/* -*-c-*-
*
- * $Id: sel.c,v 1.1 1999/05/14 21:01:14 mdw Exp $
+ * $Id: sel.c,v 1.6 1999/09/26 14:28:11 mdw Exp $
*
* I/O multiplexing support
*
- * (c) 1999 Mark Wooding
+ * (c) 1999 Straylight/Edgeware
*/
/*----- Licensing notice --------------------------------------------------*
/*----- Revision history --------------------------------------------------*
*
* $Log: sel.c,v $
+ * Revision 1.6 1999/09/26 14:28:11 mdw
+ * (sel_select): Almost pointless efficiency tweak.
+ *
+ * Revision 1.5 1999/08/31 17:42:22 mdw
+ * New function `sel_force' to force a descriptor to be `selected'.
+ *
+ * Revision 1.4 1999/08/19 18:30:26 mdw
+ * Implement hooks for foreign select-using systems (currently not well
+ * tested).
+ *
+ * Revision 1.3 1999/05/21 22:13:59 mdw
+ * Use new `tv' macros. Fix ordering bug for timeout selectors.
+ *
+ * Revision 1.2 1999/05/15 10:33:32 mdw
+ * Fix copyright notices.
+ *
* Revision 1.1 1999/05/14 21:01:14 mdw
* Integrated `select' handling bits from the background resolver project.
*
void sel_init(sel_state *s)
{
- s->files = 0;
+ int i;
+
+ for (i = 0; i < SEL_MODES; i++) {
+ s->files[i] = 0;
+ FD_ZERO(&s->fd[i]);
+ }
s->timers = 0;
- FD_ZERO(&s->fd[SEL_READ]);
- FD_ZERO(&s->fd[SEL_WRITE]);
- FD_ZERO(&s->fd[SEL_EXC]);
+ s->hooks = 0;
+ s->args = 0;
}
/* --- @sel_initfile@ --- *
void sel_addfile(sel_file *f)
{
- sel_file **ff = &f->s->files;
+ sel_file **ff = &f->s->files[f->mode];
/* --- This little dance looks like line-noise, but it does the job --- */
FD_SET(f->fd, f->s->fd + f->mode);
}
+/* --- @sel_force@ --- *
+ *
+ * Arguments: @sel_file *f@ = pointer to file selector
+ *
+ * Returns: ---
+ *
+ * Use: Forces a file selector to be considered ready. This is only
+ * useful during a call to @sel_select@. Of particular use is
+ * forcing a write selector when there's something interesting
+ * ready for it.
+ */
+
+void sel_force(sel_file *f)
+{
+ if (f->s->args)
+ FD_SET(f->fd, &f->s->args->fd[f->mode]);
+}
+
/* --- @sel_rmfile@ --- *
*
* Arguments: @sel_file *f@ = pointer to a file block
/* --- More line noise --- */
- while (*tt && tv_cmp(&(*tt)->tv, tv) > 0)
+ while (*tt && TV_CMP(&(*tt)->tv, <, tv))
tt = &(*tt)->next;
t->next = *tt;
t->prev = (sel_timer *)tt;
t->next->prev = t->prev;
}
+/* --- @sel_addhook@ --- *
+ *
+ * Arguments: @sel_state *s@ = pointer to state block
+ * @sel_hook *h@ = pointer to hook block
+ * @sel_hookfn before, after@ = hook functions
+ * @void *p@ = pointer argument to pass to hook functions
+ *
+ * Returns: ---
+ *
+ * Use: Registers hook functions to be called on each select call.
+ */
+
+void sel_addhook(sel_state *s, sel_hook *h,
+ sel_hookfn before, sel_hookfn after,
+ void *p)
+{
+ h->before = before;
+ h->after = after;
+ h->p = p;
+ h->next = s->hooks;
+ h->prev = (sel_hook *)&s->hooks;
+ if (s->hooks)
+ s->hooks->prev = h;
+ s->hooks = h;
+}
+
+/* --- @sel_rmhook@ --- *
+ *
+ * Arguments: @sel_hook *h@ = pointer to hook block
+ *
+ * Returns: ---
+ *
+ * Use: Removes hook functions.
+ */
+
+void sel_rmhook(sel_hook *h)
+{
+ if (h->next)
+ h->next->prev = h->prev;
+ h->prev->next = h->next;
+}
+
+/* --- @sel_fdmerge@ --- *
+ *
+ * Arguments: @fd_set *dest@ = destination FD set
+ * @fd_set *fd@ = pointer to set to merge
+ * @int maxfd@ = highest numbered descriptor in @fd@ + 1
+ *
+ * Returns: Actual highest numbered descriptor.
