func (h *Handlers) download(v *vagrantutil.Vagrant, box, filePath string, queue <-chan chan error) {
h.log().Debug("downloading %q box...", box)
var listeners []chan error
done := make(chan error)
go func() {
err := vagrantutil.Wait(v.BoxAdd(&vagrantutil.Box{Name: box}))
if err == vagrantutil.ErrBoxAlreadyExists {
// Ignore the above error.
err = nil
}
done <- err
}()
for {
select {
case l := <-queue:
listeners = append(listeners, l)
case err := <-done:
// Remove the box from in progress.
h.boxMu.Lock()
delete(h.boxNames, box)
delete(h.boxPaths, filePath)
h.boxMu.Unlock()
// Defensive channel drain: try to collect listeners
// that may have registered after receiving from done
// but before taking boxMu lock.
listeners = append(listeners, drain(queue)...)
// Notify all listeners.
for _, l := range listeners {
l <- err
}
h.log().Debug("downloading %q box finished: err=%v", box, err)
return
}
}
}
