【转】你真的懂select Socket模型吗?
volatile double SIGFPE_REQ = 0.0f; struct idx_info {
int read_pos_plus1;
int write_pos_plus1;
}; struct win32op {
unsigned num_fds_in_fd_sets;
int resize_out_sets;
struct win_fd_set *readset_in;
struct win_fd_set *writeset_in;
struct win_fd_set *readset_out;
struct win_fd_set *writeset_out;
struct win_fd_set *exset_out;
unsigned signals_are_broken : ;
}; static void *win32_init(struct event_base *);
static int win32_add(struct event_base *, evutil_socket_t, short old, short events, void *_idx);
static int win32_del(struct event_base *, evutil_socket_t, short old, short events, void *_idx);
static int win32_dispatch(struct event_base *base, struct timeval *);
static void win32_dealloc(struct event_base *); struct eventop win32ops = {
"win32",
win32_init,
win32_add,
win32_del,
win32_dispatch,
win32_dealloc,
, /* doesn't need reinit */
, /* No features supported. */
sizeof(struct idx_info),
}; #define FD_SET_ALLOC_SIZE(n) ((sizeof(struct win_fd_set) + ((n)-1)*sizeof(SOCKET))) static int
grow_fd_sets(struct win32op *op, unsigned new_num_fds)
{
size_t size; EVUTIL_ASSERT(new_num_fds >= op->readset_in->fd_count &&
new_num_fds >= op->writeset_in->fd_count);
EVUTIL_ASSERT(new_num_fds >= ); size = FD_SET_ALLOC_SIZE(new_num_fds);
if (!(op->readset_in = mm_realloc(op->readset_in, size)))
return (-);
if (!(op->writeset_in = mm_realloc(op->writeset_in, size)))
return (-);
op->resize_out_sets = ;
op->num_fds_in_fd_sets = new_num_fds;
return ();
} static int
do_fd_set(struct win32op *op, struct idx_info *ent, evutil_socket_t s, int read)
{
struct win_fd_set *set = read ? op->readset_in : op->writeset_in;
if (read) {
if (ent->read_pos_plus1 > )
return ();
} else {
if (ent->write_pos_plus1 > )
return ();
}
if (set->fd_count == op->num_fds_in_fd_sets) {
if (grow_fd_sets(op, op->num_fds_in_fd_sets*))
return (-);
/* set pointer will have changed and needs reiniting! */
set = read ? op->readset_in : op->writeset_in;
}
set->fd_array[set->fd_count] = s;
if (read)
ent->read_pos_plus1 = set->fd_count+;
else
ent->write_pos_plus1 = set->fd_count+;
return (set->fd_count++);
} static int
do_fd_clear(struct event_base *base,
struct win32op *op, struct idx_info *ent, int read)
{
int i;
struct win_fd_set *set = read ? op->readset_in : op->writeset_in;
if (read) {
i = ent->read_pos_plus1 - ;
ent->read_pos_plus1 = ;
} else {
i = ent->write_pos_plus1 - ;
ent->write_pos_plus1 = ;
}
if (i < )
return ();
if (--set->fd_count != (unsigned)i) {
struct idx_info *ent2;
SOCKET s2;
s2 = set->fd_array[i] = set->fd_array[set->fd_count]; ent2 = evmap_io_get_fdinfo(&base->io, s2); if (!ent2) /* This indicates a bug. */
return ();
if (read)
ent2->read_pos_plus1 = i+;
else
ent2->write_pos_plus1 = i+;
}
return ();
} #define NEVENT 32
void *
win32_init(struct event_base *_base)
{
struct win32op *winop;
size_t size;
if (!(winop = mm_calloc(, sizeof(struct win32op))))
return NULL;
winop->num_fds_in_fd_sets = NEVENT;
size = FD_SET_ALLOC_SIZE(NEVENT);
if (!(winop->readset_in = mm_malloc(size)))
goto err;
if (!(winop->writeset_in = mm_malloc(size)))
goto err;
if (!(winop->readset_out = mm_malloc(size)))
goto err;
if (!(winop->writeset_out = mm_malloc(size)))
goto err;
if (!(winop->exset_out = mm_malloc(size)))
goto err;
winop->readset_in->fd_count = winop->writeset_in->fd_count = ;
winop->readset_out->fd_count = winop->writeset_out->fd_count
= winop->exset_out->fd_count = ; if (evsig_init(_base) < )
winop->signals_are_broken = ; return (winop);
err:
XFREE(winop->readset_in);
XFREE(winop->writeset_in);
XFREE(winop->readset_out);
XFREE(winop->writeset_out);
XFREE(winop->exset_out);
XFREE(winop);
return (NULL);
} int
win32_add(struct event_base *base, evutil_socket_t fd,
short old, short events, void *_idx)
{
struct win32op *win32op = base->evbase;
