ObjFW  Artifact [4fe6de3289]

Artifact 4fe6de3289d7e7888518117dc49c2084099fd8dbe4280b9a3bf302e2a476e98b:

• File src/OFKernelEventObserver.h — 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: 6314) [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.
 */

#import "OFObject.h"

#import "socket.h"

OF_ASSUME_NONNULL_BEGIN

@class OFMutableArray OF_GENERIC(ObjectType);
@class OFDate;

/*!
 * @protocol OFKernelEventObserverDelegate
 *	     OFKernelEventObserver.h ObjFW/OFKernelEventObserver.h
 *
 * @brief A protocol that needs to be implemented by delegates for
 *	  OFKernelEventObserver.
 */
@protocol OFKernelEventObserverDelegate <OFObject>
@optional
/*!
 * @brief This callback is called when an object did get ready for reading.
 *
 * @note If the object is a subclass of @ref OFStream and
 *	 @ref OFStream::tryReadLine or @ref OFStream::tryReadTillDelimiter: has
 *	 been called on the stream, this callback will not be called again
 *	 until new data has been received, even though there is still data in
 *	 the cache. The reason for this is to prevent spinning in a loop when
 *	 there is an incomplete string in the cache. Once the string has been
 *	 completed, the callback will be called again as long there is data in
 *	 the cache.
 *
 * @param object The object which did become ready for reading
 */
- (void)objectIsReadyForReading: (id)object;

/*!
 * @brief This callback is called when an object did get ready for writing.
 *
 * @param object The object which did become ready for writing
 */
- (void)objectIsReadyForWriting: (id)object;
@end

/*!
 * @protocol OFReadyForReadingObserving
 *	     OFKernelEventObserver.h ObjFW/OFKernelEventObserver.h
 *
 * @brief This protocol is implemented by classes which can be observed for
 *	  readiness for reading by OFKernelEventObserver.
 */
@protocol OFReadyForReadingObserving <OFObject>
/*!
 * @brief Returns the file descriptor for reading that should be checked by the
 *	  OFKernelEventObserver.
 *
 * @return The file descriptor for reading that should be checked by the
 *	   OFKernelEventObserver
 */
- (int)fileDescriptorForReading;
@end

/*!
 * @protocol OFReadyForWritingObserving
 *	     OFKernelEventObserver.h ObjFW/OFKernelEventObserver.h
 *
 * @brief This protocol is implemented by classes which can be observed for
 *	  readiness for writing by OFKernelEventObserver.
 */
@protocol OFReadyForWritingObserving <OFObject>
/*!
 * @brief Returns the file descriptor for writing that should be checked by the
 *	  OFKernelEventObserver.
 *
 * @return The file descriptor for writing that should be checked by the
 *	   OFKernelEventObserver
 */
- (int)fileDescriptorForWriting;
@end

/*!
 * @class OFKernelEventObserver
 *	  OFKernelEventObserver.h ObjFW/OFKernelEventObserver.h
 *
 * @brief A class that can observe multiple kernel events (e.g. streams being
 *	  ready to read) at once.
 *
 * @note Currently, Win32 can only observe TCP and UDP sockets!
 */
@interface OFKernelEventObserver: OFObject
{
	OFMutableArray OF_GENERIC(id <OFReadyForReadingObserving>)
	    *_readObjects;
	OFMutableArray OF_GENERIC(id <OFReadyForWritingObserving>)
	    *_writeObjects;
	id <OFKernelEventObserverDelegate> _delegate;
#ifdef OF_HAVE_PIPE
	int _cancelFD[2];
#else
	of_socket_t _cancelFD[2];
	struct sockaddr_in _cancelAddr;
#endif
}

/*!
 * The delegate for the OFKernelEventObserver.
 */
@property OF_NULLABLE_PROPERTY (assign)
    id <OFKernelEventObserverDelegate> delegate;

/*!
 * @brief Creates a new OFKernelEventObserver.
 *
 * @return A new, autoreleased OFKernelEventObserver
 */
+ (instancetype)observer;

/*!
 * @brief Adds an object to observe for reading.
 *
 * This is also used to observe a listening socket for incoming connections,
 * which then triggers a read event for the observed object.
 *
 * If there is an @ref observe call blocking, it will be canceled. The reason
 * for this is to prevent blocking even though the newly added object is ready.
 *
 * @param object The object to observe for reading
 */
- (void)addObjectForReading: (id <OFReadyForReadingObserving>)object;

/*!
 * @brief Adds an object to observe for writing.
 *
 * If there is an @ref observe call blocking, it will be canceled. The reason
 * for this is to prevent blocking even though the newly added object is ready.
 *
 * @param object The object to observe for writing
 */
- (void)addObjectForWriting: (id <OFReadyForWritingObserving>)object;

/*!
 * @brief Removes an object to observe for reading.
 *
 * If there is an @ref observe call blocking, it will be canceled. The reason
 * for this is to prevent the removed object from still being observed.
 *
 * @param object The object to remove from observing for reading
 */
- (void)removeObjectForReading: (id <OFReadyForReadingObserving>)object;

/*!
 * @brief Removes an object to observe for writing.
 *
 * If there is an @ref observe call blocking, it will be canceled. The reason
 * for this is to prevent the removed object from still being observed.
 *
 * @param object The object to remove from observing for writing
 */
- (void)removeObjectForWriting: (id <OFReadyForWritingObserving>)object;

/*!
 * @brief Observes all objects and blocks until an event happens on an object.
 */
- (void)observe;

/*!
 * @brief Observes all objects until an event happens on an object or the
 *	  timeout is reached.
 *
 * @param timeInterval The time to wait for an event, in seconds
 */
- (void)observeForTimeInterval: (of_time_interval_t)timeInterval;

/*!
 * @brief Observes all objects until an event happens on an object or the
 *	  specified date is reached.
 *
 * @param date The until which to observe
 */
- (void)observeUntilDate: (OFDate*)date;

/*!
 * @brief Cancels the currently blocking observe call.
 *
 * This is automatically done when a new object is added or removed by another
 * thread, but in some circumstances, it might be desirable for a thread to
 * manually stop the observe running in another thread.
 */
- (void)cancel;
@end

OF_ASSUME_NONNULL_END