command-registry.hpp

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/*
  COMMAND-REGISTRY.hpp  -  steam-Command object registration and storage management

  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 CONTROL_COMMAND_REGISTRY_H
#define CONTROL_COMMAND_REGISTRY_H

#include "lib/error.hpp"
#include "lib/depend.hpp"
#include "lib/sync.hpp"
#include "include/logging.h"
#include "lib/nocopy.hpp"
#include "lib/util.hpp"

#include "steam/control/command.hpp"
#include "steam/control/command-signature.hpp"
#include "steam/control/command-storage-holder.hpp"
#include "lib/typed-allocation-manager.hpp"

#include <boost/functional/hash.hpp>
#include <unordered_map>
#include <memory>
#include <string>
#include <map>



namespace steam {
namespace control {
  
  using boost::hash;
  using std::shared_ptr;
  using std::unordered_map;
  using lib::TypedAllocationManager;
  using util::getValue_or_default;
  using util::contains;
  using std::string;
  using std::map;
  
  
  struct order_by_impl
    {
      bool
      operator() (const Command *pC1, const Command *pC2)  const
        {
          return (!pC1 && pC2)
              || ( pC1 && pC2  && (*pC1 < *pC2));
        }
    };
  
  
  class CommandRegistry
    : public lib::Sync<>
    , util::NonCopyable
    {
      // using a hashtable to implement the index
      typedef unordered_map<Symbol, Command, hash<Symbol>> CmdIndex;
      typedef map< const Command*, Symbol, order_by_impl> ReverseIndex;
      
      TypedAllocationManager allocator_;
      CmdIndex index_;
      ReverseIndex ridx_;
      
      
    public:
      static lib::Depend<CommandRegistry> instance;
      
      
     ~CommandRegistry()
        {
          if (0 < index_size())
            TRACE (command, "Shutting down Command system...");
          ridx_.clear();
          index_.clear();
        }
      
      
      
      void
      track (Symbol cmdID, Command const& commandHandle)
        {
          Lock sync{this};
          
          REQUIRE (commandHandle);
          if (contains (index_,cmdID) || contains(ridx_, &commandHandle))
            commandHandle.duplicate_detected(cmdID);
          
          Command& indexSlot = index_[cmdID];
          indexSlot = commandHandle;
          ridx_[&indexSlot] = cmdID;
          
          ENSURE (contains(ridx_, &indexSlot));
          ENSURE (contains(index_, cmdID));
        }
      
      
      bool
      remove (Symbol cmdID)
        {
          Lock sync{this};
          
          bool actually_remove = contains (index_,cmdID);
          if (actually_remove)
            {
              ridx_.erase(& index_[cmdID]);
              index_.erase(cmdID);
            }
          ENSURE (!contains (index_,cmdID));
          return actually_remove;
        }
      
      
      Command
      queryIndex (Symbol cmdID)
        {
          Lock sync{this};
          return getValue_or_default (index_, cmdID, Command() );
        }                                           //if not found
      
      
      Symbol
      findDefinition (Command const& cmdInstance)  const
        {
          Lock sync{this};
          return getValue_or_default (ridx_, &cmdInstance, Symbol::BOTTOM );
        }                                   //used as Key
      
      
      size_t
      index_size()  const
        {
          return index_.size();
        }
      
      
      size_t
      instance_count()  const
        {
          return allocator_.numSlots<CommandImpl>();
        }
      
      
      template< typename SIG_OPER    
              , typename SIG_CAPT    
              , typename SIG_UNDO    
              >
      shared_ptr<CommandImpl>
      newCommandImpl (function<SIG_OPER>& operFunctor
                     ,function<SIG_CAPT>& captFunctor
                     ,function<SIG_UNDO>& undoFunctor)
        {
          
          // derive the storage type necessary
          // to hold the command arguments and UNDO memento
          typedef typename UndoSignature<SIG_CAPT>::Memento Mem;
          typedef StorageHolder<SIG_OPER,Mem> Arguments;
          
          shared_ptr<Arguments> pArg (allocator_.create<Arguments>());
          
          return allocator_.create<CommandImpl> (pArg, operFunctor,captFunctor,undoFunctor);
        }
      
      
      
      
      shared_ptr<CommandImpl>
      createCloneImpl (CommandImpl const& refObject);
      
      
    };
  
  
}} // namespace steam::control
#endif