New SQLite version
[pithos-ms-client] / trunk / Pithos.Core / Agents / NetworkAgent.cs
index a6ebcb7..0bdddd1 100644 (file)
@@ -1,15 +1,56 @@
-using System;
+#region
+/* -----------------------------------------------------------------------
+ * <copyright file="NetworkAgent.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
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and
+ * documentation are those of the authors and should not be
+ * interpreted as representing official policies, either expressed
+ * or implied, of GRNET S.A.
+ * </copyright>
+ * -----------------------------------------------------------------------
+ */
+#endregion
+
+using System;
 using System.Collections.Generic;
-using System.ComponentModel;
 using System.ComponentModel.Composition;
 using System.Diagnostics;
 using System.Diagnostics.Contracts;
 using System.IO;
-using System.Linq;
 using System.Net;
-using System.Text;
+using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
+using Castle.ActiveRecord;
 using Pithos.Interfaces;
 using Pithos.Network;
 using log4net;
@@ -19,52 +60,71 @@ namespace Pithos.Core.Agents
     [Export]
     public class NetworkAgent
     {
+        private static readonly ILog Log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
         private Agent<CloudAction> _agent;
 
+        [System.ComponentModel.Composition.Import]
+        private DeleteAgent DeleteAgent { get; set; }
 
-        [Import]
+        [System.ComponentModel.Composition.Import]
         public IStatusKeeper StatusKeeper { get; set; }
-        
-        public IStatusNotification StatusNotification { get; set; }
-/*
-        [Import]
-        public FileAgent FileAgent {get;set;}
-*/
 
-       /* public int BlockSize { get; set; }
-        public string BlockHash { get; set; }*/
+        private IStatusNotification _statusNotification;
+        public IStatusNotification StatusNotification
+        {
+            get { return _statusNotification; }
+            set
+            {
+                _statusNotification = value;
+                DeleteAgent.StatusNotification = value;
+                Uploader.StatusNotification = value;
+                Downloader.StatusNotification = value;
+            }
+        }
+
+
+        [System.ComponentModel.Composition.Import]
+        public IPithosSettings Settings { get; set; }
+
+        [System.ComponentModel.Composition.Import]
+        public Uploader Uploader { get; set; }
 
-        private static readonly ILog Log = LogManager.GetLogger("NetworkAgent");
+        [System.ComponentModel.Composition.Import]
+        public Downloader Downloader { get; set; }
 
-        private List<AccountInfo> _accounts=new List<AccountInfo>();
+        //The Proceed signals the poll agent that it can proceed with polling. 
+        //Essentially it stops the poll agent to give priority to the network agent
+        //Initially the event is signalled because we don't need to pause
+        private readonly AsyncManualResetEvent _proceedEvent = new AsyncManualResetEvent(true);
 
-        public void Start(/*int blockSize, string blockHash*/)
+        public AsyncManualResetEvent ProceedEvent
         {
-/*
-            if (blockSize<0)
-                throw new ArgumentOutOfRangeException("blockSize");
-            if (String.IsNullOrWhiteSpace(blockHash))
-                throw new ArgumentOutOfRangeException("blockHash");
-            Contract.EndContractBlock();
-*/
+            get { return _proceedEvent; }
+        }
 
-/*
-            BlockSize = blockSize;
-            BlockHash = blockHash;
-*/
 
+        public void Start()
+        {
+            if (_agent != null)
+                return;
+
+            if (Log.IsDebugEnabled)
+                Log.Debug("Starting Network Agent");
 
             _agent = Agent<CloudAction>.Start(inbox =>
             {
                 Action loop = null;
                 loop = () =>
                 {
+                    DeleteAgent.ProceedEvent.Wait();
                     var message = inbox.Receive();
                     var process=message.Then(Process,inbox.CancellationToken);
                     inbox.LoopAsync(process, loop);
                 };
                 loop();
             });
+
         }
 
         private async Task Process(CloudAction action)
@@ -75,62 +135,96 @@ namespace Pithos.Core.Agents
                 throw new ArgumentException("The action.AccountInfo is empty","action");
             Contract.EndContractBlock();
 
-            var accountInfo = action.AccountInfo;
 
-            using (log4net.ThreadContext.Stacks["NETWORK"].Push("PROCESS"))
+
+
+            using (ThreadContext.Stacks["Operation"].Push(action.ToString()))
             {                
-                Log.InfoFormat("[ACTION] Start Processing {0}", action);
 
-                var localFile = action.LocalFile;
                 var cloudFile = action.CloudFile;
                 var downloadPath = action.GetDownloadPath();
 
                 try
                 {
+                    StatusNotification.SetPithosStatus(PithosStatus.LocalSyncing,"Processing");
+                    _proceedEvent.Reset();
+                    
+                    var accountInfo = action.AccountInfo;
 
