//go:build windows

package client

import (
	"errors"
	"syscall"
)

// lockPath opens the file with no sharing at all, which Windows enforces
// until the handle closes.
func lockPath(path string) (func(), error) {
	p, err := syscall.UTF16PtrFromString(path)
	if err != nil {
		return nil, err
	}
	h, err := syscall.CreateFile(p, syscall.GENERIC_READ|syscall.GENERIC_WRITE,
		0, nil, syscall.OPEN_ALWAYS, syscall.FILE_ATTRIBUTE_HIDDEN, 0)
	if err != nil {
		if errors.Is(err, errSharingViolation) {
			return nil, ErrMirrorBusy
		}
		return nil, err
	}
	return func() { syscall.CloseHandle(h) }, nil
}

// errSharingViolation is ERROR_SHARING_VIOLATION, which package syscall
// does not name.
const errSharingViolation = syscall.Errno(32)