proposal: time: add cancellable func SleepC(context.Context, Duration)

[sbalabanov]

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What did you do?

This is a feature request. time.Sleep() is a blocking call and cannot be cancelled. Add a helper to support context cancellation to help build more responsive tools.

What did you see happen?

N/A

What did you expect to see?

New function:

package time

func SleepC(ctx context.Context, d time.Duration) error {
    select {
    case <-ctx.Done():
        return ctx.Err()
    case <-time.After(d):
        return nil
    }
}

[gabyhelp]

Related Issues

• proposal: context: add Sleep #39483 (closed)
• proposal: context: Sleep(ctx, dur) #73295 (closed)
• proposal: Add time.AfterContext #40736 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[adonovan]

Today, one must write

    select {
    case <-ctx.Done():
        ... handle ctx.Err() ...
        return
    case <-time.After(d):
    }

With your proposed library function, one could write:

if err := time.SleepC(ctx, d); err != nil {
     ... handle err ...
    return
}

This is certainly more convenient, but it's not obvious that the saving justifies adding a new function--one you can easily write yourself--to the library; see https://golang.org/doc/faq#x_in_std.