-                    switch (action.Action)
+                    if (action.Action == CloudActionType.DeleteCloud)
+                    {                        
+                        //Redirect deletes to the delete agent 
+                        DeleteAgent.Post((CloudDeleteAction)action);
+                    }
+                    if (DeleteAgent.IsDeletedFile(action))
                     {
-                        case CloudActionType.UploadUnconditional:
-                            await UploadCloudFile(action);
-                            break;
-                        case CloudActionType.DownloadUnconditional:
-
-                            await DownloadCloudFile(accountInfo, cloudFile, downloadPath);
-                            break;
-                        case CloudActionType.DeleteCloud:
-                            DeleteCloudFile(accountInfo, cloudFile);
-                            break;
-                        case CloudActionType.RenameCloud:
-                            var moveAction = (CloudMoveAction)action;
-                            RenameCloudFile(accountInfo, moveAction);
-                            break;
-                        case CloudActionType.MustSynch:
-
-                            if (!File.Exists(downloadPath))
-                            {
-                                await DownloadCloudFile(accountInfo, cloudFile, downloadPath);
-                            }
-                            else
-                            {
-                                await SyncFiles(accountInfo, action);
-                            }
-                            break;
+                        //Clear the status of already deleted files to avoid reprocessing
+                        if (action.LocalFile != null)
+                            StatusKeeper.ClearFileStatus(action.LocalFile.FullName);
+                    }
+                    else
+                    {
+                        switch (action.Action)
+                        {
+                            case CloudActionType.UploadUnconditional:
+                                //Abort if the file was deleted before we reached this point
+                                await Uploader.UploadCloudFile(action);
+                                break;
+                            case CloudActionType.DownloadUnconditional:
+                                await Downloader.DownloadCloudFile(accountInfo, cloudFile, downloadPath);
+                                break;
+                            case CloudActionType.RenameCloud:
+                                var moveAction = (CloudMoveAction)action;
+                                RenameCloudFile(accountInfo, moveAction);
+                                break;
+                            case CloudActionType.RenameLocal:
+                                RenameLocalFile(accountInfo, action);
+                                break;
+                            case CloudActionType.MustSynch:
+                                if (!File.Exists(downloadPath) && !Directory.Exists(downloadPath))
+                                {
+                                    await Downloader.DownloadCloudFile(accountInfo, cloudFile, downloadPath);
+                                }
+                                else
+                                {
+                                    await SyncFiles(accountInfo, action);
+                                }
+                                break;
+                        }
                     }
-                    Log.InfoFormat("[ACTION] End Processing {0}:{1}->{2}", action.Action, action.LocalFile,
+                    Log.InfoFormat("End Processing {0}:{1}->{2}", action.Action, action.LocalFile,
                                            action.CloudFile.Name);
                 }
+/*
                 catch (WebException exc)
-                {
-                    Log.ErrorFormat("[WEB ERROR] {0} : {1} -> {2} due to exception\r\n{3}", action.Action, action.LocalFile, action.CloudFile, exc);                    
+                {                    
+                    Log.ErrorFormat("[WEB ERROR] {0} : {1} -> {2} due to exception\r\n{3}", action.Action, action.LocalFile, action.CloudFile, exc);
+                    
+                    
+                    //Actions that resulted in server errors should be retried                    
+                    var response = exc.Response as HttpWebResponse;
+                    if (response != null && response.StatusCode >= HttpStatusCode.InternalServerError)
+                    {
+                        _agent.Post(action);
+                        Log.WarnFormat("[REQUEUE] {0} : {1} -> {2}", action.Action, action.LocalFile, action.CloudFile);
+                    }
                 }
+*/
                 catch (OperationCanceledException)
                 {
                     throw;
                 }
-                catch (FileNotFoundException exc)
+                catch (DirectoryNotFoundException)
+                {
+                    Log.ErrorFormat("{0} : {1} -> {2}  failed because the directory was not found.\n Rescheduling a delete",
+                        action.Action, action.LocalFile, action.CloudFile);
+                    //Post a delete action for the missing file
+                    Post(new CloudDeleteAction(action));
+                }
+                catch (FileNotFoundException)
                 {
                     Log.ErrorFormat("{0} : {1} -> {2}  failed because the file was not found.\n Rescheduling a delete",
-                        action.Action, action.LocalFile, action.CloudFile, exc);
+                        action.Action, action.LocalFile, action.CloudFile);
                     //Post a delete action for the missing file
                     Post(new CloudDeleteAction(action));
                 }
@@ -140,10 +234,82 @@ namespace Pithos.Core.Agents
                                      action.Action, action.LocalFile, action.CloudFile, exc);
 
                     _agent.Post(action);
-                }                
+                }
+                finally
+                {
+                    if (_agent.IsEmpty)
+                        _proceedEvent.Set();
+                    UpdateStatus(PithosStatus.LocalComplete);                                        
+                }
+            }
+        }
+
+
+        private void UpdateStatus(PithosStatus status)
+        {
+            StatusNotification.SetPithosStatus(status);
+            //StatusNotification.Notify(new Notification());
+        }
+
+        private void RenameLocalFile(AccountInfo accountInfo, CloudAction action)
+        {
+            if (accountInfo == null)
+                throw new ArgumentNullException("accountInfo");
+            if (action == null)
+                throw new ArgumentNullException("action");
+            if (action.LocalFile == null)
+                throw new ArgumentException("The action's local file is not specified", "action");
+            if (!Path.IsPathRooted(action.LocalFile.FullName))
+                throw new ArgumentException("The action's local file path must be absolute", "action");
+            if (action.CloudFile == null)
+                throw new ArgumentException("The action's cloud file is not specified", "action");
+            Contract.EndContractBlock();
+            using (ThreadContext.Stacks["Operation"].Push("RenameLocalFile"))
+            {
+
+                //We assume that the local file already exists, otherwise the poll agent
+                //would have issued a download request
+
+                var currentInfo = action.CloudFile;
+                var previousInfo = action.CloudFile.Previous;
+                var fileAgent = FileAgent.GetFileAgent(accountInfo);
+
+                var previousRelativepath = previousInfo.RelativeUrlToFilePath(accountInfo.UserName);
+                var previousFile = fileAgent.GetFileSystemInfo(previousRelativepath);
+
+                //In every case we need to move the local file first
+                MoveLocalFile(accountInfo, previousFile, fileAgent, currentInfo);
             }
         }
 
