ObjFW  Artifact [6db686d146]

Artifact 6db686d1467950dcf48bb6df7f2e0c340daebdd1c6f211e06ed205f158dbebc3:

• File src/OFKernelEventObserver_poll.m — part of check-in [220513a3f5] at 2015-05-09 18:13:19 on branch trunk — More OFKernelEventObserver refactoring

  This was necessary because select(), poll() and kevent() on FreeBSD and
  OS X would sometimes return 0 events, even if there are some, and
  sometimes return the correct number of events that were pending, meaning
  the number of events returned is unreliable. To make things worse,
  whether it returns 0 or the number of events that were pending is
  completely non-deterministic on both FreeBSD and OS X (running the same
  tests multiple times in a row would make it sometimes work and sometimes
  fail).

  In order to prevent code from depending on the return value of
  -[observeForTimeInterval:] (which would depend on select(), poll() and
  kevent() returning the correct number), OFKernelObserver no longer
  returns whether there were pending events. It is expected that
  -[observe] or -[observeForTimeInterval:] is just called in a loop as
  long as events should be handled.

  The tests have been changed as well to reflect this. What they do now is
  set a deadline and call -[observeForTimeInterval:] with a small timeout
  in a loop until the deadline is reached or all events have been handled.

  Note: DragonFlyBSD has not been tested, but will most likely behave like
  FreeBSD and OS X. (user: js, size: 4504) [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 <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 __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
{
	[self OF_addObject: object
	    fileDescriptor: [object fileDescriptorForReading]
		    events: POLLIN];
}

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

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

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

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

	[self OF_processQueueAndStoreRemovedIn: nil];
	[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++) {
		if (FDs[i].fd > _maxFD)
			@throw [OFOutOfRangeException exception];

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

				OF_ENSURE(read(_cancelFD[0], &buffer, 1) == 1);
				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