State.h

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//# State.h: global display state
//# Copyright (C) 2009
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 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 Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//#        Internet email: aips2-request@nrao.edu.
//#        Postal address: AIPS++ Project Office
//#                        National Radio Astronomy Observatory
//#                        520 Edgemont Road
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//#

#ifndef CASA_DISPLAY_STATE_H_
#define CASA_DISPLAY_STATE_H_

namespace casa { //# NAMESPACE CASA - BEGIN

    namespace display { //# NAMESPACE DISPLAY - BEGIN
        class state {
            friend class stateCleanup;
        public:

            static state &instance( ) { return initialized == false ? startup( ) : *singleton; }

            // allows classes (primarily in the redisplay chain) to tell if we
            // are currently outputing to a file...
            bool fileOutputMode( );
            // begin file output
            void beginFileOutputMode( );
            // end file output
            void endFileOutputMode( );
            
        private:

            static state *singleton;

            state( ) : file_output_mode_count_(0) { }
            ~state( ) { }

            static state &startup( );
            static void shutdown( );

            int file_output_mode_count_;
            static bool initialized;

        };

        static class stateCleanup {
        public:
            stateCleanup( ) { creation_count += 1; }
            ~stateCleanup( ) { if ( --creation_count == 0 ) { state::shutdown( ); } }
        private:
            static unsigned int creation_count;
        } local_state_cleanup_object;
    }

}

#endif