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/* /////////////////////////////////////////////////////////////////////////
* File: comstl/conversion/interface_cast.hpp
*
* Purpose: Safe interface casting functions.
*
* Created: 25th June 2002
* Updated: 6th May 2010
*
* Home: http://stlsoft.org/
*
* Copyright (c) 2002-2010, 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 comstl/conversion/interface_cast.hpp
*
* \brief [C++ only] Definition of the
* comstl::interface_cast,
* comstl::interface_cast_test
* and
* comstl::try_interface_cast
* cast functions
* and the
* comstl::interface_cast_addref
* and
* comstl::interface_cast_noaddref
* cast classes.
* (\ref group__library__conversion "Conversion" Library).
*/
#ifndef COMSTL_INCL_COMSTL_CONVERSION_HPP_INTERFACE_CAST
#define COMSTL_INCL_COMSTL_CONVERSION_HPP_INTERFACE_CAST
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
# define COMSTL_VER_COMSTL_CONVERSION_HPP_INTERFACE_CAST_MAJOR 5
# define COMSTL_VER_COMSTL_CONVERSION_HPP_INTERFACE_CAST_MINOR 2
# define COMSTL_VER_COMSTL_CONVERSION_HPP_INTERFACE_CAST_REVISION 4
# define COMSTL_VER_COMSTL_CONVERSION_HPP_INTERFACE_CAST_EDIT 117
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
/* /////////////////////////////////////////////////////////////////////////
* Compatibility
*/
/*
[Incompatibilies-start]
STLSOFT_COMPILER_IS_MSVC: _MSC_VER<1200
[Incompatibilies-end]
*/
/* /////////////////////////////////////////////////////////////////////////
* Includes
*/
#ifndef COMSTL_INCL_COMSTL_H_COMSTL
# include <comstl/comstl.h>
#endif /* !COMSTL_INCL_COMSTL_H_COMSTL */
#if defined(STLSOFT_COMPILER_IS_MSVC) && \
_MSC_VER < 1200
# error comstl/conversion/interface_cast.hpp is not compatible with Visual C++ 5.0 or earlier
#endif /* compiler */
#ifndef COMSTL_INCL_COMSTL_UTIL_H_REFCOUNT_FUNCTIONS
# include <comstl/util/refcount_functions.h>
#endif /* !COMSTL_INCL_COMSTL_UTIL_H_REFCOUNT_FUNCTIONS */
#ifndef COMSTL_INCL_COMSTL_UTIL_HPP_INTERFACE_TRAITS
# include <comstl/util/interface_traits.hpp>
#endif /* !COMSTL_INCL_COMSTL_UTIL_HPP_INTERFACE_TRAITS */
#ifdef STLSOFT_CF_EXCEPTION_SUPPORT
# ifndef COMSTL_INCL_COMSTL_ERROR_HPP_BAD_INTERFACE_CAST
# include <comstl/error/bad_interface_cast.hpp>
# endif /* !COMSTL_INCL_COMSTL_ERROR_HPP_BAD_INTERFACE_CAST */
#endif /* STLSOFT_CF_EXCEPTION_SUPPORT */
#ifndef STLSOFT_INCL_STLSOFT_SMARTPTR_HPP_REF_PTR
# include <stlsoft/smartptr/ref_ptr.hpp>
#endif /* !STLSOFT_INCL_STLSOFT_SMARTPTR_HPP_REF_PTR */
#ifndef STLSOFT_INCL_STLSOFT_UTIL_HPP_OPERATOR_BOOL
# include <stlsoft/util/operator_bool.hpp>
#endif /* !STLSOFT_INCL_STLSOFT_UTIL_HPP_OPERATOR_BOOL */
/* /////////////////////////////////////////////////////////////////////////
* Namespace
*/
#ifndef _COMSTL_NO_NAMESPACE
# if defined(_STLSOFT_NO_NAMESPACE) || \
defined(STLSOFT_DOCUMENTATION_SKIP_SECTION)
/* There is no stlsoft namespace, so must define ::comstl */
namespace comstl
{
# else
/* Define stlsoft::comstl_project */
namespace stlsoft
{
namespace comstl_project
{
# endif /* _STLSOFT_NO_NAMESPACE */
#endif /* !_COMSTL_NO_NAMESPACE */
/* /////////////////////////////////////////////////////////////////////////
* Functions
*/
// This helper converts from an interface pointer to itself.
