/// <summary>
/// Открывает указанный файл для записи и чтения.
/// </summary>
/// <param name="fullPathForFile">Путь, указывающий открываемый файл.</param>
/// <returns>Поток данных файла, допускающий чтение и запись данных</returns>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="FileNotFoundException"></exception>
/// <exception cref="FileLockedException"></exception>
/// <exception cref="ObjectDisposedException"></exception>
public DataStreamReadableWritable OpenFileForWriting(string fullPathForFile)
{
MethodArgumentValidator.ThrowIfStringIsNullOrEmpty(fullPathForFile, "fullPathForFile");
try
{
NodeWithSurroundingsResolvingResult <FileNode> nodeResolvingResult;
DataStreamStructureBuilder dataStreamStructureBuilder = GetDataStreamStructureBuilderResolvingTheFile(fullPathForFile, out nodeResolvingResult);
Guid lockId = _lockingManager.AcquireLock(nodeResolvingResult, LockKind.Write);
var stream = new DataStream(dataStreamStructureBuilder, AddressingSystemParameters.Default.BlockSize, _lockingManager, lockId);
var nodeUpdatingStream = new DataStreamNodeUpdating(stream, nodeResolvingResult.ResolvedNode, _fileSystemNodeStorage);
return(nodeUpdatingStream);
}
catch (InvalidPathException)
{
throw new FileNotFoundException("Файл не найден по указанному пути (\"{0}\")".FormatWith(fullPathForFile));
}
catch (CannotAcquireLockException)
{
throw new FileLockedException(
"Не удалось открыть файл \"{0}\" с блокировкой на запись: он уже заблокирован на чтение или запись."
.FormatWith(fullPathForFile));
}
}
/// <summary>
///
/// </summary>
/// <param name="blockIndex"></param>
/// <param name="dataStreamToAddReferenceIn"></param>
/// <param name="nodeOwningTheStream"></param>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="ArgumentOutOfRangeException"></exception>
/// <exception cref="InsufficientSpaceException"></exception>
/// <exception cref="MaximumFileSizeReachedException"></exception>
public void AddBlockReference(int blockIndex, DataStreamDefinition dataStreamToAddReferenceIn, Node nodeOwningTheStream)
{
if (dataStreamToAddReferenceIn == null)
{
throw new ArgumentNullException("dataStreamToAddReferenceIn");
}
if (nodeOwningTheStream == null)
{
throw new ArgumentNullException("nodeOwningTheStream");
}
MethodArgumentValidator.ThrowIfNegative(blockIndex, "blockIndex");
var streamStructureBuilder =
new DataStreamStructureBuilder(dataStreamToAddReferenceIn, _virtualDisk, _freeBlockManager, _fileSystemNodeStorage, nodeOwningTheStream, AddressingSystemParameters.Default);
// Note: никаких настоящих блокировок не использует.
var parentFolderFileReferencesStream = new DataStream(streamStructureBuilder,
AddressingSystemParameters.Default.BlockSize,
new NullFileSystemObjectLockingManager(),
Guid.NewGuid());
var nodeUpdatingStream = new DataStreamNodeUpdating(parentFolderFileReferencesStream, nodeOwningTheStream, _fileSystemNodeStorage);
using (nodeUpdatingStream)
{
var stream = new MemoryStream();
var writer = new BinaryWriter(stream);
writer.Write(blockIndex);
nodeUpdatingStream.MoveToEnd();
nodeUpdatingStream.Write(stream.ToArray(), 0, (int)stream.Length);
}
}
/// <summary>
///
/// </summary>
/// <param name="folderToRemoveDirectoryFrom"></param>
/// <param name="indexReferenceToRemove"></param>
/// <param name="dataStreamBeingCorrected"></param>
/// <exception cref="InconsistentDataDetectedException"></exception>
public void TakeOutABlockFromBlockReferenceList(FolderNode folderToRemoveDirectoryFrom, int indexReferenceToRemove, DataStreamDefinition dataStreamBeingCorrected)
{
var streamStructureBuilder =
new DataStreamStructureBuilder(dataStreamBeingCorrected, _virtualDisk, _freeBlockManager, _fileSystemNodeStorage, folderToRemoveDirectoryFrom, AddressingSystemParameters.Default);
var lockingManager = new NullFileSystemObjectLockingManager();
var folderReferencesStream = new DataStream(streamStructureBuilder, AddressingSystemParameters.Default.BlockSize, lockingManager, Guid.NewGuid());
var nodeUpdatingStream = new DataStreamNodeUpdating(folderReferencesStream, folderToRemoveDirectoryFrom, _fileSystemNodeStorage);
var referencesToBlocks = new byte[nodeUpdatingStream.Length];
nodeUpdatingStream.Read(referencesToBlocks, 0, nodeUpdatingStream.Length);
var correctedStream = new MemoryStream(nodeUpdatingStream.Length);
var reader = new BinaryReader(new MemoryStream(referencesToBlocks, true));
var writer = new BinaryWriter(correctedStream);
int numberOfReferencesFound = 0;
while (reader.BaseStream.Position != reader.BaseStream.Length)
{
int nodeIndex = reader.ReadInt32();
if (nodeIndex != indexReferenceToRemove)
{
writer.Write(nodeIndex);
}
else
{
numberOfReferencesFound++;
}
}
if (numberOfReferencesFound != 1)
{
throw new InconsistentDataDetectedException("Обнаружены неконсистентные данные (произошла попытка удаления несуществующей ссылки на файл или папку). Возможна потеря данных. Обратитесь к разработчикам.");
}
nodeUpdatingStream.SetLength(nodeUpdatingStream.Length - Constants.BlockReferenceSizeInBytes);
var bytes = correctedStream.ToArray();
nodeUpdatingStream.SetPosition(0);
nodeUpdatingStream.Write(bytes, 0, bytes.Length);
}
