Initial revision

Lib/Debug/logstream.hxx

@@ -0,0 +1,231 @@
+// Stream based logging mechanism.
+//
+// Written by Bernie Bright, 1998
+//
+// Copyright (C) 1998  Bernie Bright - bbright@c031.aone.net.au
+//
+// 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.
+//
+// $Id$
+// (Log is kept at end of this file)
+
+#ifndef _LOGSTREAM_H
+#define _LOGSTREAM_H
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+
+#include <Include/compiler.h>
+
+#ifdef FG_HAVE_STD_INCLUDES
+# include <streambuf>
+# include <iostream>
+#else
+# include <iostream.h>
+# include "Include/fg_traits.hxx"
+#endif
+
+#include "debug_types.h"
+
+#ifndef FG_HAVE_NATIVE_SGI_COMPILERS
+FG_USING_STD(streambuf);
+FG_USING_STD(ostream);
+FG_USING_STD(cerr);
+FG_USING_STD(endl);
+#endif
+
+//
+// TODO:
+//
+// 1. Change output destination. Done.
+// 2. Make logbuf thread safe.
+// 3. Read environment for default debugClass and debugPriority.
+//
+
+//-----------------------------------------------------------------------------
+//
+// logbuf is an output-only streambuf with the ability to disable sets of
+// messages at runtime. Only messages with priority >= logbuf::logPriority
+// and debugClass == logbuf::logClass are output.
+//
+class logbuf : public streambuf
+{
+public:
+
+#ifndef FG_HAVE_STD_INCLUDES
+    typedef char_traits<char>           traits_type;
+    typedef char_traits<char>::int_type int_type;
+    typedef char_traits<char>::pos_type pos_type;
+    typedef char_traits<char>::off_type off_type;
+#endif
+//     logbuf( streambuf* sb ) : sbuf(sb) {}
+    logbuf();
+    ~logbuf();
+
+    // Is logging enabled?
+    bool enabled() { return logging_enabled; }
+
+    // Set the logging level of subsequent messages.
+    void set_log_state( fgDebugClass c, fgDebugPriority p );
+
+    // Set the global logging level.
+    static void set_log_level( fgDebugClass c, fgDebugPriority p );
+
+    //
+    void set_sb( streambuf* sb );
+
+protected:
+
+    inline virtual int sync();
+    int_type overflow( int ch );
+//     int xsputn( const char* s, istreamsize n );
+
+private:
+
+    // The streambuf used for actual output. Defaults to cerr.rdbuf().
+    static streambuf* sbuf;
+
+    static bool logging_enabled;
+    static fgDebugClass logClass;
+    static fgDebugPriority logPriority;
+
+private:
+
+    // Not defined.
+    logbuf( const logbuf& );
+    void operator= ( const logbuf& );
+};
+
+inline int
+logbuf::sync()
+{
+#ifdef FG_HAVE_STD_INCLUDES
+	return sbuf->pubsync();
+#else
+	return sbuf->sync();
+#endif
+}
+
+inline void
+logbuf::set_log_state( fgDebugClass c, fgDebugPriority p )
+{
+    logging_enabled = ((c & logClass) != 0 && p >= logPriority);
+}
+
+inline logbuf::int_type
+logbuf::overflow( int c )
+{
+    return logging_enabled ? sbuf->sputc(c) : (EOF == 0 ? 1: 0);
+}
+
+//-----------------------------------------------------------------------------
+//
+// logstream manipulator for setting the log level of a message.
+//
+struct loglevel
+{
+    loglevel( fgDebugClass c, fgDebugPriority p )
+	: logClass(c), logPriority(p) {}
+
+    fgDebugClass logClass;
+    fgDebugPriority logPriority;
+};
+
+//-----------------------------------------------------------------------------
+//
+// A helper class that ensures a streambuf and ostream are constructed and
+// destroyed in the correct order.  The streambuf must be created before the
+// ostream but bases are constructed before members.  Thus, making this class
+// a private base of logstream, declared to the left of ostream, we ensure the
+// correct order of construction and destruction.
+//
+struct logstream_base
+{
+//     logstream_base( streambuf* sb ) : lbuf(sb) {}
+    logstream_base() {}
+
+    logbuf lbuf;
+};
+
+//-----------------------------------------------------------------------------
+//
+// 
+//
+class logstream : private logstream_base, public ostream
+{
+public:
+    // The default is to send messages to cerr.
+    logstream( ostream& out )
+// 	: logstream_base(out.rdbuf()),
+	: logstream_base(),
+	  ostream(&lbuf) { lbuf.set_sb(out.rdbuf());}
+
+    void set_output( ostream& out ) { lbuf.set_sb( out.rdbuf() ); }
+
+    // Set the global log class and priority level.
+     void setLogLevels( fgDebugClass c, fgDebugPriority p );
+
+    // Output operator to capture the debug level and priority of a message.
+    inline ostream& operator<< ( const loglevel& l );
+};
+
+inline ostream&
+logstream::operator<< ( const loglevel& l )
+{
+    lbuf.set_log_state( l.logClass, l.logPriority );
+    return *this;
+}
+
+//-----------------------------------------------------------------------------
+//
+// Return the one and only logstream instance.
+// We use a function instead of a global object so we are assured that cerr
+// has been initialised.
+//
+inline logstream&
+fglog()
+{
+    static logstream logstrm( cerr );
+    return logstrm;
+}
+
+#ifdef FG_NDEBUG
+# define FG_LOG(C,P,M)
+#else
+# define FG_LOG(C,P,M) fglog() << loglevel(C,P) << M << endl
+#endif
+
+#endif // _LOGSTREAM_H
+
+// $Log$
+// Revision 1.1  1999/04/05 21:32:33  curt
+// Initial revision
+//
+// Revision 1.4  1999/03/02 01:01:47  curt
+// Tweaks for compiling with native SGI compilers.
+//
+// Revision 1.3  1999/01/19 20:53:35  curt
+// Portability updates by Bernie Bright.
+//
+// Revision 1.2  1998/11/07 19:07:02  curt
+// Enable release builds using the --without-logging option to the configure
+// script.  Also a couple log message cleanups, plus some C to C++ comment
+// conversion.
+//
+// Revision 1.1  1998/11/06 21:20:42  curt
+// Initial revision.
+//