libev/ev_select.c

/*
 * libev select fd activity backend
 *
 * Copyright (c) 2007,2008 Marc Alexander Lehmann <libev@schmorp.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 * 
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 * 
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 */

#ifndef _WIN32
/* for unix systems */
# include <sys/select.h>
# include <inttypes.h>
#endif

#ifndef EV_SELECT_USE_FD_SET
# ifdef NFDBITS
#  define EV_SELECT_USE_FD_SET 0
# else
#  define EV_SELECT_USE_FD_SET 1
# endif
#endif

#if EV_SELECT_IS_WINSOCKET
# undef EV_SELECT_USE_FD_SET
# define EV_SELECT_USE_FD_SET 1
#endif

#if !EV_SELECT_USE_FD_SET
# define NFDBYTES (NFDBITS / 8)
#endif

#include <string.h>

static void
select_modify (EV_P_ int fd, int oev, int nev)
{
  if (oev == nev)
    return;

  {
#if EV_SELECT_USE_FD_SET

    #if EV_SELECT_IS_WINSOCKET
    SOCKET handle = anfds [fd].handle;
    #else
    int handle = fd;
    #endif

    if (nev & EV_READ)
      FD_SET (handle, (fd_set *)vec_ri);
    else
      FD_CLR (handle, (fd_set *)vec_ri);

    if (nev & EV_WRITE)
      FD_SET (handle, (fd_set *)vec_wi);
    else
      FD_CLR (handle, (fd_set *)vec_wi);

#else

    int     word = fd / NFDBITS;
    fd_mask mask = 1UL << (fd % NFDBITS);

    if (expect_false (vec_max <= word))
      {
        int new_max = word + 1;

        vec_ri = ev_realloc (vec_ri, new_max * NFDBYTES);
        vec_ro = ev_realloc (vec_ro, new_max * NFDBYTES); /* could free/malloc */
        vec_wi = ev_realloc (vec_wi, new_max * NFDBYTES);
        vec_wo = ev_realloc (vec_wo, new_max * NFDBYTES); /* could free/malloc */

        for (; vec_max < new_max; ++vec_max)
          ((fd_mask *)vec_ri) [vec_max] =
          ((fd_mask *)vec_wi) [vec_max] = 0;
      }

    ((fd_mask *)vec_ri) [word] |= mask;
    if (!(nev & EV_READ))
      ((fd_mask *)vec_ri) [word] &= ~mask;

    ((fd_mask *)vec_wi) [word] |= mask;
    if (!(nev & EV_WRITE))
      ((fd_mask *)vec_wi) [word] &= ~mask;
#endif
  }
}

static void
select_poll (EV_P_ ev_tstamp timeout)
{
  struct timeval tv;
  int res;

#if EV_SELECT_USE_FD_SET
  memcpy (vec_ro, vec_ri, sizeof (fd_set));
  memcpy (vec_wo, vec_wi, sizeof (fd_set));
#else
  memcpy (vec_ro, vec_ri, vec_max * NFDBYTES);
  memcpy (vec_wo, vec_wi, vec_max * NFDBYTES);
#endif

  tv.tv_sec  = (long)timeout;
  tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);

#ifdef _WIN32
  /* pass in the write set as except set.
   * the idea behind this is to work around a windows bug that causes
   * errors to be reported as an exception and not by setting
   * the writable bit. this is so uncontrollably lame.
   */
  res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, (fd_set *)vec_wo, &tv);
#else
  res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
#endif

  if (expect_false (res < 0))
    {
      #if EV_SELECT_IS_WINSOCKET
      errno = WSAGetLastError ();
      #endif
      #ifdef WSABASEERR
      /* on windows, select returns incompatible error codes, fix this */
      if (errno >= WSABASEERR && errno < WSABASEERR + 1000)
        if (errno == WSAENOTSOCK)
          errno = EBADF;
        else
          errno -= WSABASEERR;
      #endif

