public static async Task <Frame> ReadAsync(Stream stream, CancellationToken ct, Logger logger)
{
try
{
var frameletCount = await ReadUInt16Async(stream, ct);
if (frameletCount == 0)
{
throw new EpoxyProtocolErrorException("Zero framelets");
}
var frame = new Frame(frameletCount, logger);
while (frameletCount > 0)
{
if (ct.IsCancellationRequested)
{
return(null);
}
var frameletType = await ReadUInt16Async(stream, ct);
if (!Framelet.IsKnownType(frameletType))
{
throw new EpoxyProtocolErrorException("Unknown framelet type: " + frameletType);
}
var frameletLength = await ReadUInt32Async(stream, ct);
if (frameletLength > int.MaxValue)
{
throw new EpoxyProtocolErrorException("Framelet too big: " + frameletLength);
}
byte[] frameletContents = await ReadBufferAsync(stream, unchecked ((int)frameletLength), ct);
frame.Add(new Framelet((FrameletType)frameletType, new ArraySegment <byte>(frameletContents)));
--frameletCount;
}
return(frame);
}
catch (Exception ex) when(ex is OperationCanceledException || ex is EndOfStreamException || ex is ObjectDisposedException)
{
return(null);
}
}
public void Add(Framelet framelet)
{
if (framelets.Count == UInt16.MaxValue)
{
var message = logger.Site().ErrorAndReturnFormatted("Exceeded maximum allowed count of framelets.");
throw new InvalidOperationException(message);
}
try
{
// add space for framelet type, length of message, and actual message content
TotalSize = checked (TotalSize + sizeof(UInt16) + sizeof(UInt32) + framelet.Contents.Count);
framelets.Add(framelet);
}
catch (OverflowException oex)
{
var message = logger.Site().ErrorAndReturnFormatted("Exceeded maximum size of frame.");
throw new InvalidOperationException(message, oex);
}
}
