ObjFW  Artifact [ccbb902e19]

Artifact ccbb902e19195f1b8335b0f1a865830ee6cfb34190e5395bd9c8e7aa19b72804:

• File src/OFKernelEventObserver_epoll.m — part of check-in [7ae17af9f0] at 2016-03-20 11:57:06 on branch trunk — Never block when the read buffer is non-empty

  This was broken by 88f2f03. The problem only existed when something was
  in the read buffer, but not processed completely, as after processing
  the read buffer, it would go on to wait for data - but since not the
  entire read buffer had been processed, it meant there was still data
  left there that needed to be handled first. (user: js, size: 6114) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016
 *   Jonathan Schleifer <js@heap.zone>
 *
 * 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 "OFArray.h"
#import "OFMapTable.h"
#import "OFNull.h"
#ifdef OF_HAVE_THREADS
# import "OFMutex.h"
#endif

#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
	objectsArray: (OFMutableArray*)objectsArray
{
#ifdef OF_HAVE_THREADS
	[_mutex lock];
	@try {
#endif
		struct epoll_event event;
		intptr_t events;

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

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

		[objectsArray addObject: object];

		if (epoll_ctl(_epfd,
		    (events == 0 ? EPOLL_CTL_ADD : EPOLL_CTL_MOD),
		    fd, &event) == -1) {
			[objectsArray removeObjectIdenticalTo: object];
			@throw [OFObserveFailedException
			    exceptionWithObserver: self
					    errNo: errno];
		}

		[_FDToEvents setValue: (void*)(events | addEvents)
			       forKey: (void*)(intptr_t)fd];
#ifdef OF_HAVE_THREADS
	} @finally {
		[_mutex unlock];
	}
#endif
}

- (void)OF_removeObject: (id)object
	 fileDescriptor: (int)fd
		 events: (int)removeEvents
	   objectsArray: (OFMutableArray*)objectsArray
{
#ifdef OF_HAVE_THREADS
	[_mutex lock];
	@try {
#endif
		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];
		}

		[objectsArray removeObjectIdenticalTo: object];
#ifdef OF_HAVE_THREADS
	} @finally {
		[_mutex unlock];
	}
#endif
}

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

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

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

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

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

	if ([self OF_processReadBuffers])
		return;

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

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

	for (int 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