//go:build linux

// SPDX-License-Identifier: AGPL-3.0-only

package deploy

import (
	"errors"
	"os"
	"syscall"
)

type fileLock struct{ file *os.File }

func acquireLock(path string) (*fileLock, error) {
	file, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0o600)
	if err != nil {
		return nil, err
	}
	if err := syscall.Flock(int(file.Fd()), syscall.LOCK_EX|syscall.LOCK_NB); err != nil {
		_ = file.Close()
		return nil, errors.New("deployment lock is held")
	}
	return &fileLock{file: file}, nil
}
func (l *fileLock) Close() error {
	if l == nil || l.file == nil {
		return nil
	}
	_ = syscall.Flock(int(l.file.Fd()), syscall.LOCK_UN)
	return l.file.Close()
}