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// VDKQueue.h
// Created by Bryan Jones on 28 March 2012.
// Copyright (c) 2012 Bryan D K Jones.
// You are free to use, modify and redistribute this software subject to these conditions:
// 1) I am not liable for anything that happens to you if you use this software --- including if it becomes sentient and eats your grandmother.
// 2) You keep this notice in your derivative work.
// 3) You keep Uli Kusterer's original copyright notice as well (this notice appears at the bottom of this file.)
// 4) You are awesome.
// This is an updated, modernized and streamlined version of the excellent UKKQueue class, which was authored by Uli Kusterer.
// UKKQueue was written back in 2003 and there have been many, many improvements to Objective-C since then. VDKQueue uses the
// core of Uli's original class, but makes it faster and more efficient. Method calls are reduced. Grand Central Dispatch is used in place
// of Uli's "threadProxy" objects. The new @autoreleasepool is used instead of alloc/initing a pool (which is much slower). The memory footprint
// is roughly halved, as I don't create the overhead that UKKQueue does. I take fewer locks, don't depend on notifications to get back to the main thread, and
// use modern language constructs to MASSIVELY speed up event processing compared to the original UKKQueue class.
// VDKQueue is also simplified. The option to use it as a singleton is removed. You simply alloc/init an instance and add paths you want to
// watch. Your objects can be alerted to changes either by notifications or by a delegate method (or both). See below.
// It also fixes several bugs. For one, it won't crash if it can't create a file descriptor to a file you ask it to watch. (By default, an OS X process can only
// have about 3,000 file descriptors open at once. If you hit that limit, UKKQueue will crash. VDKQueue will not.)
// VDKQueue requires OS 10.7.0+ because it relies on the @autoreleasepool language addition. If you wish to use the class on 10.6, you can
// simply replace the @autoreleasepool construct with an alloc/init-ed NSAutoReleasePool instance instead. The class will not work on versions of
// OS X below 10.6, as it requires blocks and Grand Central Dispatch.
#import <Foundation/Foundation.h>
#include <sys/types.h>
#include <sys/event.h>
// Logical OR these values into the u_int that you pass in the -addPath:notifyingAbout: method
// to specify the types of notifications you're interested in. Pass the default value to receive all of them.
#define VDKQueueNotifyAboutRename NOTE_RENAME // Item was renamed.
#define VDKQueueNotifyAboutWrite NOTE_WRITE // Item contents changed (also folder contents changed).
#define VDKQueueNotifyAboutDelete NOTE_DELETE // item was removed.
#define VDKQueueNotifyAboutAttributeChange NOTE_ATTRIB // Item attributes changed.
#define VDKQueueNotifyAboutSizeIncrease NOTE_EXTEND // Item size increased.
#define VDKQueueNotifyAboutLinkCountChanged NOTE_LINK // Item's link count changed.
#define VDKQueueNotifyAboutAccessRevocation NOTE_REVOKE // Access to item was revoked.
#define VDKQueueNotifyDefault (VDKQueueNotifyAboutRename | VDKQueueNotifyAboutWrite \
| VDKQueueNotifyAboutDelete | VDKQueueNotifyAboutAttributeChange \
| VDKQueueNotifyAboutSizeIncrease | VDKQueueNotifyAboutLinkCountChanged \
| VDKQueueNotifyAboutAccessRevocation)
// Notifications that this class sends to the NSWORKSPACE notification center.
// Object = the instance of VDKQueue that was watching for changes
// userInfo.path = the file path where the change was observed
extern NSString * VDKQueueRenameNotification;
extern NSString * VDKQueueWriteNotification;
extern NSString * VDKQueueDeleteNotification;
extern NSString * VDKQueueAttributeChangeNotification;
extern NSString * VDKQueueSizeIncreaseNotification;
extern NSString * VDKQueueLinkCountChangeNotification;
extern NSString * VDKQueueAccessRevocationNotification;
// Or, instead of subscribing to notifications, you can specify a delegate and implement this method to respond to kQueue events.
// Note the required statement! For speed, this class does not check to make sure the delegate implements this method. (When I say "required" I mean it!)
@class VDKQueue;
@protocol VDKQueueDelegate <NSObject>
-(void) VDKQueue:(VDKQueue *)queue receivedNotification:(NSString*)noteName forPath:(NSString*)fpath;
@interface VDKQueue : NSObject
id<VDKQueueDelegate> _delegate;
BOOL _alwaysPostNotifications; // By default, notifications are posted only if there is no delegate set. Set this value to YES to have notes posted even when there is a delegate.
int _coreQueueFD; // The actual kqueue ID (Unix file descriptor).
NSMutableDictionary *_watchedPathEntries; // List of VDKQueuePathEntries. Keys are NSStrings of the path that each VDKQueuePathEntry is for.
BOOL _keepWatcherThreadRunning; // Set to NO to cancel the thread that watches _coreQueueFD for kQueue events
// Note: there is no need to ask whether a path is already being watched. Just add it or remove it and this class
// will take action only if appropriate. (Add only if we're not already watching it, remove only if we are.)
// Warning: You must pass full, root-relative paths. Do not pass tilde-abbreviated paths or file URLs.
- (void) addPath:(NSString *)aPath;
- (void) addPath:(NSString *)aPath notifyingAbout:(u_int)flags; // See note above for values to pass in "flags"
- (void) removePath:(NSString *)aPath;
- (void) removeAllPaths;
- (NSUInteger) numberOfWatchedPaths; // Returns the number of paths that this VDKQueue instance is actively watching.
@property (assign) id<VDKQueueDelegate> delegate;
@property (assign) BOOL alwaysPostNotifications;
// This is the original copyright header that shipped with UKKQueue, on which VDKQueue is based:
// UKKQueue.m
// Created by Uli Kusterer on 21.12.2003
// Copyright 2003 Uli Kusterer.
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
// 1. The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software. If you use this software
// in a product, an acknowledgment in the product documentation would be
// appreciated but is not required.
// 2. Altered source versions must be plainly marked as such, and must not be
// misrepresented as being the original software.
// 3. This notice may not be removed or altered from any source
// distribution.
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