Repo created

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

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+/*
+ * Copyright (c) 2002-2004 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 <sys/types.h>
+
+#include "config.h"
+
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef HAVE_STDARG_H
+#include <stdarg.h>
+#endif
+
+#ifdef WIN32
+#include <winsock2.h>
+#endif
+
+#include "evutil.h"
+#include "event.h"
+
+/* prototypes */
+
+void bufferevent_read_pressure_cb(struct evbuffer *, size_t, size_t, void *);
+
+static int
+bufferevent_add(struct event *ev, int timeout)
+{
+	struct timeval tv, *ptv = NULL;
+
+	if (timeout) {
+		evutil_timerclear(&tv);
+		tv.tv_sec = timeout;
+		ptv = &tv;
+	}
+
+	return (event_add(ev, ptv));
+}
+
+/* 
+ * This callback is executed when the size of the input buffer changes.
+ * We use it to apply back pressure on the reading side.
+ */
+
+void
+bufferevent_read_pressure_cb(struct evbuffer *buf, size_t old, size_t now,
+    void *arg) {
+	struct bufferevent *bufev = arg;
+	/* 
+	 * If we are below the watermark then reschedule reading if it's
+	 * still enabled.
+	 */
+	if (bufev->wm_read.high == 0 || now < bufev->wm_read.high) {
+		evbuffer_setcb(buf, NULL, NULL);
+
+		if (bufev->enabled & EV_READ)
+			bufferevent_add(&bufev->ev_read, bufev->timeout_read);
+	}
+}
+
+static void
+bufferevent_readcb(int fd, short event, void *arg)
+{
+	struct bufferevent *bufev = arg;
+	int res = 0;
+	short what = EVBUFFER_READ;
+	size_t len;
+	int howmuch = -1;
+
+	if (event == EV_TIMEOUT) {
+		what |= EVBUFFER_TIMEOUT;
+		goto error;
+	}
+
+	/*
+	 * If we have a high watermark configured then we don't want to
+	 * read more data than would make us reach the watermark.
+	 */
+	if (bufev->wm_read.high != 0) {
+		howmuch = bufev->wm_read.high - EVBUFFER_LENGTH(bufev->input);
+		/* we might have lowered the watermark, stop reading */
+		if (howmuch <= 0) {
+			struct evbuffer *buf = bufev->input;
+			event_del(&bufev->ev_read);
+			evbuffer_setcb(buf,
+			    bufferevent_read_pressure_cb, bufev);
+			return;
+		}
+	}
+
+	res = evbuffer_read(bufev->input, fd, howmuch);
+	if (res == -1) {
+		if (errno == EAGAIN || errno == EINTR)
+			goto reschedule;
+		/* error case */
+		what |= EVBUFFER_ERROR;
+	} else if (res == 0) {
+		/* eof case */
+		what |= EVBUFFER_EOF;
+	}
+
+	if (res <= 0)
+		goto error;
+
+	bufferevent_add(&bufev->ev_read, bufev->timeout_read);
+
+	/* See if this callbacks meets the water marks */
+	len = EVBUFFER_LENGTH(bufev->input);
+	if (bufev->wm_read.low != 0 && len < bufev->wm_read.low)
+		return;
+	if (bufev->wm_read.high != 0 && len >= bufev->wm_read.high) {
+		struct evbuffer *buf = bufev->input;
+		event_del(&bufev->ev_read);
+
+		/* Now schedule a callback for us when the buffer changes */
+		evbuffer_setcb(buf, bufferevent_read_pressure_cb, bufev);
+	}
+
+	/* Invoke the user callback - must always be called last */
+	if (bufev->readcb != NULL)
+		(*bufev->readcb)(bufev, bufev->cbarg);
+	return;
+
+ reschedule:
+	bufferevent_add(&bufev->ev_read, bufev->timeout_read);
+	return;
+
+ error:
+	(*bufev->errorcb)(bufev, what, bufev->cbarg);
+}
+
+static void
+bufferevent_writecb(int fd, short event, void *arg)
+{
+	struct bufferevent *bufev = arg;
+	int res = 0;
+	short what = EVBUFFER_WRITE;
+
+	if (event == EV_TIMEOUT) {
+		what |= EVBUFFER_TIMEOUT;
+		goto error;
+	}
+
+	if (EVBUFFER_LENGTH(bufev->output)) {
+	    res = evbuffer_write(bufev->output, fd);
+	    if (res == -1) {
+#ifndef WIN32
+/*todo. evbuffer uses WriteFile when WIN32 is set. WIN32 system calls do not
+ *set errno. thus this error checking is not portable*/
+		    if (errno == EAGAIN ||
+			errno == EINTR ||
+			errno == EINPROGRESS)
+			    goto reschedule;
+		    /* error case */
+		    what |= EVBUFFER_ERROR;
+
+#else
+				goto reschedule;
+#endif
+
+	    } else if (res == 0) {
+		    /* eof case */
+		    what |= EVBUFFER_EOF;
+	    }
+	    if (res <= 0)
+		    goto error;
+	}
+
+	if (EVBUFFER_LENGTH(bufev->output) != 0)
+		bufferevent_add(&bufev->ev_write, bufev->timeout_write);
+
+	/*
+	 * Invoke the user callback if our buffer is drained or below the
+	 * low watermark.