+        private void MoveLocalFile(AccountInfo accountInfo, FileSystemInfo previousFile, FileAgent fileAgent,
+                                   ObjectInfo currentInfo)
+        {
+            var currentRelativepath = currentInfo.RelativeUrlToFilePath(accountInfo.UserName);
+            var newPath = Path.Combine(fileAgent.RootPath, currentRelativepath);
+
+            var isFile= (previousFile is FileInfo);
+            var previousFullPath = isFile? 
+                FileInfoExtensions.GetProperFilePathCapitalization(previousFile.FullName):
+                FileInfoExtensions.GetProperDirectoryCapitalization(previousFile.FullName);                
+            
+            using (NetworkGate.Acquire(previousFullPath, NetworkOperation.Renaming))
+            using (NetworkGate.Acquire(newPath,NetworkOperation.Renaming)) 
+            using (new SessionScope(FlushAction.Auto))
+            {
+                if (isFile)
+                    (previousFile as FileInfo).MoveTo(newPath);
+                else
+                {
+                    (previousFile as DirectoryInfo).MoveTo(newPath);
+                }
+                var state = StatusKeeper.GetStateByFilePath(previousFullPath);
+                state.FilePath = newPath;
+                state.SaveCopy();
+                StatusKeeper.SetFileState(previousFullPath,FileStatus.Deleted,FileOverlayStatus.Deleted, "Deleted");
+            }            
+        }
+
         private async Task SyncFiles(AccountInfo accountInfo,CloudAction action)
         {
             if (accountInfo == null)
@@ -157,73 +323,54 @@ namespace Pithos.Core.Agents
             if (action.CloudFile== null)
                 throw new ArgumentException("The action's cloud file is not specified", "action");
             Contract.EndContractBlock();
+            using (ThreadContext.Stacks["Operation"].Push("SyncFiles"))
+            {
 
-            var localFile = action.LocalFile;
-            var cloudFile = action.CloudFile;
-            var downloadPath=action.LocalFile.FullName.ToLower();
+                //var localFile = action.LocalFile;
+                var cloudFile = action.CloudFile;
+                var downloadPath = action.LocalFile.GetProperCapitalization();
 
-            var cloudHash = cloudFile.Hash.ToLower();
-            var localHash = action.LocalHash.Value.ToLower();
-            var topHash = action.TopHash.Value.ToLower();
+                var cloudHash = cloudFile.Hash.ToLower();
+                var previousCloudHash = cloudFile.PreviousHash.ToLower();
+                var localHash = action.TreeHash.Value.TopHash.ToHashString();// LocalHash.Value.ToLower();
+                //var topHash = action.TopHash.Value.ToLower();
 
-            //Not enough to compare only the local hashes, also have to compare the tophashes
-            
-            //If any of the hashes match, we are done
-            if ((cloudHash == localHash || cloudHash == topHash))
-            {
-                Log.InfoFormat("Skipping {0}, hashes match",downloadPath);
-                return;
-            }
+                //At this point we know that an object has changed on the server and that a local
+                //file already exists. We need to decide whether the file has only changed on 
+                //the server or there is a conflicting change on the client.
+                //
 
-            //The hashes DON'T match. We need to sync
-            var lastLocalTime = localFile.LastWriteTime;
-            var lastUpTime = cloudFile.Last_Modified;
-            
-            //If the local file is newer upload it
-            if (lastUpTime <= lastLocalTime)
-            {
-                //It probably means it was changed while the app was down                        
-                UploadCloudFile(action);
-            }
-            else
-            {
-                //It the cloud file has a later date, it was modified by another user or computer.
-                //We need to check the local file's status                
-                var status = StatusKeeper.GetFileStatus(downloadPath);
-                switch (status)
+                //If the hashes match, we are done
+                if (cloudFile != ObjectInfo.Empty && cloudHash == localHash)
                 {
-                    case FileStatus.Unchanged:                        
-                        //If the local file's status is Unchanged, we can go on and download the newer cloud file
-                        await DownloadCloudFile(accountInfo,cloudFile,downloadPath);
-                        break;
-                    case FileStatus.Modified:
-                        //If the local file is Modified, we may have a conflict. In this case we should mark the file as Conflict
-                        //We can't ensure that a file modified online since the last time will appear as Modified, unless we 
-                        //index all files before we start listening.                       
-                    case FileStatus.Created:
-                        //If the local file is Created, it means that the local and cloud files aren't related,
-                        // yet they have the same name.
-
-                        //In both cases we must mark the file as in conflict
-                        ReportConflict(downloadPath);
-                        break;
-                    default:
-                        //Other cases should never occur. Mark them as Conflict as well but log a warning
-                        ReportConflict(downloadPath);
-                        Log.WarnFormat("Unexcepted status {0} for file {1}->{2}", status,
-                                       downloadPath, action.CloudFile.Name);
-                        break;
+                    Log.InfoFormat("Skipping {0}, hashes match", downloadPath);
+                    return;
+                }
+
+                //The hashes DON'T match. We need to sync
+
+                // If the previous tophash matches the local tophash, the file was only changed on the server. 
+                if (localHash == previousCloudHash)
+                {
+                    await Downloader.DownloadCloudFile(accountInfo, cloudFile, downloadPath);
+                }
+                else
+                {
+                    //If the previous and local hash don't match, there was a local conflict
+                    //that was not uploaded to the server. We have a conflict
+                    ReportConflictForMismatch(downloadPath);
                 }
             }
         }
 
-        private void ReportConflict(string downloadPath)
+        private void ReportConflictForMismatch(string downloadPath)
         {
             if (String.IsNullOrWhiteSpace(downloadPath))
                 throw new ArgumentNullException("downloadPath");
             Contract.EndContractBlock();
 
             StatusKeeper.SetFileOverlayStatus(downloadPath, FileOverlayStatus.Conflict);
+            UpdateStatus(PithosStatus.HasConflicts);
             var message = String.Format("Conflict detected for file {0}", downloadPath);
             Log.Warn(message);
             StatusNotification.NotifyChange(message, TraceLevel.Warning);
@@ -236,260 +383,56 @@ namespace Pithos.Core.Agents
             if (cloudAction.AccountInfo==null)
                 throw new ArgumentException("The CloudAction.AccountInfo is empty","cloudAction");
             Contract.EndContractBlock();
-            
+
+            DeleteAgent.ProceedEvent.Wait();
+/*
+
             //If the action targets a local file, add a treehash calculation
-            if (cloudAction.LocalFile != null)
+            if (!(cloudAction is CloudDeleteAction) && cloudAction.LocalFile as FileInfo != null)
             {
                 var accountInfo = cloudAction.AccountInfo;
-                if (cloudAction.LocalFile.Length>accountInfo.BlockSize)
-                    cloudAction.TopHash = new Lazy<string>(() => Signature.CalculateTreeHashAsync(cloudAction.LocalFile,
-                                    accountInfo.BlockSize, accountInfo.BlockHash).Result
-                                     .TopHash.ToHashString());
+                var localFile = (FileInfo) cloudAction.LocalFile;
+
+                if (localFile.Length > accountInfo.BlockSize)
+                    cloudAction.TopHash =
+                        new Lazy<string>(() => Signature.CalculateTreeHashAsync(localFile,
+                                                                                accountInfo.BlockSize,
+                                                                                accountInfo.BlockHash, Settings.HashingParallelism).Result
+                                                    .TopHash.ToHashString());
                 else
                 {
-                    cloudAction.TopHash=new Lazy<string>(()=> cloudAction.LocalHash.Value);
+                    cloudAction.TopHash = new Lazy<string>(() => cloudAction.LocalHash.Value);
                 }
 
