/*
   Copyright 2014 CoreOS, Inc.

   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 fileutil

import (
	"io/ioutil"
	"os"
	"path"
)

const (
	privateFileMode = 0600
)

// IsDirWriteable checks if dir is writable by writing and removing a file
// to dir. It returns nil if dir is writable.
func IsDirWriteable(dir string) error {
	f := path.Join(dir, ".touch")
	if err := ioutil.WriteFile(f, []byte(""), privateFileMode); err != nil {
		return err
	}
	return os.Remove(f)
}

// ReadDir returns the filenames in the given directory.
func ReadDir(dirpath string) ([]string, error) {
	dir, err := os.Open(dirpath)
	if err != nil {
		return nil, err
	}
	defer dir.Close()
	names, err := dir.Readdirnames(-1)
	if err != nil {
		return nil, err
	}
	return names, nil
}