      #ifdef _WIN32
      /* select on windows errornously returns EINVAL when no fd sets have been
       * provided (this is documented). what microsoft doesn't tell you that this bug
       * exists even when the fd sets are provided, so we have to check for this bug
       * here and emulate by sleeping manually.
       * we also get EINVAL when the timeout is invalid, but we ignore this case here
       * and assume that EINVAL always means: you have to wait manually.
       */
      if (errno == EINVAL)
        {
          ev_sleep (timeout);
          return;
        }
      #endif

      if (errno == EBADF)
        fd_ebadf (EV_A);
      else if (errno == ENOMEM && !syserr_cb)
        fd_enomem (EV_A);
      else if (errno != EINTR)
        syserr ("(libev) select");

      return;
    }

#if EV_SELECT_USE_FD_SET

  {
    int fd;

    for (fd = 0; fd < anfdmax; ++fd)
      if (anfds [fd].events)
        {
          int events = 0;
          #if EV_SELECT_IS_WINSOCKET
          SOCKET handle = anfds [fd].handle;
          #else
          int handle = fd;
          #endif

          if (FD_ISSET (handle, (fd_set *)vec_ro)) events |= EV_READ;
          if (FD_ISSET (handle, (fd_set *)vec_wo)) events |= EV_WRITE;

          if (expect_true (events))
            fd_event (EV_A_ fd, events);
        }
  }

#else

  {
    int word, bit;
    for (word = vec_max; word--; )
      {
        fd_mask word_r = ((fd_mask *)vec_ro) [word];
        fd_mask word_w = ((fd_mask *)vec_wo) [word];

        if (word_r || word_w)
          for (bit = NFDBITS; bit--; )
            {
              fd_mask mask = 1UL << bit;
              int events = 0;

              events |= word_r & mask ? EV_READ  : 0;
              events |= word_w & mask ? EV_WRITE : 0;

              if (expect_true (events))
                fd_event (EV_A_ word * NFDBITS + bit, events);
            }
      }
  }

#endif
}

int inline_size
select_init (EV_P_ int flags)
{
  backend_fudge  = 0.; /* posix says this is zero */
  backend_modify = select_modify;
  backend_poll   = select_poll;

#if EV_SELECT_USE_FD_SET
  vec_max = FD_SETSIZE / 32;
  vec_ri  = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_ri);
  vec_ro  = ev_malloc (sizeof (fd_set));
  vec_wi  = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_wi);
  vec_wo  = ev_malloc (sizeof (fd_set));
#else
  vec_max = 0;
  vec_ri  = 0; 
  vec_ri  = 0;   
  vec_wo  = 0; 
  vec_wo  = 0; 
#endif

  return EVBACKEND_SELECT;
}

void inline_size
select_destroy (EV_P)
{
  ev_free (vec_ri);
  ev_free (vec_ro);
  ev_free (vec_wi);
  ev_free (vec_wo);
}


