1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/third_party/libevent/changelist-internal.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,101 @@
1.4 +/*
1.5 + * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson
1.6 + *
1.7 + * Redistribution and use in source and binary forms, with or without
1.8 + * modification, are permitted provided that the following conditions
1.9 + * are met:
1.10 + * 1. Redistributions of source code must retain the above copyright
1.11 + * notice, this list of conditions and the following disclaimer.
1.12 + * 2. Redistributions in binary form must reproduce the above copyright
1.13 + * notice, this list of conditions and the following disclaimer in the
1.14 + * documentation and/or other materials provided with the distribution.
1.15 + * 3. The name of the author may not be used to endorse or promote products
1.16 + * derived from this software without specific prior written permission.
1.17 + *
1.18 + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
1.19 + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
1.20 + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
1.21 + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
1.22 + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
1.23 + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1.24 + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1.25 + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.26 + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
1.27 + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.28 + */
1.29 +#ifndef _CHANGELIST_H_
1.30 +#define _CHANGELIST_H_
1.31 +
1.32 +/*
1.33 + A "changelist" is a list of all the fd status changes that should be made
1.34 + between calls to the backend's dispatch function. There are a few reasons
1.35 + that a backend would want to queue changes like this rather than processing
1.36 + them immediately.
1.37 +
1.38 + 1) Sometimes applications will add and delete the same event more than
1.39 + once between calls to dispatch. Processing these changes immediately
1.40 + is needless, and potentially expensive (especially if we're on a system
1.41 + that makes one syscall per changed event).
1.42 +
1.43 + 2) Sometimes we can coalesce multiple changes on the same fd into a single
1.44 + syscall if we know about them in advance. For example, epoll can do an
1.45 + add and a delete at the same time, but only if we have found out about
1.46 + both of them before we tell epoll.
1.47 +
1.48 + 3) Sometimes adding an event that we immediately delete can cause
1.49 + unintended consequences: in kqueue, this makes pending events get
1.50 + reported spuriously.
1.51 + */
1.52 +
1.53 +#include "event2/util.h"
1.54 +
1.55 +/** Represents a */
1.56 +struct event_change {
1.57 + /** The fd or signal whose events are to be changed */
1.58 + evutil_socket_t fd;
1.59 + /* The events that were enabled on the fd before any of these changes
1.60 + were made. May include EV_READ or EV_WRITE. */
1.61 + short old_events;
1.62 +
1.63 + /* The changes that we want to make in reading and writing on this fd.
1.64 + * If this is a signal, then read_change has EV_CHANGE_SIGNAL set,
1.65 + * and write_change is unused. */
1.66 + ev_uint8_t read_change;
1.67 + ev_uint8_t write_change;
1.68 +};
1.69 +
1.70 +/* Flags for read_change and write_change. */
1.71 +
1.72 +/* If set, add the event. */
1.73 +#define EV_CHANGE_ADD 0x01
1.74 +/* If set, delete the event. Exclusive with EV_CHANGE_ADD */
1.75 +#define EV_CHANGE_DEL 0x02
1.76 +/* If set, this event refers a signal, not an fd. */
1.77 +#define EV_CHANGE_SIGNAL EV_SIGNAL
1.78 +/* Set for persistent events. Currently not used. */
1.79 +#define EV_CHANGE_PERSIST EV_PERSIST
1.80 +/* Set for adding edge-triggered events. */
1.81 +#define EV_CHANGE_ET EV_ET
1.82 +
1.83 +/* The value of fdinfo_size that a backend should use if it is letting
1.84 + * changelist handle its add and delete functions. */
1.85 +#define EVENT_CHANGELIST_FDINFO_SIZE sizeof(int)
1.86 +
1.87 +/** Set up the data fields in a changelist. */
1.88 +void event_changelist_init(struct event_changelist *changelist);
1.89 +/** Remove every change in the changelist, and make corresponding changes
1.90 + * in the event maps in the base. This function is generally used right
1.91 + * after making all the changes in the changelist. */
1.92 +void event_changelist_remove_all(struct event_changelist *changelist,
1.93 + struct event_base *base);
1.94 +/** Free all memory held in a changelist. */
1.95 +void event_changelist_freemem(struct event_changelist *changelist);
1.96 +
1.97 +/** Implementation of eventop_add that queues the event in a changelist. */
1.98 +int event_changelist_add(struct event_base *base, evutil_socket_t fd, short old, short events,
1.99 + void *p);
1.100 +/** Implementation of eventop_del that queues the event in a changelist. */
1.101 +int event_changelist_del(struct event_base *base, evutil_socket_t fd, short old, short events,
1.102 + void *p);
1.103 +
1.104 +#endif
