gvpe/src/iom.C

/*
    iom.C -- generic I/O multiplexor
    Copyright (C) 2003, 2004 Marc Lehmann <pcg@goof.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. 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <cstdio>
#include <cstdlib>
#include <cerrno>

#include <sys/select.h>
#include <sys/time.h>

#include "iom.h"

// TSTAMP_MAX must still fit into a positive struct timeval
#define TSTAMP_MAX (double)(1UL<<31)

tstamp NOW;
static bool iom_valid;
io_manager iom;

template<class watcher>
void io_manager::reg (watcher *w, io_manager_vec<watcher> &queue)
{
  if (!iom_valid)
    abort ();

  if (!w->active)
    {
      queue.push_back (w);
      w->active = queue.size ();
    }
}

template<class watcher>
void io_manager::unreg (watcher *w, io_manager_vec<watcher> &queue)
{
  if (!iom_valid)
    return;

  if (w->active)
    {
      queue [w->active - 1] = 0;
      w->active = 0;
    }
}

#if IOM_TIME
void time_watcher::trigger ()
{
  call (*this);

  iom.reg (this);
}

void io_manager::reg (time_watcher *w) { reg (w, tw); }
void io_manager::unreg (time_watcher *w) { unreg (w, tw); }
#endif

#if IOM_IO
void io_manager::reg (io_watcher *w) { reg (w, iow); } 
void io_manager::unreg (io_watcher *w) { unreg (w, iow); }
#endif

#if IOM_CHECK
void io_manager::reg (check_watcher *w) { reg (w, cw); }
void io_manager::unreg (check_watcher *w) { unreg (w, cw); }
#endif

#if IOM_IDLE
void io_manager::reg (idle_watcher *w) { reg (w, iw); }
void io_manager::unreg (idle_watcher *w) { unreg (w, iw); }
#endif

#if IOM_TIME
inline void set_now (void)
{
  struct timeval tv;

  gettimeofday (&tv, 0);

  NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
#endif
}

void io_manager::loop ()
{
#if IOM_TIME
  set_now ();
#endif

  for (;;)
    {
      struct timeval *to = 0;
      struct timeval tval;

#if IOM_IDLE
      if (iw.size ())
        {
          tval.tv_sec  = 0;
          tval.tv_usec = 0;
          to = &tval;
        }
      else
#endif
        {
#if IOM_TIME
          time_watcher *next;

          for (;;)
            {
              next = tw[0]; // the first time-watcher must exist at ALL times

              for (int i = tw.size (); i--; )
                if (!tw[i])
                  tw.erase_unordered (i);
                else if (tw[i]->at < next->at)
                  next = tw[i];

              if (next->at > NOW)
                {
                  if (next != tw[0])
                    {
                      double diff = next->at - NOW;
                      tval.tv_sec  = (int)diff;
                      tval.tv_usec = (int)((diff - tval.tv_sec) * 1000000);
                      to = &tval;
                    }
                  break;
                }
              else
                {
                  unreg (next);
                  next->call (*next);
                }
            }
#endif
        }

#if IOM_CHECK
      for (int i = cw.size (); i--; )
        if (!cw[i])
          cw.erase_unordered (i);
        else
          cw[i]->call (*cw[i]);
#endif

#if IOM_IO
      fd_set rfd, wfd, efd;

      FD_ZERO (&rfd);
      FD_ZERO (&wfd);

      int fds = 0;

      for (io_manager_vec<io_watcher>::iterator i = iow.end (); i-- > iow.begin (); )
        if (*i)
          {
            if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
            if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);

            if ((*i)->fd >= fds) fds = (*i)->fd + 1;
          }

      if (!to && !fds) //TODO: also check idle_watchers and check_watchers
        break; // no events

      fds = select (fds, &rfd, &wfd, &efd, to);
# if IOM_TIME
      set_now ();
# endif

      if (fds > 0)
        for (int i = iow.size (); i--; )
          if (!iow[i])
            iow.erase_unordered (i);
          else
            {
              short revents = iow[i]->events;

              if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
              if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE;

              if (revents)
                iow[i]->call (*iow[i], revents);
            }
      else if (fds < 0 && errno != EINTR)
        {
          perror ("Error while waiting for I/O or time event");
          abort ();
        }
#if IOM_IDLE
      else
        for (int i = iw.size (); i--; )
          if (!iw[i])
            iw.erase_unordered (i);
          else
            iw[i]->call (*iw[i]);
#endif

