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Clean up error handling in epoll_apply_one_change() a little

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The old code was more or less:
   if (op == X && errno == FOO) {
     ...
   } else if (op == Y && errno == BAR) {
     ...
   }
but really we wanted to do a switch (op) to avoid needless checks
and branches.

This patch leaves the indentation a little weird so as to make it
easier to see what changed; the next patch will fix the indentation.
This commit is contained in:
Nick Mathewson 2010-12-16 14:25:04 -05:00
parent 8c83eb6948
commit 2d55a190e1
1 changed files with 34 additions and 18 deletions
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52
epoll.c
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@ -356,8 +356,20 @@ epoll_apply_one_change(struct event_base *base,
memset(&epev, 0, sizeof(epev)); memset(&epev, 0, sizeof(epev));
epev.data.fd = ch->fd; epev.data.fd = ch->fd;
epev.events = events; epev.events = events;
if (epoll_ctl(epollop->epfd, op, ch->fd, &epev) == -1) { if (epoll_ctl(epollop->epfd, op, ch->fd, &epev) == 0) {
if (op == EPOLL_CTL_MOD && errno == ENOENT) { event_debug(("Epoll %s(%d) on fd %d okay. [old events were %d; read change was %d; write change was %d]",
epoll_op_to_string(op),
(int)epev.events,
(int)ch->fd,
ch->old_events,
ch->read_change,
ch->write_change));
return 0;
}
switch (op) {
case EPOLL_CTL_MOD:
if (errno == ENOENT) {
/* If a MOD operation fails with ENOENT, the /* If a MOD operation fails with ENOENT, the
* fd was probably closed and re-opened. We * fd was probably closed and re-opened. We
* should retry the operation as an ADD. * should retry the operation as an ADD.
@ -370,8 +382,12 @@ epoll_apply_one_change(struct event_base *base,
event_debug(("Epoll MOD(%d) on %d retried as ADD; succeeded.", event_debug(("Epoll MOD(%d) on %d retried as ADD; succeeded.",
(int)epev.events, (int)epev.events,
ch->fd)); ch->fd));
return 0;
} }
} else if (op == EPOLL_CTL_ADD && errno == EEXIST) { }
break;
case EPOLL_CTL_ADD:
if (errno == EEXIST) {
/* If an ADD operation fails with EEXIST, /* If an ADD operation fails with EEXIST,
* either the operation was redundant (as with a * either the operation was redundant (as with a
* precautionary add), or we ran into a fun * precautionary add), or we ran into a fun
@ -387,10 +403,13 @@ epoll_apply_one_change(struct event_base *base,
event_debug(("Epoll ADD(%d) on %d retried as MOD; succeeded.", event_debug(("Epoll ADD(%d) on %d retried as MOD; succeeded.",
(int)epev.events, (int)epev.events,
ch->fd)); ch->fd));
return 0;
} }
} else if (op == EPOLL_CTL_DEL && }
(errno == ENOENT || errno == EBADF || break;
errno == EPERM)) { case EPOLL_CTL_DEL:
if (errno == ENOENT || errno == EBADF ||
errno == EPERM) {
/* If a delete fails with one of these errors, /* If a delete fails with one of these errors,
* that's fine too: we closed the fd before we * that's fine too: we closed the fd before we
* got around to calling epoll_dispatch. */ * got around to calling epoll_dispatch. */
@ -398,7 +417,14 @@ epoll_apply_one_change(struct event_base *base,
(int)epev.events, (int)epev.events,
ch->fd, ch->fd,
strerror(errno))); strerror(errno)));
} else { return 0;
}
break;
default:
break;
}
if (1) {
event_warn("Epoll %s(%d) on fd %d failed. Old events were %d; read change was %d (%s); write change was %d (%s)", event_warn("Epoll %s(%d) on fd %d failed. Old events were %d; read change was %d (%s); write change was %d (%s)",
epoll_op_to_string(op), epoll_op_to_string(op),
(int)epev.events, (int)epev.events,
@ -408,19 +434,9 @@ epoll_apply_one_change(struct event_base *base,
change_to_string(ch->read_change), change_to_string(ch->read_change),
ch->write_change, ch->write_change,
change_to_string(ch->write_change)); change_to_string(ch->write_change));
return -1;
} }
} else { return -1;
event_debug(("Epoll %s(%d) on fd %d okay. [old events were %d; read change was %d; write change was %d]",
epoll_op_to_string(op),
(int)epev.events,
(int)ch->fd,
ch->old_events,
ch->read_change,
ch->write_change));
}
} }
return 0;
} }
static int static int