private unsafe void AioReceive(List <TSocket> readableSockets)
{
long PackReceiveState(int received, int advanced, int iovLength) => ((long)received << 32) + (advanced << 8) + (iovLength);
(int received, int advanced, int iovLength) UnpackReceiveState(long data) => ((int)(data >> 32), (int)((data >> 8) & 0xffffff), (int)(data & 0xff));
int readableSocketCount = readableSockets.Count;
AioCb * aioCb = AioCbs;
IOVector * ioVectors = IoVectorTable;
PosixResult * receiveResults = stackalloc PosixResult[readableSocketCount];
Span <MemoryHandle> receiveMemoryHandles = MemoryHandles;
int receiveMemoryHandleCount = 0;
for (int i = 0; i < readableSocketCount; i++)
{
TSocket socket = readableSockets[i];
var memoryAllocation = socket.DetermineMemoryAllocationForReceive(IoVectorsPerAioSocket);
int advanced = socket.FillReceiveIOVector(memoryAllocation, ioVectors, receiveMemoryHandles);
aioCb->Fd = socket.Fd;
aioCb->Data = PackReceiveState(0, advanced, memoryAllocation.IovLength);
aioCb->OpCode = AioOpCode.PReadv;
aioCb->Buffer = ioVectors;
aioCb->Length = memoryAllocation.IovLength;
aioCb++;
ioVectors += memoryAllocation.IovLength;
receiveMemoryHandleCount += memoryAllocation.IovLength;
receiveMemoryHandles = receiveMemoryHandles.Slice(memoryAllocation.IovLength);
}
int eAgainCount = 0;
while (readableSocketCount > 0)
{
IntPtr ctxp = _aioContext;
PosixResult res = AioInterop.IoSubmit(ctxp, readableSocketCount, AioCbsTable);
if (res != readableSocketCount)
{
throw new NotSupportedException("Unexpected IoSubmit retval " + res);
}
AioEvent *aioEvents = AioEvents;
res = AioInterop.IoGetEvents(ctxp, readableSocketCount, aioEvents);
if (res != readableSocketCount)
{
throw new NotSupportedException("Unexpected IoGetEvents retval " + res);
}
int socketsRemaining = readableSocketCount;
bool allEAgain = true;
AioEvent *aioEvent = aioEvents;
for (int i = 0; i < readableSocketCount; i++)
{
PosixResult result = aioEvent->Result;
int socketIndex = i; // assumes in-order events
TSocket socket = readableSockets[socketIndex];
(int received, int advanced, int iovLength) = UnpackReceiveState(aioEvent->Data);
(bool done, PosixResult retval) = socket.InterpretReceiveResult(result, ref received, advanced, (IOVector *)aioEvent->AioCb->Buffer, iovLength);
if (done)
{
receiveResults[socketIndex] = retval;
socketsRemaining--;
aioEvent->AioCb->OpCode = AioOpCode.Noop;
allEAgain = false;
}
else if (retval != PosixResult.EAGAIN)
{
aioEvent->AioCb->Data = PackReceiveState(received, advanced, iovLength);
allEAgain = false;
}
aioEvent++;
}
if (socketsRemaining > 0)
{
if (allEAgain)
{
eAgainCount++;
if (eAgainCount == TransportConstants.MaxEAgainCount)
{
throw new NotSupportedException("Too many EAGAIN, unable to receive available bytes.");
}
}
else
{
aioCb = AioCbs;
AioCb *aioCbWriteAt = aioCb;
// The kernel doesn't handle Noop, we need to remove them from the aioCbs
for (int i = 0; i < readableSocketCount; i++)
{
if (aioCb[i].OpCode != AioOpCode.Noop)
{
if (aioCbWriteAt != aioCb)
{
*aioCbWriteAt = *aioCb;
}
aioCbWriteAt++;
}
aioCb++;
}
readableSocketCount = socketsRemaining;
eAgainCount = 0;
}
}
else
{
readableSocketCount = 0;
}
}
receiveMemoryHandles = MemoryHandles;
for (int i = 0; i < receiveMemoryHandleCount; i++)
{
receiveMemoryHandles[i].Dispose();
}
for (int i = 0; i < readableSockets.Count; i++)
{
readableSockets[i].OnReceiveFromSocket(receiveResults[i]);
}
readableSockets.Clear();
}