private async Task <List <IListElement <T> > > ReadListElementsAsync()
{
try
{
using (var stream = FabricFile.Open(this.FilePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, FileOptions.SequentialScan))
{
var intSegment = new ArraySegment <byte>(new byte[sizeof(int)]);
var metadataMarker = await SerializationHelper.ReadIntAsync(intSegment, stream).ConfigureAwait(false);
if (metadataMarker != CheckpointFileHelper.MetadataMarker)
{
throw new InvalidDataException(
string.Format(
"Stream does not begin with metadata marker. Expected: {0} Actual: {1}",
CheckpointFileHelper.MetadataMarker,
metadataMarker));
}
var versionRead = await SerializationHelper.ReadIntAsync(intSegment, stream).ConfigureAwait(false);
if (versionRead != FileVersion)
{
throw new InvalidDataException(
string.Format("Unsupported ReliableConcurrentQueue checkpoint version. Expected: {0} Actual: {1}", FileVersion, versionRead));
}
var listElements = new List <IListElement <T> >();
while (true)
{
var marker = await SerializationHelper.ReadIntAsync(intSegment, stream).ConfigureAwait(false);
if (marker == CheckpointFileHelper.BeginFrameMarker)
{
var chunkListElements = await CheckpointFrame <T> .ReadAsync(stream, this.valueSerializer, this.traceType).ConfigureAwait(false);
listElements.AddRange(chunkListElements);
}
else if (marker == CheckpointFileHelper.EndFramesMarker)
{
return(listElements);
}
else
{
throw new InvalidDataException(string.Format("marker: {0}", marker));
}
}
}
}
catch (Exception ex)
{
FabricEvents.Events.ReliableConcurrentQueue_ReadCheckpointError("ReliableConcurrentQueueCheckpointFile.ReadCheckpointFileAsync@", ex.ToString());
throw;
}
}
public async Task WriteAsync()
{
if (this.ListElements == null)
{
TestableAssertHelper.FailArgumentNull(this.traceType, "Checkpoint.WriteAsync", "this.ListElements == null");
}
if (this.valueSerializer == null)
{
TestableAssertHelper.FailArgumentNull(this.traceType, "Checkpoint.WriteAsync", "this.valueSerializer == null");
}
using (var stream = FabricFile.Open(this.FilePath, FileMode.Create, FileAccess.Write, FileShare.None, 4096, FileOptions.SequentialScan))
{
await
stream.WriteAsync(
CheckpointFileHelper.MetadataMarkerSegment.Array,
CheckpointFileHelper.MetadataMarkerSegment.Offset,
CheckpointFileHelper.MetadataMarkerSegment.Count).ConfigureAwait(false);
var versionBytes = BitConverter.GetBytes(FileVersion);
await stream.WriteAsync(versionBytes, 0, versionBytes.Length).ConfigureAwait(false);
var frame = new CheckpointFrame <T>(this.valueSerializer);
foreach (var listElement in this.ListElements)
{
if (frame.Size >= CheckpointFileHelper.ChunkWriteThreshold)
{
await
stream.WriteAsync(
CheckpointFileHelper.BeginChunkMarkerSegment.Array,
CheckpointFileHelper.BeginChunkMarkerSegment.Offset,
CheckpointFileHelper.BeginChunkMarkerSegment.Count).ConfigureAwait(false);
await frame.WriteAsync(stream).ConfigureAwait(false);
frame.Reset();
}
frame.AddListElement(listElement);
}
if (frame.ListElementsCount > 0)
{
await
stream.WriteAsync(
CheckpointFileHelper.BeginChunkMarkerSegment.Array,
CheckpointFileHelper.BeginChunkMarkerSegment.Offset,
CheckpointFileHelper.BeginChunkMarkerSegment.Count).ConfigureAwait(false);
await frame.WriteAsync(stream).ConfigureAwait(false);
frame.Reset();
}
await
stream.WriteAsync(
CheckpointFileHelper.EndFramesMarkerSegment.Array,
CheckpointFileHelper.EndFramesMarkerSegment.Offset,
CheckpointFileHelper.EndFramesMarkerSegment.Count).ConfigureAwait(false);
}
}