You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
103 lines
4.5 KiB
103 lines
4.5 KiB
/*
|
|
* Copyright (c) 2009-2012 Niels Provos and Nick Mathewson
|
|
*
|
|
* 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.
|
|
*/
|
|
#ifndef CHANGELIST_INTERNAL_H_INCLUDED_
|
|
#define CHANGELIST_INTERNAL_H_INCLUDED_
|
|
|
|
/*
|
|
A "changelist" is a list of all the fd status changes that should be made
|
|
between calls to the backend's dispatch function. There are a few reasons
|
|
that a backend would want to queue changes like this rather than processing
|
|
them immediately.
|
|
|
|
1) Sometimes applications will add and delete the same event more than
|
|
once between calls to dispatch. Processing these changes immediately
|
|
is needless, and potentially expensive (especially if we're on a system
|
|
that makes one syscall per changed event).
|
|
|
|
2) Sometimes we can coalesce multiple changes on the same fd into a single
|
|
syscall if we know about them in advance. For example, epoll can do an
|
|
add and a delete at the same time, but only if we have found out about
|
|
both of them before we tell epoll.
|
|
|
|
3) Sometimes adding an event that we immediately delete can cause
|
|
unintended consequences: in kqueue, this makes pending events get
|
|
reported spuriously.
|
|
*/
|
|
|
|
#include "event2/util.h"
|
|
|
|
/** Represents a */
|
|
struct event_change {
|
|
/** The fd or signal whose events are to be changed */
|
|
evutil_socket_t fd;
|
|
/* The events that were enabled on the fd before any of these changes
|
|
were made. May include EV_READ or EV_WRITE. */
|
|
short old_events;
|
|
|
|
/* The changes that we want to make in reading and writing on this fd.
|
|
* If this is a signal, then read_change has EV_CHANGE_SIGNAL set,
|
|
* and write_change is unused. */
|
|
ev_uint8_t read_change;
|
|
ev_uint8_t write_change;
|
|
ev_uint8_t close_change;
|
|
};
|
|
|
|
/* Flags for read_change and write_change. */
|
|
|
|
/* If set, add the event. */
|
|
#define EV_CHANGE_ADD 0x01
|
|
/* If set, delete the event. Exclusive with EV_CHANGE_ADD */
|
|
#define EV_CHANGE_DEL 0x02
|
|
/* If set, this event refers a signal, not an fd. */
|
|
#define EV_CHANGE_SIGNAL EV_SIGNAL
|
|
/* Set for persistent events. Currently not used. */
|
|
#define EV_CHANGE_PERSIST EV_PERSIST
|
|
/* Set for adding edge-triggered events. */
|
|
#define EV_CHANGE_ET EV_ET
|
|
|
|
/* The value of fdinfo_size that a backend should use if it is letting
|
|
* changelist handle its add and delete functions. */
|
|
#define EVENT_CHANGELIST_FDINFO_SIZE sizeof(int)
|
|
|
|
/** Set up the data fields in a changelist. */
|
|
void event_changelist_init_(struct event_changelist *changelist);
|
|
/** Remove every change in the changelist, and make corresponding changes
|
|
* in the event maps in the base. This function is generally used right
|
|
* after making all the changes in the changelist. */
|
|
void event_changelist_remove_all_(struct event_changelist *changelist,
|
|
struct event_base *base);
|
|
/** Free all memory held in a changelist. */
|
|
void event_changelist_freemem_(struct event_changelist *changelist);
|
|
|
|
/** Implementation of eventop_add that queues the event in a changelist. */
|
|
int event_changelist_add_(struct event_base *base, evutil_socket_t fd, short old, short events,
|
|
void *p);
|
|
/** Implementation of eventop_del that queues the event in a changelist. */
|
|
int event_changelist_del_(struct event_base *base, evutil_socket_t fd, short old, short events,
|
|
void *p);
|
|
|
|
#endif
|