//
// It explicitly takes and returns pointer so that it disambiguates from any
// overload that takes an interface wrapper instance by value/reference.
template <ss_typename_param_k I>
inline I* simple_interface_cast(I* pi)
{
return pi;
}
/* /////////////////////////////////////////////////////////////////////////
* Functionals
*/
/** \brief A function class that does not throw any exceptions. For use with
* comstl::interface_cast_noaddref and comstl::interface_cast_addref cast
* classes.
*
* \ingroup group__library__conversion
*/
// [[synesis:class:exception-policy: ignore_interface_cast_exception]]
struct ignore_interface_cast_exception
{
public:
/// The exception type
struct thrown_type
{
};
public:
/// The function call operator, which does not throw an exception
///
/// \param hr The HRESULT that caused the error
/// \param riid The REFIID that could not be acquired
void operator ()(HRESULT hr, REFIID riid) stlsoft_throw_0()
{
STLSOFT_SUPPRESS_UNUSED(hr);
STLSOFT_SUPPRESS_UNUSED(riid);
// Do nothing
}
};
#ifdef STLSOFT_CF_EXCEPTION_SUPPORT
/** \brief A function class that throws the
* \link comstl::bad_interface_cast bad_interface_cast\endlink exception
* class. For use with
* comstl::interface_cast_noaddref and comstl::interface_cast_addref cast
* classes.
*
* \ingroup group__library__conversion
*/
// [[synesis:class:exception-policy: throw_bad_interface_cast_exception]]
struct throw_bad_interface_cast_exception
{
public:
/// The exception type
typedef bad_interface_cast thrown_type;
public:
/// The function call operator, which throws the exception
///
/// \param hr The HRESULT that caused the error
/// \param riid The REFIID that could not be acquired
void operator ()(HRESULT hr, REFIID riid) stlsoft_throw_1(bad_interface_cast)
{
STLSOFT_THROW_X(bad_interface_cast(riid, hr));
}
};
#endif /* STLSOFT_CF_EXCEPTION_SUPPORT */
/** \brief A function class that calls Release() on the interface. For use with
* comstl::interface_cast_noaddref and comstl::interface_cast_addref cast
* classes.
*
* \ingroup group__library__conversion
*/
template <ss_typename_param_k I>
struct noaddref_release
{
public:
/// The function call operator, that calls Release() on the interface
///
/// \param pi The interface pointer
void operator ()(I pi)
{
release(pi);
}
};
/** \brief A function class that does not call Release() on the interface. For use with
* comstl::interface_cast_noaddref and comstl::interface_cast_addref cast
* classes.
*
* \ingroup group__library__conversion
*/
template <ss_typename_param_k I>
struct addref_release
{
public:
/// The function call operator, which does not call Release() on the interface
///
/// \param pi The interface pointer
void operator ()(I pi)
{
STLSOFT_SUPPRESS_UNUSED(pi);
}
};
/* /////////////////////////////////////////////////////////////////////////
* Raw-pointer safety
*
* Alas this requires partial template specialisation, so is not available in
* all environments.
*/
#ifdef STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT
# ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
template <ss_typename_param_k I>
struct interface_pointer_traits;
template <ss_typename_param_k I>
struct interface_pointer_traits<I*>
{
typedef I interface_type;
};
# endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
/** \brief A veneer interface that hides the AddRef() and Release() methods.
* For use with comstl::interface_cast_noaddref and
* comstl::interface_cast_addref cast classes.
