HTTPLoader（改良してみるなど）

gistfile1.txt

//
//  HTTPLoader.m
//  HTTPLoader
//
//  Created by Keisuke Kimura on 2012/08/08.
//  Copyright (c) 2012年 Keisuke Kimura. All rights reserved.
//

#import "HTTPLoader.h"

static NSOperationQueue* operationQueue;
static dispatch_queue_t serialQueue;

@implementation HTTPLoader

+ (NSOperationQueue*)operationQueue
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        operationQueue = [[NSOperationQueue alloc] init];
        [operationQueue setMaxConcurrentOperationCount:5];
    });
    
    return operationQueue;
}

+ (dispatch_queue_t)serialDispatchQueue
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        serialQueue = dispatch_queue_create("com.corosuke.httploader.serial",NULL);
    });
    return serialQueue;
}

+ (void)loadAsync:(NSURLRequest*)request
            owner:(id)owner
         complete:(CompleteWithWeakSelfBlock)completeBlock
{
    
    __block id inBlockSelf = owner;
    
    dispatch_sync([HTTPLoader serialDispatchQueue], ^{
        
        __block NSBlockOperation* operation = [[NSBlockOperation alloc] init];
        
        [operation addExecutionBlock:^{
            
            NSData* responseData = nil;
            NSURLResponse* response = nil;
            NSError* error = nil;
            
            responseData = [NSURLConnection sendSynchronousRequest:request
                                                 returningResponse:&response
                                                             error:&error];
            
            if(!operation.isCancelled){
                dispatch_sync(dispatch_get_main_queue(), ^{
                    completeBlock(responseData, error, inBlockSelf);
                });
            }
            
        }];
        
        [[HTTPLoader operationQueue] addOperation:operation];
    });

}

+ (void)cancelAll
{
    dispatch_sync([HTTPLoader serialDispatchQueue], ^{
        [[HTTPLoader operationQueue] cancelAllOperations];
    });
}

@end