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;

      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:	1.19
Committed:	Sun Mar 28 01:53:33 2004 UTC (20 years, 2 months ago) by pcg
Content type:	text/plain
Branch:	MAIN
Changes since 1.18:	+1 -1 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	1.18	#if 1 // older unices need these includes for select (2)
27	pcg	1.15	# 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	pcg	1.18	static struct tw0 : time_watcher
45	pcg	1.14	{
46	pcg	1.18	void cb (time_watcher &w)
47			{
48			// should never get called
49			// reached end-of-time, or tstamp has a bogus definition,
50			// or compiler initilization order broken, or somethine else :)
51			abort ();
52			}
53	pcg	1.14
54	pcg	1.18	tw0 ()
55			: time_watcher (this, &tw0::cb)
56			{ }}
57			tw0;
58	pcg	1.14
59	pcg	1.10	tstamp NOW;
60	pcg	1.13	static bool iom_valid;
61	pcg	1.10	io_manager iom;
62
63	pcg	1.13	template<class watcher>
64			void io_manager::reg (watcher *w, io_manager_vec<watcher> &queue)
65	pcg	1.4	{
66	pcg	1.13	if (!iom_valid)
67			abort ();
68	pcg	1.4
69	pcg	1.13	if (!w->active)
70	pcg	1.11	{
71	pcg	1.17	#if IOM_CHECK
72			queue.activity = true;
73			#endif
74	pcg	1.13	queue.push_back (w);
75			w->active = queue.size ();
76	pcg	1.11	}
77	pcg	1.10	}
78
79	pcg	1.13	template<class watcher>
80			void io_manager::unreg (watcher *w, io_manager_vec<watcher> &queue)
81	pcg	1.10	{
82	pcg	1.13	if (!iom_valid)
83			return;
84	pcg	1.10
85	pcg	1.13	if (w->active)
86	pcg	1.11	{
87	pcg	1.13	queue [w->active - 1] = 0;
88			w->active = 0;
89	pcg	1.11	}
90	pcg	1.1	}
91
92	pcg	1.13	#if IOM_TIME
93			void time_watcher::trigger ()
94	pcg	1.1	{
95	pcg	1.13	call (*this);
96	pcg	1.11
97	pcg	1.13	iom.reg (this);
98	pcg	1.1	}
99
100	pcg	1.13	void io_manager::reg (time_watcher *w) { reg (w, tw); }
101			void io_manager::unreg (time_watcher *w) { unreg (w, tw); }
102			#endif
103	pcg	1.6
104	pcg	1.13	#if IOM_IO
105	pcg	1.18	void io_manager::reg (io_watcher *w) { reg (w, iow); }
106	pcg	1.13	void io_manager::unreg (io_watcher *w) { unreg (w, iow); }
107			#endif
108	pcg	1.7
109	pcg	1.13	#if IOM_CHECK
110			void io_manager::reg (check_watcher *w) { reg (w, cw); }
111			void io_manager::unreg (check_watcher *w) { unreg (w, cw); }
112			#endif
113	pcg	1.1
114	pcg	1.13	#if IOM_IDLE
115			void io_manager::reg (idle_watcher *w) { reg (w, iw); }
116			void io_manager::unreg (idle_watcher *w) { unreg (w, iw); }
117			#endif
118	pcg	1.1
119	pcg	1.13	#if IOM_TIME
120	pcg	1.1	inline void set_now (void)
121			{
122			struct timeval tv;
123
124			gettimeofday (&tv, 0);
125
126	pcg	1.2	NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
127	pcg	1.13	#endif
128	pcg	1.1	}
129
130			void io_manager::loop ()
131			{
132	pcg	1.13	#if IOM_TIME
133	pcg	1.1	set_now ();
134	pcg	1.13	#endif
135	pcg	1.1
136	pcg	1.4	for (;;)
137	pcg	1.1	{
138	pcg	1.13	struct timeval *to = 0;
139			struct timeval tval;
140
141			#if IOM_IDLE
142			if (iw.size ())
143			{
144			tval.tv_sec = 0;
145			tval.tv_usec = 0;
