \c this with \c rhs
///
/// \note It provides the no-throw guarantee
void swap(class_type& rhs) { interface_type* t = rhs.m_pi; rhs.m_pi = m_pi; m_pi = t; }
/// \brief Assigns a reference-counted type to the smart pointer.
///
/// \param c Pointer to a counted_type. May be NULL
/// \param bAddRef parameter that determines whether reference will be
/// <i>consumed</i> (<code>false</code>) or <i>borrowed</i>
/// (<code>true</code>).
void set(counted_type* c, bool_type bAddRef) { class_type t(c, bAddRef);
t.swap(*this); }
/// Closes the instance, releasing the managed pointer.
///
/// \note Calling this method more than once has no effect.
void close() { if(NULL != m_pi) { release_reference(m_pi); m_pi = NULL; } }
/// \brief Detaches the managed instance, and returns it to the caller, which
/// takes responsibility for ensuring that the resource is not leaked
counted_type* detach() { counted_type* r = class_type::c_from_i(m_pi);
m_pi = NULL;
return r; } /// @}
/// \name Equality Comparison
/// @{
public: /// \brief Evaluates whether two instances are equal
bool_type equal(class_type const& rhs) const { return m_pi == rhs.m_pi; } /// @}
/// \name Accessors
/// @{
public: /// \brief Determines whether the instance is empty
bool_type empty() const { return NULL == m_pi; }
/// \brief Determines whether the instance is empty
bool_type operator !() const { return empty(); }
/// \brief Provides raw-pointer access to the instance
counted_type* get() const { return class_type::c_from_i(m_pi); }
/// \brief Returns the interface pointer
///
/// \pre The instance must not be empty; otherwise behaviour is
/// undefined
counted_type* operator ->() { STLSOFT_MESSAGE_ASSERT("Dereferencing a NULL pointer!", NULL != m_pi);
return class_type::c_from_i(m_pi); }
/// \brief Returns the interface pointer
///
/// \pre The instance must not be empty; otherwise behaviour is
/// undefined
counted_type const* operator ->() const { STLSOFT_MESSAGE_ASSERT("Dereferencing a NULL pointer!", NULL != m_pi);
return class_type::c_from_i(m_pi); }
/// \brief Returns a reference to the managed instance
///
/// \pre The instance must not be empty; otherwise behaviour is
/// undefined
counted_type& operator *() { STLSOFT_MESSAGE_ASSERT("Dereferencing a NULL pointer!", NULL != m_pi);
return *class_type::c_from_i(m_pi); }
/// \brief Returns a reference to the managed instance
///
/// \pre The instance must not be empty; otherwise behaviour is
/// undefined
counted_type const& operator *() const { STLSOFT_MESSAGE_ASSERT("Dereferencing a NULL pointer!", NULL != m_pi);
return *class_type::c_from_i(m_pi); } /// @}
/// \name Members
/// @{
private: interface_type* m_pi; /// @}
};
/* /////////////////////////////////////////////////////////////////////////
* Operators */
template< ss_typename_param_k T , ss_typename_param_k I , ss_typename_param_k U > inline ss_bool_t operator ==(ref_ptr<T, I, U> const& lhs, ref_ptr<T, I, U> const& rhs) { return lhs.equal(rhs); }
template< ss_typename_param_k T , ss_typename_param_k I , ss_typename_param_k U > inline ss_bool_t operator !=(ref_ptr<T, I, U> const& lhs, ref_ptr<T, I, U> const& rhs) { return !lhs.equal(rhs); }
/* /////////////////////////////////////////////////////////////////////////
* swapping */
template< ss_typename_param_k T , ss_typename_param_k I , ss_typename_param_k U > inline void swap(ref_ptr<T, I, U>& lhs, ref_ptr<T, I, U>& rhs) { lhs.swap(rhs); }
/* /////////////////////////////////////////////////////////////////////////
* Shims */
/** \brief is_empty shim
* * \ingroup group__library__smart_pointers */ template< ss_typename_param_k T , ss_typename_param_k I /* = T */ , ss_typename_param_k U /* = I */ > inline ss_bool_t is_empty(ref_ptr<T, I, U> const& p) { return NULL == p.get(); }
/** \brief get_ptr shim
* * \ingroup group__library__smart_pointers */ template< ss_typename_param_k T , ss_typename_param_k I /* = T */ , ss_typename_param_k U /* = I */ > inline T* get_ptr(ref_ptr<T, I, U> const& p) { return p.get(); }
/** \brief Insertion operator shim
* * \ingroup group__library__smart_pointers */ template< ss_typename_param_k S , ss_typename_param_k T , ss_typename_param_k I /* = T */ , ss_typename_param_k U /* = I */ > inline S& operator <<(S& s, ref_ptr<T, I, U> const& p) { return s << *p; }
/* /////////////////////////////////////////////////////////////////////////
* Unit-testing */
#ifdef STLSOFT_UNITTEST
# include "./unittest/ref_ptr_unittest_.h"
#endif /* STLSOFT_UNITTEST */
/* ////////////////////////////////////////////////////////////////////// */
#ifndef _STLSOFT_NO_NAMESPACE
} // namespace stlsoft
#endif /* _STLSOFT_NO_NAMESPACE */
/* In the special case of Intel behaving as VC++ 7.0 or earlier on Win32, we
* illegally insert into the std namespace. */ #if defined(STLSOFT_CF_std_NAMESPACE)
# if ( ( defined(STLSOFT_COMPILER_IS_INTEL) && \
defined(_MSC_VER))) && \ _MSC_VER < 1310 namespace std { template< ss_typename_param_k T , ss_typename_param_k I , ss_typename_param_k U > inline void swap(stlsoft_ns_qual(ref_ptr)<T, I, U>& lhs, stlsoft_ns_qual(ref_ptr)<T, I, U>& rhs) { lhs.swap(rhs); } } // namespace std
# endif /* INTEL && _MSC_VER < 1310 */
#endif /* STLSOFT_CF_std_NAMESPACE */
/* ////////////////////////////////////////////////////////////////////// */
#endif /* !STLSOFT_INCL_STLSOFT_SMARTPTR_HPP_REF_PTR */
/* ///////////////////////////// end of file //////////////////////////// */
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