struct idx_info *idx = _idx; if ((events & EV_SIGNAL) && win32op->signals_are_broken)
return (-); if (!(events & (EV_READ|EV_WRITE)))
return (); event_debug(("%s: adding event for %d", __func__, (int)fd));
if (events & EV_READ) {
if (do_fd_set(win32op, idx, fd, )<)
return (-);
}
if (events & EV_WRITE) {
if (do_fd_set(win32op, idx, fd, )<)
return (-);
}
return ();
} int
win32_del(struct event_base *base, evutil_socket_t fd, short old, short events,
void *_idx)
{
struct win32op *win32op = base->evbase;
struct idx_info *idx = _idx; event_debug(("%s: Removing event for "EV_SOCK_FMT,
__func__, EV_SOCK_ARG(fd)));
if (events & EV_READ)
do_fd_clear(base, win32op, idx, );
if (events & EV_WRITE)
do_fd_clear(base, win32op, idx, ); return ;
} static void
fd_set_copy(struct win_fd_set *out, const struct win_fd_set *in)
{
out->fd_count = in->fd_count;
memcpy(out->fd_array, in->fd_array, in->fd_count * (sizeof(SOCKET)));
} /*
static void dump_fd_set(struct win_fd_set *s)
{
unsigned int i;
printf("[ ");
for(i=0;i<s->fd_count;++i)
printf("%d ",(int)s->fd_array[i]);
printf("]\n");
}
*/ int
win32_dispatch(struct event_base *base, struct timeval *tv)
{
struct win32op *win32op = base->evbase;
int res = ;
unsigned j, i;
int fd_count;
SOCKET s; if (win32op->resize_out_sets) {
size_t size = FD_SET_ALLOC_SIZE(win32op->num_fds_in_fd_sets);
if (!(win32op->readset_out = mm_realloc(win32op->readset_out, size)))
return (-);
if (!(win32op->exset_out = mm_realloc(win32op->exset_out, size)))
return (-);
if (!(win32op->writeset_out = mm_realloc(win32op->writeset_out, size)))
return (-);
win32op->resize_out_sets = ;
} fd_set_copy(win32op->readset_out, win32op->readset_in);
fd_set_copy(win32op->exset_out, win32op->writeset_in);
fd_set_copy(win32op->writeset_out, win32op->writeset_in); fd_count =
(win32op->readset_out->fd_count > win32op->writeset_out->fd_count) ?
win32op->readset_out->fd_count : win32op->writeset_out->fd_count; if (!fd_count) {
long msec = tv ? evutil_tv_to_msec(tv) : LONG_MAX;
/* Sleep's DWORD argument is unsigned long */
if (msec < )
msec = LONG_MAX;
/* Windows doesn't like you to call select() with no sockets */
Sleep(msec);
return ();
} EVBASE_RELEASE_LOCK(base, th_base_lock); res = select(fd_count,
(struct fd_set*)win32op->readset_out,
(struct fd_set*)win32op->writeset_out,
(struct fd_set*)win32op->exset_out, tv); EVBASE_ACQUIRE_LOCK(base, th_base_lock); event_debug(("%s: select returned %d", __func__, res)); if (res <= ) {
return res;
} if (win32op->readset_out->fd_count) {
i = rand() % win32op->readset_out->fd_count;
for (j=; j<win32op->readset_out->fd_count; ++j) {
if (++i >= win32op->readset_out->fd_count)
i = ;
s = win32op->readset_out->fd_array[i];
evmap_io_active(base, s, EV_READ);
}
}
if (win32op->exset_out->fd_count) {
i = rand() % win32op->exset_out->fd_count;
for (j=; j<win32op->exset_out->fd_count; ++j) {
if (++i >= win32op->exset_out->fd_count)
i = ;
s = win32op->exset_out->fd_array[i];
evmap_io_active(base, s, EV_WRITE);
}
}
if (win32op->writeset_out->fd_count) {
SOCKET s;
i = rand() % win32op->writeset_out->fd_count;
for (j=; j<win32op->writeset_out->fd_count; ++j) {
if (++i >= win32op->writeset_out->fd_count)
i = ;
s = win32op->writeset_out->fd_array[i];
evmap_io_active(base, s, EV_WRITE);
}
}
return ();
} void
win32_dealloc(struct event_base *_base)
{
struct win32op *win32op = _base->evbase; evsig_dealloc(_base);
if (win32op->readset_in)
mm_free(win32op->readset_in);
if (win32op->writeset_in)
mm_free(win32op->writeset_in);
if (win32op->readset_out)
mm_free(win32op->readset_out);
if (win32op->writeset_out)
mm_free(win32op->writeset_out);
if (win32op->exset_out)
mm_free(win32op->exset_out);
/* XXXXX free the tree. */ memset(win32op, , sizeof(win32op));
mm_free(win32op);
}
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