///////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  File:   Libraries\Resiliency\Log.sg
//
//  Note:   
//
using System;
using System.Collections;

namespace Microsoft.Singularity.Resiliency
{
    public class Log : IEnumerable
    {
        protected IList!        log;
        protected IEnumerator   enumerator;

        public Log()
        {
            log = new ArrayList();
        }

        public void Record(uint msg, IList args)
        {
            if (enumerator != null) {
                enumerator = null;
            }
            log.Add(new LogData(msg, args));
        }

        public void Record(uint msg)
        {
            this.Record(msg, null);
        }

        public bool Playback(out uint message, out IList args)
        {
            LogData data;

            if (enumerator == null) {
                enumerator = log.GetEnumerator();
            }

            try {
                enumerator.MoveNext();
            }
            catch (Exception) {
                enumerator.Reset();
                enumerator = null;
                message = 0;
                args = null;
                return false;
            }

            try {
                data = (LogData)enumerator.Current;
                if (data == null) {
                    enumerator = null;
                    message = 0;
                    args = null;
                    return false;
                }
                else {
                    message = data.Message;
                    args = data.Arguments;
                    return true;
                }
            }
            catch (Exception) {
                //DebugStub.Print("Log: {0}\n", __arglist(e.ToString()));
                message = 0;
                args = null;
                return false;
            }
        }

        public void Flush()
        {
            enumerator = null;
            log.Clear();
        }

        public int Count
        {
            get { return log.Count; }
            private set {}
        }

        public IEnumerator GetEnumerator()
        {
            return log.GetEnumerator();
        }
    } // class
}