/// <summary>
/// Find a place for data item with the specified timestamp
/// </summary>
/// <exception cref="System.IO.FileNotFoundException">
/// File found in the data file container was not found on disk, by virtue of <see cref="RepositoryFileAccessor.ReadFromFile"/>.
/// Possible concurrent update; better shut down.
/// </exception>
private void Seek(DateTime seekTimestamp)
{
if (null == _currentFolder ||
!IsCovering(_currentFolder, seekTimestamp))
{
// need to change current leaf data folder
_currentFolder = _targetFolder.RootDataFolder.GetLeafFolder(seekTimestamp, true);
}
IRepositoryFileName targetFile;
IRepositoryFileName predecessor;
IRepositoryFileName successor;
_currentFolder.DataFileBrowser.GetDataFiles(seekTimestamp, out predecessor, out targetFile, out successor);
bool openingExistingFile = targetFile != null;
if (!openingExistingFile)
{
// new file needed
targetFile = _targetFolder.Repository.ObjectFactory.CreateNewFile(_targetFolder);
}
_currentAccessor = GetAccessor(targetFile);
if (openingExistingFile)
{
// will throw exception if file was not found or failed to read
_currentAccessor.ReadFromFile();
}
_currentAccessor.Encryptor = this.Encryptor;
// set timestamp limits
if (null != predecessor)
{
_currentAccessor.MinTimestampToAccept = predecessor.LastItemTimestamp.AddTicks(1);
}
else
{
_currentAccessor.MinTimestampToAccept = _currentFolder.Start;
}
if (null != successor)
{
_currentAccessor.MaxTimestampToAccept = successor.FirstItemTimestamp.AddTicks(-1);
}
else
{
_currentAccessor.MaxTimestampToAccept = _currentFolder.End.AddTicks(-1);
}
Check.Ensure(null != _currentAccessor);
}
private void CloseAccessor()
{
if (null != _currentAccessor)
{
Flush();
_currentAccessor.Close();
_currentAccessor = null;
}
else
{
DropUnsavedItems();
}
}
/// <summary>
/// Loads the specified file and positions at the first data item.
/// </summary>
/// <exception cref="System.IO.FileNotFoundException">
/// The <paramref name="dataFile"/> does not exist on disk.
/// </exception>
private void ReadFile(IRepositoryFile dataFile)
{
// passing null for equally timestamped items comparer, data items are read in the same
// order as they were written; no sorting when reading by design
IDataFileAccessor accessor = GetAccessor(dataFile);
// will throw exception if file not found or failed to read
accessor.ReadFromFile();
IList <IDataItem> dataList = accessor.GetAllItems();
if (Backwards)
{
_listReader = new BackwardListReader <IDataItem>(dataList);
}
else
{
_listReader = new ForwardListReader <IDataItem>(dataList);
}
this.LoadedFile = dataFile;
Check.Ensure(_listReader.HasItem);
Check.Ensure(CurrentItem != null);
}
