ObjFW  Artifact [dc0778aa90]

Artifact dc0778aa908bb362dd0313c9ccf11253f39578d41a3e67111a1128011b9e5d71:

• File src/OFKernelEventObserver_LockedQueue.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: 4890) [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"

#import "OFKernelEventObserver_LockedQueue.h"
#import "OFArray.h"
#import "OFDataArray.h"
#ifdef OF_HAVE_THREADS
# import "OFMutex.h"
#endif

#import "OFInitializationFailedException.h"

enum {
	QUEUE_ADD = 0,
	QUEUE_REMOVE = 1,
	QUEUE_READ = 0,
	QUEUE_WRITE = 2
};
#define QUEUE_ACTION (QUEUE_ADD | QUEUE_REMOVE)

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

	@try {
		_queueActions = [[OFDataArray alloc]
		    initWithItemSize: sizeof(int)];
		_queueFDs = [[OFDataArray alloc] initWithItemSize: sizeof(int)];
		_queueObjects = [[OFMutableArray alloc] init];

#ifdef OF_HAVE_THREADS
		_mutex = [[OFMutex alloc] init];
#endif
	} @catch (id e) {
		@throw [OFInitializationFailedException
		    exceptionWithClass: [self class]];
	}

	return self;
}

- (void)dealloc
{
	[_queueActions release];
	[_queueFDs release];
	[_queueObjects release];
#ifdef OF_HAVE_THREADS
	[_mutex release];
#endif

	[super dealloc];
}

- (void)addObjectForReading: (id <OFReadyForReadingObserving>)object
{
#ifdef OF_HAVE_THREADS
	[_mutex lock];
	@try {
#endif
		int qi = QUEUE_ADD | QUEUE_READ;
		int fd = [object fileDescriptorForReading];

		[_queueActions addItem: &qi];
		[_queueFDs addItem: &fd];
		[_queueObjects addObject: object];
#ifdef OF_HAVE_THREADS
	} @finally {
		[_mutex unlock];
	}
#endif

	[self cancel];
}

- (void)addObjectForWriting: (id <OFReadyForWritingObserving>)object
{
#ifdef OF_HAVE_THREADS
	[_mutex lock];
	@try {
#endif
		int qi = QUEUE_ADD | QUEUE_WRITE;
		int fd = [object fileDescriptorForWriting];

		[_queueActions addItem: &qi];
		[_queueFDs addItem: &fd];
		[_queueObjects addObject: object];
#ifdef OF_HAVE_THREADS
	} @finally {
		[_mutex unlock];
	}
#endif

	[self cancel];
}

- (void)removeObjectForReading: (id <OFReadyForReadingObserving>)object
{
#ifdef OF_HAVE_THREADS
	[_mutex lock];
	@try {
#endif
		int qi = QUEUE_REMOVE | QUEUE_READ;
		int fd = [object fileDescriptorForReading];

		[_queueActions addItem: &qi];
		[_queueFDs addItem: &fd];
		[_queueObjects addObject: object];
#ifdef OF_HAVE_THREADS
	} @finally {
		[_mutex unlock];
	}
#endif

	[self cancel];
}

- (void)removeObjectForWriting: (id <OFReadyForWritingObserving>)object
{
#ifdef OF_HAVE_THREADS
	[_mutex lock];
	@try {
#endif
		int qi = QUEUE_REMOVE | QUEUE_WRITE;
		int fd = [object fileDescriptorForWriting];

		[_queueActions addItem: &qi];
		[_queueFDs addItem: &fd];
		[_queueObjects addObject: object];
#ifdef OF_HAVE_THREADS
	} @finally {
		[_mutex unlock];
	}
#endif

	[self cancel];
}

- (void)OF_addObjectForReading: (id)object
		fileDescriptor: (int)fd
{
	OF_UNRECOGNIZED_SELECTOR
}

- (void)OF_addObjectForWriting: (id)object
		fileDescriptor: (int)fd
{
	OF_UNRECOGNIZED_SELECTOR
}

- (void)OF_removeObjectForReading: (id)object
		   fileDescriptor: (int)fd
{
	OF_UNRECOGNIZED_SELECTOR
}

- (void)OF_removeObjectForWriting: (id)object
		   fileDescriptor: (int)fd
{
	OF_UNRECOGNIZED_SELECTOR
}

- (void)OF_processQueue
{
#ifdef OF_HAVE_THREADS
	[_mutex lock];
	@try {
#endif
		int *queueActions = [_queueActions items];
		int *queueFDs = [_queueFDs items];
		id const *queueObjects = [_queueObjects objects];
		size_t i, count = [_queueActions count];

		OF_ENSURE([_queueFDs count] == count);
		OF_ENSURE([_queueObjects count] == count);

		for (i = 0; i < count; i++) {
			int action = queueActions[i];
			int fd = queueFDs[i];
			id object = queueObjects[i];

			switch (action) {
			case QUEUE_ADD | QUEUE_READ:
				[_readObjects addObject: object];

				[self OF_addObjectForReading: object
					      fileDescriptor: fd];

				break;
			case QUEUE_ADD | QUEUE_WRITE:
				[_writeObjects addObject: object];

				[self OF_addObjectForWriting: object
					      fileDescriptor: fd];

				break;
			case QUEUE_REMOVE | QUEUE_READ:
				[self OF_removeObjectForReading: object
						 fileDescriptor: fd];

				[_readObjects removeObjectIdenticalTo: object];

				break;
			case QUEUE_REMOVE | QUEUE_WRITE:
				[self OF_removeObjectForWriting: object
						 fileDescriptor: fd];

				[_writeObjects removeObjectIdenticalTo: object];

				break;
			default:
				OF_ENSURE(0);
			}
		}

		[_queueActions removeAllItems];
		[_queueFDs removeAllItems];
		[_queueObjects removeAllObjects];
#ifdef OF_HAVE_THREADS
	} @finally {
		[_mutex unlock];
	}
#endif
}
@end