Synnefo » Pithos MS Client

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

// <copyright file="FileInfoExtensions.cs" company="GRNET">

// Copyright 2011 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>

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

using System;

using System.Collections.Generic;

using System.Diagnostics.Contracts;

using System.Linq;

using System.Text;

using System.IO;

using System.Text.RegularExpressions;

using System.Threading.Tasks;

using Pithos.Network;

namespace Pithos.Core.Agents

{

    static class BlockExtensions

    {

        public static int Read(this FileInfo fileInfo,byte[] buffer,int offset,int count)

        {            

            //Open the stream only long enough to read a block

            using (var stream = fileInfo.OpenRead())

            {

                stream.Seek(offset, SeekOrigin.Begin);

                return  stream.Read(buffer, 0, count);                

            }

        }

       public static string CalculateHash(this FileSystemInfo info,int blockSize,string algorithm)

        {

            if (info==null)

                throw new ArgumentNullException("info");

            if (String.IsNullOrWhiteSpace(info.FullName))

                throw new ArgumentException("info");

            if (blockSize<=0)

                throw new ArgumentOutOfRangeException("blockSize",blockSize,"blockSize must be greater than 0");

            if (String.IsNullOrWhiteSpace(algorithm))

                throw new ArgumentNullException("algorithm");

            Contract.EndContractBlock();

           //The hash for directories is an empty string

           if (info is DirectoryInfo)

                return String.Empty;

           var fileInfo = (FileInfo)info;

           if (fileInfo.Length <= blockSize)

                return Signature.CalculateMD5(info.FullName);

            else

                return Signature.CalculateTreeHash(info.FullName, blockSize, algorithm).TopHash.ToHashString();

        }

    }

}

        public IEnumerable<string> EnumerateFilesSystemInfosAsRelativeUrls(string searchPattern="*")

        {

            var rootDir = new DirectoryInfo(RootPath);

            var monitoredFiles = from file in rootDir.EnumerateFileSystemInfos(searchPattern, SearchOption.AllDirectories)

                                 where !Ignore(file.FullName)

                                 select file.AsRelativeUrlTo(RootPath);

            return monitoredFiles;

        }                

        private bool _firstPoll = true;

            _firstPoll = true;

                    _firstPoll = false;

                    //Get the poll time now. We may miss some deletions but it's better to keep a file that was deleted

                    //than delete a file that was created while we were executing the poll

                    var pollTime = DateTime.Now;

                        //TODO: Change the way deleted objects are detected.

                        //The list operation returns all existing objects so we could detect deleted remote objects

                        //by detecting objects that exist only locally. There are several cases where this is NOT the case:

                        //1.    The first time the application runs, as there may be files that were added while 

                        //      the application was down.

                        //2.    An object that is currently being uploaded will not appear in the remote list

                        //      until the upload finishes.

                        //      SOLUTION 1: Check the upload/download queue for the file

                        //      SOLUTION 2: Check the SQLite states for the file's entry. If it is being uploaded, 

                        //          or its last modification was after the current poll, don't delete it. This way we don't

                        //          delete objects whose upload finished too late to be included in the list.

                        //We need to detect and protect against such situations

                        //TODO: Does FileState have a LastModification field?

                        //TODO: How do we update the LastModification field? Do we need to add SQLite triggers?

                        //      Do we need to use a proper SQLite schema?

                        //      We can create a trigger with 

                        // CREATE TRIGGER IF NOT EXISTS update_last_modified UPDATE ON FileState FOR EACH ROW

                        //  BEGIN

                        //      UPDATE FileState SET LastModification=datetime('now')  WHERE Id=old.Id;

                        //  END;

                        //

                        //NOTE: Some files may have been deleted remotely while the application was down. 

                        //  We DO have to delete those files. Checking the trash makes it easy to detect them,

                        //  Otherwise, we can't be really sure whether we need to upload or delete 

                        //  the local-only files.

                        //  SOLUTION 1: Ask the user when such a local-only file is detected during the first poll.

