dispatcher_r_0.h

Go to the documentation of this file.

/** @file
 *  @author Bram de Greve (bram@cocamware.com)
 *  @author Tom De Muer (tom@cocamware.com)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2004-2025 the Initial Developer.
 *  All Rights Reserved.
 *  
 *  Contributor(s):
 *
 *  Alternatively, the contents of this file may be used under the terms of the 
 *  GNU General Public License Version 2 or later (the GPL), in which case the 
 *  provisions of GPL are applicable instead of those above.  If you wish to allow use
 *  of your version of this file only under the terms of the GPL and not to allow 
 *  others to use your version of this file under the CPAL, indicate your decision by 
 *  deleting the provisions above and replace them with the notice and other 
 *  provisions required by the GPL License. If you do not delete the provisions above,
 *  a recipient may use your version of this file under either the CPAL or the GPL.
 *  
 *  *** END LICENSE INFORMATION ***
 */
 
#ifndef LASS_GUARDIAN_OF_INCLUSION_UTIL_IMPL_DISPATCHER_R_0_H
#define LASS_GUARDIAN_OF_INCLUSION_UTIL_IMPL_DISPATCHER_R_0_H
 
#include "dispatcher_allocator.h"
#include "../callback_common.h"
 
// --- NEW INTERFACES ----------------------------------------------------------
 
namespace lass
{
namespace util
{
namespace impl
{
 
/** abstract base class of all dispatchers for lass::util::CallbackR0.
 *  @internal
 *  @sa CallbackR0
 *  @author Bram de Greve [Bramz]
 */
template
<
    typename R
>
class DispatcherR0: public TDispatcherAllocatorBase
{
public:
 
    DispatcherR0() {}
    virtual ~DispatcherR0() {}
    R call() const 
    { 
        return doCall(); 
    }
    bool isEquivalent(const DispatcherR0<R>* iOther) const
    {
        return doIsEquivalent(iOther);
    }
 
protected:
 
    DispatcherR0(const DispatcherR0<R>& /*iOther*/) {}
 
private:
 
    virtual R doCall() const = 0;
    virtual bool doIsEquivalent(const DispatcherR0<R>* iOther) const = 0;
 
    DispatcherR0& operator=(const DispatcherR0<R>& iOther);
};
 
 
 
/** Dispatcher for lass::util::CallbackR0 to a free function:
 *  @internal
 *  @sa CallbackR0
 *  @author Bram de Greve [Bramz]
 */
template
<
    typename R,
    typename FunctionType,
    typename Enable = void
>
class DispatcherR0Function: public DispatcherR0<R>
{
public:
 
    typedef DispatcherR0Function<R, FunctionType, Enable> TSelf;
    typedef FunctionType TFunction;
 
    DispatcherR0Function(typename CallTraits<TFunction>::TParam iFunction):
        function_(iFunction)
    {
    }
 
    const TFunction& function() const
    {
        return function_;
    }
 
private:
 
    R doCall() const override
    {
        if (!function_)
        {
            LASS_THROW_EX(EmptyCallback, "You've tried to call an empty CallbackR0.  Can't return a value.");
        }
        return function_();
    }
    bool doIsEquivalent(const DispatcherR0<R>* other) const override
    {
        if constexpr (impl::IsEqualityComparable<TFunction>::value)
        {
            return other && typeid( *other ) == typeid( TSelf )
                && static_cast<const TSelf*>(other)->function_ == function_;
        }
        else
        {
            return false;
        }
    }
 
    TFunction function_;
};
 
 
 
#if LASS_HAVE_CPP_STD_11 && !LASS_HAVE_LAMBDA_OPERATOR_NOT
 
/** Dispatcher for lass::util::CallbackR0 to a callable that does not support operator!
 *  @internal
 *  @sa CallbackR0
 *  @author Bram de Greve [Bramz]
 * 
 *  With C++11, lambdas can also be used as callables. But the MSVC compiler did not support
 *  the unary ! operator. This was fixed in VS 2019 version 16.2.
 *  https://twitter.com/lunasorcery/status/1092870113374687232
 */
template
<
    typename R,
    typename FunctionType
>
class DispatcherR0Function
    <
        R,
        FunctionType,
        typename meta::EnableIf<!HasOperatorNot<FunctionType>::value>::Type
    >
    : public DispatcherR0<R>
{
public:
 
    typedef FunctionType TFunction;
 
    DispatcherR0Function(typename CallTraits<TFunction>::TParam iFunction):
        function_(iFunction)
    {
    }
 
    const TFunction& function() const
    {
        return function_;
    }
 
private:
 
    R doCall() const override
    {
        return function_();
    }
    bool doIsEquivalent(const DispatcherR0<R>* /*iOther*/) const override
    {
        return false;
    }
 
    TFunction function_;
};
 
#endif
 
 
 
/** Dispatcher for lass::util::CallbackR0 to an object/method pair.
 *  @internal
 *  @sa CallbackR0
 *  @author Bram de Greve [Bramz]
 */
template
<
    typename R,
    typename ObjectPtr,
    typename Method
>
class DispatcherR0Method: public DispatcherR0<R>
{
public:
 
    typedef DispatcherR0Method<R, ObjectPtr, Method> TSelf;
 
    DispatcherR0Method(typename CallTraits<ObjectPtr>::TParam iObject,
                       typename CallTraits<Method>::TParam iMethod):
        object_(iObject),
        method_(iMethod)
    {
    }
 
private:
 
    R doCall() const override
    {
        if (!object_ || !method_)
        {
            LASS_THROW_EX(EmptyCallback, "You've tried to call an empty CallbackR0.  Can't return a value.");
        }
        return ((*object_).*method_)();
    }
    bool doIsEquivalent(const DispatcherR0<R>* iOther) const override
    {
        const TSelf* other = dynamic_cast<const TSelf*>(iOther);
        return other && object_ == other->object_ && method_ == other->method_;
    }
 
    ObjectPtr object_;
    Method method_;
};
 
}
 
}
 
}
 
#endif // Guardian of Inclusion
 
 
// EOF