GaudiComponentVisitor.h

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/*
  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
*/
 
/* Dear emacs, this is -*-c++-*- */
#ifndef _ComponentVisitor_H_
#define _ComponentVisitor_H_
 
#include <vector>
#include <set>
#include <type_traits>
#include <regex>
 
#include "GaudiKernel/IAlgTool.h"
#include "GaudiKernel/Algorithm.h"
 
namespace xGaudi {
   class ComponentVisitorBase {
   protected:
      static const std::regex s_noFilter;
   };

   template <class T_Component, class T_TestVisited = std::set<T_Component*> >
   class ComponentVisitor : public ComponentVisitorBase {
      struct IVisitor {
         virtual ~IVisitor()                      = default;
         virtual void visit( T_Component* ) const = 0;
      };
 
   public:
      static std::vector<T_Component *> *getChilds(T_Component *a_component);

      template <typename Callable, typename = std::enable_if_t<std::is_invocable_r_v<void, Callable, T_Component*>>>
      static T_TestVisited visit( const std::vector<T_Component*>& components,
                                  Callable& callable,
                                  const std::regex& reject_filter = ComponentVisitorBase::s_noFilter,
                                  T_TestVisited &&ignore = T_TestVisited()) {
         class Visitor final : public IVisitor {
            const Callable* m_func;
 
         public:
            Visitor( Callable* f ) : m_func{f} {}
            void visit( T_Component* a_component ) const override { std::invoke( *m_func, a_component ); }
         };
         recursiveVisit( components, Visitor{&callable}, reject_filter, ignore );
         return std::move (ignore);
      }
 
   private:
      static void             recursiveVisit( const std::vector<T_Component*>& components, IVisitor const& visitor,
                                              const std::regex& reject_filter,
                                              T_TestVisited &visited);
   };
 
   class NoVisitTester {
   public:
      std::pair<bool,bool> insert(const Gaudi::Algorithm *) { return std::make_pair(true,true); }
   };
 
   using ToolVisitor      = ComponentVisitor<IAlgTool>;
   using AlgorithmVisitor = ComponentVisitor<Gaudi::Algorithm, NoVisitTester>;
}
#endif