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)

// 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
// (must come _before_ iom is being defined)
static struct tw0 : time_watcher {
  void cb (time_watcher &w)
  {
    // should never get called
    // reached end-of-time, or tstamp has a bogus definition,
    // or compiler initilization order broken, or somethine else :)
    abort ();
  }

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

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
    }
}

io_manager::io_manager ()
{
  iom_valid = true;

#if IOM_TIME
  set_now ();

  tw0.start (TSTAMP_MAX);
  printf ("abort, %f but inly on %f\n", NOW, tw0.at);
#endif
}

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

Revision:	1.14
Committed:	Sat Jan 17 14:08:57 2004 UTC (22 years, 8 months ago) by pcg
Content type:	text/plain
Branch:	MAIN
Changes since 1.13:	+19 -16 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	1.14	// this is a dummy time watcher to ensure that the first
33			// time watcher is _always_ valid, this gets rid of a lot
34			// of null-pointer-checks
35			// (must come _before_ iom is being defined)
36			static struct tw0 : time_watcher {
37			void cb (time_watcher &w)
38			{
39			// should never get called
40			// reached end-of-time, or tstamp has a bogus definition,
41			// or compiler initilization order broken, or somethine else :)
42			abort ();
43			}
44
45			tw0()
46			: time_watcher (this, &tw0::cb)
47			{ }
48			} tw0;
49
50	pcg	1.10	tstamp NOW;
51	pcg	1.13	static bool iom_valid;
52	pcg	1.10	io_manager iom;
53
54	pcg	1.13	template<class watcher>
55			void io_manager::reg (watcher *w, io_manager_vec<watcher> &queue)
56	pcg	1.4	{
57	pcg	1.13	if (!iom_valid)
58			abort ();
59	pcg	1.4
60	pcg	1.13	if (!w->active)
61	pcg	1.11	{
62	pcg	1.13	queue.push_back (w);
63			w->active = queue.size ();
64	pcg	1.11	}
65	pcg	1.10	}
66
67	pcg	1.13	template<class watcher>
68			void io_manager::unreg (watcher *w, io_manager_vec<watcher> &queue)
69	pcg	1.10	{
70	pcg	1.13	if (!iom_valid)
71			return;
72	pcg	1.10
73	pcg	1.13	if (w->active)
74	pcg	1.11	{
75	pcg	1.13	queue [w->active - 1] = 0;
76			w->active = 0;
77	pcg	1.11	}
78	pcg	1.1	}
79
80	pcg	1.13	#if IOM_TIME
81			void time_watcher::trigger ()
82	pcg	1.1	{
83	pcg	1.13	call (*this);
84	pcg	1.11
85	pcg	1.13	iom.reg (this);
86	pcg	1.1	}
87
88	pcg	1.13	void io_manager::reg (time_watcher *w) { reg (w, tw); }
89			void io_manager::unreg (time_watcher *w) { unreg (w, tw); }
90			#endif
91	pcg	1.6
92	pcg	1.13	#if IOM_IO
93			void io_manager::reg (io_watcher *w) { reg (w, iow); }
94			void io_manager::unreg (io_watcher *w) { unreg (w, iow); }
95			#endif
96	pcg	1.7
97	pcg	1.13	#if IOM_CHECK
98			void io_manager::reg (check_watcher *w) { reg (w, cw); }
99			void io_manager::unreg (check_watcher *w) { unreg (w, cw); }
100			#endif
101	pcg	1.1
102	pcg	1.13	#if IOM_IDLE
103			void io_manager::reg (idle_watcher *w) { reg (w, iw); }
104			void io_manager::unreg (idle_watcher *w) { unreg (w, iw); }
105			#endif
106	pcg	1.1
107	pcg	1.13	#if IOM_TIME
108	pcg	1.1	inline void set_now (void)
109			{
110			struct timeval tv;
111
112			gettimeofday (&tv, 0);
113
114	pcg	1.2	NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