*
* \ingroup group__library__conversion
*/
template <ss_typename_param_k I>
interface protect_refcount
: public I
{
private:
STDMETHOD_(ULONG, AddRef)()
{
I* pi = static_cast<I*>(this);
return pi->AddRef();
}
STDMETHOD_(ULONG, Release)()
{
I* pi = static_cast<I*>(this);
return pi->Release();
}
};
#endif /* STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
/* /////////////////////////////////////////////////////////////////////////
* Classes
*/
/** \brief Base class for the interface cast classes
* comstl::interface_cast_noaddref and comstl::interface_cast_addref.
*
* \ingroup group__library__conversion
*
* This class serves only as a base, and cannot be used in isolation
*
* \param I The interface pointer type
* \param R The release type
* \param X The exception type
*/
// [[synesis:class:implementation: comstl::interface_cast_base]]
template< ss_typename_param_k I
, ss_typename_param_k R
, ss_typename_param_k X
>
class interface_cast_base
{
/// \name Member Types
/// @{
public:
/// The interface pointer type
typedef I interface_pointer_type;
#ifdef STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT
/// The interface type
typedef ss_typename_type_k interface_pointer_traits<I>::interface_type interface_type;
#endif /* STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
/// The release type
typedef R release_type;
/// The exception type
typedef X exception_policy_type;
/// The thrown type
typedef ss_typename_type_k exception_policy_type::thrown_type thrown_type;
/// The type of the current parameterisation
typedef interface_cast_base<I, R, X> class_type;
/// @}
/// \name Member Constants
/// @{
protected:
enum NullThrowPermission
{
allowNull
, throwOnNull
};
/// @}
/// \name Construction
/// @{
protected:
/// Constructor that attempts the speculative cast
#ifdef STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT
template <ss_typename_param_k J>
ss_explicit_k interface_cast_base(J &j, NullThrowPermission permission)
: m_pi(do_cast(simple_interface_cast(j), permission))
{}
#else /* ? STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT */
ss_explicit_k interface_cast_base(LPUNKNOWN punk, NullThrowPermission permission)
: m_pi(do_cast(punk, permission))
{}
#endif /* STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT */
/// Constructor that directly casts (without calling QueryInterface())
ss_explicit_k interface_cast_base(interface_pointer_type pi)
: m_pi(pi)
{
addref(m_pi);
}
/// Releases the acquired interface pointer according to the \c release_type policy
~interface_cast_base() stlsoft_throw_0()
{
if(NULL != m_pi)
{
release_type()(m_pi);
}
}
/// @}
/// \name Implementation
/// @{
private:
/// Perform the cast, throwing the \c exception_policy_type's \c thrown_type if the
/// requested interface cannot be acquired.
///
/// \param punk The interface pointer to cast
/// \return The converted interface pointer
static interface_pointer_type do_cast(LPUNKNOWN punk, NullThrowPermission permission) stlsoft_throw_1(thrown_type)
{
interface_pointer_type pi;
if(NULL == punk)
{
if(throwOnNull == permission)
{
exception_policy_type()(E_INVALIDARG, IID_traits<interface_pointer_type>().iid());
COMSTL_MESSAGE_ASSERT("The derived class does not support null pointers, but the exception policy failed to throw an exception: the program's behaviour will be undefined!", 0);
}
pi = NULL;
}
else
{
REFIID iid = IID_traits<interface_pointer_type>().iid();
HRESULT hr = punk->QueryInterface(iid, reinterpret_cast<void**>(&pi));
if(FAILED(hr))
{
exception_policy_type()(hr, iid);
pi = NULL;
}
}
return pi;
}
/// @}
/// \name Accessors
/// @{
protected:
/// Returns a non-mutating reference to the acquired interface pointer
interface_pointer_type const& get_pointer_()
{
return m_pi;
}
/// Returns a copy of the acquired interface pointer
interface_pointer_type get_pointer_() const
{
return m_pi;
}
/// @}
/// \name Members
/// @{
private:
interface_pointer_type const m_pi;
/// @}
/// \name Not to be implemented
/// @{
protected:
interface_cast_base(class_type const& rhs);
private:
class_type const& operator =(class_type const& rhs);
/// @}
};
#ifdef STLSOFT_CF_EXCEPTION_SUPPORT
/** \brief Interface cast for raw pointers that does not add a net reference count
*
* \ingroup group__library__conversion
*
* This class provides a cast between interface pointers, but does not add a net reference count
*
* \param I The interface pointer type
* \param X The exception type
*
* \note This class is not defined when exception-handling is not supported.
