ESRunLoopOperation.h

#import <Foundation/Foundation.h>

enum ESOperationState {
    kESOperationStateInited, 
    kESOperationStateExecuting, 
    kESOperationStateFinished
};
typedef enum ESOperationState ESOperationState;

/**
 * An abstract subclass of NSOperation for async run loop based operations.
 */

@interface ESRunLoopOperation : NSOperation

///-----------------------------------------
/// @name Configure before queuing operation
///-----------------------------------------

// IMPORTANT: Do not change these after queuing the operation; it's very likely that 
// bad things will happen if you do.

@property NSThread *runLoopThread; // default is nil, implying main thread
@property (copy) NSSet *runLoopModes; // default is nil, implying set containing NSDefaultRunLoopMode

///-----------------------------
/// @name Valid after completion
///-----------------------------

@property (copy, readonly) NSError *error;

///----------------------
/// @name Operation state
///----------------------

@property (readonly) ESOperationState state;
@property (readonly) NSThread *actualRunLoopThread; // main thread if runLoopThread is nil, runLoopThread otherwise
@property (readonly) BOOL isActualRunLoopThread; // YES if the current thread is the actual run loop thread
@property (copy, readonly) NSSet *actualRunLoopModes; // set containing NSDefaultRunLoopMode if runLoopModes is nil or empty, runLoopModes otherwise

@end

@interface ESRunLoopOperation (SubClassSupport)

// Override points

// A subclass will probably need to override -operationDidStart and -operationWillFinish 
// to set up and tear down its run loop sources, respectively.  These are always called 
// on the actual run loop thread.
//
// Note that -operationWillFinish will be called even if the operation is cancelled. 
//
// -operationWillFinish can check the error property to see whether the operation was 
// successful.  error will be NSCocoaErrorDomain/NSUserCancelledError on cancellation. 
//
// -operationDidStart is allowed to call -finishWithError:.

- (void)operationDidStart;
- (void)operationWillFinish;

// Support methods

// A subclass should call finishWithError: when the operation is complete, passing nil 
// for no error and an error otherwise.  It must call this on the actual run loop thread. 
// 
// Note that this will call -operationWillFinish before returning.

- (void)finishWithError:(NSError *)error;

- (void)setError:(NSError *)error;

@end

/*
 File:       QRunLoopOperation.h
 
 Contains:   An abstract subclass of NSOperation for async run loop based operations.
 
 Written by: DTS
 
 Copyright:  Copyright (c) 2010 Apple Inc. All Rights Reserved.
 
 Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc.
 ("Apple") in consideration of your agreement to the following
 terms, and your use, installation, modification or
 redistribution of this Apple software constitutes acceptance of
 these terms.  If you do not agree with these terms, please do
 not use, install, modify or redistribute this Apple software.
 
 In consideration of your agreement to abide by the following
 terms, and subject to these terms, Apple grants you a personal,
 non-exclusive license, under Apple's copyrights in this
 original Apple software (the "Apple Software"), to use,
 reproduce, modify and redistribute the Apple Software, with or
 without modifications, in source and/or binary forms; provided
 that if you redistribute the Apple Software in its entirety and
 without modifications, you must retain this notice and the
 following text and disclaimers in all such redistributions of
 the Apple Software. Neither the name, trademarks, service marks
 or logos of Apple Inc. may be used to endorse or promote
 products derived from the Apple Software without specific prior
 written permission from Apple.  Except as expressly stated in
 this notice, no other rights or licenses, express or implied,
 are granted by Apple herein, including but not limited to any
 patent rights that may be infringed by your derivative works or
 by other works in which the Apple Software may be incorporated.
 
 The Apple Software is provided by Apple on an "AS IS" basis. 
 APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT,
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING
 THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN
 COMBINATION WITH YOUR PRODUCTS.
 
 IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT,
 INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) ARISING IN ANY WAY
 OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION
 OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY
 OF CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY OR
 OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE POSSIBILITY OF
 SUCH DAMAGE.
 
 */

//
//  ESRunLoopOperation.h
//
//  Created by Doug Russell
//  Copyright (c) 2011 Doug Russell. All rights reserved.
//  
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//  
//  http://www.apache.org/licenses/LICENSE-2.0
//  
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//