public async Task ReceiveAsync()
{
const int standardBufferLength = 1024 * 4;
int currentMessageLength = 0;
byte[] buffer = ArrayPool <byte> .Shared.Rent(standardBufferLength);
ReceiveResult?result = null;
try
{
result = await _handler.GetReceiveResult(buffer);
while (result?.Closed == false)
{
currentMessageLength += result.Read;
if (currentMessageLength >= MAX_POOLED_SIZE)
{
throw new InvalidOperationException("Message too long");
}
if (result.EndOfMessage)
{
// process the already filled bytes
await ProcessAsync(new ArraySegment <byte>(buffer, 0, currentMessageLength));
currentMessageLength = 0; // reset message length
// if we grew the buffer too big lets reset it
if (buffer.Length > 2 * standardBufferLength)
{
ArrayPool <byte> .Shared.Return(buffer);
buffer = ArrayPool <byte> .Shared.Rent(standardBufferLength);
}
}
else if (buffer.Length - currentMessageLength < standardBufferLength) // there is little room in current buffer
{
// grow the buffer 4x, but not more than max
int newLength = Math.Min(buffer.Length * 4, MAX_POOLED_SIZE);
if (newLength > buffer.Length)
{
byte[] newBuffer = ArrayPool <byte> .Shared.Rent(newLength);
buffer.CopyTo(newBuffer, 0);
ArrayPool <byte> .Shared.Return(buffer);
buffer = newBuffer;
}
}
// receive only new bytes, leave already filled buffer alone
result = await _handler.GetReceiveResult(new ArraySegment <byte>(buffer, currentMessageLength, buffer.Length - currentMessageLength));
}
}
finally
{
await _handler.CloseAsync(result);
ArrayPool <byte> .Shared.Return(buffer);
}
}