*/
// [[synesis:class:cast: comstl::interface_cast_noaddref]]
template< ss_typename_param_k I
, ss_typename_param_k X = throw_bad_interface_cast_exception
>
class interface_cast_noaddref
: protected interface_cast_base<I, noaddref_release<I>, X>
{
private: // Member Types
typedef interface_cast_base<I, noaddref_release<I>, X> parent_class_type;
public:
/// The type of the current parameterisation
typedef interface_cast_noaddref<I, X> class_type;
/// The interface pointer type
typedef ss_typename_type_k parent_class_type::interface_pointer_type interface_pointer_type;
# ifdef STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT
/// The interface type
typedef ss_typename_type_k parent_class_type::interface_type interface_type;
typedef protect_refcount<interface_type>* protected_interface_pointer_type;
# else /* ? STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
typedef interface_pointer_type protected_interface_pointer_type;
# endif /* STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
public: // Construction
/// Constructor that attempts the speculative cast
# ifdef STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT
template <ss_typename_param_k J>
ss_explicit_k interface_cast_noaddref(J &j)
: parent_class_type(j, parent_class_type::throwOnNull)
{
COMSTL_MESSAGE_ASSERT("Cannot initialise with a null pointer. Program behaviour will be undefined when it this instance is dereference", NULL != this->parent_class_type::get_pointer_());
}
# else /* ? STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT */
ss_explicit_k interface_cast_noaddref(LPUNKNOWN punk)
: parent_class_type(punk, parent_class_type::throwOnNull)
{
COMSTL_MESSAGE_ASSERT("Cannot initialise with a null pointer. Program behaviour will be undefined when it this instance is dereference", NULL != this->parent_class_type::get_pointer_());
}
# endif /* STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT */
/// Constructor that directly casts (without calling QueryInterface())
ss_explicit_k interface_cast_noaddref(interface_pointer_type pi)
: parent_class_type(pi, parent_class_type::throwOnNull)
{
COMSTL_MESSAGE_ASSERT("Cannot initialise with a null pointer. Program behaviour will be undefined when it this instance is dereference", NULL != this->parent_class_type::get_pointer_());
}
# ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
~interface_cast_noaddref() stlsoft_throw_0()
{} // We need to provide this to persuade VC6 to call the parent class dtor
# endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
// Accessors
public:
/// Access the members of the interface
protected_interface_pointer_type operator -> () const
{
COMSTL_MESSAGE_ASSERT("Attempting to dereference null pointer. Exception model should not be null", NULL != this->parent_class_type::get_pointer_());
return static_cast<protected_interface_pointer_type>(this->parent_class_type::get_pointer_());
}
// Not to be implemented
private:
interface_cast_noaddref(class_type const& rhs);
class_type const& operator =(class_type const& rhs);
// These are defined to placate Borland C/C++
void* operator new(cs_size_t /* si */) { return 0; }
void operator delete(void* /* pv */) {}
};
#endif /* STLSOFT_CF_EXCEPTION_SUPPORT */
/** \brief Interface cast for raw pointers that does add a net reference count
*
* \ingroup group__library__conversion
*
* This class provides a cast between interface pointers, that adds a net reference count
*
* \param I The interface pointer type
* \param X The exception type, defaulted to ignore_interface_cast_exception
*/
// [[synesis:class:cast: comstl::interface_cast_addref]]
template< ss_typename_param_k I
, ss_typename_param_k X = ignore_interface_cast_exception
>
class interface_cast_addref
: protected interface_cast_base<I, addref_release<I>, X>
{
private: // Member Types
typedef interface_cast_base<I, addref_release<I>, X> parent_class_type;
public:
/// The type of the current parameterisation
typedef interface_cast_addref<I, X> class_type;
/// The interface pointer type
typedef ss_typename_type_k parent_class_type::interface_pointer_type interface_pointer_type;
public: // Construction
/// Constructor that attempts the speculative cast
#ifdef STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT
template <ss_typename_param_k J>
ss_explicit_k interface_cast_addref(J j)