+	 */
+	if (bufev->writecb != NULL &&
+	    EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low)
+		(*bufev->writecb)(bufev, bufev->cbarg);
+
+	return;
+
+ reschedule:
+	if (EVBUFFER_LENGTH(bufev->output) != 0)
+		bufferevent_add(&bufev->ev_write, bufev->timeout_write);
+	return;
+
+ error:
+	(*bufev->errorcb)(bufev, what, bufev->cbarg);
+}
+
+/*
+ * Create a new buffered event object.
+ *
+ * The read callback is invoked whenever we read new data.
+ * The write callback is invoked whenever the output buffer is drained.
+ * The error callback is invoked on a write/read error or on EOF.
+ *
+ * Both read and write callbacks maybe NULL.  The error callback is not
+ * allowed to be NULL and have to be provided always.
+ */
+
+struct bufferevent *
+bufferevent_new(int fd, evbuffercb readcb, evbuffercb writecb,
+    everrorcb errorcb, void *cbarg)
+{
+	struct bufferevent *bufev;
+
+	if ((bufev = calloc(1, sizeof(struct bufferevent))) == NULL)
+		return (NULL);
+
+	if ((bufev->input = evbuffer_new()) == NULL) {
+		free(bufev);
+		return (NULL);
+	}
+
+	if ((bufev->output = evbuffer_new()) == NULL) {
+		evbuffer_free(bufev->input);
+		free(bufev);
+		return (NULL);
+	}
+
+	event_set(&bufev->ev_read, fd, EV_READ, bufferevent_readcb, bufev);
+	event_set(&bufev->ev_write, fd, EV_WRITE, bufferevent_writecb, bufev);
+
+	bufferevent_setcb(bufev, readcb, writecb, errorcb, cbarg);
+
+	/*
+	 * Set to EV_WRITE so that using bufferevent_write is going to
+	 * trigger a callback.  Reading needs to be explicitly enabled
+	 * because otherwise no data will be available.
+	 */
+	bufev->enabled = EV_WRITE;
+
+	return (bufev);
+}
+
+void
+bufferevent_setcb(struct bufferevent *bufev,
+    evbuffercb readcb, evbuffercb writecb, everrorcb errorcb, void *cbarg)
+{
+	bufev->readcb = readcb;
+	bufev->writecb = writecb;
+	bufev->errorcb = errorcb;
+
+	bufev->cbarg = cbarg;
+}
+
+void
+bufferevent_setfd(struct bufferevent *bufev, int fd)
+{
+	event_del(&bufev->ev_read);
+	event_del(&bufev->ev_write);
+
+	event_set(&bufev->ev_read, fd, EV_READ, bufferevent_readcb, bufev);
+	event_set(&bufev->ev_write, fd, EV_WRITE, bufferevent_writecb, bufev);
+	if (bufev->ev_base != NULL) {
+		event_base_set(bufev->ev_base, &bufev->ev_read);
+		event_base_set(bufev->ev_base, &bufev->ev_write);
+	}
+
+	/* might have to manually trigger event registration */
+}
+
+int
+bufferevent_priority_set(struct bufferevent *bufev, int priority)
+{
+	if (event_priority_set(&bufev->ev_read, priority) == -1)
+		return (-1);
+	if (event_priority_set(&bufev->ev_write, priority) == -1)
+		return (-1);
+
+	return (0);
+}
+
+/* Closing the file descriptor is the responsibility of the caller */
+
+void
+bufferevent_free(struct bufferevent *bufev)
+{
+	event_del(&bufev->ev_read);
+	event_del(&bufev->ev_write);
+
+	evbuffer_free(bufev->input);
+	evbuffer_free(bufev->output);
+
+	free(bufev);
+}
+
+/*
+ * Returns 0 on success;
+ *        -1 on failure.
