/// <summary>
/// </summary>
/// <param name="items"> (must not be null)</param>
/// <param name="itemsCount"></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(SelectItem[] items, int itemsCount, long timeout)
{
if (items == null)
{
throw new ArgumentNullException("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.Handle.Connected)
{
m_checkRead.Add(pollItem.Socket.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 = string.Format("In Selector.Select, Socket.Select({0}, {1}, {2}, {3}) threw a SocketException: {4}", textOfListRead, textOfListWrite, textOfListError, currentTimeoutMicroSeconds, 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);
}
/// <summary>
/// This method is the polling-loop that is invoked on a background thread when Start is called.
/// As long as Stop hasn't been called: execute the timers, and invoke the handler-methods on each of the saved PollSets.
/// </summary>
private void Loop()
{
var readList = new List <Socket>();
// var writeList = new List<Socket>();
var errorList = new List <Socket>();
while (!m_stopping)
{
// Transfer any sockets from the add-list.
m_handles.AddRange(m_addList);
m_addList.Clear();
// Execute any due timers.
int timeout = ExecuteTimers();
readList.AddRange(m_checkRead.ToArray());
// writeList.AddRange(m_checkWrite.ToArray());
errorList.AddRange(m_checkError.ToArray());
try
{
SocketUtility.Select(readList, /*writeList*/ null, errorList, timeout != 0 ? timeout * 1000 : -1);
}
catch (SocketException)
{
continue;
}
// For every PollSet in our list.
foreach (var pollSet in m_handles)
{
if (pollSet.Cancelled)
{
continue;
}
// Invoke its handler's InEvent if it's in our error-list.
if (errorList.Contains(pollSet.Socket))
{
try
{
pollSet.Handler.InEvent();
}
catch (TerminatingException)
{
}
}
if (pollSet.Cancelled)
{
continue;
}
// // Invoke its handler's OutEvent if it's in our write-list.
// if (writeList.Contains(pollSet.Socket))
// {
// try
// {
// pollSet.Handler.OutEvent();
// }
// catch (TerminatingException)
// {
// }
// }
//
// if (pollSet.Cancelled)
// continue;
// Invoke its handler's InEvent if it's in our read-list.
if (readList.Contains(pollSet.Socket))
{
try
{
pollSet.Handler.InEvent();
}
catch (TerminatingException)
{
}
}
}
errorList.Clear();
// writeList.Clear();
readList.Clear();
if (m_retired)
{
// Take any sockets that have been cancelled out of the list.
foreach (var item in m_handles.Where(k => k.Cancelled).ToList())
{
m_handles.Remove(item);
}
m_retired = false;
}
}
m_stopped = true;
}
/// <summary>
/// This method is the polling-loop that is invoked on a background thread when Start is called.
/// As long as Stop hasn't been called: execute the timers, and invoke the handler-methods on each of the saved PollSets.
/// </summary>
private void Loop()
{
var readList = new List <Socket>();
// var writeList = new List<Socket>();
var errorList = new List <Socket>();
while (!m_stopping)
{
// Transfer any sockets from the add-list.
m_handles.AddRange(m_addList);
m_addList.Clear();
// Execute any due timers.
int timeout = ExecuteTimers();
readList.AddRange(m_checkRead.ToArray());
// writeList.AddRange(m_checkWrite.ToArray());
errorList.AddRange(m_checkError.ToArray());
try
{
timeout = timeout != 0 ? timeout * 1000 : -1;
#if NETFRAMEWORK
Socket.Select(readList, null, errorList, timeout);
#else
if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
{
// Socket.Select does not work properly on macOS .NET Core when readList and errorList are passed
// together. To avoid this problem, we call the Select function separately for errorList.
// Please refer to this issue: https://github.com/dotnet/corefx/issues/39617
SocketUtility.Select(readList, null, null, timeout);
SocketUtility.Select(null, null, errorList, timeout);
}
else
{
Socket.Select(readList, null, errorList, timeout);
}
#endif
}
catch (SocketException)
{
continue;
}
// For every PollSet in our list.
foreach (var pollSet in m_handles)
{
if (pollSet.Cancelled)
{
continue;
}
// Invoke its handler's InEvent if it's in our error-list.
if (errorList.Contains(pollSet.Socket))
{
try
{
pollSet.Handler.InEvent();
}
catch (TerminatingException)
{
}
}
if (pollSet.Cancelled)
{
continue;
}
// // Invoke its handler's OutEvent if it's in our write-list.
// if (writeList.Contains(pollSet.Socket))
// {
// try
// {
// pollSet.Handler.OutEvent();
// }
// catch (TerminatingException)
// {
// }
// }
//
// if (pollSet.Cancelled)
// continue;
// Invoke its handler's InEvent if it's in our read-list.
if (readList.Contains(pollSet.Socket))
{
try
{
pollSet.Handler.InEvent();
}
catch (TerminatingException)
{
}
}
}
errorList.Clear();
// writeList.Clear();
readList.Clear();
if (m_retired)
{
// Take any sockets that have been cancelled out of the list.
foreach (var item in m_handles.Where(k => k.Cancelled).ToList())
{
m_handles.Remove(item);
}
m_retired = false;
}
}
m_stopped = true;
}