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/time.h>

#if 1 // older unices need these includes for select(2)
# include <unistd.h>
# include <sys/types.h>
#endif

// if the BSDs would at least be marginally POSIX-compatible.. *sigh*
// until that happens, sys/select.h must come last
#include <sys/select.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)
    {
#if IOM_CHECK
      queue.activity = true;
#endif
      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
      tw.activity = false;

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

      if (tw.activity)
        {
          tval.tv_sec  = 0;
          tval.tv_usec = 0;
          to = &tval;
        }
#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);
#endif
}

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

Revision:	1.17
Committed:	Thu Jan 29 23:17:39 2004 UTC (20 years, 4 months ago) by pcg
Content type:	text/plain
Branch:	MAIN
Changes since 1.16:	+12 -0 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	1.15	#include <sys/time.h>
25
26			#if 1 // older unices need these includes for select(2)
27			# include <unistd.h>
28			# include <sys/types.h>
29			#endif
30
31			// if the BSDs would at least be marginally POSIX-compatible.. sigh
32			// until that happens, sys/select.h must come last
33	pcg	1.13	#include <sys/select.h>
34	pcg	1.1
35	pcg	1.13	#include "iom.h"
36	pcg	1.11
37	pcg	1.13	// TSTAMP_MAX must still fit into a positive struct timeval
38			#define TSTAMP_MAX (double)(1UL<<31)
39	pcg	1.1
40	pcg	1.14	// this is a dummy time watcher to ensure that the first
41			// time watcher is _always_ valid, this gets rid of a lot
42			// of null-pointer-checks
43			// (must come _before_ iom is being defined)
44			static struct tw0 : time_watcher {
45			void cb (time_watcher &w)
46			{
47			// should never get called
48			// reached end-of-time, or tstamp has a bogus definition,
49			// or compiler initilization order broken, or somethine else :)
50			abort ();
51			}
52
53			tw0()
54			: time_watcher (this, &tw0::cb)
55			{ }
56			} tw0;
57
58	pcg	1.10	tstamp NOW;
59	pcg	1.13	static bool iom_valid;
60	pcg	1.10	io_manager iom;
61
62	pcg	1.13	template<class watcher>
63			void io_manager::reg (watcher *w, io_manager_vec<watcher> &queue)
64	pcg	1.4	{
65	pcg	1.13	if (!iom_valid)
66			abort ();
67	pcg	1.4
68	pcg	1.13	if (!w->active)
69	pcg	1.11	{
70	pcg	1.17	#if IOM_CHECK
71			queue.activity = true;
72			#endif
73	pcg	1.13	queue.push_back (w);
74			w->active = queue.size ();
75	pcg	1.11	}
76	pcg	1.10	}
77
78	pcg	1.13	template<class watcher>
79			void io_manager::unreg (watcher *w, io_manager_vec<watcher> &queue)
80	pcg	1.10	{
81	pcg	1.13	if (!iom_valid)
82			return;
83	pcg	1.10
84	pcg	1.13	if (w->active)
85	pcg	1.11	{
86	pcg	1.13	queue [w->active - 1] = 0;
87			w->active = 0;
88	pcg	1.11	}
89	pcg	1.1	}
90
91	pcg	1.13	#if IOM_TIME
92			void time_watcher::trigger ()
93	pcg	1.1	{
94	pcg	1.13	call (*this);
95	pcg	1.11
96	pcg	1.13	iom.reg (this);
97	pcg	1.1	}
98
99	pcg	1.13	void io_manager::reg (time_watcher *w) { reg (w, tw); }
100			void io_manager::unreg (time_watcher *w) { unreg (w, tw); }
101			#endif
102	pcg	1.6
103	pcg	1.13	#if IOM_IO
104			void io_manager::reg (io_watcher *w) { reg (w, iow); }
105			void io_manager::unreg (io_watcher *w) { unreg (w, iow); }
106			#endif
107	pcg	1.7
108	pcg	1.13	#if IOM_CHECK
109			void io_manager::reg (check_watcher *w) { reg (w, cw); }
110			void io_manager::unreg (check_watcher *w) { unreg (w, cw); }
111			#endif
112	pcg	1.1
113	pcg	1.13	#if IOM_IDLE
114			void io_manager::reg (idle_watcher *w) { reg (w, iw); }
