Proposal: simplified Select(..) method

[cmaglie]

I'm using this library in my serial library project here an extract:

r := &goselect.FDSet{}
r.Set(uintptr(port.handle))
r.Set(uintptr(port.closeSignal.ReadFD()))
e := &goselect.FDSet{}
e.Set(uintptr(port.handle))
e.Set(uintptr(port.closeSignal.ReadFD()))

max := port.closeSignal.ReadFD()
if port.handle > max {
    max = port.handle
}
if err = goselect.Select(max+1, r, nil, e, -1); err != nil {
    return 0, err
}

I'm wondering if it's possible to make a Select method that reduce the boilerplate code and handles all the boring stuff automatically (for example the very annoting max+1 bit).

A proposal for a possible API, to simplify the above use case, may be the following:

// NewSet creates an array that holds all the file descriptors
// and automatically converts them from int to uintptr if needed
fds := goselect.NewSet(port.handle, port.closeSignal.ReadFD())

// The same set can be used for read, write and error
// (max+1) is determined internally
res, err := goselect.Select(fds, nil, fds)
if err != nil {
    return err
}

// The result contains all the three result sets (read, write, errors) and each one
// can be queried
if res.IsReadable(port.handle) {
    ...do something...
}

Is this a proposal that can be considered?

Thanks!

[creack]

I think we should keep the Select itself as close as the syscall as possible, but a helper doing what you suggest would be welcome.

I might also consider renaming Select into SysSelect or something like that and use Select for the simplified version.

[cmaglie]

Ok, I'll give it a try and make a PR (unless you want to work on it :wink:)

[creack]

I'd love to work on it, but time is scarce ^^ so be my guest! :)

[walles]

Also, the timeout could be a *time.Duration with nil meaning "no timeout".

Negative durations should result in errors.