+ */
+
+int
+bufferevent_write(struct bufferevent *bufev, const void *data, size_t size)
+{
+	int res;
+
+	res = evbuffer_add(bufev->output, data, size);
+
+	if (res == -1)
+		return (res);
+
+	/* If everything is okay, we need to schedule a write */
+	if (size > 0 && (bufev->enabled & EV_WRITE))
+		bufferevent_add(&bufev->ev_write, bufev->timeout_write);
+
+	return (res);
+}
+
+int
+bufferevent_write_buffer(struct bufferevent *bufev, struct evbuffer *buf)
+{
+	int res;
+
+	res = bufferevent_write(bufev, buf->buffer, buf->off);
+	if (res != -1)
+		evbuffer_drain(buf, buf->off);
+
+	return (res);
+}
+
+size_t
+bufferevent_read(struct bufferevent *bufev, void *data, size_t size)
+{
+	struct evbuffer *buf = bufev->input;
+
+	if (buf->off < size)
+		size = buf->off;
+
+	/* Copy the available data to the user buffer */
+	memcpy(data, buf->buffer, size);
+
+	if (size)
+		evbuffer_drain(buf, size);
+
+	return (size);
+}
+
+int
+bufferevent_enable(struct bufferevent *bufev, short event)
+{
+	if (event & EV_READ) {
+		if (bufferevent_add(&bufev->ev_read, bufev->timeout_read) == -1)
+			return (-1);
+	}
+	if (event & EV_WRITE) {
+		if (bufferevent_add(&bufev->ev_write, bufev->timeout_write) == -1)
+			return (-1);
+	}
+
+	bufev->enabled |= event;
+	return (0);
+}
+
+int
+bufferevent_disable(struct bufferevent *bufev, short event)
+{
+	if (event & EV_READ) {
+		if (event_del(&bufev->ev_read) == -1)
+			return (-1);
+	}
+	if (event & EV_WRITE) {
+		if (event_del(&bufev->ev_write) == -1)
+			return (-1);
+	}
+
+	bufev->enabled &= ~event;
+	return (0);
+}
+
+/*
+ * Sets the read and write timeout for a buffered event.
+ */
+
+void
+bufferevent_settimeout(struct bufferevent *bufev,
+    int timeout_read, int timeout_write) {
+	bufev->timeout_read = timeout_read;
+	bufev->timeout_write = timeout_write;
+
+	if (event_pending(&bufev->ev_read, EV_READ, NULL))
+		bufferevent_add(&bufev->ev_read, timeout_read);
+	if (event_pending(&bufev->ev_write, EV_WRITE, NULL))
+		bufferevent_add(&bufev->ev_write, timeout_write);
+}
+
+/*
+ * Sets the water marks
+ */
+
+void
+bufferevent_setwatermark(struct bufferevent *bufev, short events,
+    size_t lowmark, size_t highmark)
+{
+	if (events & EV_READ) {
+		bufev->wm_read.low = lowmark;
+		bufev->wm_read.high = highmark;
+	}
+
+	if (events & EV_WRITE) {
+		bufev->wm_write.low = lowmark;
+		bufev->wm_write.high = highmark;
+	}
+
+	/* If the watermarks changed then see if we should call read again */
+	bufferevent_read_pressure_cb(bufev->input,
+	    0, EVBUFFER_LENGTH(bufev->input), bufev);
+}
+
+int
+bufferevent_base_set(struct event_base *base, struct bufferevent *bufev)
+{
+	int res;
+
+	bufev->ev_base = base;
+
+	res = event_base_set(base, &bufev->ev_read);
+	if (res == -1)
+		return (res);
+
+	res = event_base_set(base, &bufev->ev_write);
+	return (res);
+}