#elif IOM_TIME
      if (!to)
        break;

      select (0, 0, 0, 0, &to);
      set_now ();
#else
      break;
#endif
    }
}

// this is a dummy time watcher to ensure that the first
// time watcher is _always_ valid, this gets rid of a lot
// of null-pointer-checks
static struct tw0 : time_watcher {
  void cb (time_watcher &w)
  {
    // should never get called
    // reached end-of-time, or tstamp has a bogus definition :)
    abort ();
  }

  tw0()
  : time_watcher (this, &tw0::cb)
  { }
} tw0;

io_manager::io_manager ()
{
  iom_valid = true;

#if IOM_TIME
  set_now ();

  tw0.start (TSTAMP_MAX);
#endif
}

io_manager::~io_manager ()
{
  iom_valid = false;
}

Revision:	1.13
Committed:	Sat Jan 17 01:18:36 2004 UTC (20 years, 4 months ago) by pcg
Content type:	text/plain
Branch:	MAIN
Changes since 1.12:	+170 -153 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	pcg	1.1	/*
2	pcg	1.12	iom.C -- generic I/O multiplexor
3	pcg	1.13	Copyright (C) 2003, 2004 Marc Lehmann <pcg@goof.com>
4	pcg	1.1
5			This program is free software; you can redistribute it and/or modify
6			it under the terms of the GNU General Public License as published by
7			the Free Software Foundation; either version 2 of the License, or
8			(at your option) any later version.
9
10			This program is distributed in the hope that it will be useful,
11			but WITHOUT ANY WARRANTY; without even the implied warranty of
12			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13			GNU General Public License for more details.
14
15			You should have received a copy of the GNU General Public License
16			along with this program; if not, write to the Free Software
17			Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18			*/
19
20	pcg	1.13	#include <cstdio>
21			#include <cstdlib>
22			#include <cerrno>
23	pcg	1.1
24	pcg	1.13	#include <sys/select.h>
25	pcg	1.1	#include <sys/time.h>
26
27	pcg	1.13	#include "iom.h"
28	pcg	1.11
29	pcg	1.13	// TSTAMP_MAX must still fit into a positive struct timeval
30			#define TSTAMP_MAX (double)(1UL<<31)
31	pcg	1.1
32	pcg	1.10	tstamp NOW;
33	pcg	1.13	static bool iom_valid;
34	pcg	1.10	io_manager iom;
35
36	pcg	1.13	template<class watcher>
37			void io_manager::reg (watcher *w, io_manager_vec<watcher> &queue)
38	pcg	1.4	{
39	pcg	1.13	if (!iom_valid)
40			abort ();
41	pcg	1.4
42	pcg	1.13	if (!w->active)
43	pcg	1.11	{
44	pcg	1.13	queue.push_back (w);
45			w->active = queue.size ();
46	pcg	1.11	}
47	pcg	1.10	}
48
49	pcg	1.13	template<class watcher>
50			void io_manager::unreg (watcher *w, io_manager_vec<watcher> &queue)
51	pcg	1.10	{
52	pcg	1.13	if (!iom_valid)
53			return;
54	pcg	1.10
55	pcg	1.13	if (w->active)
56	pcg	1.11	{
57	pcg	1.13	queue [w->active - 1] = 0;
58			w->active = 0;
59	pcg	1.11	}
60	pcg	1.1	}
61
62	pcg	1.13	#if IOM_TIME
63			void time_watcher::trigger ()
64	pcg	1.1	{
65	pcg	1.13	call (*this);
66	pcg	1.11
67	pcg	1.13	iom.reg (this);
68	pcg	1.1	}
69
70	pcg	1.13	void io_manager::reg (time_watcher *w) { reg (w, tw); }
71			void io_manager::unreg (time_watcher *w) { unreg (w, tw); }
72			#endif
73	pcg	1.6
74	pcg	1.13	#if IOM_IO
75			void io_manager::reg (io_watcher *w) { reg (w, iow); }
76			void io_manager::unreg (io_watcher *w) { unreg (w, iow); }
77			#endif
78	pcg	1.7
79	pcg	1.13	#if IOM_CHECK
80			void io_manager::reg (check_watcher *w) { reg (w, cw); }
81			void io_manager::unreg (check_watcher *w) { unreg (w, cw); }
82			#endif
83	pcg	1.1
84	pcg	1.13	#if IOM_IDLE
85			void io_manager::reg (idle_watcher *w) { reg (w, iw); }
86			void io_manager::unreg (idle_watcher *w) { unreg (w, iw); }
87			#endif
88	pcg	1.1
89	pcg	1.13	#if IOM_TIME
90	pcg	1.1	inline void set_now (void)
91			{
92			struct timeval tv;
93
