private Cursor WriteFileDescriptor(IFileEntry file, bool isNewFile)
{
_logger.Information($"Start writing file descriptor for filename {file.EntryName}");
var allocatedCursor = _allocator.AllocateFile(file.DataLength, isNewFile);
var filesystemDescriptor = _filesystemDescriptorAccessor.Value;
var createdOn = DateTime.UtcNow.ToUnixTime();
var updatedOn = createdOn;
var id = Guid.NewGuid();
var fileDescriptor = new EntryDescriptor(id, file.ParentEntryId, file.EntryName, EntryType.File, createdOn, updatedOn, allocatedCursor.Offset, file.DataLength);
var fileDescriptorOffset = -FilesystemDescriptor.BytesTotal -
(filesystemDescriptor.EntryDescriptorsCount *
filesystemDescriptor.EntryDescriptorLength)
- filesystemDescriptor.EntryDescriptorLength;
var origin = SeekOrigin.End;
var cursor = new Cursor(fileDescriptorOffset, origin);
var storageItem = new StorageItem <EntryDescriptor>(in fileDescriptor, in cursor);
_entryDescriptorRepository.Write(storageItem);
_logger.Information($"Done writing file descriptor for filename {file.EntryName}");
return(allocatedCursor);
}
/// <inheritdoc/>
public void Create(DirectoryEntry directoryEntry)
{
_logger.Information($"Start writing entry descriptor for directory {directoryEntry.EntryName}");
var filesystemDescriptor = _filesystemDescriptorAccessor.Value;
var createdOn = DateTime.UtcNow.ToUnixTime();
var updatedOn = createdOn;
var entryDescriptor = new EntryDescriptor(
directoryEntry.Id,
directoryEntry.ParentEntryId,
directoryEntry.EntryName,
EntryType.Directory,
createdOn,
updatedOn,
0,
0);
var entryDescriptorOffset = -FilesystemDescriptor.BytesTotal -
(filesystemDescriptor.EntryDescriptorsCount *
filesystemDescriptor.EntryDescriptorLength)
- filesystemDescriptor.EntryDescriptorLength;
var origin = SeekOrigin.End;
var cursor = new Cursor(entryDescriptorOffset, origin);
var storageItem = new StorageItem <EntryDescriptor>(in entryDescriptor, in cursor);
_entryDescriptorRepository.Write(storageItem);
_logger.Information($"Done writing entry descriptor for directory {directoryEntry.EntryName}");
IncreaseEntriesCount(1);
}
/// <inheritdoc />
public void Delete(string entryName)
{
// 1. Find last descriptor
var filesystemDescriptor = _filesystemDescriptorAccessor.Value;
var lastDescriptorCursor = new Cursor(
-FilesystemDescriptor.BytesTotal -
(filesystemDescriptor.EntryDescriptorsCount *
filesystemDescriptor.EntryDescriptorLength),
SeekOrigin.End);
var lastDescriptor = _entryDescriptorRepository.Read(lastDescriptorCursor).Value;
// 2. Find current descriptor
var descriptorItem = _entryDescriptorRepository.Find(entryName);
var cursor = descriptorItem.Cursor;
// 3. Save last descriptor in new empty space (perform swap with last)
_entryDescriptorRepository.Write(new StorageItem <EntryDescriptor>(lastDescriptor, cursor));
// 4. Decrease count of descriptors
IncreaseEntriesCount(-1);
}
private void CreateRootDirectory()
{
var rootDirectoryId = Guid.NewGuid();
var createdOn = DateTime.UtcNow.ToUnixTime();
var updatedOn = createdOn;
var rootDirectory = new EntryDescriptor(
rootDirectoryId,
rootDirectoryId,
"/",
EntryType.Directory,
createdOn,
updatedOn,
0,
0);
// Write root directory descriptor
var filesystemDescriptor = _filesystemDescriptorAccessor.Value;
var cursor = new Cursor(-FilesystemDescriptor.BytesTotal - filesystemDescriptor.EntryDescriptorLength, SeekOrigin.End);
_entryDescriptorRepository.Write(new StorageItem <EntryDescriptor>(rootDirectory, cursor));
}
private StorageItem <EntryDescriptor> CopyFile(EntryDescriptor entryDescriptor, Cursor cursor, int destinationOffset)
{
var newDescriptor = new EntryDescriptor(
entryDescriptor.Id,
entryDescriptor.ParentId,
entryDescriptor.Name,
entryDescriptor.Type,
entryDescriptor.CreatedOn,
entryDescriptor.UpdatedOn,
destinationOffset,
entryDescriptor.DataLength);
var newStorageItem = new StorageItem <EntryDescriptor>(in newDescriptor, in cursor);
_logger.Information($"Moving {entryDescriptor.DataLength} bytes of data from {entryDescriptor.DataOffset} to {destinationOffset}");
PerformCopy(entryDescriptor.DataOffset, destinationOffset, entryDescriptor.DataLength);
_entryDescriptorRepository.Write(newStorageItem);
_logger.Information($"{entryDescriptor.DataLength} bytes of data moved to offset {destinationOffset}");
return(newStorageItem);
}
