command.hpp

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/*
  COMMAND.hpp  -  Key abstraction for steam/edit operations and UNDO 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_H
#define CONTROL_COMMAND_H

#include "lib/error.hpp"
#include "lib/symbol.hpp"
#include "steam/common.hpp"
#include "steam/control/argument-erasure.hpp"
#include "steam/control/argument-tuple-accept.hpp"
#include "steam/control/handling-pattern.hpp"
#include "lib/meta/tuple-helper.hpp"
#include "lib/diff/gen-node.hpp"
#include "lib/handle.hpp"

#include <string>


namespace lumiera {
namespace error {
  LUMIERA_ERROR_DECLARE (UNBOUND_ARGUMENTS);  
  LUMIERA_ERROR_DECLARE (INVALID_COMMAND);    
  LUMIERA_ERROR_DECLARE (DUPLICATE_COMMAND);  
  LUMIERA_ERROR_DECLARE (INVALID_ARGUMENTS);  
  LUMIERA_ERROR_DECLARE (MISSING_MEMENTO);  
}}

namespace steam {
namespace control {
  
  using std::string;
  using lib::Symbol;
  using std::shared_ptr;
  using lib::meta::Tuple;
  using lib::meta::Types;
  
  using FuncPtr = void*;
  
  class CommandDef;
  class CommandImpl;
  
  
  class Command
    : public AcceptAnyBinding<Command       // accepts arbitrary bind(..) calls (with runtime check)
           , Command&                      //  (return value of bind() functions is *this)
           , lib::Handle<CommandImpl>     //   actually implemented as ref counting Handle
           >                             //
    {
      typedef lib::Handle<CommandImpl> _Handle;
      
    public:
      /* === command registry === */
      static Command get (Symbol cmdID);
      static bool remove (Symbol cmdID);
      
      Command storeDef (Symbol newCmdID)  const;
      Command newInstance ()  const;
      
      static Command maybeGetNewInstance (Symbol cmdID);
      
      
      Command (Symbol cmdID) { *this = get (cmdID); }
      Command() { }          
     ~Command();
      
      // default copy acceptable
      Command (Command &&)  = default;
      Command (Command const&) = default;
      Command& operator= (Command &&) = default;
      Command& operator= (Command const&) = default;
      
      
      
      /* === command lifecycle === */
      
      template<typename...TYPES>
      Command& bindArg (std::tuple<TYPES...> const&);
      
      Command& bindArg (lib::diff::Rec const&);
      
      Command& unbind();
      
      
      ExecResult operator() () ;
      ExecResult exec () ;
      ExecResult undo () ;
      
      
      ExecResult exec (HandlingPattern const& execPattern);
      ExecResult exec (HandlingPattern::ID);
      
      ExecResult undo (HandlingPattern const& execPattern);
      ExecResult undo (HandlingPattern::ID);
      
      ExecResult execSync ();
      
      HandlingPattern::ID getDefaultHandlingPattern()  const;
      
      HandlingPattern::ID setHandlingPattern (HandlingPattern::ID);
      
      
      
      /* === diagnostics === */
      
      static size_t definition_count();
      static size_t instance_count();
      
      bool canExec()  const;
      bool canUndo()  const;
      
      static bool defined (Symbol cmdID);
      static bool canExec (Symbol cmdID);
      static bool canUndo (Symbol cmdID);
      
      void duplicate_detected (Symbol)  const;
      
      Symbol getID() const noexcept;
      bool isAnonymous() const;
      
      operator string() const;
      friend bool operator== (Command const&, Command const&);
      friend bool operator<  (Command const&, Command const&);
      
      
    protected:
      static Command fetchDef (Symbol cmdID);
      void activate (shared_ptr<CommandImpl> &&, Symbol cmdID =0);
      
      friend class CommandDef; //...invoking those two functions during definition stage
      
      
    private:
      void setArguments (Arguments&);
      void setArguments (lib::diff::Rec const&);
    };
  
  
  
  
  
  inline ExecResult
  Command::operator() ()
  {
    return exec (getDefaultHandlingPattern());
  }
  
  inline ExecResult
  Command::exec ()
  {
    return exec (getDefaultHandlingPattern());
  }
  
  inline ExecResult
  Command::undo ()
  {
    return undo (getDefaultHandlingPattern());
  }
  
  
  template<typename...TYPES>
  inline Command&
  Command::bindArg (std::tuple<TYPES...> const& tuple)
  {
    TypedArguments<std::tuple<TYPES...>> args(tuple);
    this->setArguments (args);
    return *this;
  }
  
  
  inline Command&
  Command::bindArg (lib::diff::Rec const& paramData)
  {
    this->setArguments (paramData);
    return *this;
  }

  
  
  
  /* == state predicate shortcuts == */
  
  inline bool
  Command::defined (Symbol cmdID)
  {
    return fetchDef(cmdID).isValid();
  }
  
  
#define _FAILSAFE_COMMAND_QUERY(_ID_, _QUERY_) \
      try                                       \
        {                                        \
          return Command::get(_ID_)._QUERY_;      \
        }                                          \
      catch(lumiera::error::Invalid&)              \
        {                                          \
          lumiera_error(); /* ignore errorstate */ \
          return false;                            \
        }
  
  
  inline bool
  Command::canExec (Symbol cmdID)
  {
    _FAILSAFE_COMMAND_QUERY (cmdID, canExec() );
  }
  
  
  inline bool
  Command::canUndo (Symbol cmdID)
  {
    _FAILSAFE_COMMAND_QUERY (cmdID, canUndo() );
  }

#undef _FAILSAFE_COMMAND_QUERY
  
  
  
  
  inline bool
  operator== (Command const& c1, Command const& c2)
  {
    return (!c1 && !c2)
        || ( c1 &&  c2  && (&c1.impl() == &c2.impl()));
  }
  
  inline bool
  operator!= (Command const& c1, Command const& c2)
  {
    return not (c1 == c2);
  }
  
  inline bool
  operator< (Command const& c1, Command const& c2)
  {
    return (!c1 && c2)
        || ( c1 && c2 && (&c1.impl() < &c2.impl()));
  }
  
  
  
  
}} // namespace steam::control
#endif