/// <summary>
/// Initializes a new instance of the <see cref="PinSizeHistory" /> class.
/// </summary>
private PinSizeHistory(IClock clock, PinHistoryBuffer pinHistoryBuffer, long timestampInTick, AbsolutePath directoryPath)
{
Contract.Requires(clock != null);
Contract.Requires(pinHistoryBuffer != null);
Contract.Requires(directoryPath != null);
_clock = clock;
_pinHistoryBuffer = pinHistoryBuffer;
_timestampInTick = timestampInTick;
_directoryPath = directoryPath;
}
/// <summary>
/// Loads pin history from disk if exists, otherwise create a new instance.
/// </summary>
public static async Task <PinSizeHistory> LoadOrCreateNewAsync(
IAbsFileSystem fileSystem,
IClock clock,
AbsolutePath directoryPath,
int?newCapacity = default(int?))
{
Contract.Requires(fileSystem != null);
Contract.Requires(directoryPath != null);
var filePath = directoryPath / BinaryFileName;
try
{
if (!fileSystem.FileExists(filePath))
{
return(new PinSizeHistory(
clock,
newCapacity.HasValue ? PinHistoryBuffer.Create(newCapacity.Value) : PinHistoryBuffer.Create(),
clock.UtcNow.Ticks,
directoryPath));
}
using (var stream = await fileSystem.OpenReadOnlySafeAsync(filePath, FileShare.Delete))
{
using (var reader = new BinaryReader(stream))
{
var pinHistoryBuffer = PinHistoryBuffer.Deserialize(reader, newCapacity);
var timeStampInTick = reader.ReadInt64();
return(new PinSizeHistory(clock, pinHistoryBuffer, timeStampInTick, directoryPath));
}
}
}
catch (IOException)
{
return(new PinSizeHistory(
clock,
newCapacity.HasValue ? PinHistoryBuffer.Create(newCapacity.Value) : PinHistoryBuffer.Create(),
clock.UtcNow.Ticks,
directoryPath));
}
}