             }
-            _agent.Post(cloudAction);
-        }
-
-       /* class ObjectInfoByNameComparer:IEqualityComparer<ObjectInfo>
-        {
-            public bool Equals(ObjectInfo x, ObjectInfo y)
-            {
-                return x.Name.Equals(y.Name,StringComparison.InvariantCultureIgnoreCase);
-            }
-
-            public int GetHashCode(ObjectInfo obj)
+            else
             {
-                return obj.Name.ToLower().GetHashCode();
+                //The hash for a directory is the empty string
+                cloudAction.TopHash = new Lazy<string>(() => String.Empty);
             }
-        }*/
-
-        
-
-        //Remote files are polled periodically. Any changes are processed
-        public Task ProcessRemoteFiles(DateTime? since=null)
-        {
-            return Task<Task>.Factory.StartNewDelayed(10000, () =>
-            {
-                using (log4net.ThreadContext.Stacks["Retrieve Remote"].Push("All accounts"))
-                {
-                    //Next time we will check for all changes since the current check minus 1 second
-                    //This is done to ensure there are no discrepancies due to clock differences
-                    DateTime nextSince = DateTime.Now.AddSeconds(-1);
-                    
-                    var tasks=from accountInfo in _accounts
-                              select ProcessAccountFiles(accountInfo, since);
-                    var process=Task.Factory.Iterate(tasks);
-
-                    return process.ContinueWith(t =>
-                    {
-                        if (t.IsFaulted)
-                        {
-                            Log.Error("Error while processing accounts");
-                            t.Exception.Handle(exc=>
-                                                   {
-                                                       Log.Error("Details:", exc);
-                                                       return true;
-                                                   });                            
-                        }
-                        ProcessRemoteFiles(nextSince);
-                    });
-                }
-            });            
-        }
-
-        public Task ProcessAccountFiles(AccountInfo accountInfo,DateTime? since=null)
-        {   
-            if (accountInfo==null)
-                throw new ArgumentNullException("accountInfo");
-            if (String.IsNullOrWhiteSpace(accountInfo.AccountPath))
-                throw new ArgumentException("The AccountInfo.AccountPath is empty","accountInfo");
-            Contract.EndContractBlock();
-
-            using (log4net.ThreadContext.Stacks["Retrieve Remote"].Push(accountInfo.UserName))
-            {
-                Log.Info("Scheduled");
-                var client=new CloudFilesClient(accountInfo);
-
-                var containers = client.ListContainers(accountInfo.UserName);
-                
-                CreateContainerFolders(accountInfo, containers);
-
-
-                //Get the list of server objects changed since the last check
-                var listObjects = from container in containers
-                                  select Task<IList<ObjectInfo>>.Factory.StartNew(_ =>
-                                        client.ListObjects(accountInfo.UserName, container.Name, since),container.Name);
-
-                var listAll = Task.Factory.WhenAll(listObjects.ToArray());
-                
-                
-
-                //Get the list of deleted objects since the last check
-/*
-                var listTrash = Task<IList<ObjectInfo>>.Factory.StartNew(() =>
-                                client.ListObjects(accountInfo.UserName, FolderConstants.TrashContainer, since));
-
-                var listShared = Task<IList<ObjectInfo>>.Factory.StartNew(() =>
-                                client.ListSharedObjects(since));
-
-                var listAll = Task.Factory.TrackedSequence(
-                    () => listObjects,
-                    () => listTrash,
-                    () => listShared);
 */
-
-
-
-                var enqueueFiles = listAll.ContinueWith(task =>
-                {
-                    if (task.IsFaulted)
-                    {
-                        //ListObjects failed at this point, need to reschedule
-                        Log.ErrorFormat("[FAIL] ListObjects for{0} in ProcessRemoteFiles with {1}", accountInfo.UserName,task.Exception);
-                        return;
-                    }
-                    using (log4net.ThreadContext.Stacks["SCHEDULE"].Push("Process Results"))
-                    {
-                        var dict=task.Result.ToDictionary(t=> t.AsyncState);
-                        
-                        //Get all non-trash objects. Remember, the container name is stored in AsyncState
-                        var remoteObjects = from objectList in task.Result
-                                            where (string)objectList.AsyncState != "trash"
-                                            from obj in objectList.Result
-                                            select obj;
-                                                                       
-                        var trashObjects = dict["trash"].Result;
-                        //var sharedObjects = ((Task<IList<ObjectInfo>>) task.Result[2]).Result;
-
-                        //Items with the same name, hash may be both in the container and the trash
-                        //Don't delete items that exist in the container
-                        var realTrash = from trash in trashObjects
-                                        where !remoteObjects.Any(info => info.Name == trash.Name &&  info.Hash == trash.Hash)
-                                        select trash;
-                        ProcessDeletedFiles(accountInfo,realTrash);                        
-
-
-                        var remote = from info in remoteObjects//.Union(sharedObjects)
-                                     let name = info.Name
-                                     where !name.EndsWith(".ignore", StringComparison.InvariantCultureIgnoreCase) &&
-                                           !name.StartsWith(FolderConstants.CacheFolder +"/", StringComparison.InvariantCultureIgnoreCase)
-                                     select info;
-
-                        //Create a list of actions from the remote files
-                        var allActions = ObjectsToActions(accountInfo,remote);
-                       
-                        //And remove those that are already being processed by the agent
-                        var distinctActions = allActions
-                            .Except(_agent.GetEnumerable(), new PithosMonitor.LocalFileComparer())
-                            .ToList();
-
-                        //Queue all the actions
-                        foreach (var message in distinctActions)
-                        {
-                            Post(message);
-                        }
-
-                        /*                        //Report the number of new files
-                                                var remoteCount = distinctActions.Count(action=>
-                                                    action.Action==CloudActionType.DownloadUnconditional);
-
-                                                if ( remoteCount > 0)
-                                                    StatusNotification.NotifyChange(String.Format("Processing {0} new files", remoteCount));
-                        */
-
-                        Log.Info("[LISTENER] End Processing");                        
-                    }
-                });
-
-                var log = enqueueFiles.ContinueWith(t =>
-                {                    
-                    if (t.IsFaulted)
-                    {
-                        Log.Error("[LISTENER] Exception", t.Exception);
-                    }
-                    else
-                    {
-                        Log.Info("[LISTENER] Finished");
-                    }
-                });
-                return log;
-            }
+            
+            if (cloudAction is CloudDeleteAction)
+                DeleteAgent.Post((CloudDeleteAction)cloudAction);
+            else
+                _agent.Post(cloudAction);
         }
+       
 