146			to = &tval;
147			}
148			else
149			#endif
150	pcg	1.18
151	pcg	1.4	{
152	pcg	1.13	#if IOM_TIME
153			time_watcher *next;
154	pcg	1.7
155	pcg	1.13	for (;;)
156			{
157			next = tw[0]; // the first time-watcher must exist at ALL times
158
159			for (int i = tw.size (); i--; )
160			if (!tw[i])
161			tw.erase_unordered (i);
162			else if (tw[i]->at < next->at)
163			next = tw[i];
164
165			if (next->at > NOW)
166			{
167			if (next != tw[0])
168			{
169			double diff = next->at - NOW;
170			tval.tv_sec = (int)diff;
171	pcg	1.18	tval.tv_usec = (int) ((diff - tval.tv_sec) * 1000000);
172	pcg	1.13	to = &tval;
173			}
174			break;
175			}
176			else
177			{
178			unreg (next);
179			next->call (*next);
180			}
181			}
182			#endif
183	pcg	1.18
184	pcg	1.13	}
185	pcg	1.1
186	pcg	1.13	#if IOM_CHECK
187	pcg	1.17	tw.activity = false;
188
189	pcg	1.13	for (int i = cw.size (); i--; )
190			if (!cw[i])
191			cw.erase_unordered (i);
192			else
193			cw[i]->call (*cw[i]);
194	pcg	1.17
195			if (tw.activity)
196			{
197			tval.tv_sec = 0;
198			tval.tv_usec = 0;
199			to = &tval;
200			}
201	pcg	1.13	#endif
202
203			#if IOM_IO
204	pcg	1.18	fd_set rfd, wfd;
205	pcg	1.7
206	pcg	1.13	FD_ZERO (&rfd);
207			FD_ZERO (&wfd);
208	pcg	1.7
209	pcg	1.13	int fds = 0;
210
211			for (io_manager_vec<io_watcher>::iterator i = iow.end (); i-- > iow.begin (); )
212			if (*i)
213			{
214			if ((i)->events & EVENT_READ ) FD_SET ((i)->fd, &rfd);
215			if ((i)->events & EVENT_WRITE) FD_SET ((i)->fd, &wfd);
216	pcg	1.1
217	pcg	1.13	if ((i)->fd >= fds) fds = (i)->fd + 1;
218			}
219	pcg	1.1
220	pcg	1.13	if (!to && !fds) //TODO: also check idle_watchers and check_watchers
221			break; // no events
222	pcg	1.1
223	pcg	1.19	fds = select (fds, &rfd, &wfd, NULL, to);
224	pcg	1.13	# if IOM_TIME
225	pcg	1.4	set_now ();
226	pcg	1.13	# endif
227	pcg	1.1
228	pcg	1.13	if (fds > 0)
229			for (int i = iow.size (); i--; )
230			if (!iow[i])
231			iow.erase_unordered (i);
232			else
233			{
234			short revents = iow[i]->events;
235
236			if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
237			if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE;
238
239			if (revents)
240			iow[i]->call (*iow[i], revents);
241			}
242			else if (fds < 0 && errno != EINTR)
243			{
244			perror ("Error while waiting for I/O or time event");
245			abort ();
246			}
247			#if IOM_IDLE
248			else
249			for (int i = iw.size (); i--; )
250			if (!iw[i])
251			iw.erase_unordered (i);
252			else
253			iw[i]->call (*iw[i]);
254			#endif
255
256			#elif IOM_TIME
257			if (!to)
258			break;
259	pcg	1.9
260	pcg	1.13	select (0, 0, 0, 0, &to);
261			set_now ();
262			#else
263			break;
264			#endif
265	pcg	1.18
266	pcg	1.1	}
267			}
268
269			io_manager::io_manager ()
270			{
271	pcg	1.10	iom_valid = true;
272
273	pcg	1.13	#if IOM_TIME
274	pcg	1.1	set_now ();
275	pcg	1.13
276			tw0.start (TSTAMP_MAX);
277			#endif
278	pcg	1.1	}
279
280			io_manager::~io_manager ()
281			{
282	pcg	1.10	iom_valid = false;
283	pcg	1.1	}
284