Synnefo » Pithos MS Client

#region

/* -----------------------------------------------------------------------

 * <copyright file="FileEventIdleBatch.cs" company="GRNet">

 * 

 * Copyright 2011-2012 GRNET S.A. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or

 * without modification, are permitted provided that the following

 * conditions are met:

 *

 *   1. Redistributions of source code must retain the above

 *      copyright notice, this list of conditions and the following

 *      disclaimer.

 *

 *   2. Redistributions in binary form must reproduce the above

 *      copyright notice, this list of conditions and the following

 *      disclaimer in the documentation and/or other materials

 *      provided with the distribution.

 *

 *

 * THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS

 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED

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 * The views and conclusions contained in the software and

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 * </copyright>

 * -----------------------------------------------------------------------

 */

#endregion

using System;

using System.Collections.Generic;

using System.Diagnostics.Contracts;

using System.IO;

using System.Linq;

using System.Reflection;

using log4net;

namespace Pithos.Core.Agents

{

    public class FileEventIdleBatch

    {

        //Requirements

        //------------

        //* The class should group workflow actions according to file name and type

        //* The class should pass all batched actions to a continuation when

        //* the batch is triggered.

        //* Actions should not survice a trigger

        private static readonly ILog Log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        private readonly IdleBatch<FileSystemEventArgs> _idleBatch;

        private readonly Action<Dictionary<string, FileSystemEventArgs[]>> _callback;

        public FileEventIdleBatch(int idleTimeout, Action<Dictionary<string, FileSystemEventArgs[]>> callback)

        {

            _callback = callback;

            _idleBatch = new IdleBatch<FileSystemEventArgs>(idleTimeout, Process);

        }

        public void Post(FileSystemEventArgs arg)

        {

            if (arg is RenamedEventArgs)

                throw new ArgumentException("arg");

            Contract.EndContractBlock();

            if (Log.IsDebugEnabled)

                Log.DebugFormat("Batch Post  {0}:{1}", arg.ChangeType.ToString("g"), arg.FullPath);

            _idleBatch.Post(arg);

        }

        public void ForceTrigger()

        {

            _idleBatch.ForceTrigger();

        }

        protected virtual void Process(FileSystemEventArgs[] args)

        {

            var dict = new Dictionary<string, FileSystemEventArgs[]>();

            foreach (var arg in args)

            {

                if (arg.ChangeType == WatcherChangeTypes.Created )

                    dict[arg.FullPath] = new[] { arg };

                else if (arg.ChangeType == WatcherChangeTypes.Renamed)

                {

                    var renamedArg = (MovedEventArgs)arg;

                    FileSystemEventArgs[] oldValue;

                    if (dict.TryGetValue(renamedArg.OldFullPath, out oldValue))

                    {

                        dict.Remove(renamedArg.OldFullPath);

                        var last = oldValue.Last();

                        if (last.ChangeType == WatcherChangeTypes.Created)

                        {

                            var createRenamed = new FileSystemEventArgs(WatcherChangeTypes.Created, Path.GetDirectoryName(renamedArg.FullPath),

                                                                        renamedArg.Name);

                            dict[renamedArg.FullPath] = new[] {createRenamed};

                        }

                        else

                            dict[renamedArg.FullPath] = new[] { renamedArg };

                    }

                    else

                        dict[renamedArg.FullPath] = new[] { renamedArg};

                }

                else

                {

                    FileSystemEventArgs[] oldValue;

                    var hasValue=dict.TryGetValue(arg.FullPath, out oldValue);

                    var last = hasValue?oldValue.LastOrDefault():null;

                    if (last==null || last.ChangeType == WatcherChangeTypes.Changed)

                    {

                        dict[arg.FullPath] = new[] { arg};

                    }

                    else if (arg.ChangeType == WatcherChangeTypes.Deleted)

                    {

                        if (last.ChangeType == WatcherChangeTypes.Created)

                            dict.Remove(arg.FullPath);

                        else

                        {

                            dict[arg.FullPath] = new[] { arg };

                        }

                    }

                    else if (last.ChangeType == WatcherChangeTypes.Renamed && arg.ChangeType == WatcherChangeTypes.Changed)

                    {

                        var newValue = oldValue.Concat(new[] { arg }).ToArray();

                        dict[arg.FullPath] = newValue;

                    }

                }

            }

            _callback(dict);

        }

    }

}