Reimplements the C-based wepoll backend in Rust, using some handwritten code. This PR also implements bindings to the I/O Completion Ports and \Device\Afd APIs. For more information on the latter, see my blog post on the subject: https://notgull.github.io/device-afd/
Note that the IOCP API is wrapped using a `Pin`-oriented "CompletionHandle" system that is relatively brittle. This should be replaced with a better model when one becomes available.
This replaces Poller.insert() and Poller.interest() with Poller.add()
and Poller.modify(), and renames Poller.remove() to Poller.delete().
The method Poller.add() is used for adding a new file descriptor, while
Poller.modify() is used for updating an existing one. Poller.remove() is
renamed to Poller.delete() so the naming scheme of these methods follows
that of epoll, wepoll, etc.
This new setup means that adding a new socket only requires a single
call of Poller.add(), instead of a combination of Poller.insert() and
Poller.interest(). This reduces the amount of system calls necessary,
and leads to a more pleasant API.
On systems that use kqueue or ports, the behaviour of Poller.add() and
Poller.modify() is the same. This is because on these systems adding an
already existing file descriptor will just update its configuration.
This however is an implementation detail and should not be relied upon
by users.
Migrating to this new API is pretty simple, simply replace this:
poller.insert(&socket);
poller.interest(&socket, event);
With this:
poller.add(&socket, event);
And for cases where Poller.interest() was used for updating an existing
file descriptor, simply replace it will a call to Poller.modify().
See https://github.com/stjepang/polling/issues/16 and
https://github.com/stjepang/polling/pull/17 for more information.
This adds redundant system call overhead for file descriptors which have
already been turned into non-blocking file descriptors. In addition, the
polling crate doesn't need to implement platform specific code for
enabling non-blocking mode. Instead, users of polling can do so using
(for example) standard library methods such as
TcpListener.set_nonblocking().
See https://github.com/stjepang/polling/issues/16 for more information.
John Nunley
Taiki Endo
Kestrer
Stjepan Glavina
Yorick Peterse
Mike Zeller
Guillaume Gomez