: parent_class_type(j, parent_class_type::allowNull)
{}
#else /* ? STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT */
ss_explicit_k interface_cast_addref(LPUNKNOWN punk)
: parent_class_type(punk, parent_class_type::allowNull)
{}
#endif /* STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT */
/// Constructor that directly casts (without calling QueryInterface())
ss_explicit_k interface_cast_addref(interface_pointer_type pi)
: parent_class_type(pi, parent_class_type::allowNull)
{}
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
~interface_cast_addref() stlsoft_throw_0()
{} // We need to provide this to persuade VC6 to call the parent class dtor
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
// Accessors
public:
/// A pointer to the acquired interface
operator interface_pointer_type ()
{
return this->parent_class_type::get_pointer_();
}
// Not to be implemented
private:
interface_cast_addref(class_type const& rhs);
class_type const& operator =(class_type const& rhs);
// These are defined to placate Borland C/C++
void* operator new(cs_size_t /* si */) { return 0; }
void operator delete(void* /* pv */) {}
};
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
// [[synesis:class:cast: comstl::interface_cast_tester]]
template< ss_typename_param_k I
>
class interface_cast_tester
: protected interface_cast_base<I, noaddref_release<I>, ignore_interface_cast_exception>
{
private: // Member Types
typedef interface_cast_base<I, noaddref_release<I>, ignore_interface_cast_exception> parent_class_type;
public:
/// The type of the current parameterisation
typedef interface_cast_tester<I> class_type;
/// The interface pointer type
typedef ss_typename_type_k parent_class_type::interface_pointer_type interface_pointer_type;
#ifdef STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT
/// The interface type
typedef ss_typename_type_k parent_class_type::interface_type interface_type;
typedef protect_refcount<interface_type>* protected_interface_pointer_type;
#else /* ? STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
typedef interface_pointer_type protected_interface_pointer_type;
#endif /* STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
public: // Construction
/// Constructor that attempts the speculative cast
#ifdef STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT
template <ss_typename_param_k J>
ss_explicit_k interface_cast_tester(J &j)
: parent_class_type(j, parent_class_type::allowNull)
{}
#else /* ? STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT */
ss_explicit_k interface_cast_tester(LPUNKNOWN punk)
: parent_class_type(punk, parent_class_type::allowNull)
{}
#endif /* STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT */
/// Constructor that directly casts (without calling QueryInterface())
ss_explicit_k interface_cast_tester(interface_pointer_type pi)
: parent_class_type(pi, parent_class_type::allowNull)
{}
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
~interface_cast_tester() stlsoft_throw_0()
{} // We need to provide this to persuade VC6 to call the parent class dtor
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
/// \name State
/// @{
private:
STLSOFT_DEFINE_OPERATOR_BOOL_TYPES_T(class_type, operator_bool_generator_type, operator_bool_type);
public:
/// Represents whether the cast succeeded
///
/// \retval true The interface cast succeeded
/// \retval false The interface cast failed
operator operator_bool_type() const
{
return operator_bool_generator_type::translate(NULL != this->parent_class_type::get_pointer_());
}
/// Represents whether the cast failed
///
/// \retval true The interface cast failed
/// \retval false The interface cast succeeded
cs_bool_t operator !() const
{
return NULL == this->parent_class_type::get_pointer_();
}
/// @}
// Not to be implemented
private:
interface_cast_tester(class_type const& rhs);
class_type const& operator =(class_type const& rhs);
// These are defined to placate Borland C/C++
void* operator new(cs_size_t /* si */) { return 0; }
void operator delete(void* /* pv */) {}
};
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
/** \brief Determines whether an interface is available on an object
*
* \ingroup group__library__conversion
*
* \param src The object whose capabilities will be tested. May be NULL
*
\code
IStream* stm = . . .
