package cliutil

import (

"io"

"sync"

)

type discardAfterClose struct {

sync.Mutex

wc io.WriteCloser

closed bool

}

// DiscardAfterClose is an io.WriteCloser that discards writes after it is closed without errors.

// It is useful as a target for a slog.Sink such that an underlying WriteCloser, like a file, can

// be cleaned up without race conditions from still-active loggers.

func DiscardAfterClose(wc io.WriteCloser) io.WriteCloser {

return &discardAfterClose{wc: wc}

}

func (d *discardAfterClose) Write(p []byte) (n int, err error) {

d.Lock()

defer d.Unlock()

if d.closed {

return len(p), nil

}

return d.wc.Write(p)

}

func (d *discardAfterClose) Close() error {

d.Lock()

defer d.Unlock()

if d.closed {

return nil

}

d.closed = true

return d.wc.Close()

}