/// <summary>
/// Deserialzies the FileMetadata from stream.
/// </summary>
/// <param name="reader"></param>
/// <param name="tracer"></param>
/// <returns></returns>
/// <remarks>
/// Name || Size
///
/// TotalNumberOfEntries 8
/// NumberOfValidEntries 8
/// NumberOfDeletedEntries 8
/// TimeStamp 8
///
/// FileId 4
/// CanBeDeleted 1
/// RESERVED 3
///
/// FileName N
/// PADDING (N % 8 ==0) ? 0 : 8 - (N % 8)
///
/// RESERVED: Fixed padding that is usable to add fields in future.
/// PADDING: Due to dynamic size, cannot be used for adding fields.
///
/// </remarks>
public static FileMetadata Read(InMemoryBinaryReader reader, string tracer)
{
Utility.Assert(reader.IsAligned(), "must be aligned");
var totalNumberOfEntries = reader.ReadInt64();
var numberOfValidEntries = reader.ReadInt64();
var numberOfDeletedEntries = reader.ReadInt64();
var timeStamp = reader.ReadInt64();
var fileId = reader.ReadUInt32();
reader.ReadPaddingUntilAligned(true);
var fileName = reader.ReadString();
reader.ReadPaddingUntilAligned(false);
Utility.Assert(reader.IsAligned(), "must be aligned");
return(new FileMetadata(tracer, fileId,
fileName, totalNumberOfEntries,
numberOfValidEntries, timeStamp,
numberOfDeletedEntries, false,
FileMetadata.InvalidTimeStamp,
FileMetadata.InvalidTimeStamp));
}
private static async Task <ConditionalValue <CheckpointManager <T> > > TryReadCheckpointFile(
string directory,
string fileName,
IStateSerializer <T> valueSerializer,
string traceType)
{
var filePath = Path.Combine(directory, fileName);
if (!FabricFile.Exists(filePath))
{
return(new ConditionalValue <CheckpointManager <T> >(false, default(CheckpointManager <T>)));
}
using (var stream = FabricFile.Open(filePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, FileOptions.SequentialScan))
{
var intSegment = new ArraySegment <byte>(new byte[sizeof(int)]);
var versionRead = await SerializationHelper.ReadIntAsync(intSegment, stream).ConfigureAwait(false);
if (versionRead != FileVersion)
{
throw new InvalidDataException(string.Format("versionRead '{0}' != FileVersion '{1}'", versionRead, FileVersion));
}
var nameLength = await SerializationHelper.ReadIntAsync(intSegment, stream).ConfigureAwait(false);
if (nameLength < 0)
{
throw new InvalidDataException(string.Format("nameLength '{0}' < 0", nameLength));
}
if (nameLength == 0)
{
return(new ConditionalValue <CheckpointManager <T> >(true, new CheckpointManager <T>(null, directory, fileName, valueSerializer, traceType)));
}
var nameSegment = new ArraySegment <byte>(new byte[nameLength]);
await SerializationHelper.ReadBytesAsync(nameSegment, nameLength, stream).ConfigureAwait(false);
string name;
using (var reader = new InMemoryBinaryReader(new MemoryStream(nameSegment.Array)))
{
name = reader.ReadString();
}
var path = Path.Combine(directory, name);
if (!FabricFile.Exists(path))
{
throw new InvalidDataException(string.Format("Current checkpoint file does not exist: {0}", path));
}
return(new ConditionalValue <CheckpointManager <T> >(
true,
new CheckpointManager <T>(new Checkpoint <T>(directory, name, valueSerializer, traceType), directory, fileName, valueSerializer, traceType)));
}
}