/*
Copyright 2017 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package file

import (
	"os"
)

// FileExists checks if specified file exists.
func FileExists(filename string) (bool, error) {
	if _, err := os.Stat(filename); os.IsNotExist(err) {
		return false, nil
	} else if err != nil {
		return false, err
	}
	return true, nil
}

// FileOrSymlinkExists checks if specified file or symlink exists.
func FileOrSymlinkExists(filename string) (bool, error) {
	if _, err := os.Lstat(filename); os.IsNotExist(err) {
		return false, nil
	} else if err != nil {
		return false, err
	}
	return true, nil
}

// ReadDirNoStat returns a string of files/directories contained
// in dirname without calling lstat on them.
func ReadDirNoStat(dirname string) ([]string, error) {
	if dirname == "" {
		dirname = "."
	}

	f, err := os.Open(dirname)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	return f.Readdirnames(-1)
}