Revision:	1.32
Committed:	Mon May 26 03:54:40 2008 UTC (15 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.31:	+9 -0 lines
Log Message:	* empty log message *
#	Content
1	/*
2	* libev select fd activity backend
3	*
4	* Copyright (c) 2007,2008 Marc Alexander Lehmann <libev@schmorp.de>
5	* All rights reserved.
6	*
7	* Redistribution and use in source and binary forms, with or without modifica-
8	* tion, are permitted provided that the following conditions are met:
9	*
10	* 1. Redistributions of source code must retain the above copyright notice,
11	* this list of conditions and the following disclaimer.
12	*
13	* 2. Redistributions in binary form must reproduce the above copyright
14	* notice, this list of conditions and the following disclaimer in the
15	* documentation and/or other materials provided with the distribution.
16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19	* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20	* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
21	* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23	* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
25	* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26	* OF THE POSSIBILITY OF SUCH DAMAGE.
27	*
28	* Alternatively, the contents of this file may be used under the terms of
29	* the GNU General Public License ("GPL") version 2 or any later version,
30	* in which case the provisions of the GPL are applicable instead of
31	* the above. If you wish to allow the use of your version of this file
32	* only under the terms of the GPL and not to allow others to use your
33	* version of this file under the BSD license, indicate your decision
34	* by deleting the provisions above and replace them with the notice
35	* and other provisions required by the GPL. If you do not delete the
36	* provisions above, a recipient may use your version of this file under
37	* either the BSD or the GPL.
38	*/
39
40	#ifndef _WIN32
41	/* for unix systems */
42	# include <sys/select.h>
43	# include <inttypes.h>
44	#endif
45
46	#ifndef EV_SELECT_USE_FD_SET
47	# ifdef NFDBITS
48	# define EV_SELECT_USE_FD_SET 0
49	# else
50	# define EV_SELECT_USE_FD_SET 1
51	# endif
52	#endif
53
54	#if EV_SELECT_IS_WINSOCKET
55	# undef EV_SELECT_USE_FD_SET
56	# define EV_SELECT_USE_FD_SET 1
57	#endif
58
59	#if !EV_SELECT_USE_FD_SET
60	# define NFDBYTES (NFDBITS / 8)
61	#endif
62
63	#include <string.h>
64
65	static void
66	select_modify (EV_P_ int fd, int oev, int nev)
67	{
68	if (oev == nev)
69	return;
70
71	{
72	#if EV_SELECT_USE_FD_SET
73
74	#if EV_SELECT_IS_WINSOCKET
75	SOCKET handle = anfds [fd].handle;
76	#else
77	int handle = fd;
78	#endif
79
80	if (nev & EV_READ)
81	FD_SET (handle, (fd_set *)vec_ri);
82	else
83	FD_CLR (handle, (fd_set *)vec_ri);
84
85	if (nev & EV_WRITE)
86	FD_SET (handle, (fd_set *)vec_wi);
87	else
88	FD_CLR (handle, (fd_set *)vec_wi);
89
90	#else
91
92	int word = fd / NFDBITS;
93	fd_mask mask = 1UL << (fd % NFDBITS);
94
95	if (expect_false (vec_max <= word))
96	{
97	int new_max = word + 1;
98
99	vec_ri = ev_realloc (vec_ri, new_max * NFDBYTES);
100	vec_ro = ev_realloc (vec_ro, new_max * NFDBYTES); /* could free/malloc */
101	vec_wi = ev_realloc (vec_wi, new_max * NFDBYTES);
102	vec_wo = ev_realloc (vec_wo, new_max * NFDBYTES); /* could free/malloc */
103
104	for (; vec_max < new_max; ++vec_max)
105	((fd_mask *)vec_ri) [vec_max] =
106	((fd_mask *)vec_wi) [vec_max] = 0;
107	}
108
109	((fd_mask *)vec_ri) [word] \|= mask;
110	if (!(nev & EV_READ))
111	((fd_mask *)vec_ri) [word] &= ~mask;
112
113	((fd_mask *)vec_wi) [word] \|= mask;
114	if (!(nev & EV_WRITE))
115	((fd_mask *)vec_wi) [word] &= ~mask;
116	#endif
117	}
118	}
119
120	static void
121	select_poll (EV_P_ ev_tstamp timeout)