-        private static void CreateContainerFolders(AccountInfo accountInfo, IList<ContainerInfo> containers)
+        public IEnumerable<CloudAction> GetEnumerable()
         {
-            var containerPaths = from container in containers
-                                 let containerPath = Path.Combine(accountInfo.AccountPath, container.Name)
-                                 where container.Name != FolderConstants.TrashContainer && !Directory.Exists(containerPath)
-                                 select containerPath;
-
-            foreach (var path in containerPaths)
-            {
-                Directory.CreateDirectory(path);
-            }
+            return _agent.GetEnumerable();
         }
 
-        //Creates an appropriate action for each server file
-        private IEnumerable<CloudAction> ObjectsToActions(AccountInfo accountInfo,IEnumerable<ObjectInfo> remote)
+        public Task GetDeleteAwaiter()
         {
-            if (remote==null)
-                throw new ArgumentNullException();
-            Contract.EndContractBlock();
-            var fileAgent = GetFileAgent(accountInfo);
-
-            //In order to avoid multiple iterations over the files, we iterate only once
-            //over the remote files
-            foreach (var objectInfo in remote)
-            {
-                var relativePath = objectInfo.RelativeUrlToFilePath(accountInfo.UserName);
-                //and remove any matching objects from the list, adding them to the commonObjects list
-                
-                if (fileAgent.Exists(relativePath))
-                {
-                    var localFile = fileAgent.GetFileInfo(relativePath);
-                    var state = FileState.FindByFilePath(localFile.FullName);
-                    //Common files should be checked on a per-case basis to detect differences, which is newer
-
-                    yield return new CloudAction(accountInfo,CloudActionType.MustSynch,
-                                                   localFile, objectInfo, state, accountInfo.BlockSize,
-                                                   accountInfo.BlockHash);
-                }
-                else
-                {
-                    //If there is no match we add them to the localFiles list
-                    //but only if the file is not marked for deletion
-                    var targetFile = Path.Combine(accountInfo.AccountPath, relativePath);
-                    var fileStatus = StatusKeeper.GetFileStatus(targetFile);
-                    if (fileStatus != FileStatus.Deleted)
-                    {
-                        //Remote files should be downloaded
-                        yield return new CloudDownloadAction(accountInfo,objectInfo);
-                    }
-                }
-            }            
+            return DeleteAgent.ProceedEvent.WaitAsync();
         }
-
-        private static FileAgent GetFileAgent(AccountInfo accountInfo)
+        public CancellationToken CancellationToken
         {
-            return AgentLocator<FileAgent>.Get(accountInfo.AccountPath);
+            get { return _agent.CancellationToken; }
         }
 
-        private void ProcessDeletedFiles(AccountInfo accountInfo,IEnumerable<ObjectInfo> trashObjects)
-        {
-            var fileAgent = GetFileAgent(accountInfo);
-            foreach (var trashObject in trashObjects)
-            {
-                var barePath = trashObject.RelativeUrlToFilePath(accountInfo.UserName);
-                //HACK: Assume only the "pithos" container is used. Must find out what happens when
-                //deleting a file from a different container
-                var relativePath = Path.Combine("pithos", barePath);
-                fileAgent.Delete(relativePath);                                
-            }
-        }
 
 
         private void RenameCloudFile(AccountInfo accountInfo,CloudMoveAction action)
@@ -507,433 +450,43 @@ namespace Pithos.Core.Agents
             if (action.OldCloudFile==null)
                 throw new ArgumentException("OldCloudFile","action");
             Contract.EndContractBlock();
-            
-            var newFilePath = action.LocalFile.FullName;            
-            //The local file is already renamed
-            this.StatusKeeper.SetFileOverlayStatus(newFilePath, FileOverlayStatus.Modified);
-
 
-            var account = action.CloudFile.Account ?? accountInfo.UserName;
-            var container = action.CloudFile.Container;
-            
-            var client = new CloudFilesClient(accountInfo);
-            client.MoveObject(account, container, action.OldCloudFile.Name, container, action.CloudFile.Name);
-
-            this.StatusKeeper.SetFileStatus(newFilePath, FileStatus.Unchanged);
-            this.StatusKeeper.SetFileOverlayStatus(newFilePath, FileOverlayStatus.Normal);
-            NativeMethods.RaiseChangeNotification(newFilePath);
-        }
-
-        private void DeleteCloudFile(AccountInfo accountInfo, ObjectInfo cloudFile)
-        {
-            if (accountInfo == null)
-                throw new ArgumentNullException("accountInfo");
-            if (cloudFile==null)
-                throw new ArgumentNullException("cloudFile");
-
-            if (String.IsNullOrWhiteSpace(cloudFile.Container))
-                throw new ArgumentException("Invalid container", "cloudFile");
-            Contract.EndContractBlock();
-            
-            var fileAgent = GetFileAgent(accountInfo);
-
-            using ( log4net.ThreadContext.Stacks["DeleteCloudFile"].Push("Delete"))
+            using (ThreadContext.Stacks["Operation"].Push("RenameCloudFile"))
             {
-                var fileName= cloudFile.RelativeUrlToFilePath(accountInfo.UserName);
-                var info = fileAgent.GetFileInfo(fileName);                
-                var fullPath = info.FullName.ToLower();
 
