Add eio support

[williameggers]

https://pecl.php.net/package/eio

The eio package is a reasonably well-established PECL extension commonly used as an alternative to libuv for non-blocking file operations in projects like ReactPHP Filesystem - https://github.com/reactphp/filesystem. It would be great if support could be added for this extension.

[henderkes]

Libeio has no 1.0 release and development is inactive. It says to use libev for now, which saw its last commits 2/5/9 years ago.

Libev is available through the ev extension.

Libevent on the other hand is actively maintained and widely used, available in the event extension.

Libuv is also actively maintained and widely used, available in the uv extension.

Is there any real benefit to adding eio?

[williameggers]

That’s a good question. The main issue is that the ReactPHP async filesystem ecosystem isn’t very mature, and libeio is still actively relied on by the ReactPHP team. While uv can be used, it introduces complications with file-based streams in ReactPHP using the ReactPHP Stream library - for example, you’ll see warnings like uv_poll_init_socket(): invalid resource passed, this plain files are not supported. Because of this, eio seems like the practical fallback if you want to stick with the regular StreamSelectLoop and still get non-blocking filesystem I/O. Otherwise, the filesystem library just falls back to blocking function calls, which is less than ideal.

I’m definitely not an expert here - I’m just learning as I go. If adding this is too much hassle, that’s totally fine - no pressure.

[henderkes]

In that case, I think this would be better handled in the ReactPHP library, rather than by implementing eio here. They list libuv, a much more stable and cross-platform solution over libeio, as a supported backend, so it should optimally be used without warnings.

[williameggers]

Understood. Thank you for considering my request. I'll close this issue.

[henderkes]

Let's keep this open until we get a decision from ReactPHP. If they would rather drop the libuv backend, we can implement eio support.

[williameggers]

Okay, sure thing!