ObjFW  Artifact [66c27474d9]

Artifact 66c27474d9689bf90efe50397d903869d7b6fc9e661875160085308ec2c1d614:

• File src/OFKernelEventObserver_poll.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: 4559) [annotate] [blame] [check-ins using]

/*
 * 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.
 */

#define __NO_EXT_QNX

#include "config.h"

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

#ifdef HAVE_POLL_H
# include <poll.h>
#endif

#import "OFKernelEventObserver.h"
#import "OFKernelEventObserver+Private.h"
#import "OFKernelEventObserver_poll.h"
#import "OFDataArray.h"

#import "OFObserveFailedException.h"
#import "OFOutOfRangeException.h"

#import "socket_helpers.h"

#ifdef OF_WII
# define pollfd pollsd
# define fd socket
#endif

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

	@try {
		struct pollfd p = { _cancelFD[0], POLLIN, 0 };

		_FDs = [[OFDataArray alloc] initWithItemSize:
		    sizeof(struct pollfd)];
		[_FDs addItem: &p];

		_maxFD = _cancelFD[0];
		_FDToObject = [self allocMemoryWithSize: sizeof(id)
						  count: _maxFD + 1];
	} @catch (id e) {
		[self release];
		@throw e;
	}

	return self;
}

- (void)dealloc
{
	[_FDs release];

	[super dealloc];
}

- (void)OF_addObject: (id)object
      fileDescriptor: (int)fd
	      events: (short)events
{
	struct pollfd *FDs = [_FDs items];
	size_t i, count = [_FDs count];
	bool found = false;

	for (i = 0; i < count; i++) {
		if (FDs[i].fd == fd) {
			FDs[i].events |= events;
			found = true;
			break;
		}
	}

	if (!found) {
		struct pollfd p = { fd, events, 0 };

		if (fd > _maxFD) {
			_maxFD = fd;
			_FDToObject = [self resizeMemory: _FDToObject
						    size: sizeof(id)
						   count: _maxFD + 1];
		}

		_FDToObject[fd] = object;
		[_FDs addItem: &p];
	}
}

- (void)OF_removeObject: (id)object
	 fileDescriptor: (int)fd
		 events: (short)events
{
	struct pollfd *FDs = [_FDs items];
	size_t i, nFDs = [_FDs count];

	for (i = 0; i < nFDs; i++) {
		if (FDs[i].fd == fd) {
			FDs[i].events &= ~events;

			if (FDs[i].events == 0) {
				/*
				 * TODO: Remove from and resize _FDToObject,
				 *	 adjust _maxFD.
				 */
				[_FDs removeItemAtIndex: i];
			}

			break;
		}
	}
}

- (void)OF_addObjectForReading: (id)object
		fileDescriptor: (int)fd
{
	[self OF_addObject: object
	    fileDescriptor: fd
		    events: POLLIN];
}

- (void)OF_addObjectForWriting: (id)object
		fileDescriptor: (int)fd
{
	[self OF_addObject: object
	    fileDescriptor: fd
		    events: POLLOUT];
}

- (void)OF_removeObjectForReading: (id)object
		   fileDescriptor: (int)fd
{
	[self OF_removeObject: object
	       fileDescriptor: fd
		       events: POLLIN];
}

- (void)OF_removeObjectForWriting: (id)object
		   fileDescriptor: (int)fd
{
	[self OF_removeObject: object
	       fileDescriptor: fd
		       events: POLLOUT];
}

- (void)observeForTimeInterval: (of_time_interval_t)timeInterval
{
	void *pool = objc_autoreleasePoolPush();
	struct pollfd *FDs;
	int events;
	size_t i, nFDs;

	[self OF_processQueue];
	[self OF_processReadBuffers];

	objc_autoreleasePoolPop(pool);

	FDs = [_FDs items];
	nFDs = [_FDs count];

#ifdef OPEN_MAX
	if (nFDs > OPEN_MAX)
		@throw [OFOutOfRangeException exception];
#endif

	events = poll(FDs, (nfds_t)nFDs,
	    (int)(timeInterval != -1 ? timeInterval * 1000 : -1));

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

	for (i = 0; i < nFDs; i++) {
		assert(FDs[i].fd <= _maxFD);

		if (FDs[i].revents & POLLIN) {
			if (FDs[i].fd == _cancelFD[0]) {
				char buffer;

#ifdef OF_HAVE_PIPE
				OF_ENSURE(read(_cancelFD[0], &buffer, 1) == 1);
#else
				OF_ENSURE(recvfrom(_cancelFD[0], &buffer, 1,
				    0, NULL, NULL) == 1);
#endif
				FDs[i].revents = 0;

				continue;
			}

			pool = objc_autoreleasePoolPush();

			if ([_delegate respondsToSelector:
			    @selector(objectIsReadyForReading:)])
				[_delegate objectIsReadyForReading:
				    _FDToObject[FDs[i].fd]];

			objc_autoreleasePoolPop(pool);
		}

		if (FDs[i].revents & POLLOUT) {
			pool = objc_autoreleasePoolPush();

			if ([_delegate respondsToSelector:
			    @selector(objectIsReadyForWriting:)])
				[_delegate objectIsReadyForWriting:
				    _FDToObject[FDs[i].fd]];

			objc_autoreleasePoolPop(pool);
		}

		FDs[i].revents = 0;
	}
}
@end