-                this.StatusKeeper.SetFileOverlayStatus(fullPath, FileOverlayStatus.Modified);
+                var newFilePath = action.LocalFile.FullName;
 
-                var account = cloudFile.Account ?? accountInfo.UserName;
-                var container = cloudFile.Container ;//?? FolderConstants.PithosContainer;
+                //How do we handle concurrent renames and deletes/uploads/downloads?
+                //* A conflicting upload means that a file was renamed before it had a chance to finish uploading
+                //  This should never happen as the network agent executes only one action at a time
+                //* A conflicting download means that the file was modified on the cloud. While we can go on and complete
+                //  the rename, there may be a problem if the file is downloaded in blocks, as subsequent block requests for the 
+                //  same name will fail.
+                //  This should never happen as the network agent executes only one action at a time.
+                //* A conflicting delete can happen if the rename was followed by a delete action that didn't have the chance
+                //  to remove the rename from the queue.
+                //  We can probably ignore this case. It will result in an error which should be ignored            
 
-                var client = new CloudFilesClient(accountInfo);
-                client.DeleteObject(account, container, cloudFile.Name);
 
-                this.StatusKeeper.ClearFileStatus(fullPath);
-            }
-        }
+                //The local file is already renamed
+                StatusKeeper.SetFileOverlayStatus(newFilePath, FileOverlayStatus.Modified);
 
-        //Download a file.
-        private async Task DownloadCloudFile(AccountInfo accountInfo, ObjectInfo cloudFile , string localPath)
-        {
-            if (accountInfo == null)
-                throw new ArgumentNullException("accountInfo");
-            if (cloudFile == null)
-                throw new ArgumentNullException("cloudFile");
-            if (String.IsNullOrWhiteSpace(cloudFile.Account))
-                throw new ArgumentNullException("cloudFile");
-            if (String.IsNullOrWhiteSpace(cloudFile.Container))
-                throw new ArgumentNullException("cloudFile");
-            if (String.IsNullOrWhiteSpace(localPath))
-                throw new ArgumentNullException("localPath");
-            if (!Path.IsPathRooted(localPath))
-                throw new ArgumentException("The localPath must be rooted", "localPath");
-            Contract.EndContractBlock();
-                       
-            Uri relativeUrl = new Uri(cloudFile.Name, UriKind.Relative);
 
-            var url = relativeUrl.ToString();
-            if (cloudFile.Name.EndsWith(".ignore", StringComparison.InvariantCultureIgnoreCase))
-                return;
+                var account = action.CloudFile.Account ?? accountInfo.UserName;
+                var container = action.CloudFile.Container;
 
