goutil/copy.go

package goutil

/*
Copied from https://github.com/otiai10/copy and slightly altered.

The MIT License (MIT)

Copyright (c) 2019 Alexander Weinhold
Copyright (c) 2018 otiai10

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

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

// Copy copies src to dest, doesn't matter if src is a directory or a file
func Copy(src, dest string) error {
	info, err := os.Lstat(src)
	if err != nil {
		return err
	}
	return copy(src, dest, info)
}

func copy(src, dest string, info os.FileInfo) error {
	if info.Mode()&os.ModeSymlink != 0 {
		return linkcopy(src, dest, info)
	}
	if info.IsDir() {
		return dircopy(src, dest, info)
	}
	return filecopy(src, dest, info)
}

func filecopy(src, dest string, info os.FileInfo) error {
	if err := os.MkdirAll(filepath.Dir(dest), os.ModePerm); err != nil {
		return err
	}
	f, err := os.Create(dest)
	if err != nil {
		return err
	}
	defer f.Close()
	if err = os.Chmod(f.Name(), info.Mode()); err != nil {
		return err
	}
	if err = os.Chtimes(f.Name(), info.ModTime(), info.ModTime()); err != nil {
		return err
	}
	s, err := os.Open(src)
	if err != nil {
		return err
	}
	defer s.Close()
	_, err = io.Copy(f, s)
	return err
}

func dircopy(srcdir, destdir string, info os.FileInfo) error {
	if err := os.MkdirAll(destdir, info.Mode()); err != nil {
		return err
	}
	contents, err := ioutil.ReadDir(srcdir)
	if err != nil {
		return err
	}
	for _, content := range contents {
		cs, cd := filepath.Join(srcdir, content.Name()), filepath.Join(destdir, content.Name())
		if err := copy(cs, cd, content); err != nil {
			return err
		}
	}
	return nil
}

func linkcopy(src, dest string, info os.FileInfo) error {
	src, err := os.Readlink(src)
	if err != nil {
		return err
	}
	return os.Symlink(src, dest)
}