1 /** \file logstream.hxx
2 * Stream based logging mechanism.
5 // Written by Bernie Bright, 1998
7 // Copyright (C) 1998 Bernie Bright - bbright@c031.aone.net.au
9 // This library is free software; you can redistribute it and/or
10 // modify it under the terms of the GNU Library General Public
11 // License as published by the Free Software Foundation; either
12 // version 2 of the License, or (at your option) any later version.
14 // This library is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 // Library General Public License for more details.
19 // You should have received a copy of the GNU Library General Public
20 // License along with this library; if not, write to the
21 // Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 // Boston, MA 02111-1307, USA.
29 #include <simgear/compiler.h>
31 // At least Irix needs this
32 #ifdef SG_HAVE_NATIVE_SGI_COMPILERS
33 #include <char_traits.h>
36 #ifdef SG_HAVE_STD_INCLUDES
40 # include <iostream.h>
41 # include <simgear/sg_traits.hxx>
44 #include <simgear/debug/debug_types.h>
46 #ifndef SG_HAVE_NATIVE_SGI_COMPILERS
47 SG_USING_STD(streambuf);
48 SG_USING_STD(ostream);
53 SG_USING_STD(char_traits);
57 SG_USING_STD(iostream);
63 // 1. Change output destination. Done.
64 // 2. Make logbuf thread safe.
65 // 3. Read environment for default debugClass and debugPriority.
69 * logbuf is an output-only streambuf with the ability to disable sets of
70 * messages at runtime. Only messages with priority >= logbuf::logPriority
71 * and debugClass == logbuf::logClass are output.
73 class logbuf : public streambuf
77 #ifndef SG_HAVE_STD_INCLUDES
78 typedef char_traits<char> traits_type;
79 typedef char_traits<char>::int_type int_type;
80 // typedef char_traits<char>::pos_type pos_type;
81 // typedef char_traits<char>::off_type off_type;
83 // logbuf( streambuf* sb ) : sbuf(sb) {}
92 * @return true or false*/
93 bool enabled() { return logging_enabled; }
96 * Set the logging level of subsequent messages.
97 * @param c debug class
100 void set_log_state( sgDebugClass c, sgDebugPriority p );
103 * Set the global logging level.
104 * @param c debug class
107 static void set_log_level( sgDebugClass c, sgDebugPriority p );
111 * Set the allowed logging classes.
112 * @param c All enabled logging classes anded together.
114 static void set_log_classes (sgDebugClass c);
118 * Get the logging classes currently enabled.
119 * @return All enabled debug logging anded together.
121 static sgDebugClass get_log_classes ();
125 * Set the logging priority.
126 * @param c The priority cutoff for logging messages.
128 static void set_log_priority (sgDebugPriority p);
132 * Get the current logging priority.
133 * @return The priority cutoff for logging messages.
135 static sgDebugPriority get_log_priority ();
139 * Set the stream buffer
140 * @param sb stream buffer
142 void set_sb( streambuf* sb );
147 inline virtual int sync();
150 int_type overflow( int ch );
151 // int xsputn( const char* s, istreamsize n );
155 // The streambuf used for actual output. Defaults to cerr.rdbuf().
156 static streambuf* sbuf;
158 static bool logging_enabled;
159 static sgDebugClass logClass;
160 static sgDebugPriority logPriority;
165 logbuf( const logbuf& );
166 void operator= ( const logbuf& );
172 #ifdef SG_HAVE_STD_INCLUDES
173 return sbuf->pubsync();
180 logbuf::set_log_state( sgDebugClass c, sgDebugPriority p )
182 logging_enabled = ((c & logClass) != 0 && p >= logPriority);
185 inline logbuf::int_type
186 logbuf::overflow( int c )
188 return logging_enabled ? sbuf->sputc(c) : (EOF == 0 ? 1: 0);
192 * logstream manipulator for setting the log level of a message.
196 loglevel( sgDebugClass c, sgDebugPriority p )
197 : logClass(c), logPriority(p) {}
199 sgDebugClass logClass;
200 sgDebugPriority logPriority;
204 * A helper class that ensures a streambuf and ostream are constructed and
205 * destroyed in the correct order. The streambuf must be created before the
206 * ostream but bases are constructed before members. Thus, making this class
207 * a private base of logstream, declared to the left of ostream, we ensure the
208 * correct order of construction and destruction.
210 struct logstream_base
212 // logstream_base( streambuf* sb ) : lbuf(sb) {}
219 * Class to manage the debug logging stream.
221 class logstream : private logstream_base, public ostream
225 * The default is to send messages to cerr.
226 * @param out output stream
228 logstream( ostream& out )
229 // : logstream_base(out.rdbuf()),
231 ostream(&lbuf) { lbuf.set_sb(out.rdbuf());}
234 * Set the output stream
235 * @param out output stream
237 void set_output( ostream& out ) { lbuf.set_sb( out.rdbuf() ); }
240 * Set the global log class and priority level.
241 * @param c debug class
244 void setLogLevels( sgDebugClass c, sgDebugPriority p );
247 * Output operator to capture the debug level and priority of a message.
250 inline ostream& operator<< ( const loglevel& l );
254 logstream::operator<< ( const loglevel& l )
256 lbuf.set_log_state( l.logClass, l.logPriority );
260 extern logstream *global_logstream;
264 * Return the one and only logstream instance.
265 * We use a function instead of a global object so we are assured that cerr
266 * has been initialised.
267 * @return current logstream
272 if (global_logstream == NULL) {
276 * There appears to be a bug in the C++ runtime in Mac OS X that
277 * will crash if certain funtions are called (in this case
278 * cerr.rdbuf()) during static initialization of a class. This
279 * print statement is hack to kick the library in the pants so it
280 * won't crash when cerr.rdbuf() is first called -DW
282 cout << "Using Mac OS X hack for initializing C++ stdio..." << endl;
284 global_logstream = new logstream (cerr);
287 return *global_logstream;
291 /** \def SG_LOG(C,P,M)
293 * @param C debug class
298 # define SG_LOG(C,P,M)
299 #elif defined( __MWERKS__ )
300 # define SG_LOG(C,P,M) ::sglog() << ::loglevel(C,P) << M << std::endl
302 # define SG_LOG(C,P,M) sglog() << loglevel(C,P) << M << endl
306 #endif // _LOGSTREAM_H