-            //Are we already downloading or uploading the file? 
-            using (var gate=NetworkGate.Acquire(localPath, NetworkOperation.Downloading))
-            {
-                if (gate.Failed)
-                    return;
-                //The file's hashmap will be stored in the same location with the extension .hashmap
-                //var hashPath = Path.Combine(FileAgent.CachePath, relativePath + ".hashmap");
-                
                 var client = new CloudFilesClient(accountInfo);
-                var account = cloudFile.Account;
-                var container = cloudFile.Container;
-
-                //Retrieve the hashmap from the server
-                var serverHash = await client.GetHashMap(account, container, url);
-                //If it's a small file
-                if (serverHash.Hashes.Count == 1 )
-                    //Download it in one go
-                    await DownloadEntireFileAsync(accountInfo, client, cloudFile, relativeUrl, localPath, serverHash);
-                    //Otherwise download it block by block
-                else
-                    await DownloadWithBlocks(accountInfo,client, cloudFile, relativeUrl, localPath, serverHash);                
-
-                if (cloudFile.AllowedTo == "read")
-                {
-                    var attributes=File.GetAttributes(localPath);
-                    File.SetAttributes(localPath,attributes|FileAttributes.ReadOnly);
-                }
-                
-                //Now we can store the object's metadata without worrying about ghost status entries
-                StatusKeeper.StoreInfo(localPath, cloudFile);
-                
-            }
-        }
-
-        //Download a small file with a single GET operation
-        private async Task DownloadEntireFileAsync(AccountInfo accountInfo, CloudFilesClient client, ObjectInfo cloudFile, Uri relativeUrl, string localPath,TreeHash serverHash)
-        {
-            if (client == null)
-                throw new ArgumentNullException("client");
-            if (cloudFile==null)
-                throw new ArgumentNullException("cloudFile");
-            if (relativeUrl == null)
-                throw new ArgumentNullException("relativeUrl");
-            if (String.IsNullOrWhiteSpace(localPath))
-                throw new ArgumentNullException("localPath");
-            if (!Path.IsPathRooted(localPath))
-                throw new ArgumentException("The localPath must be rooted", "localPath");
-            Contract.EndContractBlock();
-
-            //If the file already exists
-            if (File.Exists(localPath))
-            {
-                //First check with MD5 as this is a small file
-                var localMD5 = Signature.CalculateMD5(localPath);
-                var cloudHash=serverHash.TopHash.ToHashString();
-                if (localMD5==cloudHash)
-                    return;
-                //Then check with a treehash
-                var localTreeHash = Signature.CalculateTreeHash(localPath, serverHash.BlockSize, serverHash.BlockHash);
-                var localHash = localTreeHash.TopHash.ToHashString();
-                if (localHash==cloudHash)
-                    return;
-            }
-
-            var fileAgent = GetFileAgent(accountInfo);
-            //Calculate the relative file path for the new file
-            var relativePath = relativeUrl.RelativeUriToFilePath();
-            //The file will be stored in a temporary location while downloading with an extension .download
-            var tempPath = Path.Combine(fileAgent.CachePath, relativePath + ".download");
-            //Make sure the target folder exists. DownloadFileTask will not create the folder
-            var tempFolder = Path.GetDirectoryName(tempPath);
-            if (!Directory.Exists(tempFolder))
-                Directory.CreateDirectory(tempFolder);
-
-            //Download the object to the temporary location
-            await client.GetObject(cloudFile.Account, cloudFile.Container, relativeUrl.ToString(), tempPath).ContinueWith(t =>
-            {
-                t.PropagateExceptions();
-                //Create the local folder if it doesn't exist (necessary for shared objects)
-                var localFolder = Path.GetDirectoryName(localPath);
-                if (!Directory.Exists(localFolder))
-                    Directory.CreateDirectory(localFolder);
-                //And move it to its actual location once downloading is finished
-                if (File.Exists(localPath))
-                    File.Replace(tempPath,localPath,null,true);
-                else
-                    File.Move(tempPath,localPath);
-                //Notify listeners that a local file has changed
-                StatusNotification.NotifyChangedFile(localPath);
-
-            });            
-        }
-
-        //Download a file asynchronously using blocks
-        public async Task DownloadWithBlocks(AccountInfo accountInfo, CloudFilesClient client, ObjectInfo cloudFile, Uri relativeUrl, string localPath, TreeHash serverHash)
-        {
-            if (client == null)
-                throw new ArgumentNullException("client");
-            if (cloudFile == null)
-                throw new ArgumentNullException("cloudFile");
-            if (relativeUrl == null)
-                throw new ArgumentNullException("relativeUrl");
-            if (String.IsNullOrWhiteSpace(localPath))
-                throw new ArgumentNullException("localPath");
-            if (!Path.IsPathRooted(localPath))
-                throw new ArgumentException("The localPath must be rooted", "localPath");
-            if (serverHash == null)
-                throw new ArgumentNullException("serverHash");
-            Contract.EndContractBlock();
-            
-           var fileAgent = GetFileAgent(accountInfo);
-            
-            //Calculate the relative file path for the new file
-            var relativePath = relativeUrl.RelativeUriToFilePath();
-            var blockUpdater = new BlockUpdater(fileAgent.CachePath, localPath, relativePath, serverHash);
-
-            
-                        
-            //Calculate the file's treehash
-            var treeHash = await Signature.CalculateTreeHashAsync(localPath, serverHash.BlockSize, serverHash.BlockHash);
-                
-            //And compare it with the server's hash
-            var upHashes = serverHash.GetHashesAsStrings();
-            var localHashes = treeHash.HashDictionary;
-            for (int i = 0; i < upHashes.Length; i++)
-            {
-                //For every non-matching hash
-                var upHash = upHashes[i];
-                if (!localHashes.ContainsKey(upHash))
-                {
-                    if (blockUpdater.UseOrphan(i, upHash))
-                    {
-                        Log.InfoFormat("[BLOCK GET] ORPHAN FOUND for {0} of {1} for {2}", i, upHashes.Length, localPath);
-                        continue;
-                    }
-                    Log.InfoFormat("[BLOCK GET] START {0} of {1} for {2}", i, upHashes.Length, localPath);
-                    var start = i*serverHash.BlockSize;
-                    //To download the last block just pass a null for the end of the range
-                    long? end = null;
-                    if (i < upHashes.Length - 1 )
-                        end= ((i + 1)*serverHash.BlockSize) ;
-                            
-                    //Download the missing block
-                    var block = await client.GetBlock(cloudFile.Account, cloudFile.Container, relativeUrl, start, end);
+                //TODO: What code is returned when the source file doesn't exist?
+                client.MoveObject(account, container, action.OldCloudFile.Name, container, action.CloudFile.Name);
 
-                    //and store it
-                    blockUpdater.StoreBlock(i, block);
-
-
-                    Log.InfoFormat("[BLOCK GET] FINISH {0} of {1} for {2}", i, upHashes.Length, localPath);
-                }
+                StatusKeeper.SetFileStatus(newFilePath, FileStatus.Unchanged);
+                StatusKeeper.SetFileOverlayStatus(newFilePath, FileOverlayStatus.Normal);
+                NativeMethods.RaiseChangeNotification(newFilePath);
             }
-
-            //Want to avoid notifications if no changes were made
-            var hasChanges = blockUpdater.HasBlocks;
-            blockUpdater.Commit();
-            
-            if (hasChanges)
-                //Notify listeners that a local file has changed
-                StatusNotification.NotifyChangedFile(localPath);
-
-            Log.InfoFormat("[BLOCK GET] COMPLETE {0}", localPath);            
         }
 
