////////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  File:  NotifyContract.sg
//

using Microsoft.SingSharp;
using Microsoft.Singularity.Channels;

namespace Microsoft.Singularity.Directory
{
    public enum NotifyType 
    {
        Creation, 
        Deletion,
        Modification
    }

    public contract NotifyContract
    {
        in  message Begin(); 
 
        in message ChangeNotification(char []! in ExHeap path, NotifyType type); 
        out  message AckChangeNotification(); 
      
        state Start : Begin? -> Notify; 
                  
        state Notify : ChangeNotification? -> NotifyAck;
        state NotifyAck: AckChangeNotification! -> Notify; 
    }
}