//SCTaskRunner.h
#import <Foundation/Foundation.h>
@class SCTaskRunner;
@protocol SCTaskRunnerDelegate <NSObject>
@optional
- (void) taskRunner:(SCTaskRunner *) taskRunner didReadDataFromStdOut:(NSData *) data;
- (void) taskRunner:(SCTaskRunner *) taskRunner didReadDataFromStdErr:(NSData *) data;
- (void) taskRunnerTerminated:(SCTaskRunner *) taskRunner;
@end
@interface SCTaskRunner : NSObject
@property (assign) NSObject <SCTaskRunnerDelegate> * delegate;
@property NSTask * task;
@property NSPipe * standardInput;
@property NSPipe * standardOutput;
@property NSPipe * standardError;
- (id) initWithStandardInput:(NSPipe *) pipe;
@end

//SCTaskRunner.m

#import "SCTaskRunner.h"

@implementation SCTaskRunner

- (id) init {
	self = [super init];
	self.task = [[NSTask alloc] init];
	[self setupPipesAndNotifications];
	return self;
}

- (id) initWithStandardInput:(NSPipe *) standardInput {
	self = [self init];
	self.standardInput = standardInput;
	return self;
}

- (void) setupPipesAndNotifications {
	self.standardOutput = [[NSPipe alloc] init];
	self.standardError = [[NSPipe alloc] init];
	
	//add notification to task for termination
	NSNotificationCenter * nfc = [NSNotificationCenter defaultCenter];
	[nfc addObserver:self selector:@selector(taskTerminated:) name:NSTaskDidTerminateNotification object:self.task];
	
	//add notifications for read data on standard out and standard error
	self.task.standardOutput = self.standardOutput;
	self.task.standardError = self.standardError;
	[nfc addObserver:self selector:@selector(dataAvailable:) name:NSFileHandleReadCompletionNotification object:self.standardOutput.fileHandleForReading];
	[nfc addObserver:self selector:@selector(dataAvailable:) name:NSFileHandleReadCompletionNotification object:self.standardError.fileHandleForReading];
	[self.standardOutput.fileHandleForReading readInBackgroundAndNotify];
	[self.standardError.fileHandleForReading readInBackgroundAndNotify];
	
	if(self.standardInput) {
		self.task.standardInput = self.standardInput;
	}
}

- (void) dataAvailable:(NSNotification *) notification {
	NSData * data = [notification.userInfo objectForKey:NSFileHandleNotificationDataItem];
	if(notification.object == self.standardOutput.fileHandleForReading) {
		if(self.delegate && [self.delegate respondsToSelector:@selector(taskRunner:didReadDataFromStdOut:)]) {
			[self.delegate taskRunner:self didReadDataFromStdOut:data];
		}
	} else if(notification.object == self.standardError.fileHandleForReading) {
		if(self.delegate && [self.delegate respondsToSelector:@selector(taskRunner:didReadDataFromStdErr:)]) {
			[self.delegate taskRunner:self didReadDataFromStdErr:data];
		}
	}
}

- (void) taskTerminated:(NSNotification *) notification {
	if(self.delegate && [self.delegate respondsToSelector:@selector(taskRunnerTerminated:)]) {
		[self.delegate taskRunnerTerminated:self];
	}
}

- (void) dealloc {
	NSLog(@"DEALLOC: SCTaskRunner");
	[[NSNotificationCenter defaultCenter] removeObserver:self];
	self.task = nil;
	self.delegate = nil;
	self.standardOutput = nil;
	self.standardError = nil;
	self.standardInput = nil;
}

@end