fs: add into_std implementation for File

[afinch7]

This should be a fairly simple one. Just reintroducing a function that got left behind at some point.

[carllerche]

Ah... yeah, this can panic if there is an in-flight job working with the file. I'm not sure what to do about this.

[taiki-e]

I'm not sure if it would be an alternative for a method, but I was thinking about adding a TryFrom implementation like this:

use std::convert::TryFrom;

impl TryFrom<File> for sys::File {
    type Error = File;

    fn try_from(f: File) -> Result<Self, Self::Error> {
        let File {
            std,
            state,
            last_write_err,
        } = f;
        Arc::try_unwrap(std).map_err(|std| File {
            std,
            state,
            last_write_err,
        })
    }
}

[carllerche]

We could do that, but the caller has no way to know if the file is at a point where it can succeed.

We could make it an async fn...

[afinch7]

I didn't really want to make this async, but we could just 'try_clone' the std file and return that.

let std = self.std.clone();
asyncify(move || std.try_clone())

[carllerche]

I think a TryFrom might work...

[carllerche]

Thanks for the work. I'm sorry it didn't pan out. I'm going to close this as it is not possible to add IntoRaw* implementations. I did add AsRaw* implementations here: #1827