Repo created

TMessagesProj/jni/voip/webrtc/base/third_party/libevent/poll.c

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+/*	$OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $	*/
+
+/*
+ * Copyright 2000-2003 Niels Provos <provos@citi.umich.edu>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, 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 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include <sys/types.h>
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#else
+#include <sys/_libevent_time.h>
+#endif
+#include <sys/queue.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#ifdef CHECK_INVARIANTS
+#include <assert.h>
+#endif
+
+#include "event.h"
+#include "event-internal.h"
+#include "evsignal.h"
+#include "log.h"
+
+struct pollop {
+	int event_count;		/* Highest number alloc */
+	int nfds;                       /* Size of event_* */
+	int fd_count;                   /* Size of idxplus1_by_fd */
+	struct pollfd *event_set;
+	struct event **event_r_back;
+	struct event **event_w_back;
+	int *idxplus1_by_fd; /* Index into event_set by fd; we add 1 so
+			      * that 0 (which is easy to memset) can mean
+			      * "no entry." */
+};
+
+static void *poll_init	(struct event_base *);
+static int poll_add		(void *, struct event *);
+static int poll_del		(void *, struct event *);
+static int poll_dispatch	(struct event_base *, void *, struct timeval *);
+static void poll_dealloc	(struct event_base *, void *);
+
+const struct eventop pollops = {
+	"poll",
+	poll_init,
+	poll_add,
+	poll_del,
+	poll_dispatch,
+	poll_dealloc,
+    0
+};
+
+static void *
+poll_init(struct event_base *base)
+{
+	struct pollop *pollop;
+
+	/* Disable poll when this environment variable is set */
+	if (evutil_getenv("EVENT_NOPOLL"))
+		return (NULL);
+
+	if (!(pollop = calloc(1, sizeof(struct pollop))))
+		return (NULL);
+
+	evsignal_init(base);
+
+	return (pollop);
+}
+
+#ifdef CHECK_INVARIANTS
+static void
+poll_check_ok(struct pollop *pop)
+{
+	int i, idx;
+	struct event *ev;
+
+	for (i = 0; i < pop->fd_count; ++i) {
+		idx = pop->idxplus1_by_fd[i]-1;
+		if (idx < 0)
+			continue;
+		assert(pop->event_set[idx].fd == i);
+		if (pop->event_set[idx].events & POLLIN) {
+			ev = pop->event_r_back[idx];
+			assert(ev);
+			assert(ev->ev_events & EV_READ);
+			assert(ev->ev_fd == i);
+		}
+		if (pop->event_set[idx].events & POLLOUT) {
+			ev = pop->event_w_back[idx];
+			assert(ev);
+			assert(ev->ev_events & EV_WRITE);
+			assert(ev->ev_fd == i);
+		}
+	}
+	for (i = 0; i < pop->nfds; ++i) {
+		struct pollfd *pfd = &pop->event_set[i];
+		assert(pop->idxplus1_by_fd[pfd->fd] == i+1);
+	}
+}
+#else
+#define poll_check_ok(pop)
+#endif
+
+static int
+poll_dispatch(struct event_base *base, void *arg, struct timeval *tv)
+{
+	int res, i, j, msec = -1, nfds;
+	struct pollop *pop = arg;
+
+	poll_check_ok(pop);
+
+	if (tv != NULL)
+		msec = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000;
+
+	nfds = pop->nfds;
+	res = poll(pop->event_set, nfds, msec);
+
+	if (res == -1) {
+		if (errno != EINTR) {
+                        event_warn("poll");
+			return (-1);
+		}
+
+		evsignal_process(base);
+		return (0);
+	} else if (base->sig.evsignal_caught) {
+		evsignal_process(base);
+	}
+
+	event_debug(("%s: poll reports %d", __func__, res));
+
+	if (res == 0 || nfds == 0)
+		return (0);
+
+	i = random() % nfds;
+	for (j = 0; j < nfds; j++) {
+		struct event *r_ev = NULL, *w_ev = NULL;
+		int what;
+		if (++i == nfds)
+			i = 0;
+		what = pop->event_set[i].revents;
+
+		if (!what)
+			continue;
+
+		res = 0;
+
+		/* If the file gets closed notify */
+		if (what & (POLLHUP|POLLERR))
+			what |= POLLIN|POLLOUT;
+		if (what & POLLIN) {
+			res |= EV_READ;
+			r_ev = pop->event_r_back[i];
+		}
+		if (what & POLLOUT) {
+			res |= EV_WRITE;
+			w_ev = pop->event_w_back[i];
+		}
+		if (res == 0)
+			continue;
+
+		if (r_ev && (res & r_ev->ev_events)) {
+			event_active(r_ev, res & r_ev->ev_events, 1);
+		}
+		if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
+			event_active(w_ev, res & w_ev->ev_events, 1);
+		}
+	}
+
+	return (0);
+}
+
+static int
+poll_add(void *arg, struct event *ev)
+{