115	pcg	1.13	#endif
116	pcg	1.1	}
117
118			void io_manager::loop ()
119			{
120	pcg	1.13	#if IOM_TIME
121	pcg	1.1	set_now ();
122	pcg	1.13	#endif
123	pcg	1.1
124	pcg	1.4	for (;;)
125	pcg	1.1	{
126	pcg	1.13	struct timeval *to = 0;
127			struct timeval tval;
128
129			#if IOM_IDLE
130			if (iw.size ())
131			{
132			tval.tv_sec = 0;
133			tval.tv_usec = 0;
134			to = &tval;
135			}
136			else
137			#endif
138	pcg	1.4	{
139	pcg	1.13	#if IOM_TIME
140			time_watcher *next;
141	pcg	1.7
142	pcg	1.13	for (;;)
143			{
144			next = tw[0]; // the first time-watcher must exist at ALL times
145
146			for (int i = tw.size (); i--; )
147			if (!tw[i])
148			tw.erase_unordered (i);
149			else if (tw[i]->at < next->at)
150			next = tw[i];
151
152			if (next->at > NOW)
153			{
154			if (next != tw[0])
155			{
156			double diff = next->at - NOW;
157			tval.tv_sec = (int)diff;
158			tval.tv_usec = (int)((diff - tval.tv_sec) * 1000000);
159			to = &tval;
160			}
161			break;
162			}
163			else
164			{
165			unreg (next);
166			next->call (*next);
167			}
168			}
169			#endif
170			}
171	pcg	1.1
172	pcg	1.13	#if IOM_CHECK
173			for (int i = cw.size (); i--; )
174			if (!cw[i])
175			cw.erase_unordered (i);
176			else
177			cw[i]->call (*cw[i]);
178			#endif
179
180			#if IOM_IO
181			fd_set rfd, wfd, efd;
182	pcg	1.7
183	pcg	1.13	FD_ZERO (&rfd);
184			FD_ZERO (&wfd);
185	pcg	1.7
186	pcg	1.13	int fds = 0;
187
188			for (io_manager_vec<io_watcher>::iterator i = iow.end (); i-- > iow.begin (); )
189			if (*i)
190			{
191			if ((i)->events & EVENT_READ ) FD_SET ((i)->fd, &rfd);
192			if ((i)->events & EVENT_WRITE) FD_SET ((i)->fd, &wfd);
193	pcg	1.1
194	pcg	1.13	if ((i)->fd >= fds) fds = (i)->fd + 1;
195			}
196	pcg	1.1
197	pcg	1.13	if (!to && !fds) //TODO: also check idle_watchers and check_watchers
198			break; // no events
199	pcg	1.1
200	pcg	1.13	fds = select (fds, &rfd, &wfd, &efd, to);
201			# if IOM_TIME
202	pcg	1.4	set_now ();
203	pcg	1.13	# endif
204	pcg	1.1
205	pcg	1.13	if (fds > 0)
206			for (int i = iow.size (); i--; )
207			if (!iow[i])
208			iow.erase_unordered (i);
209			else
210			{
211			short revents = iow[i]->events;
212
213			if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
214			if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE;
215
216			if (revents)
217			iow[i]->call (*iow[i], revents);
218			}
219			else if (fds < 0 && errno != EINTR)
220			{
221			perror ("Error while waiting for I/O or time event");
222			abort ();
223			}
224			#if IOM_IDLE
225			else
226			for (int i = iw.size (); i--; )
227			if (!iw[i])
228			iw.erase_unordered (i);
229			else
230			iw[i]->call (*iw[i]);
231			#endif
232
233			#elif IOM_TIME
234			if (!to)
235			break;
236	pcg	1.9
237	pcg	1.13	select (0, 0, 0, 0, &to);
238			set_now ();
239			#else
240			break;
241			#endif
242	pcg	1.1	}
243			}
244
245			io_manager::io_manager ()
246			{
247	pcg	1.10	iom_valid = true;
248
249	pcg	1.13	#if IOM_TIME
250	pcg	1.1	set_now ();
251	pcg	1.13
252			tw0.start (TSTAMP_MAX);
253	pcg	1.14	printf ("abort, %f but inly on %f\n", NOW, tw0.at);
254	pcg	1.13	#endif
255	pcg	1.1	}
256
257			io_manager::~io_manager ()
258			{
259	pcg	1.10	iom_valid = false;
260	pcg	1.1	}
261