ObjFW  Artifact [02fb70080b]

Artifact 02fb70080bdb4d3134b936523214db91655d556447df47e59aae4c2f85cc13c6:

• File src/OFKernelEventObserver_epoll.m — part of check-in [e9b4700cb6] at 2015-12-29 21:33:07 on branch trunk — Refactor OFKernelEventObserver

  This moves the locked queue for actions to
  OFKernelEventObserver_LockedQueue, which is now used for select and
  poll, but skipped for kqueue and epoll, as they natively support changes
  from another thread.

  This fixes the problem that removing an object is delayed until the next
  observe call - at which point it might have already been closed, meaning
  the fd is no longer available. This was mainly a problem with kqueue, as
  closing the fd already removed it from the kqueue, which then resulted
  in an error being returned when trying to manually remove the fd from
  the kqueue. (user: js, size: 5811) [annotate] [blame] [check-ins using] [more...]

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015
 *   Jonathan Schleifer <js@webkeks.org>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#include "config.h"

#include <assert.h>
#include <errno.h>

#include <fcntl.h>
#include <unistd.h>

#include <sys/epoll.h>

#import "OFKernelEventObserver.h"
#import "OFKernelEventObserver+Private.h"
#import "OFKernelEventObserver_epoll.h"
#import "OFMapTable.h"
#import "OFNull.h"

#import "OFInitializationFailedException.h"
#import "OFObserveFailedException.h"

#define EVENTLIST_SIZE 64

static const of_map_table_functions_t mapFunctions = { NULL };

@implementation OFKernelEventObserver_epoll
- init
{
	self = [super init];

	@try {
		struct epoll_event event;

#ifdef HAVE_EPOLL_CREATE1
		if ((_epfd = epoll_create1(EPOLL_CLOEXEC)) == -1)
			@throw [OFInitializationFailedException exception];
#else
		int flags;

		if ((_epfd = epoll_create(1)) == -1)
			@throw [OFInitializationFailedException exception];

		if ((flags = fcntl(_epfd, F_GETFD, 0)) != -1)
			fcntl(_epfd, F_SETFD, flags | FD_CLOEXEC);
#endif

		_FDToEvents = [[OFMapTable alloc]
		    initWithKeyFunctions: mapFunctions
			  valueFunctions: mapFunctions];

		memset(&event, 0, sizeof(event));
		event.events = EPOLLIN;
		event.data.ptr = [OFNull null];

		if (epoll_ctl(_epfd, EPOLL_CTL_ADD, _cancelFD[0], &event) == -1)
			@throw [OFInitializationFailedException exception];
	} @catch (id e) {
		[self release];
		@throw e;
	}

	return self;
}

- (void)dealloc
{
	close(_epfd);

	[_FDToEvents release];

	[super dealloc];
}

- (void)OF_addObject: (id)object
      fileDescriptor: (int)fd
	      events: (int)addEvents
{
	intptr_t events;

	events = (intptr_t)[_FDToEvents valueForKey: (void*)(intptr_t)fd];
	if (events == 0) {
		struct epoll_event event;

		memset(&event, 0, sizeof(event));
		event.events = addEvents;
		event.data.ptr = object;

		if (epoll_ctl(_epfd, EPOLL_CTL_ADD, fd, &event) == -1)
			@throw [OFObserveFailedException
			    exceptionWithObserver: self
					    errNo: errno];

		[_FDToEvents setValue: (void*)(intptr_t)addEvents
			       forKey: (void*)(intptr_t)fd];
	} else {
		struct epoll_event event;

		memset(&event, 0, sizeof(event));
		event.events = (int)events | addEvents;
		event.data.ptr = object;

		if (epoll_ctl(_epfd, EPOLL_CTL_MOD, fd, &event) == -1)
			@throw [OFObserveFailedException
			    exceptionWithObserver: self
					    errNo: errno];

		[_FDToEvents setValue: (void*)(events | addEvents)
			       forKey: (void*)(intptr_t)fd];
	}
}

- (void)OF_removeObject: (id)object
	 fileDescriptor: (int)fd
		 events: (int)removeEvents
{
	intptr_t events;

	events = (intptr_t)[_FDToEvents valueForKey: (void*)(intptr_t)fd];
	events &= ~removeEvents;

	if (events == 0) {
		if (epoll_ctl(_epfd, EPOLL_CTL_DEL, fd, NULL) == -1)
			@throw [OFObserveFailedException
			    exceptionWithObserver: self
					    errNo: errno];

		[_FDToEvents removeValueForKey: (void*)(intptr_t)fd];
	} else {
		struct epoll_event event;

		memset(&event, 0, sizeof(event));
		event.events = (int)events;
		event.data.ptr = object;

		if (epoll_ctl(_epfd, EPOLL_CTL_MOD, fd, &event) == -1)
			@throw [OFObserveFailedException
			    exceptionWithObserver: self
					    errNo: errno];

		[_FDToEvents setValue: (void*)events
			       forKey: (void*)(intptr_t)fd];
	}
}

- (void)addObjectForReading: (id <OFReadyForReadingObserving>)object
{
	[self OF_addObject: object
	    fileDescriptor: [object fileDescriptorForReading]
		    events: EPOLLIN];
}

- (void)addObjectForWriting: (id <OFReadyForWritingObserving>)object
{
	[self OF_addObject: object
	    fileDescriptor: [object fileDescriptorForWriting]
		    events: EPOLLOUT];
}

- (void)removeObjectForReading: (id <OFReadyForReadingObserving>)object
{
	[self OF_removeObject: object
	       fileDescriptor: [object fileDescriptorForReading]
		       events: EPOLLIN];
}

- (void)removeObjectForWriting: (id <OFReadyForWritingObserving>)object
{
	[self OF_removeObject: object
	       fileDescriptor: [object fileDescriptorForWriting]
		       events: EPOLLOUT];
}

- (void)observeForTimeInterval: (of_time_interval_t)timeInterval
{
	OFNull *nullObject = [OFNull null];
	void *pool = objc_autoreleasePoolPush();
	struct epoll_event eventList[EVENTLIST_SIZE];
	int i, events;

	[self OF_processReadBuffers];

	objc_autoreleasePoolPop(pool);

	events = epoll_wait(_epfd, eventList, EVENTLIST_SIZE,
	    (timeInterval != -1 ? timeInterval * 1000 : -1));

	if (events < 0)
		@throw [OFObserveFailedException exceptionWithObserver: self
								 errNo: errno];

	for (i = 0; i < events; i++) {
		if (eventList[i].data.ptr == nullObject) {
			char buffer;

			assert(eventList[i].events == EPOLLIN);
			OF_ENSURE(read(_cancelFD[0], &buffer, 1) == 1);

			continue;
		}

		if (eventList[i].events & EPOLLIN) {
			pool = objc_autoreleasePoolPush();

			if ([_delegate respondsToSelector:
			    @selector(objectIsReadyForReading:)])
				[_delegate objectIsReadyForReading:
				    eventList[i].data.ptr];

			objc_autoreleasePoolPop(pool);
		}

		if (eventList[i].events & EPOLLOUT) {
			pool = objc_autoreleasePoolPush();

			if ([_delegate respondsToSelector:
			    @selector(objectIsReadyForWriting:)])
				[_delegate objectIsReadyForWriting:
				    eventList[i].data.ptr];

			objc_autoreleasePoolPop(pool);
		}

		assert((eventList[i].events & ~(EPOLLIN | EPOLLOUT)) == 0);
	}
}
@end