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>

#include <assert.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>

// for IOM_SIG
#include <signal.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

#if IOM_SIG
// race conditions galore

void io_manager::sighandler (int signum)
{
  assert (0 < signum && signum <= iom.sw.size ());

  sig_vec &sv = *iom.sw [signum - 1];

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

void io_manager::reg (sig_watcher *w)
{
  assert (0 < w->signum);

  sw.reserve (w->signum);

  sig_vec *&sv = sw [w->signum - 1];

  if (!sv)
    {
      sv = new sig_vec;

      struct sigaction sa;
      sa.sa_handler = io_manager::sighandler;
      sigfillset (&sa.sa_mask);
      sa.sa_flags = 0;

      if (sigaction (w->signum, &sa, 0))
        {
          perror ("Error while installing signal handler");
          abort ();
        }
    }

  reg (w, *sv);
}

void io_manager::unreg (sig_watcher *w)
{
  assert (0 < w->signum && w->signum <= sw.size ());
  
  unreg (w, *sw [w->signum - 1]);
}

void sig_watcher::start (int signum)
{
  stop ();
  this->signum = signum;
  iom.reg (this);
}
#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;

      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, NULL, 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:	1.20
Committed:	Fri Apr 2 14:42:45 2004 UTC (20 years, 1 month ago) by pcg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	VPE_1_6, VPE-1_6_1
Changes since 1.19:	+65 -2 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	pcg	1.20	#include <assert.h>
27
28	pcg	1.18	#if 1 // older unices need these includes for select (2)
29	pcg	1.15	# include <unistd.h>
30			# include <sys/types.h>
31			#endif
32
33			// if the BSDs would at least be marginally POSIX-compatible.. sigh
34			// until that happens, sys/select.h must come last
35	pcg	1.13	#include <sys/select.h>
36	pcg	1.1
37	pcg	1.20	// for IOM_SIG
38			#include <signal.h>
39
40	pcg	1.13	#include "iom.h"
41	pcg	1.11
42	pcg	1.13	// TSTAMP_MAX must still fit into a positive struct timeval
43			#define TSTAMP_MAX (double)(1UL<<31)
44	pcg	1.1
45	pcg	1.14	// this is a dummy time watcher to ensure that the first
46			// time watcher is _always_ valid, this gets rid of a lot
47			// of null-pointer-checks
48			// (must come _before_ iom is being defined)
49	pcg	1.18	static struct tw0 : time_watcher
50	pcg	1.14	{
51	pcg	1.18	void cb (time_watcher &w)
52			{
53			// should never get called
54			// reached end-of-time, or tstamp has a bogus definition,
55			// or compiler initilization order broken, or somethine else :)
56			abort ();
57			}
58	pcg	1.14
59	pcg	1.18	tw0 ()
60			: time_watcher (this, &tw0::cb)
61	pcg	1.20	{ }
62			} tw0;
63	pcg	1.14
64	pcg	1.10	tstamp NOW;
65	pcg	1.13	static bool iom_valid;
66	pcg	1.10	io_manager iom;
67
68	pcg	1.13	template<class watcher>
69			void io_manager::reg (watcher *w, io_manager_vec<watcher> &queue)
70	pcg	1.4	{
71	pcg	1.13	if (!iom_valid)
72			abort ();
73	pcg	1.4
74	pcg	1.13	if (!w->active)
75	pcg	1.11	{
