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/*
* Copyright 2012 Canonical Ltd.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 3, as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranties of
* MERCHANTABILITY, SATISFACTORY QUALITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* version 3 along with this program. If not, see
* <http://www.gnu.org/licenses/>
*
* Authored by: Sam Spilsbury <sam.spilsbury@canonical.com>
*
*/
#ifndef _UNITY_ABSTRACT_INTERFACE_GENERATOR_H
#define _UNITY_ABSTRACT_INTERFACE_GENERATOR_H
#include <memory>
#include <functional>
namespace unity
{
namespace internal
{
template <class ConcreteCollection>
class ReverseWrapper
{
private:
ConcreteCollection const& collection_;
public:
ReverseWrapper(ConcreteCollection const& collection)
: collection_(collection)
{
}
decltype(collection_.rbegin ()) begin() const { return collection_.rbegin(); }
decltype(collection_.rend ()) end () const { return collection_.rend(); }
};
}
/*
* This can be passed to objects which want to visit some interfaces
* they can use from a collection of concrete objects they do not need
* to know about
*/
template <class AbstractInterface>
class AbstractInterfaceGenerator
{
public:
typedef std::shared_ptr <AbstractInterfaceGenerator<AbstractInterface> > Ptr;
typedef std::function <void (AbstractInterface &)> InterfaceVisitor;
virtual ~AbstractInterfaceGenerator () {}
virtual void VisitEachInterface (InterfaceVisitor const& visit) = 0;
virtual void VisitEachInterfaceReverse (InterfaceVisitor const& visit) = 0;
};
/*
* This is a helper template to retrieve abstract interfaces from collections
* containing concrete types. For example a CompWindowList or CompWindowVector
* for which you might want to retreive a relevant FooInterface from each
* element.
*/
template <class AbstractInterface, class ConcreteCollection>
class AbstractInterfaceCollectionGenerator :
public AbstractInterfaceGenerator <AbstractInterface>
{
public:
typedef AbstractInterfaceGenerator<AbstractInterface> InterfaceGenerator;
typedef typename InterfaceGenerator::InterfaceVisitor Visitor;
typedef std::function <AbstractInterface & (typename ConcreteCollection::value_type const&) >
ElementRetrievalFunc;
AbstractInterfaceCollectionGenerator (ConcreteCollection const& collection,
ElementRetrievalFunc const& retrieval)
: collection_(collection)
, retrieval_(retrieval)
{
}
void VisitEachInterface(Visitor const& visit)
{
VisitEachInterfaceInternal(collection_, visit);
}
void VisitEachInterfaceReverse(Visitor const& visit)
{
VisitEachInterfaceInternal(internal::ReverseWrapper<ConcreteCollection> (collection_), visit);
}
private:
template <class Container>
void VisitEachInterfaceInternal(Container const& container,
Visitor const& visit)
{
for (typename ConcreteCollection::value_type const& item : container)
{
AbstractInterface& interface (retrieval_ (item));
visit (interface);
}
}
ConcreteCollection const& collection_;
ElementRetrievalFunc retrieval_;
};
}
#endif
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