if(comstl::interface_cast_test<IStorage*>(stm))
{
printf("Object has IStorage interface\n");
}
else
{
printf("Object does not have IStorage interface\n");
}
\endcode
*/
template< ss_typename_param_k IDest
, ss_typename_param_k ISrc
>
#if defined(STLSOFT_COMPILER_IS_MSVC) && \
_MSC_VER < 1300
// This workaround is required to stop the poor dear from instantiating
// interface_cast_tester on ISrc rather than IDest.
inline cs_bool_t interface_cast_test(ISrc* src, IDest* = NULL)
#else /* ? compiler */
inline cs_bool_t interface_cast_test(ISrc* src)
#endif /* compiler */
{
interface_cast_tester<IDest> b(src);
return !!b;
}
/** \brief Determines whether an interface is available on an object
*
* \ingroup group__library__conversion
*
\code
stlsoft::ref_ptr<IStream> stm = . . .
if(comstl::interface_cast_test<IStorage>(stm))
{
printf("Wrapper object has IStorage interface\n");
}
else
{
printf("Wrapper object does not have IStorage interface\n");
}
\endcode
*
* \param src wrapper instance holding the object whose capabilities
* will be tested. May be empty.
*/
template< ss_typename_param_k IDest
, ss_typename_param_k ISrc
>
#if defined(STLSOFT_COMPILER_IS_MSVC) && \
_MSC_VER < 1300
// This workaround is required to stop the poor dear from instantiating
// interface_cast_tester on ISrc rather than IDest.
inline cs_bool_t interface_cast_test(stlsoft_ns_qual(ref_ptr)<ISrc> &src, IDest* = NULL)
#else /* ? compiler */
inline cs_bool_t interface_cast_test(stlsoft_ns_qual(ref_ptr)<ISrc> &src)
#endif /* compiler */
{
return interface_cast_test<IDest*>(src.get());
}
#ifdef STLSOFT_CF_EXCEPTION_SUPPORT
/** \brief Casts a raw interface pointer to a wrapped instance.
*
* \ingroup group__library__conversion
*
\code
IStream* stm = . . .
try
{
stlsoft::ref_ptr<IStorage> stg = comstl::interface_cast<IStorage>(stm);
printf("Object has IStorage interface\n");
}
catch(comstl::bad_interface_cast &)
{
printf("Object does not have IStorage interface\n");
}
\endcode
*
* \note For technical reasons, the cast destination type differs from the
* conventional behaviour. Rather than specifying the actual resultant
* type, e.g. <code>stlsoft::ref_ptr<IStream></code>, just the destination
* interface type must be specified, e.g.
* <code>interface_cast<IStream></code>.
*
* \exception comstl::bad_interface_cast When compiling with exception -
* detected when <code>STLSOFT_CF_EXCEPTION_SUPPORT</code> is defined -
* this will throw an instance of comstl::bad_interface_cast if the
* requested interface cannot be acquired. When compiling absent exception
* support, this cast function is not defined; instead use
* comstl::try_interface_cast.