 
-        private async Task UploadCloudFile(CloudAction action)
-        {
-            if (action == null)
-                throw new ArgumentNullException("action");           
-            Contract.EndContractBlock();
-
-            try
-            {
-                if (action == null)
-                    throw new ArgumentNullException("action");
-                Contract.EndContractBlock();
-
-                var accountInfo = action.AccountInfo;
-
-                var fileInfo = action.LocalFile;
-
-                if (fileInfo.Extension.Equals("ignore", StringComparison.InvariantCultureIgnoreCase))
-                    return;
-
-                var relativePath = fileInfo.AsRelativeTo(accountInfo.AccountPath);
-                if (relativePath.StartsWith(FolderConstants.OthersFolder))
-                {
-                    var parts = relativePath.Split('\\');
-                    var accountName = parts[1];
-                    var oldName = accountInfo.UserName;
-                    var absoluteUri = accountInfo.StorageUri.AbsoluteUri;
-                    var nameIndex = absoluteUri.IndexOf(oldName);
-                    var root = absoluteUri.Substring(0, nameIndex);
-
-                    accountInfo = new AccountInfo
-                    {
-                        UserName = accountName,
-                        AccountPath = Path.Combine(accountInfo.AccountPath, parts[0], parts[1]),
-                        StorageUri = new Uri(root + accountName),
-                        BlockHash = accountInfo.BlockHash,
-                        BlockSize = accountInfo.BlockSize,
-                        Token = accountInfo.Token
-                    };
-                }
-
-
-                var fullFileName = fileInfo.FullName;
-                using (var gate = NetworkGate.Acquire(fullFileName, NetworkOperation.Uploading))
-                {
-                    //Abort if the file is already being uploaded or downloaded
-                    if (gate.Failed)
-                        return;
-
-                    var cloudFile = action.CloudFile;
-                    var account = cloudFile.Account ?? accountInfo.UserName;
-
-                    var client = new CloudFilesClient(accountInfo);
-                    //Even if GetObjectInfo times out, we can proceed with the upload            
-                    var info = client.GetObjectInfo(account, cloudFile.Container, cloudFile.Name);
-                    var cloudHash = info.Hash.ToLower();
-
-                    var hash = action.LocalHash.Value;
-                    var topHash = action.TopHash.Value;
-
-                    //If the file hashes match, abort the upload
-                    if (hash == cloudHash || topHash == cloudHash)
-                    {
-                        //but store any metadata changes 
-                        this.StatusKeeper.StoreInfo(fullFileName, info);
-                        Log.InfoFormat("Skip upload of {0}, hashes match", fullFileName);
-                        return;
-                    }
-
-                    if (info.AllowedTo == "read")
-                        return;
 
-                    //Mark the file as modified while we upload it
-                    StatusKeeper.SetFileOverlayStatus(fullFileName, FileOverlayStatus.Modified);
-                    //And then upload it
-
-                    //Upload even small files using the Hashmap. The server may already containt
-                    //the relevant folder
-
-                    //First, calculate the tree hash
-                    var treeHash = await Signature.CalculateTreeHashAsync(fileInfo.FullName, accountInfo.BlockSize,
-                        accountInfo.BlockHash);
-
-                    await UploadWithHashMap(accountInfo, cloudFile, fileInfo, cloudFile.Name, treeHash);
-
-                    //If everything succeeds, change the file and overlay status to normal
-                    this.StatusKeeper.SetFileState(fullFileName, FileStatus.Unchanged, FileOverlayStatus.Normal);
-                }
-                //Notify the Shell to update the overlays
-                NativeMethods.RaiseChangeNotification(fullFileName);
-                StatusNotification.NotifyChangedFile(fullFileName);
-            }
-            catch (AggregateException ex)
-            {
-                var exc = ex.InnerException as WebException;
-                if (exc == null)
-                    throw ex.InnerException;
-                if (HandleUploadWebException(action, exc)) 
-                    return;
-                throw;
-            }
-            catch (WebException ex)
-            {
-                if (HandleUploadWebException(action, ex))
-                    return;
-                throw;
-            }
-            catch (Exception ex)
-            {
-                Log.Error("Unexpected error while uploading file", ex);
-                throw;
-            }
-
-        }
-
-        private bool HandleUploadWebException(CloudAction action, WebException exc)
-        {
-            var response = exc.Response as HttpWebResponse;
-            if (response == null)
-                throw exc;
-            if (response.StatusCode == HttpStatusCode.Unauthorized)
-            {
-                Log.Error("Not allowed to upload file", exc);
-                var message = String.Format("Not allowed to uplad file {0}", action.LocalFile.FullName);
-                StatusKeeper.SetFileState(action.LocalFile.FullName, FileStatus.Unchanged, FileOverlayStatus.Normal);
-                StatusNotification.NotifyChange(message, TraceLevel.Warning);
-                return true;
-            }
-            return false;
-        }
-
-        public async Task UploadWithHashMap(AccountInfo accountInfo,ObjectInfo cloudFile,FileInfo fileInfo,string url,TreeHash treeHash)
-        {
-            if (accountInfo == null)
-                throw new ArgumentNullException("accountInfo");
-            if (cloudFile==null)
-                throw new ArgumentNullException("cloudFile");
-            if (fileInfo == null)
-                throw new ArgumentNullException("fileInfo");
-            if (String.IsNullOrWhiteSpace(url))
-                throw new ArgumentNullException(url);
-            if (treeHash==null)
-                throw new ArgumentNullException("treeHash");
-            if (String.IsNullOrWhiteSpace(cloudFile.Container) )
-                throw new ArgumentException("Invalid container","cloudFile");
-            Contract.EndContractBlock();
-
-            var fullFileName = fileInfo.FullName;
-
-            var account = cloudFile.Account ?? accountInfo.UserName;
-            var container = cloudFile.Container ;
-
-            var client = new CloudFilesClient(accountInfo);
-            //Send the hashmap to the server            
-            var missingHashes =  await client.PutHashMap(account, container, url, treeHash);
-            //If the server returns no missing hashes, we are done
-            while (missingHashes.Count > 0)
-            {
-
-                var buffer = new byte[accountInfo.BlockSize];
-                foreach (var missingHash in missingHashes)
-                {
-                    //Find the proper block
-                    var blockIndex = treeHash.HashDictionary[missingHash];
-                    var offset = blockIndex*accountInfo.BlockSize;
-
-                    var read = fileInfo.Read(buffer, offset, accountInfo.BlockSize);
-
-                    try
-                    {
-                        //And upload the block                
-                        await client.PostBlock(account, container, buffer, 0, read);
-                        Log.InfoFormat("[BLOCK] Block {0} of {1} uploaded", blockIndex, fullFileName);
-                    }
-                    catch (Exception exc)
-                    {
-                        Log.ErrorFormat("[ERROR] uploading block {0} of {1}\n{2}", blockIndex, fullFileName, exc);
-                    }
-
-                }
-
-                //Repeat until there are no more missing hashes                
-                missingHashes = await client.PutHashMap(account, container, url, treeHash);
-            }
-        }
-
-
-        public void AddAccount(AccountInfo accountInfo)
-        {            
-            if (!_accounts.Contains(accountInfo))
-                _accounts.Add(accountInfo);
-        }
     }