DisplayState.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