*/
template< ss_typename_param_k IDest
, ss_typename_param_k ISrc
>
inline stlsoft_ns_qual(ref_ptr)<IDest> interface_cast(ISrc* src)
{
interface_cast_addref<IDest*, throw_bad_interface_cast_exception> ptr(src); // This has to be separate, otherwise G++ has a spit
return stlsoft_ns_qual(ref_ptr)<IDest>(static_cast<IDest*>(ptr), false);
}
/** \brief Casts between instances of wrapped instances
*
* \ingroup group__library__conversion
*
\code
stlsoft::ref_ptr<IStream> stm = . . .
try
{
stlsoft::ref_ptr<IStorage> stg = comstl::interface_cast<IStorage>(stm);
printf("Wrapper object has IStorage interface\n");
}
catch(comstl::bad_interface_cast &)
{
printf("Wrapper object does not have IStorage interface\n");
}
\endcode
*
* \note For technical reasons, the cast destination type differs from the
* conventional behaviour. Rather than specifying the actual resultant
* type, e.g. <code>stlsoft::ref_ptr<IStream></code>, just the destination
* interface type must be specified, e.g.
* <code>interface_cast<IStream></code>.
*
* \exception comstl::bad_interface_cast When compiling with exception -
* detected when <code>STLSOFT_CF_EXCEPTION_SUPPORT</code> is defined -
* this will throw an instance of comstl::bad_interface_cast if the
* requested interface cannot be acquired. When compiling absent exception
* support, this cast function is not defined; instead use
* comstl::try_interface_cast.
*/
template< ss_typename_param_k IDest
, ss_typename_param_k ISrc
>
inline stlsoft_ns_qual(ref_ptr)<IDest> interface_cast(stlsoft_ns_qual(ref_ptr)<ISrc> src)
{
return interface_cast<IDest>(src.get());
}
#endif /* STLSOFT_CF_EXCEPTION_SUPPORT */
/** \brief Attempts to cast a raw interface pointer to a wrapped instance.
*
* \ingroup group__library__conversion
*
\code
IStream* pstm = . . .
stlsoft::ref_ptr<IStorage> stg = comstl::interface_cast<IStorage>(pstm);
if(!stg.empty())
{
. . . // use stg->
}
\endcode
*
* \note For technical reasons, the cast destination type differs from the
* conventional behaviour. Rather than specifying the actual resultant
* type, e.g. <code>stlsoft::ref_ptr<IStream></code>, just the destination
* interface type must be specified, e.g.
* <code>interface_cast<IStream></code>.
*
* \return
*/
template< ss_typename_param_k IDest
, ss_typename_param_k ISrc
>
inline stlsoft_ns_qual(ref_ptr)<IDest> try_interface_cast(ISrc* src)
{
interface_cast_addref<IDest*> ptr(src); // This has to be separate, otherwise G++ has a spit
return stlsoft_ns_qual(ref_ptr)<IDest>(static_cast<IDest*>(ptr), false);
}
/** \brief Attempts to cast between instances of wrapped instances
*
* \ingroup group__library__conversion
*
* \note For technical reasons, the cast destination type differs from the
* conventional behaviour. Rather than specifying the actual resultant
* type, e.g. <code>stlsoft::ref_ptr<IStream></code>, just the destination
* interface type must be specified, e.g.
* <code>interface_cast<IStream></code>.
