WIEventQueue.m

/* $Id$ */

/*
 *  Copyright (c) 2005-2009 Axel Andersson
 *  All rights reserved.
 * 
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#import <WiredFoundation/WIEventQueue.h>

NSString * const WIEventFileDeleteNotification                          = @"WIEventFileDeleteNotification";
NSString * const WIEventFileWriteNotification                           = @"WIEventFileWriteNotification";
NSString * const WIEventFileExtendNotification                          = @"WIEventFileExtendNotification";
NSString * const WIEventFileAttributeChangeNotification         = @"WIEventFileAttributeChangeNotification";
NSString * const WIEventFileLinkCountChangeNotification         = @"WIEventFileLinkCountChangeNotification";
NSString * const WIEventFileRenameNotification                          = @"WIEventFileRenameNotification";
NSString * const WIEventFileRevokeNotification                          = @"WIEventFileRevokeNotification";



@interface WIEventFile : WIObject {
        NSString                                *_path;
        int                                             _fd;
}


- (id)initWithPath:(NSString *)path fileDescriptor:(int)fd;
- (NSString *)path;
- (int)fileDescriptor;

@end


@implementation WIEventFile

- (id)initWithPath:(NSString *)path fileDescriptor:(int)fd {
        self = [super init];
        
        _path = [path retain];
        _fd = fd;
        
        return self;
}



- (void)dealloc {
        [_path release];
        
        [super dealloc];
}



#pragma mark -

- (NSString *)path {
        return _path;
}



- (int)fileDescriptor {
        return _fd;
}

@end



@interface WIEventQueue(Private)

- (void)_processQueue;

@end


@implementation WIEventQueue(Private)

- (void)_processQueue {
        NSString                                *path;
        struct timespec                 ts = { 0, 0 };
        struct kevent                   ev;
        
        while(kevent(_fd, NULL, 0, &ev, 1, &ts) > 0) {
                if(ev.filter == EVFILT_VNODE) {
                        path = [(NSString *) ev.udata retain];
                        
                        if(ev.fflags & NOTE_DELETE)
                                [_center postNotificationName:WIEventFileDeleteNotification object:path];
                        
                        if(ev.fflags & NOTE_WRITE)
                                [_center postNotificationName:WIEventFileWriteNotification object:path];
                        
                        if(ev.fflags & NOTE_EXTEND)
                                [_center postNotificationName:WIEventFileExtendNotification object:path];
                        
                        if(ev.fflags & NOTE_ATTRIB)
                                [_center postNotificationName:WIEventFileAttributeChangeNotification object:path];
                        
                        if(ev.fflags & NOTE_LINK)
                                [_center postNotificationName:WIEventFileLinkCountChangeNotification object:path];
                        
                        if(ev.fflags & NOTE_RENAME)
                                [_center postNotificationName:WIEventFileRenameNotification object:path];
                        
                        if(ev.fflags & NOTE_REVOKE)
                                [_center postNotificationName:WIEventFileRevokeNotification object:path];
                        
                        [path release];
                }
        }
}

@end



@implementation WIEventQueue

+ (WIEventQueue *)sharedQueue {
        static WIEventQueue             *sharedQueue;

        if(!sharedQueue)
                sharedQueue = [[self alloc] init];

        return sharedQueue;
}



- (id)init {
        self = [super init];
        
        _fd = kqueue();
        
        if(_fd < 0) {
                [self release];
                
                return NULL;
        }
        
        _fileHandle = [[NSFileHandle alloc] initWithFileDescriptor:_fd];
        [_fileHandle waitForDataInBackgroundAndNotify];
        
        [[NSNotificationCenter defaultCenter]
                addObserver:self
                   selector:@selector(fileHandleDataAvailable:)
                           name:NSFileHandleDataAvailableNotification
                         object:_fileHandle];
        
        _center = [[NSNotificationCenter alloc] init];
        _files = [[NSMutableDictionary alloc] init];
        
        return self;
}



- (void)dealloc {
        [self removeAllPaths];
        
        [_center release];
        [_fileHandle release];
        
        if(close(_fd) < 0)
                NSLog(@"*** %@: close(): %s", [self class], strerror(errno));
        
        [_files release];
        
        [super dealloc];
}



#pragma mark -

- (void)fileHandleDataAvailable:(NSNotification *)notification {
        [self _processQueue];
        
        [_fileHandle waitForDataInBackgroundAndNotify];
}



#pragma mark -

- (NSNotificationCenter *)notificationCenter {
        return _center;
}



#pragma mark -

- (void)addPath:(NSString *)path {
        [self addPath:path forMode:WIEventFileDelete |
                                                           WIEventFileWrite |
                                                           WIEventFileRename |
                                                           WIEventFileAttributeChange];
}



- (void)addPath:(NSString *)path forMode:(WIEventMode)mode {
        WIEventFile             *file;
        struct kevent   ev;
        int                             fd;
        
        fd = open([path fileSystemRepresentation], O_EVTONLY, 0);
        
        if(fd < 0) {
                NSLog(@"*** %@: open(): %s", [self class], strerror(errno));
                
                return;
        }
        
        file = [[WIEventFile alloc] initWithPath:path fileDescriptor:fd];
        
        EV_SET(&ev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR, mode, 0, path);
        
        if(kevent(_fd, &ev, 1, NULL, 0, NULL) < 0) {
                [file release];
                
                return;
        }
        
        [_files setObject:file forKey:path];
        [file release];
}



- (void)removePath:(NSString *)path {
        WIEventFile             *file;
        
        file = [_files objectForKey:path];
        
        if(!file)
                return;
        
        if(close([file fileDescriptor]) < 0)
                NSLog(@"*** %@: close(): %s", [self class], strerror(errno));
        
        [_files removeObjectForKey:path];
}



- (void)removeAllPaths {
        NSEnumerator    *enumerator;
        WIEventFile             *file;
        
        enumerator = [_files objectEnumerator];
        
        while((file = [enumerator nextObject])) {
                if(close([file fileDescriptor]) < 0)
                        NSLog(@"*** %@: close(): %s", [self class], strerror(errno));
        }
        
        [_files removeAllObjects];
}

@end