94			gettimeofday (&tv, 0);
95
96	pcg	1.2	NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
97	pcg	1.13	#endif
98	pcg	1.1	}
99
100			void io_manager::loop ()
101			{
102	pcg	1.13	#if IOM_TIME
103	pcg	1.1	set_now ();
104	pcg	1.13	#endif
105	pcg	1.1
106	pcg	1.4	for (;;)
107	pcg	1.1	{
108	pcg	1.13	struct timeval *to = 0;
109			struct timeval tval;
110
111			#if IOM_IDLE
112			if (iw.size ())
113			{
114			tval.tv_sec = 0;
115			tval.tv_usec = 0;
116			to = &tval;
117			}
118			else
119			#endif
120	pcg	1.4	{
121	pcg	1.13	#if IOM_TIME
122			time_watcher *next;
123	pcg	1.7
124	pcg	1.13	for (;;)
125			{
126			next = tw[0]; // the first time-watcher must exist at ALL times
127
128			for (int i = tw.size (); i--; )
129			if (!tw[i])
130			tw.erase_unordered (i);
131			else if (tw[i]->at < next->at)
132			next = tw[i];
133
134			if (next->at > NOW)
135			{
136			if (next != tw[0])
137			{
138			double diff = next->at - NOW;
139			tval.tv_sec = (int)diff;
140			tval.tv_usec = (int)((diff - tval.tv_sec) * 1000000);
141			to = &tval;
142			}
143			break;
144			}
145			else
146			{
147			unreg (next);
148			next->call (*next);
149			}
150			}
151			#endif
152			}
153	pcg	1.1
154	pcg	1.13	#if IOM_CHECK
155			for (int i = cw.size (); i--; )
156			if (!cw[i])
157			cw.erase_unordered (i);
158			else
159			cw[i]->call (*cw[i]);
160			#endif
161
162			#if IOM_IO
163			fd_set rfd, wfd, efd;
164	pcg	1.7
165	pcg	1.13	FD_ZERO (&rfd);
166			FD_ZERO (&wfd);
167	pcg	1.7
168	pcg	1.13	int fds = 0;
169
170			for (io_manager_vec<io_watcher>::iterator i = iow.end (); i-- > iow.begin (); )
171			if (*i)
172			{
173			if ((i)->events & EVENT_READ ) FD_SET ((i)->fd, &rfd);
174			if ((i)->events & EVENT_WRITE) FD_SET ((i)->fd, &wfd);
175	pcg	1.1
176	pcg	1.13	if ((i)->fd >= fds) fds = (i)->fd + 1;
177			}
178	pcg	1.1
179	pcg	1.13	if (!to && !fds) //TODO: also check idle_watchers and check_watchers
180			break; // no events
181	pcg	1.1
182	pcg	1.13	fds = select (fds, &rfd, &wfd, &efd, to);
183			# if IOM_TIME
184	pcg	1.4	set_now ();
185	pcg	1.13	# endif
186	pcg	1.1
187	pcg	1.13	if (fds > 0)
188			for (int i = iow.size (); i--; )
189			if (!iow[i])
190			iow.erase_unordered (i);
191			else
192			{
193			short revents = iow[i]->events;
194
195			if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
196			if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE;
197
198			if (revents)
199			iow[i]->call (*iow[i], revents);
200			}
201			else if (fds < 0 && errno != EINTR)
202			{
203			perror ("Error while waiting for I/O or time event");
204			abort ();
205			}
206			#if IOM_IDLE
207			else
208			for (int i = iw.size (); i--; )
209			if (!iw[i])
210			iw.erase_unordered (i);
211			else
212			iw[i]->call (*iw[i]);
213			#endif
214
215			#elif IOM_TIME
216			if (!to)
217			break;
218	pcg	1.9
219	pcg	1.13	select (0, 0, 0, 0, &to);
220			set_now ();
221			#else
222			break;
223			#endif
224	pcg	1.1	}
225			}
226
227	pcg	1.13	// this is a dummy time watcher to ensure that the first
228			// time watcher is _always_ valid, this gets rid of a lot
229			// of null-pointer-checks
230			static struct tw0 : time_watcher {
231			void cb (time_watcher &w)
232			{
233			// should never get called
234			// reached end-of-time, or tstamp has a bogus definition :)
235			abort ();
236			}
237
238			tw0()
239			: time_watcher (this, &tw0::cb)
240			{ }
241			} tw0;
242	pcg	1.4
243	pcg	1.1	io_manager::io_manager ()
244			{
245	pcg	1.10	iom_valid = true;
246
247	pcg	1.13	#if IOM_TIME
248	pcg	1.1	set_now ();
249	pcg	1.13
250			tw0.start (TSTAMP_MAX);
251			#endif
252	pcg	1.1	}
253
254			io_manager::~io_manager ()
255			{
256	pcg	1.10	iom_valid = false;
257	pcg	1.1	}
258