include/qore/QoreNodeEvalOptionalRefHolder.h (4311)

/* -*- mode: c++; indent-tabs-mode: nil -*- */
/*
  QoreNodeEvalOptionalRefHolder.h
  
  Qore Programming Language

  Copyright 2003 - 2011 David Nichols

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#ifndef _QORE_QORENODEEVALOPTIONALREFHOLDER_H

#define _QORE_QORENODEEVALOPTIONALREFHOLDER_H


class QoreNodeEvalOptionalRefHolder {
   private:
      AbstractQoreNode *val;
      ExceptionSink *xsink;
      bool needs_deref;

      DLLLOCAL void discard_intern() {
         if (needs_deref && val)
            val->deref(xsink);
      }

      DLLLOCAL QoreNodeEvalOptionalRefHolder(const QoreNodeEvalOptionalRefHolder&);

      DLLLOCAL QoreNodeEvalOptionalRefHolder& operator=(const QoreNodeEvalOptionalRefHolder&);


      DLLLOCAL void *operator new(size_t);

   public:
      DLLLOCAL QoreNodeEvalOptionalRefHolder(ExceptionSink *n_xsink) : val(0), xsink(n_xsink), needs_deref(false) {
      }

      DLLLOCAL QoreNodeEvalOptionalRefHolder(const AbstractQoreNode *exp, ExceptionSink *n_xsink) : xsink(n_xsink) {
         if (exp)
            val = exp->eval(needs_deref, xsink);
         else {
            val = 0;
            needs_deref = false;
         }          
      }

      DLLLOCAL ~QoreNodeEvalOptionalRefHolder() {
         discard_intern();
      }
      
      DLLLOCAL void discard() {
         discard_intern();
         needs_deref = false;
         val = 0;
      }

      DLLLOCAL void assign(bool n_needs_deref, AbstractQoreNode *n_val) {
         discard_intern();
         needs_deref = n_needs_deref;
         val = n_val;
      }

      DLLLOCAL AbstractQoreNode *getReferencedValue() {
         if (needs_deref)
            needs_deref = false;
         else if (val)
            val->ref();
         return val;
      }

      DLLLOCAL const AbstractQoreNode *operator->() const { return val; }

      DLLLOCAL const AbstractQoreNode *operator*() const { return val; }

      DLLLOCAL operator bool() const { return val != 0; }

      DLLLOCAL bool isTemp() const { return needs_deref; }

};

#endif