+ *
+ * Use: Merges file descriptor sets, and returns an accurate @maxfd@
+ * value.
+ */
+
+int sel_fdmerge(fd_set *dest, fd_set *fd, int maxfd)
+{
+ int i, m = -1;
+
+ for (i = 0; i < maxfd; i++) {
+ if (FD_ISSET(i, fd)) {
+ FD_SET(i, dest);
+ m = i;
+ }
+ }
+
+ return (m + 1);
+}
+
/* --- @sel_select@ --- *
*
* Arguments: @sel_state *s@ = pointer to state block
int sel_select(sel_state *s)
{
- fd_set fd[SEL_MODES];
- struct timeval tv;
+ sel_args a;
int err;
- memcpy(fd, s->fd, sizeof(s->fd));
- if (s->timers) {
- struct timeval now;
- gettimeofday(&now, 0);
- tv_sub(&tv, &now, &s->timers->tv);
- err = select(s->files ? s->files->fd + 1 : 0,
- fd + SEL_READ, fd + SEL_WRITE, fd + SEL_EXC,
- &tv);
- gettimeofday(&tv, 0);
- } else
- err = select(s->files ? s->files->fd + 1 : 0,
- fd + SEL_READ, fd + SEL_WRITE, fd + SEL_EXC,
- 0);
-
- if (err < 0)
+ /* --- Initialize the argument block --- */
+
+ {
+ int i;
+ a.maxfd = 0;
+ for (i = 0; i < SEL_MODES; i++) {
+ if (s->files[i] && s->files[i]->fd >= a.maxfd)
+ a.maxfd = s->files[i]->fd + 1;
+ }
+ }
+
+ memcpy(a.fd, s->fd, sizeof(a.fd));
+ if (s->timers || s->hooks)
+ gettimeofday(&a.now, 0);
+ if (!s->timers)
+ a.tvp = 0;
+ else {
+ TV_SUB(&a.tv, &s->timers->tv, &a.now);
+ a.tvp = &a.tv;
+ }
+ s->args = &a;
+
+ /* --- Grind through the pre hooks --- */
+
+ {
+ sel_hook *h = s->hooks;
+ while (h) {
+ sel_hook *hh = h;
+ h = h->next;
+ if (hh->before)
+ hh->before(s, &a, hh->p);
+ }
+ }
+
+ /* --- Run the @select@ call --- */
+
+ if ((err = select(a.maxfd,
+ &a.fd[SEL_READ], &a.fd[SEL_WRITE], &a.fd[SEL_EXC],
+ a.tvp)) < 0) {
+ s->args = 0;
return (err);
+ }
+
+ if (a.tvp)
+ gettimeofday(&a.now, 0);
+
+ /* --- Run through the hooks again --- */
+
+ {
+ sel_hook *h = s->hooks;
+ while (h) {
+ sel_hook *hh = h;
+ h = h->next;
+ if (hh->after)
+ hh->after(s, &a, hh->p);
+ }
+ }
+
+ /* --- Run through the timers --- */
{
sel_timer *t, *tt;
- for (t = s->timers; t && tv_cmp(&t->tv, &tv) <= 0; t = tt) {
+ for (t = s->timers; t && TV_CMP(&t->tv, <=, &a.now); t = tt) {
tt = t->next;
t->next = t->prev = t;
- t->func(&tv, t->p);
+ t->func(&a.now, t->p);
}
s->timers = t;
if (t)
t->prev = (sel_timer *)&s->timers;
}
+ /* --- And finally run through the files --- *
+ *
+ * Do reads first. It's quite possible that a read might prompt a write,
+ * but the other way around is less likely. Fortunately, the modes are
+ * in the right order for this.
+ */
+
{
- sel_file *f, *ff;
- for (f = s->files; f; f = ff) {
- ff = f->next;
- if (FD_ISSET(f->fd, fd + f->mode))
- f->func(f->fd, f->mode, f->p);
+ int i;
+
+ for (i = 0; i < SEL_MODES; i++) {
+ sel_file *f, *ff;
+ for (f = s->files[i]; f; f = ff) {
+ ff = f->next;
+ if (FD_ISSET(f->fd, a.fd + i))
+ f->func(f->fd, i, f->p);
+ }
}
}
+ s->args = 0;
return (0);
}
~mdw / mLib / blobdiff