am I crazy?

SMOperationQueueOperation.m

//
//  SMOperationQueueOperation.m
//  DorsiaFoundation
//
//  Created by Zac Bowling on 4/4/12.
//  Copyright (c) 2012 SeatMe, Inc. All rights reserved.
//

#import "SMOperationQueueOperation.h"

@implementation SMOperationQueueOperation {
    NSOperationQueue *_queue;
    BOOL _finished;
    BOOL _executing;
}

- (id) init {
    self = [super init];
    if (self) {
        _queue = [[NSOperationQueue alloc] init];
        [_queue setMaxConcurrentOperationCount:4];
        [_queue setSuspended:YES];
    }
    return self;
}

- (void)start {
    if (![self isReady]) 
        return;
    
    [self willChangeValueForKey:@"isExecuting"];
    _executing = YES;
    [self didChangeValueForKey:@"isExecuting"];
    
    if ([self isCancelled]) {
        [self willChangeValueForKey:@"isFinished"];
        [self willChangeValueForKey:@"isExecuting"];
        _finished = YES;
        _executing = NO;
        [self didChangeValueForKey:@"isExecuting"];
        [self didChangeValueForKey:@"isFinished"];
        return;
    }
    
    __weak SMOperationQueueOperation *weakSelf = self;
    NSOperation *lastOperation = [NSBlockOperation blockOperationWithBlock:^{
        [weakSelf willChangeValueForKey:@"isFinished"];
        [weakSelf willChangeValueForKey:@"isExecuting"];
        _finished = YES;
        _executing = NO;
        [weakSelf didChangeValueForKey:@"isExecuting"];
        [weakSelf didChangeValueForKey:@"isFinished"];
    }];
    
    for (NSOperation *op in _queue.operations) {
        [lastOperation addDependency:op];
    }
    
    [_queue addOperation:lastOperation];
    [_queue setSuspended:NO];
}

- (void)addOperation:(NSOperation *)operation {
    if (!_executing && !_finished) {
        [_queue addOperation:operation];
    }
}

- (BOOL)isConcurrent {
    return YES;
}

- (BOOL)isFinished {
    return _finished;
}

- (BOOL)isExecuting {
    return _executing;
}

- (void)cancel {
    [super cancel];
    [_queue cancelAllOperations];
    [self willChangeValueForKey:@"isFinished"];
    [self willChangeValueForKey:@"isExecuting"];
    _finished = YES;
    _executing = NO;
    [self didChangeValueForKey:@"isExecuting"];
    [self didChangeValueForKey:@"isFinished"];
}

@end