122	{
123	struct timeval tv;
124	int res;
125
126	#if EV_SELECT_USE_FD_SET
127	memcpy (vec_ro, vec_ri, sizeof (fd_set));
128	memcpy (vec_wo, vec_wi, sizeof (fd_set));
129	#else
130	memcpy (vec_ro, vec_ri, vec_max * NFDBYTES);
131	memcpy (vec_wo, vec_wi, vec_max * NFDBYTES);
132	#endif
133
134	tv.tv_sec = (long)timeout;
135	tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
136
137	#ifdef _WIN32
138	/* pass in the write set as except set.
139	* the idea behind this is to work around a windows bug that causes
140	* errors to be reported as an exception and not by setting
141	* the writable bit. this is so uncontrollably lame.
142	*/
143	res = select (vec_max * NFDBITS, (fd_set )vec_ro, (fd_set )vec_wo, (fd_set *)vec_wo, &tv);
144	#else
145	res = select (vec_max * NFDBITS, (fd_set )vec_ro, (fd_set )vec_wo, 0, &tv);
146	#endif
147
148	if (expect_false (res < 0))
149	{
150	#if EV_SELECT_IS_WINSOCKET
151	errno = WSAGetLastError ();
152	#endif
153	#ifdef WSABASEERR
154	/* on windows, select returns incompatible error codes, fix this */
155	if (errno >= WSABASEERR && errno < WSABASEERR + 1000)
156	if (errno == WSAENOTSOCK)
157	errno = EBADF;
158	else
159	errno -= WSABASEERR;
160	#endif
161
162	#ifdef _WIN32
163	/* select on windows errornously returns EINVAL when no fd sets have been
164	* provided (this is documented). what microsoft doesn't tell you that this bug
165	* exists even when the fd sets are provided, so we have to check for this bug
166	* here and emulate by sleeping manually.
167	* we also get EINVAL when the timeout is invalid, but we ignore this case here
168	* and assume that EINVAL always means: you have to wait manually.
169	*/
170	if (errno == EINVAL)
171	{
172	ev_sleep (timeout);
173	return;
174	}
175	#endif
176
177	if (errno == EBADF)
178	fd_ebadf (EV_A);
179	else if (errno == ENOMEM && !syserr_cb)
180	fd_enomem (EV_A);
181	else if (errno != EINTR)
182	syserr ("(libev) select");
183
184	return;
185	}
186
187	#if EV_SELECT_USE_FD_SET
188
189	{
190	int fd;
191
192	for (fd = 0; fd < anfdmax; ++fd)
193	if (anfds [fd].events)
194	{
195	int events = 0;
196	#if EV_SELECT_IS_WINSOCKET
197	SOCKET handle = anfds [fd].handle;
198	#else
199	int handle = fd;
200	#endif
201
202	if (FD_ISSET (handle, (fd_set *)vec_ro)) events \|= EV_READ;
203	if (FD_ISSET (handle, (fd_set *)vec_wo)) events \|= EV_WRITE;
204
205	if (expect_true (events))
206	fd_event (EV_A_ fd, events);
207	}
208	}
209
210	#else
211
212	{
213	int word, bit;
214	for (word = vec_max; word--; )
215	{
216	fd_mask word_r = ((fd_mask *)vec_ro) [word];
217	fd_mask word_w = ((fd_mask *)vec_wo) [word];
218
219	if (word_r \|\| word_w)
220	for (bit = NFDBITS; bit--; )
221	{
222	fd_mask mask = 1UL << bit;
223	int events = 0;
224
225	events \|= word_r & mask ? EV_READ : 0;
226	events \|= word_w & mask ? EV_WRITE : 0;
227
228	if (expect_true (events))
229	fd_event (EV_A_ word * NFDBITS + bit, events);
230	}
231	}
232	}
233
234	#endif
235	}
236
237	int inline_size
238	select_init (EV_P_ int flags)
239	{
240	backend_fudge = 0.; /* posix says this is zero */
241	backend_modify = select_modify;
242	backend_poll = select_poll;
243
244	#if EV_SELECT_USE_FD_SET
245	vec_max = FD_SETSIZE / 32;
246	vec_ri = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_ri);
247	vec_ro = ev_malloc (sizeof (fd_set));
248	vec_wi = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_wi);
249	vec_wo = ev_malloc (sizeof (fd_set));
250	#else
251	vec_max = 0;
252	vec_ri = 0;
253	vec_ri = 0;
254	vec_wo = 0;
255	vec_wo = 0;
256	#endif
257
258	return EVBACKEND_SELECT;
259	}
260
261	void inline_size
262	select_destroy (EV_P)
263	{
264	ev_free (vec_ri);
265	ev_free (vec_ro);
266	ev_free (vec_wi);
267	ev_free (vec_wo);
268	}
269
270