scope-query.hpp

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/*
  SCOPE-QUERY.hpp  -  query to discover the contents of a container-like part of the model

  Copyright (C)         Lumiera.org
    2009,               Hermann Vosseler <Ichthyostega@web.de>

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of
  the License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY 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
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/


#ifndef STEAM_MOBJECT_SESSION_SCOPE_QUERY_H
#define STEAM_MOBJECT_SESSION_SCOPE_QUERY_H


#include "steam/mobject/placement.hpp"
#include "common/query/query-resolver.hpp"
#include "lib/format-string.hpp"

#include <functional>


namespace steam {
namespace mobject {
namespace session {
  
  using std::bind;
  using std::function;
  using std::placeholders::_1;
  
  using lumiera::Goal;
  using lumiera::Query;
  
  
  
  template<class MO>
  class DiscoveryQuery
    : public Query<Placement<MO>>
    {
      typedef Query<Placement<MO>> _Query;
      
      
    public:      
      typedef typename _Query::iterator iterator;
      
      typedef function<bool(PlacementMO const&)> ContentFilter;
      
      
      ContentFilter
      contentFilter () const
        {
          return buildContentFilter();
        }

    protected:
      virtual ContentFilter  buildContentFilter()  const  =0;
      
      
      
      
      DiscoveryQuery ()
        : _Query (_Query::defineQueryTypeID (Goal::DISCOVERY)
                 , lib::QueryText(""))  //  syntactic representation supplied on demand
        { }
      
    private:
      DiscoveryQuery const& operator=(DiscoveryQuery const&);
    };
  
  
  enum ScopeQueryKind
    { CONTENTS = 0      
    , CHILDREN          
    , PARENTS           
    , PATH              
    };
  
  
  template<class MO>
  class ScopeQuery
    : public DiscoveryQuery<MO>
    {
      typedef DiscoveryQuery<MO>   _Parent;
      typedef Query<Placement<MO>> _Query;
      
      
      PlacementMO::ID    startPoint_;
      ScopeQueryKind    to_discover_;
      
    public:
      typedef typename _Parent::iterator      iterator;
      typedef typename _Parent::ContentFilter ContentFilter;
      
      
      ScopeQuery (PlacementMO  const& scope,
                  ScopeQueryKind direction)
        : startPoint_(scope)
        , to_discover_(direction)
        { }
      
      
      
      PlacementMO::ID const&
      searchScope ()  const
        {
          return startPoint_;
        }
      
      ScopeQueryKind
      searchDirection ()  const
        {
          return to_discover_;
        }
      
      
      
    private:
      ContentFilter
      buildContentFilter()  const
        {
          return bind (&PlacementMO::isCompatible<MO>, _1 );
        }
      
      lib::QueryText
      buildSyntacticRepresentation()  const
        {
          using util::_Fmt;
          TODO ("valid syntactic representation of scope queries");
          return lib::QueryText (_Fmt ("scope(X, %08X), scopeRelation(X, %d)")
                                      % hash_value(searchScope())        
                                      % uint(searchDirection()));        
        }
    };
  
  
  template<class MO>
  struct ContentsQuery
    : ScopeQuery<MO>
    {
      ContentsQuery (PlacementMO  const& scope)
        : ScopeQuery<MO> (scope, CONTENTS)
        { }
      
    };
  
  
  template<class MO>
  struct PathQuery
    : ScopeQuery<MO>
    {
      PathQuery (PlacementMO  const& scope)
        : ScopeQuery<MO> (scope, PARENTS)
        { }
      
    };
  
  


}}} // namespace steam::mobject::session
#endif