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newlib-cygwin
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Improve and simplify select(). 

* select.h: Eliminate redundant select_stuff::select_loop state.
* select.cc (select): Eliminate redundant
  select_stuff::select_loop state.  Eliminate redundant code for
  zero timeout.  Do not return early on early timer return.
  (select_stuff::wait): Eliminate redundant
  select_stuff::select_loop state.
This commit is contained in:
John Hood 2016-05-18 19:14:17 -04:00 committed by Corinna Vinschen
parent a23e6a35d8
commit e5665d8c93
2 changed files with 15 additions and 49 deletions
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63
winsup/cygwin/select.cc
View File

@ -32,7 +32,6 @@ details. */
#include "pinfo.h"
#include "sigproc.h"
#include "cygtls.h"
#include "cygwait.h"
/*
* All these defines below should be in sys/types.h
@ -156,7 +155,7 @@ static int
select (int maxfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
LONGLONG us)
{
select_stuff::wait_states wait_state = select_stuff::select_loop;
select_stuff::wait_states wait_state = select_stuff::select_set_zero;
int ret = 0;
/* Record the current time for later use. */
@ -182,30 +181,7 @@ select (int maxfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
}
select_printf ("sel.always_ready %d", sel.always_ready);
/* Degenerate case. No fds to wait for. Just wait for time to run out
or signal to arrive. */
if (sel.start.next == NULL)
switch (cygwait (us * 1000ULL))
{
case WAIT_SIGNALED:
select_printf ("signal received");
/* select() is always interrupted by a signal so set EINTR,
unconditionally, ignoring any SA_RESTART detection by
call_signal_handler(). */
_my_tls.call_signal_handler ();
set_sig_errno (EINTR);
wait_state = select_stuff::select_signalled;
break;
case WAIT_CANCELED:
sel.destroy ();
pthread::static_cancel_self ();
/*NOTREACHED*/
default:
/* Set wait_state to zero below. */
wait_state = select_stuff::select_set_zero;
break;
}
else if (sel.always_ready || us == 0)
if (sel.always_ready || us == 0)
/* Catch any active fds via sel.poll() below */
wait_state = select_stuff::select_ok;
else
@ -214,29 +190,24 @@ select (int maxfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
select_printf ("sel.wait returns %d", wait_state);
if (wait_state >= select_stuff::select_ok)
if (wait_state == select_stuff::select_ok)
{
UNIX_FD_ZERO (readfds, maxfds);
UNIX_FD_ZERO (writefds, maxfds);
UNIX_FD_ZERO (exceptfds, maxfds);
if (wait_state == select_stuff::select_set_zero)
ret = 0;
else
{
/* Set bit mask from sel records. This also sets ret to the
right value >= 0, matching the number of bits set in the
fds records. if ret is 0, continue to loop. */
ret = sel.poll (readfds, writefds, exceptfds);
if (!ret)
wait_state = select_stuff::select_loop;
}
/* Set bit mask from sel records. This also sets ret to the
right value >= 0, matching the number of bits set in the
fds records. if ret is 0, continue to loop. */
ret = sel.poll (readfds, writefds, exceptfds);
if (!ret)
wait_state = select_stuff::select_set_zero;
}
/* Always clean up everything here. If we're looping then build it
all up again. */
sel.cleanup ();
sel.destroy ();
/* Recalculate time remaining to wait if we are going to be looping. */
if (wait_state == select_stuff::select_loop && us != -1)
/* Check and recalculate timeout. */
if (us != -1LL && wait_state == select_stuff::select_set_zero)
{
select_printf ("recalculating us");
LONGLONG now = gtod.usecs ();
@ -258,7 +229,7 @@ select (int maxfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
}
}
}
while (wait_state == select_stuff::select_loop);
while (wait_state == select_stuff::select_set_zero);
if (wait_state < select_stuff::select_ok)
ret = -1;
@ -494,7 +465,7 @@ next_while:;
to wait for. */
default:
s = &start;
bool gotone = false;
res = select_set_zero;
/* Some types of objects (e.g., consoles) wake up on "inappropriate"
events like mouse movements. The verify function will detect these
situations. If it returns false, then this wakeup was a false alarm
@ -508,13 +479,9 @@ next_while:;
}
else if ((((wait_ret >= m && s->windows_handle) || s->h == w4[wait_ret]))
&& s->verify (s, readfds, writefds, exceptfds))
gotone = true;
res = select_ok;
if (!gotone)
res = select_loop;
else
res = select_ok;
select_printf ("gotone %d", gotone);
select_printf ("res after verify %d", res);
break;
}
out:

1
winsup/cygwin/select.h
View File

@ -78,7 +78,6 @@ public:
enum wait_states
{
select_signalled = -3,
select_loop = -2,
select_error = -1,
select_ok = 0,
select_set_zero = 1