                        //  SOLUTION 2: Mark conflict and ask the user as in #1

                        ProcessTrashedFiles(accountInfo, realTrash);

                        var cleanRemotes = from info in remoteObjects

                        var allActions = ObjectsToActions(accountInfo, cleanRemotes);

                        ProcessDeletedFiles(accountInfo, cleanRemotes, pollTime);

                        //var relativePath = objectInfo.RelativeUrlToFilePath(accountInfo.UserName);

        /// <summary>

        /// Deletes local files that are not found in the list of cloud files

        /// </summary>

        /// <param name="accountInfo"></param>

        /// <param name="cloudFiles"></param>

        /// <param name="pollTime"></param>

        private void ProcessDeletedFiles(AccountInfo accountInfo, IEnumerable<ObjectInfo> cloudFiles, DateTime pollTime)

        {

            if (accountInfo == null)

                throw new ArgumentNullException("accountInfo");

            if (String.IsNullOrWhiteSpace(accountInfo.AccountPath))

                throw new ArgumentException("The AccountInfo.AccountPath is empty", "accountInfo");

            if (cloudFiles == null)

                throw new ArgumentNullException("cloudFiles");

            Contract.EndContractBlock();

            if (_firstPoll) return;

            var deleteCandidates = from state in FileState.Queryable

                                   let stateUrl = FileInfoExtensions.FromPath(state.FilePath)

                                       .AsRelativeUrlTo(accountInfo.AccountPath)

                                   where state.Modified <= pollTime &&

                                         !cloudFiles.Any(r => r.Name == stateUrl)

                                   select state;

            foreach (var deleteCandidate in deleteCandidates)

            {

                File.Delete(deleteCandidate.FilePath);

                StatusKeeper.ClearFileStatus(deleteCandidate.FilePath);

            }

        }

        private void ProcessTrashedFiles(AccountInfo accountInfo,IEnumerable<ObjectInfo> trashObjects)

using System.Text;

            CreateTrigger();

        }

        private void CreateTrigger()

        {

            using (var connection = GetConnection())

            using (var triggerCommand = connection.CreateCommand())

            {

                var cmdText = new StringBuilder()

                    .AppendLine("CREATE TRIGGER IF NOT EXISTS update_last_modified UPDATE ON FileState FOR EACH ROW")

                    .AppendLine("BEGIN")

                    .AppendLine("UPDATE FileState SET Modified=datetime('now')  WHERE Id=old.Id;")

                    .AppendLine("END;")

                    .AppendLine("CREATE TRIGGER IF NOT EXISTS insert_last_modified INSERT ON FileState FOR EACH ROW")

                    .AppendLine("BEGIN")

                    .AppendLine("UPDATE FileState SET Modified=datetime('now')  WHERE Id=new.Id;")

                    .AppendLine("END;")

                    .ToString();

                triggerCommand.CommandText = cmdText;                

                triggerCommand.ExecuteNonQuery();

            }

        }

using Pithos.Network;

        [Property]

        public DateTime Modified { get; set; }

        public FileSystemInfo GetFileSystemInfo()

        {

            if (String.IsNullOrWhiteSpace(FilePath))

                throw new InvalidOperationException();

            Contract.EndContractBlock();

            return Directory.Exists(FilePath) ?

                (FileSystemInfo)new DirectoryInfo(FilePath)

                : new FileInfo(FilePath);

        }

        public string GetRelativeUrl(AccountInfo accountInfo)

        {

            if (accountInfo==null)

                throw new ArgumentNullException("accountInfo");

            Contract.EndContractBlock();

            var fsi=GetFileSystemInfo();

            return fsi.AsRelativeUrlTo(accountInfo.AccountPath);

        }

    <Compile Include="Agents\BlockExtensions.cs" />

        public static FileSystemInfo FromPath(string filePath)

        {

            if (String.IsNullOrWhiteSpace(filePath))

                throw new ArgumentNullException("filePath");

            Contract.EndContractBlock();

            return Directory.Exists(filePath) ? 

                (FileSystemInfo) new DirectoryInfo(filePath) 

                : new FileInfo(filePath);

        }