*/
template< ss_typename_param_k IDest
, ss_typename_param_k ISrc
>
inline stlsoft_ns_qual(ref_ptr)<IDest> try_interface_cast(stlsoft_ns_qual(ref_ptr)<ISrc> src)
{
return try_interface_cast<IDest>(src.get());
}
/* /////////////////////////////////////////////////////////////////////////
* Shims
*/
#ifdef STLSOFT_CF_EXCEPTION_SUPPORT
# if !defined(STLSOFT_COMPILER_IS_COMO) && \
!defined(STLSOFT_COMPILER_IS_GCC)
/** \brief Attribute shim to retrieve the interface pointer of the given cast instance
*
* \ingroup group__concept__shim__pointer_attribute__get_ptr
*
* \param p The cast instance
*/
template< ss_typename_param_k I
, ss_typename_param_k X
>
inline I get_ptr(comstl_ns_qual(interface_cast_noaddref)<I, X> &p)
{
return p.operator -> ();
}
# endif /* compiler */
/** \brief Attribute shim to retrieve the interface pointer of the given cast instance
*
* \ingroup group__concept__shim__pointer_attribute__get_ptr
*
* \param p The cast instance
*/
template< ss_typename_param_k I
, ss_typename_param_k X
>
inline I get_ptr(comstl_ns_qual(interface_cast_noaddref)<I, X> const& p)
{
return p.operator -> ();
}
#endif /* STLSOFT_CF_EXCEPTION_SUPPORT */
/** \brief Attribute shim to retrieve the interface pointer of the given cast instance
*
* \ingroup group__concept__shim__pointer_attribute__get_ptr
*
* \param p The cast instance
*/
template< ss_typename_param_k I
, ss_typename_param_k X
>
inline I get_ptr(comstl_ns_qual(interface_cast_addref)<I, X> &p)
{
return p;
}
/** \brief Attribute shim to retrieve the interface pointer of the given cast instance
*
* \ingroup group__concept__shim__pointer_attribute__get_ptr
*
* \param p The cast instance
*/
template< ss_typename_param_k I
, ss_typename_param_k X
>
inline I const get_ptr(comstl_ns_qual(interface_cast_addref)<I, X> const& p)
{
return p;
}
/* /////////////////////////////////////////////////////////////////////////
* Deprecated Shims
*/
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
# ifdef STLSOFT_CF_EXCEPTION_SUPPORT
template< ss_typename_param_k I
, ss_typename_param_k X
>
inline cs_bool_t is_empty(comstl_ns_qual(interface_cast_noaddref)<I, X> const& p)
{
return NULL != get_ptr(p);
}
# endif /* STLSOFT_CF_EXCEPTION_SUPPORT */
template< ss_typename_param_k I
, ss_typename_param_k X
>
inline cs_bool_t is_empty(comstl_ns_qual(interface_cast_addref)<I, X> const& p)
{
return NULL != get_ptr(p);
}
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
////////////////////////////////////////////////////////////////////////////
// Unit-testing
#ifdef STLSOFT_UNITTEST
# include "./unittest/interface_cast_unittest_.h"
#endif /* STLSOFT_UNITTEST */
/* ////////////////////////////////////////////////////////////////////// */
#ifndef _COMSTL_NO_NAMESPACE
# if defined(_STLSOFT_NO_NAMESPACE) || \
defined(STLSOFT_DOCUMENTATION_SKIP_SECTION)
} // namespace comstl
# else
} // namespace comstl_project
} // namespace stlsoft
# endif /* _STLSOFT_NO_NAMESPACE */
#endif /* !_COMSTL_NO_NAMESPACE */
/* /////////////////////////////////////////////////////////////////////////
* Namespace
*
* The string access shims exist either in the stlsoft namespace, or in the
* global namespace. This is required by the lookup rules.
*
*/
#ifndef _COMSTL_NO_NAMESPACE
# if !defined(_STLSOFT_NO_NAMESPACE) && \
!defined(STLSOFT_DOCUMENTATION_SKIP_SECTION)
namespace stlsoft
{
# else /* ? _STLSOFT_NO_NAMESPACE */
/* There is no stlsoft namespace, so must define in the global namespace */
# endif /* !_STLSOFT_NO_NAMESPACE */
using ::comstl::get_ptr;
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
using ::comstl::is_empty;
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
# if !defined(_STLSOFT_NO_NAMESPACE) && \
!defined(STLSOFT_DOCUMENTATION_SKIP_SECTION)
} // namespace stlsoft
# else /* ? _STLSOFT_NO_NAMESPACE */
/* There is no stlsoft namespace, so must define in the global namespace */
# endif /* !_STLSOFT_NO_NAMESPACE */
#endif /* !_COMSTL_NO_NAMESPACE */
/* ////////////////////////////////////////////////////////////////////// */
#endif /* !COMSTL_INCL_COMSTL_CONVERSION_HPP_INTERFACE_CAST */
/* ///////////////////////////// end of file //////////////////////////// */