76	pcg	1.17	#if IOM_CHECK
77			queue.activity = true;
78			#endif
79	pcg	1.13	queue.push_back (w);
80			w->active = queue.size ();
81	pcg	1.11	}
82	pcg	1.10	}
83
84	pcg	1.13	template<class watcher>
85			void io_manager::unreg (watcher *w, io_manager_vec<watcher> &queue)
86	pcg	1.10	{
87	pcg	1.13	if (!iom_valid)
88			return;
89	pcg	1.10
90	pcg	1.13	if (w->active)
91	pcg	1.11	{
92	pcg	1.13	queue [w->active - 1] = 0;
93			w->active = 0;
94	pcg	1.11	}
95	pcg	1.1	}
96
97	pcg	1.13	#if IOM_TIME
98			void time_watcher::trigger ()
99	pcg	1.1	{
100	pcg	1.13	call (*this);
101	pcg	1.11
102	pcg	1.13	iom.reg (this);
103	pcg	1.1	}
104
105	pcg	1.13	void io_manager::reg (time_watcher *w) { reg (w, tw); }
106			void io_manager::unreg (time_watcher *w) { unreg (w, tw); }
107			#endif
108	pcg	1.6
109	pcg	1.13	#if IOM_IO
110	pcg	1.18	void io_manager::reg (io_watcher *w) { reg (w, iow); }
111	pcg	1.13	void io_manager::unreg (io_watcher *w) { unreg (w, iow); }
112			#endif
113	pcg	1.7
114	pcg	1.13	#if IOM_CHECK
115			void io_manager::reg (check_watcher *w) { reg (w, cw); }
116			void io_manager::unreg (check_watcher *w) { unreg (w, cw); }
117			#endif
118	pcg	1.1
119	pcg	1.13	#if IOM_IDLE
120			void io_manager::reg (idle_watcher *w) { reg (w, iw); }
121			void io_manager::unreg (idle_watcher *w) { unreg (w, iw); }
122			#endif
123	pcg	1.1
124	pcg	1.13	#if IOM_TIME
125	pcg	1.1	inline void set_now (void)
126			{
127			struct timeval tv;
128
129			gettimeofday (&tv, 0);
130
131	pcg	1.2	NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
132	pcg	1.20	}
133	pcg	1.13	#endif
134	pcg	1.20
135			#if IOM_SIG
136			// race conditions galore
137
138			void io_manager::sighandler (int signum)
139			{
140			assert (0 < signum && signum <= iom.sw.size ());
141
142			sig_vec &sv = *iom.sw [signum - 1];
143
144			for (int i = sv.size (); i--; )
145			if (!sv[i])
146			sv.erase_unordered (i);
147			else
148			sv[i]->call (*sv[i]);
149	pcg	1.1	}
150
151	pcg	1.20	void io_manager::reg (sig_watcher *w)
152			{
153			assert (0 < w->signum);
154
155			sw.reserve (w->signum);
156
157			sig_vec *&sv = sw [w->signum - 1];
158
159			if (!sv)
160			{
161			sv = new sig_vec;
162
163			struct sigaction sa;
164			sa.sa_handler = io_manager::sighandler;
165			sigfillset (&sa.sa_mask);
166			sa.sa_flags = 0;
167
168			if (sigaction (w->signum, &sa, 0))
169			{
170			perror ("Error while installing signal handler");
171			abort ();
172			}
173			}
174
175			reg (w, *sv);
176			}
177
178			void io_manager::unreg (sig_watcher *w)
179			{
180			assert (0 < w->signum && w->signum <= sw.size ());
181
182			unreg (w, *sw [w->signum - 1]);
183			}
184
185			void sig_watcher::start (int signum)
186			{
187			stop ();
188			this->signum = signum;
189			iom.reg (this);
190			}
191			#endif
192
193	pcg	1.1	void io_manager::loop ()
194			{
195	pcg	1.13	#if IOM_TIME
196	pcg	1.1	set_now ();
197	pcg	1.13	#endif
198	pcg	1.1
199	pcg	1.4	for (;;)
200	pcg	1.1	{
201	pcg	1.13	struct timeval *to = 0;
202			struct timeval tval;
203
204			#if IOM_IDLE
205			if (iw.size ())
206			{
