/// <summary>
/// Select on NetMQSocket or Socket, similar behavior to Socket.Select.
/// </summary>
/// <param name="items">Items to select on (must not be null)</param>
/// <param name="itemsCount">Number of items in the array to select on</param>
/// <param name="timeout">a time-out period, in milliseconds</param>
/// <returns></returns>
/// <exception cref="FaultException">The internal select operation failed.</exception>
/// <exception cref="ArgumentNullException"><paramref name="items"/> is <c>null</c>.</exception>
/// <exception cref="TerminatingException">The socket has been stopped.</exception>
public bool Select([NotNull] Item[] items, int itemsCount, long timeout)
{
if (items == null)
{
throw new ArgumentNullException(nameof(items));
}
if (itemsCount == 0)
{
return(false);
}
bool firstPass = true;
int numberOfEvents = 0;
Stopwatch stopwatch = null;
while (true)
{
long currentTimeoutMicroSeconds;
if (firstPass)
{
currentTimeoutMicroSeconds = 0;
}
else if (timeout < 0)
{
// Consider everything below 0 to be infinite
currentTimeoutMicroSeconds = -1;
}
else
{
currentTimeoutMicroSeconds = (timeout - stopwatch.ElapsedMilliseconds) * 1000;
if (currentTimeoutMicroSeconds < 0)
{
currentTimeoutMicroSeconds = 0;
}
else if (currentTimeoutMicroSeconds > int.MaxValue)
{
currentTimeoutMicroSeconds = int.MaxValue;
}
}
m_checkRead.Clear();
m_checkWrite.Clear();
m_checkError.Clear();
for (int i = 0; i < itemsCount; i++)
{
var pollItem = items[i];
if (pollItem.Socket != null)
{
if (pollItem.Event != PollEvents.None && pollItem.Socket.SocketHandle.Handle.Connected)
{
m_checkRead.Add(pollItem.Socket.SocketHandle.Handle);
}
}
else
{
if (pollItem.Event.HasIn())
{
m_checkRead.Add(pollItem.FileDescriptor);
}
if (pollItem.Event.HasOut())
{
m_checkWrite.Add(pollItem.FileDescriptor);
}
}
}
try
{
SocketUtility.Select(m_checkRead, m_checkWrite, m_checkError, (int)currentTimeoutMicroSeconds);
}
catch (SocketException x)
{
#if DEBUG
string textOfListRead = StringLib.AsString(m_checkRead);
string textOfListWrite = StringLib.AsString(m_checkWrite);
string textOfListError = StringLib.AsString(m_checkError);
string xMsg = $"In Selector.Select, Socket.Select({textOfListRead}, {textOfListWrite}, {textOfListError}, {currentTimeoutMicroSeconds}) threw a SocketException: {x.Message}";
Debug.WriteLine(xMsg);
throw new FaultException(innerException: x, message: xMsg);
#else
throw new FaultException(innerException: x, message: "Within SocketUtility.Select");
#endif
}
for (int i = 0; i < itemsCount; i++)
{
var selectItem = items[i];
selectItem.ResultEvent = PollEvents.None;
if (selectItem.Socket != null)
{
var events = (PollEvents)selectItem.Socket.GetSocketOption(ZmqSocketOption.Events);
if (selectItem.Event.HasIn() && events.HasIn())
{
selectItem.ResultEvent |= PollEvents.PollIn;
}
if (selectItem.Event.HasOut() && events.HasOut())
{
selectItem.ResultEvent |= PollEvents.PollOut;
}
}
else
{
if (m_checkRead.Contains(selectItem.FileDescriptor))
{
selectItem.ResultEvent |= PollEvents.PollIn;
}
if (m_checkWrite.Contains(selectItem.FileDescriptor))
{
selectItem.ResultEvent |= PollEvents.PollOut;
}
}
if (selectItem.ResultEvent != PollEvents.None)
{
numberOfEvents++;
}
}
if (timeout == 0)
{
break;
}
if (numberOfEvents > 0)
{
break;
}
if (timeout < 0)
{
if (firstPass)
{
firstPass = false;
}
continue;
}
if (firstPass)
{
stopwatch = Stopwatch.StartNew();
firstPass = false;
continue;
}
// Check also equality as it might frequently occur on 1000Hz clock
if (stopwatch.ElapsedMilliseconds >= timeout)
{
break;
}
}
return(numberOfEvents > 0);
}