transmitter.h

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/*
 * Copyright (C) 1998-2016 Paul Davis <paul@linuxaudiosystems.com>
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
#ifndef __libmisc_transmitter_h__
#define __libmisc_transmitter_h__
 
#include <sstream>
#include <iostream>
 
#include <pbd/signals.h>
 
#include "pbd/libpbd_visibility.h"
 
class LIBPBD_API Transmitter : public std::stringstream
 
{
  public:
        enum Channel {
                Debug,
                Info,
                Error,
                Warning,
                Fatal,
                Throw
        };
 
        Transmitter (Channel);
 
        PBD::Signal2<void,Channel, const char *> &sender() {
                return *send;
        }
 
        bool does_not_return ();
 
  protected:
        virtual void deliver ();
        friend std::ostream& endmsg (std::ostream &);
 
  private:
        Channel channel;
        PBD::Signal2<void, Channel, const char *> *send;
 
        PBD::Signal2<void, Channel, const char *> debug;
        PBD::Signal2<void, Channel, const char *> info;
        PBD::Signal2<void, Channel, const char *> warning;
        PBD::Signal2<void, Channel, const char *> error;
        PBD::Signal2<void, Channel, const char *> fatal;
};
 
/* for EGCS 2.91.66, if this function is not compiled within the same
   compilation unit as the one where a ThrownError is thrown, then
   nothing will catch the error. This is a pretty small function, so
   inlining it here seems like a reasonable workaround.
*/
 
inline std::ostream &
endmsg (std::ostream &ostr)
 
{
        Transmitter *t;
 
        /* There is a serious bug in the Cygnus/GCC libstdc++ library:
           cout is not actually an ostream, but a trick was played
           to make the compiler think that it is. This will cause
           the dynamic_cast<> to fail with SEGV. So, first check to
           see if ostr == cout, and handle it specially.
        */
 
        if (&ostr == &std::cout) {
                std::cout << std::endl;
                return ostr;
        } else if (&ostr == &std::cerr) {
                std::cerr << std::endl;
                return ostr;
        }
 
        if ((t = dynamic_cast<Transmitter *> (&ostr)) != 0) {
                t->deliver ();
        } else {
                /* hmm. not a Transmitter, so just put a newline on
                   it and assume that that will be enough.
                */
 
                ostr << std::endl;
        }
 
        return ostr;
}
 
 
extern "C" { LIBPBD_API void pbd_c_error (const char *); }
 
#endif // __libmisc_transmitter_h__