ObjFW  Artifact [331bf675cd]

Artifact 331bf675cdfb2d299651adbc0f088f6746f3fb613da792dcd8abc37050cc53b3:

• File src/OFKernelEventObserver_select.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: 4581) [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"

#ifdef _WIN32
/* Win32 has a ridiculous default of 64, even though it supports much more. */
# define FD_SETSIZE 1024
#endif

#include <errno.h>
#include <math.h>
#include <string.h>

#include <sys/time.h>

#import "OFKernelEventObserver.h"
#import "OFKernelEventObserver+Private.h"
#import "OFKernelEventObserver_select.h"
#import "OFArray.h"

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

#import "socket_helpers.h"

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

#ifndef _WIN32
	if (_cancelFD[0] >= FD_SETSIZE)
		@throw [OFInitializationFailedException exception];
#endif

	FD_ZERO(&_readFDs);
	FD_ZERO(&_writeFDs);
	FD_SET(_cancelFD[0], &_readFDs);

	_maxFD = _cancelFD[0];

	return self;
}

- (void)OF_addObjectForReading: (id)object
{
	int fd = [object fileDescriptorForReading];

	if (fd > INT_MAX - 1)
		@throw [OFOutOfRangeException exception];

#ifndef _WIN32
	if (fd >= FD_SETSIZE)
		@throw [OFOutOfRangeException exception];
#endif

	if (fd > _maxFD)
		_maxFD = fd;

	FD_SET(fd, &_readFDs);
}

- (void)OF_addObjectForWriting: (id)object
{
	int fd = [object fileDescriptorForWriting];

	if (fd > INT_MAX - 1)
		@throw [OFOutOfRangeException exception];

#ifndef _WIN32
	if (fd >= FD_SETSIZE)
		@throw [OFOutOfRangeException exception];
#endif

	if (fd > _maxFD)
		_maxFD = fd;

	FD_SET(fd, &_writeFDs);
}

- (void)OF_removeObjectForReading: (id)object
{
	/* TODO: Adjust _maxFD */

	int fd = [object fileDescriptorForReading];

	if (fd >= FD_SETSIZE)
		@throw [OFOutOfRangeException exception];

	FD_CLR(fd, &_readFDs);
}

- (void)OF_removeObjectForWriting: (id)object
{
	/* TODO: Adjust _maxFD */

	int fd = [object fileDescriptorForWriting];

	if (fd >= FD_SETSIZE)
		@throw [OFOutOfRangeException exception];

	FD_CLR(fd, &_writeFDs);
}

- (void)observeForTimeInterval: (of_time_interval_t)timeInterval
{
	void *pool = objc_autoreleasePoolPush();
	id const *objects;
	fd_set readFDs;
	fd_set writeFDs;
	struct timeval timeout;
	int events;
	size_t i, count;

	[self OF_processQueueAndStoreRemovedIn: nil];
	[self OF_processReadBuffers];

	objc_autoreleasePoolPop(pool);

#ifdef FD_COPY
	FD_COPY(&_readFDs, &readFDs);
	FD_COPY(&_writeFDs, &writeFDs);
#else
	readFDs = _readFDs;
	writeFDs = _writeFDs;
#endif

	/*
	 * We cast to int before assigning to tv_usec in order to avoid a
	 * warning with Apple GCC on PPC. POSIX defines this as suseconds_t,
	 * however, this is not available on Win32. As an int should always
	 * satisfy the required range, we just cast to int.
	 */
#ifndef _WIN32
	timeout.tv_sec = (time_t)timeInterval;
#else
	timeout.tv_sec = (long)timeInterval;
#endif
	timeout.tv_usec = (int)lrint((timeInterval - timeout.tv_sec) * 1000);

	events = select(_maxFD + 1, &readFDs, &writeFDs, NULL,
	    (timeInterval != -1 ? &timeout : NULL));

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

	if (FD_ISSET(_cancelFD[0], &readFDs)) {
		char buffer;

#ifndef _WIN32
		OF_ENSURE(read(_cancelFD[0], &buffer, 1) == 1);
#else
		OF_ENSURE(recvfrom(_cancelFD[0], &buffer, 1, 0, NULL,
		    NULL) == 1);
#endif
	}

	objects = [_readObjects objects];
	count = [_readObjects count];

	for (i = 0; i < count; i++) {
		int fd = [objects[i] fileDescriptorForReading];

		pool = objc_autoreleasePoolPush();

		if (FD_ISSET(fd, &readFDs) && [_delegate respondsToSelector:
		    @selector(objectIsReadyForReading:)])
			[_delegate objectIsReadyForReading: objects[i]];

		objc_autoreleasePoolPop(pool);
	}

	objects = [_writeObjects objects];
	count = [_writeObjects count];

	for (i = 0; i < count; i++) {
		int fd = [objects[i] fileDescriptorForWriting];

		pool = objc_autoreleasePoolPush();

		if (FD_ISSET(fd, &writeFDs) && [_delegate respondsToSelector:
		    @selector(objectIsReadyForWriting:)])
			[_delegate objectIsReadyForWriting: objects[i]];

		objc_autoreleasePoolPop(pool);
	}
}
@end