115			void io_manager::unreg (idle_watcher *w) { unreg (w, iw); }
116			#endif
117	pcg	1.1
118	pcg	1.13	#if IOM_TIME
119	pcg	1.1	inline void set_now (void)
120			{
121			struct timeval tv;
122
123			gettimeofday (&tv, 0);
124
125	pcg	1.2	NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
126	pcg	1.13	#endif
127	pcg	1.1	}
128
129			void io_manager::loop ()
130			{
131	pcg	1.13	#if IOM_TIME
132	pcg	1.1	set_now ();
133	pcg	1.13	#endif
134	pcg	1.1
135	pcg	1.4	for (;;)
136	pcg	1.1	{
137	pcg	1.13	struct timeval *to = 0;
138			struct timeval tval;
139
140			#if IOM_IDLE
141			if (iw.size ())
142			{
143			tval.tv_sec = 0;
144			tval.tv_usec = 0;
145			to = &tval;
146			}
147			else
148			#endif
149	pcg	1.4	{
150	pcg	1.13	#if IOM_TIME
151			time_watcher *next;
152	pcg	1.7
153	pcg	1.13	for (;;)
154			{
155			next = tw[0]; // the first time-watcher must exist at ALL times
156
157			for (int i = tw.size (); i--; )
158			if (!tw[i])
159			tw.erase_unordered (i);
160			else if (tw[i]->at < next->at)
161			next = tw[i];
162
163			if (next->at > NOW)
164			{
165			if (next != tw[0])
166			{
167			double diff = next->at - NOW;
168			tval.tv_sec = (int)diff;
169			tval.tv_usec = (int)((diff - tval.tv_sec) * 1000000);
170			to = &tval;
171			}
172			break;
173			}
174			else
175			{
176			unreg (next);
177			next->call (*next);
178			}
179			}
180			#endif
181			}
182	pcg	1.1
183	pcg	1.13	#if IOM_CHECK
184	pcg	1.17	tw.activity = false;
185
186	pcg	1.13	for (int i = cw.size (); i--; )
187			if (!cw[i])
188			cw.erase_unordered (i);
189			else
190			cw[i]->call (*cw[i]);
191	pcg	1.17
192			if (tw.activity)
193			{
194			tval.tv_sec = 0;
195			tval.tv_usec = 0;
196			to = &tval;
197			}
198	pcg	1.13	#endif
199
200			#if IOM_IO
201			fd_set rfd, wfd, efd;
202	pcg	1.7
203	pcg	1.13	FD_ZERO (&rfd);
204			FD_ZERO (&wfd);
205	pcg	1.7
206	pcg	1.13	int fds = 0;
207
208			for (io_manager_vec<io_watcher>::iterator i = iow.end (); i-- > iow.begin (); )
209			if (*i)
210			{
211			if ((i)->events & EVENT_READ ) FD_SET ((i)->fd, &rfd);
212			if ((i)->events & EVENT_WRITE) FD_SET ((i)->fd, &wfd);
213	pcg	1.1
214	pcg	1.13	if ((i)->fd >= fds) fds = (i)->fd + 1;
215			}
216	pcg	1.1
217	pcg	1.13	if (!to && !fds) //TODO: also check idle_watchers and check_watchers
218			break; // no events
219	pcg	1.1
220	pcg	1.13	fds = select (fds, &rfd, &wfd, &efd, to);
221			# if IOM_TIME
222	pcg	1.4	set_now ();
223	pcg	1.13	# endif
224	pcg	1.1
225	pcg	1.13	if (fds > 0)
226			for (int i = iow.size (); i--; )
227			if (!iow[i])
228			iow.erase_unordered (i);
229			else
230			{
231			short revents = iow[i]->events;
232
233			if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
234			if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE;
235
236			if (revents)
237			iow[i]->call (*iow[i], revents);
238			}
239			else if (fds < 0 && errno != EINTR)
240			{
241			perror ("Error while waiting for I/O or time event");
242			abort ();
243			}
244			#if IOM_IDLE
245			else
246			for (int i = iw.size (); i--; )
247			if (!iw[i])
248			iw.erase_unordered (i);
249			else
250			iw[i]->call (*iw[i]);
251			#endif
252
253			#elif IOM_TIME
254			if (!to)
255			break;
256	pcg	1.9
257	pcg	1.13	select (0, 0, 0, 0, &to);
258			set_now ();
259			#else
260			break;
261			#endif
262	pcg	1.1	}
263			}
264
265			io_manager::io_manager ()
266			{
267	pcg	1.10	iom_valid = true;
268
269	pcg	1.13	#if IOM_TIME
270	pcg	1.1	set_now ();
271	pcg	1.13
272			tw0.start (TSTAMP_MAX);
273			#endif
274	pcg	1.1	}
275
276			io_manager::~io_manager ()
277			{
278	pcg	1.10	iom_valid = false;
279	pcg	1.1	}
280