+	struct pollop *pop = arg;
+	struct pollfd *pfd = NULL;
+	int i;
+
+	if (ev->ev_events & EV_SIGNAL)
+		return (evsignal_add(ev));
+	if (!(ev->ev_events & (EV_READ|EV_WRITE)))
+		return (0);
+
+	poll_check_ok(pop);
+	if (pop->nfds + 1 >= pop->event_count) {
+		struct pollfd *tmp_event_set;
+		struct event **tmp_event_r_back;
+		struct event **tmp_event_w_back;
+		int tmp_event_count;
+
+		if (pop->event_count < 32)
+			tmp_event_count = 32;
+		else
+			tmp_event_count = pop->event_count * 2;
+
+		/* We need more file descriptors */
+		tmp_event_set = realloc(pop->event_set,
+				 tmp_event_count * sizeof(struct pollfd));
+		if (tmp_event_set == NULL) {
+			event_warn("realloc");
+			return (-1);
+		}
+		pop->event_set = tmp_event_set;
+
+		tmp_event_r_back = realloc(pop->event_r_back,
+			    tmp_event_count * sizeof(struct event *));
+		if (tmp_event_r_back == NULL) {
+			/* event_set overallocated; that's okay. */
+			event_warn("realloc");
+			return (-1);
+		}
+		pop->event_r_back = tmp_event_r_back;
+
+		tmp_event_w_back = realloc(pop->event_w_back,
+			    tmp_event_count * sizeof(struct event *));
+		if (tmp_event_w_back == NULL) {
+			/* event_set and event_r_back overallocated; that's
+			 * okay. */
+			event_warn("realloc");
+			return (-1);
+		}
+		pop->event_w_back = tmp_event_w_back;
+
+		pop->event_count = tmp_event_count;
+	}
+	if (ev->ev_fd >= pop->fd_count) {
+		int *tmp_idxplus1_by_fd;
+		int new_count;
+		if (pop->fd_count < 32)
+			new_count = 32;
+		else
+			new_count = pop->fd_count * 2;
+		while (new_count <= ev->ev_fd)
+			new_count *= 2;
+		tmp_idxplus1_by_fd =
+			realloc(pop->idxplus1_by_fd, new_count * sizeof(int));
+		if (tmp_idxplus1_by_fd == NULL) {
+			event_warn("realloc");
+			return (-1);
+		}
+		pop->idxplus1_by_fd = tmp_idxplus1_by_fd;
+		memset(pop->idxplus1_by_fd + pop->fd_count,
+		       0, sizeof(int)*(new_count - pop->fd_count));
+		pop->fd_count = new_count;
+	}
+
+	i = pop->idxplus1_by_fd[ev->ev_fd] - 1;
+	if (i >= 0) {
+		pfd = &pop->event_set[i];
+	} else {
+		i = pop->nfds++;
+		pfd = &pop->event_set[i];
+		pfd->events = 0;
+		pfd->fd = ev->ev_fd;
+		pop->event_w_back[i] = pop->event_r_back[i] = NULL;
+		pop->idxplus1_by_fd[ev->ev_fd] = i + 1;
+	}
+
+	pfd->revents = 0;
+	if (ev->ev_events & EV_WRITE) {
+		pfd->events |= POLLOUT;
+		pop->event_w_back[i] = ev;
+	}
+	if (ev->ev_events & EV_READ) {
+		pfd->events |= POLLIN;
+		pop->event_r_back[i] = ev;
+	}
+	poll_check_ok(pop);
+
+	return (0);
+}
+
+/*
+ * Nothing to be done here.
+ */
+
+static int
+poll_del(void *arg, struct event *ev)
+{
+	struct pollop *pop = arg;
+	struct pollfd *pfd = NULL;
+	int i;
+
+	if (ev->ev_events & EV_SIGNAL)
+		return (evsignal_del(ev));
+
+	if (!(ev->ev_events & (EV_READ|EV_WRITE)))
+		return (0);
+
+	poll_check_ok(pop);
+	i = pop->idxplus1_by_fd[ev->ev_fd] - 1;
+	if (i < 0)
+		return (-1);
+
+	/* Do we still want to read or write? */
+	pfd = &pop->event_set[i];
+	if (ev->ev_events & EV_READ) {
+		pfd->events &= ~POLLIN;
+		pop->event_r_back[i] = NULL;
+	}
+	if (ev->ev_events & EV_WRITE) {
+		pfd->events &= ~POLLOUT;
+		pop->event_w_back[i] = NULL;
+	}
+	poll_check_ok(pop);
+	if (pfd->events)
+		/* Another event cares about that fd. */
+		return (0);
+
+	/* Okay, so we aren't interested in that fd anymore. */
+	pop->idxplus1_by_fd[ev->ev_fd] = 0;
+
+	--pop->nfds;
+	if (i != pop->nfds) {
+		/* 
+		 * Shift the last pollfd down into the now-unoccupied
+		 * position.
+		 */
+		memcpy(&pop->event_set[i], &pop->event_set[pop->nfds],
+		       sizeof(struct pollfd));
+		pop->event_r_back[i] = pop->event_r_back[pop->nfds];
+		pop->event_w_back[i] = pop->event_w_back[pop->nfds];
+		pop->idxplus1_by_fd[pop->event_set[i].fd] = i + 1;
+	}
+
+	poll_check_ok(pop);
+	return (0);
+}
+
+static void
+poll_dealloc(struct event_base *base, void *arg)
+{
+	struct pollop *pop = arg;
+
+	evsignal_dealloc(base);
+	if (pop->event_set)
+		free(pop->event_set);
+	if (pop->event_r_back)
+		free(pop->event_r_back);
+	if (pop->event_w_back)
+		free(pop->event_w_back);
+	if (pop->idxplus1_by_fd)
+		free(pop->idxplus1_by_fd);
+
+	memset(pop, 0, sizeof(struct pollop));
+	free(pop);
+}