207			tval.tv_sec = 0;
208			tval.tv_usec = 0;
209			to = &tval;
210			}
211			else
212			#endif
213	pcg	1.18
214	pcg	1.4	{
215	pcg	1.13	#if IOM_TIME
216			time_watcher *next;
217	pcg	1.7
218	pcg	1.13	for (;;)
219			{
220			next = tw[0]; // the first time-watcher must exist at ALL times
221
222			for (int i = tw.size (); i--; )
223			if (!tw[i])
224			tw.erase_unordered (i);
225			else if (tw[i]->at < next->at)
226			next = tw[i];
227
228			if (next->at > NOW)
229			{
230			if (next != tw[0])
231			{
232			double diff = next->at - NOW;
233			tval.tv_sec = (int)diff;
234	pcg	1.18	tval.tv_usec = (int) ((diff - tval.tv_sec) * 1000000);
235	pcg	1.13	to = &tval;
236			}
237			break;
238			}
239			else
240			{
241			unreg (next);
242			next->call (*next);
243			}
244			}
245			#endif
246	pcg	1.18
247	pcg	1.13	}
248	pcg	1.1
249	pcg	1.13	#if IOM_CHECK
250	pcg	1.17	tw.activity = false;
251
252	pcg	1.13	for (int i = cw.size (); i--; )
253			if (!cw[i])
254			cw.erase_unordered (i);
255			else
256			cw[i]->call (*cw[i]);
257	pcg	1.17
258			if (tw.activity)
259			{
260			tval.tv_sec = 0;
261			tval.tv_usec = 0;
262			to = &tval;
263			}
264	pcg	1.13	#endif
265
266			#if IOM_IO
267	pcg	1.18	fd_set rfd, wfd;
268	pcg	1.7
269	pcg	1.13	FD_ZERO (&rfd);
270			FD_ZERO (&wfd);
271	pcg	1.7
272	pcg	1.13	int fds = 0;
273
274			for (io_manager_vec<io_watcher>::iterator i = iow.end (); i-- > iow.begin (); )
275			if (*i)
276			{
277			if ((i)->events & EVENT_READ ) FD_SET ((i)->fd, &rfd);
278			if ((i)->events & EVENT_WRITE) FD_SET ((i)->fd, &wfd);
279	pcg	1.1
280	pcg	1.13	if ((i)->fd >= fds) fds = (i)->fd + 1;
281			}
282	pcg	1.1
283	pcg	1.13	if (!to && !fds) //TODO: also check idle_watchers and check_watchers
284			break; // no events
285	pcg	1.1
286	pcg	1.19	fds = select (fds, &rfd, &wfd, NULL, to);
287	pcg	1.13	# if IOM_TIME
288	pcg	1.4	set_now ();
289	pcg	1.13	# endif
290	pcg	1.1
291	pcg	1.13	if (fds > 0)
292			for (int i = iow.size (); i--; )
293			if (!iow[i])
294			iow.erase_unordered (i);
295			else
296			{
297			short revents = iow[i]->events;
298
299			if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
300			if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE;
301
302			if (revents)
303			iow[i]->call (*iow[i], revents);
304			}
305			else if (fds < 0 && errno != EINTR)
306			{
307			perror ("Error while waiting for I/O or time event");
308			abort ();
309			}
310			#if IOM_IDLE
311			else
312			for (int i = iw.size (); i--; )
313			if (!iw[i])
314			iw.erase_unordered (i);
315			else
316			iw[i]->call (*iw[i]);
317			#endif
318
319			#elif IOM_TIME
320			if (!to)
321			break;
322	pcg	1.9
323	pcg	1.13	select (0, 0, 0, 0, &to);
324			set_now ();
325			#else
326			break;
327			#endif
328	pcg	1.18
329	pcg	1.1	}
330			}
331
332			io_manager::io_manager ()
333			{
334	pcg	1.10	iom_valid = true;
335
336	pcg	1.13	#if IOM_TIME
337	pcg	1.1	set_now ();
338	pcg	1.13
339			tw0.start (TSTAMP_MAX);
340			#endif
341	pcg	1.1	}
342
343			io_manager::~io_manager ()
344			{
345	pcg	1.10	iom_valid = false;
346	pcg	1.1	}
347