internal static int FillFdSetFromSocketList(ref Interop.libc.fd_set fdset, IList socketList)
{
if (socketList == null || socketList.Count == 0)
{
return(0);
}
int maxFd = -1;
for (int i = 0; i < socketList.Count; i++)
{
var socket = socketList[i] as Socket;
if (socket == null)
{
throw new ArgumentException(SR.Format(SR.net_sockets_select, socketList[i].GetType().FullName, typeof(System.Net.Sockets.Socket).FullName), "socketList");
}
int fd = socket._handle.FileDescriptor;
fdset.Set(fd);
if (fd > maxFd)
{
maxFd = fd;
}
}
return(maxFd + 1);
}
// Transform the list socketList such that the only sockets left are those
// with a file descriptor contained in the array "fileDescriptorArray".
internal static void FilterSocketListUsingFdSet(ref Interop.libc.fd_set fdset, IList socketList)
{
if (socketList == null || socketList.Count == 0)
{
return;
}
lock (socketList)
{
for (int i = socketList.Count - 1; i >= 0; i--)
{
var socket = (Socket)socketList[i];
if (!fdset.IsSet(socket._handle.FileDescriptor))
{
socketList.RemoveAt(i);
}
}
}
}
public static unsafe SocketError Select(IList checkRead, IList checkWrite, IList checkError, int microseconds)
{
var readSet = new Interop.libc.fd_set();
int maxReadFd = Socket.FillFdSetFromSocketList(ref readSet, checkRead);
var writeSet = new Interop.libc.fd_set();
int maxWriteFd = Socket.FillFdSetFromSocketList(ref writeSet, checkWrite);
var errorSet = new Interop.libc.fd_set();
int maxErrorFd = Socket.FillFdSetFromSocketList(ref errorSet, checkError);
int nfds = 0;
Interop.libc.fd_set* readfds = null;
Interop.libc.fd_set* writefds = null;
Interop.libc.fd_set* errorfds = null;
if (maxReadFd != 0)
{
readfds = &readSet;
nfds = maxReadFd;
}
if (maxWriteFd != 0)
{
writefds = &writeSet;
if (maxWriteFd > nfds)
{
nfds = maxWriteFd;
}
}
if (maxErrorFd != 0)
{
errorfds = &errorSet;
if (maxErrorFd > nfds)
{
nfds = maxErrorFd;
}
}
int socketCount;
if (microseconds != -1)
{
var tv = new Interop.libc.timeval(microseconds);
socketCount = Interop.libc.select(nfds, readfds, writefds, errorfds, &tv);
}
else
{
socketCount = Interop.libc.select(nfds, readfds, writefds, errorfds, null);
}
GlobalLog.Print("Socket::Select() Interop.libc.select returns socketCount:" + socketCount);
if (socketCount == -1)
{
return SocketError.SocketError; // TODO: should this be SCH.GetLastSocketError()?
}
Socket.FilterSocketListUsingFdSet(ref readSet, checkRead);
Socket.FilterSocketListUsingFdSet(ref writeSet, checkWrite);
Socket.FilterSocketListUsingFdSet(ref errorSet, checkError);
return (SocketError)socketCount;
}
public static unsafe SocketError Poll(SafeCloseSocket handle, int microseconds, SelectMode mode, out bool status)
{
var fdset = new Interop.libc.fd_set();
fdset.Set(handle.FileDescriptor);
// TODO: this should probably be 0 if readfds, writefds, and errorfds are all null
int nfds = handle.FileDescriptor + 1;
Interop.libc.fd_set* readfds = mode == SelectMode.SelectRead ? &fdset : null;
Interop.libc.fd_set* writefds = mode == SelectMode.SelectWrite ? &fdset : null;
Interop.libc.fd_set* errorfds = mode == SelectMode.SelectError ? &fdset : null;
int socketCount = 0;
if (microseconds != -1)
{
var tv = new Interop.libc.timeval(microseconds);
socketCount = Interop.libc.select(nfds, readfds, writefds, errorfds, &tv);
}
else
{
socketCount = Interop.libc.select(nfds, readfds, writefds, errorfds, null);
}
if (socketCount == -1)
{
status = false;
return SocketError.SocketError; // TODO: should this be SCH.GetLastSocketError()?
}
status = fdset.IsSet(handle.FileDescriptor);
return (SocketError)socketCount;
}
