Should be able to poll on a &TcpListener

[jethrogb]

Version

0.1.x

Subcrates

tokio-tcp

Description

Accepting a connection in std doesn't require mutable access to the TcpListener, so polling for the same should also not require it. However, there is currently no way to poll a &TcpListener.

TcpStream does support this through impl AsyncRead|AsyncWrite for &'_ TcpStream (although this was recently removed in master)

[carllerche]

Can you describe why you want this? In general, TcpStream supports Sync but TcpStream does not support concurrent polling of poll_read. This is why &mut self is used.

[jethrogb]

TcpStream does not support concurrent polling of poll_read

As mentioned this is supported through impl AsyncRead|AsyncWrite for &'_ TcpStream

[carllerche]

@jethrogb one task can call poll_ready concurrently to another calling poll_write, but two tasks cannot concurrently call poll_read. This is due to only one one task being notified.

Could you describe the use case? There could be a better way to model what you are trying to do.

[Darksonn]

This is not a feature we want for now. Split the TcpStream instead.

[jethrogb]

@Darksonn not sure what you're talking about? This issue is about TcpListener, not TcpStream.

[Darksonn]

Oh sorry, I misread the issue title.

[Darksonn]

Still, I don't think this is possible with how mio works. When you poll something, only the last used Waker is notified of updates, so if you poll it from many places, only one of them will actually work.

[jethrogb]

That seems fine, the woken up place will accept a connection and other place will get woken up next time?

[Darksonn]

No, if you poll it from two places, one of them will keep getting all of the connections and the other is never woken up again. This is because only the last waker is woken.

[carllerche]

This is covered by #2779 and will be supported once that lands.