systools.go

package codesnippets

//SysTools (Create Dir, Copy File, Copy Dir)

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

// CreateDir checks for directory and creates one if it does not
func CreateDir(dir string) error {
	if _, err := os.Stat(dir); os.IsNotExist(err) {
		if err := os.MkdirAll(dir, os.ModePerm); err != nil {
			return err
		}
	}
	return nil
}

// CopyDir recursively copies a directory tree
func CopyDir(src string, dst string) error {
	src = filepath.Clean(src)
	dst = filepath.Clean(dst)

	si, err := os.Stat(src)
	if err != nil {
		return err
	}
	if !si.IsDir() {
		return fmt.Errorf("source is not a directory")
	}

	_, err = os.Stat(dst)
	if err != nil && !os.IsNotExist(err) {
		return err
	}
	if err == nil {
		return fmt.Errorf("destination already exists")
	}

	err = os.MkdirAll(dst, si.Mode())
	if err != nil {
		return err
	}

	entries, err := ioutil.ReadDir(src)
	if err != nil {
		return err
	}

	for _, entry := range entries {
		srcPath := filepath.Join(src, entry.Name())
		dstPath := filepath.Join(dst, entry.Name())

		if entry.IsDir() {
			err = CopyDir(srcPath, dstPath)
			if err != nil {
				return err
			}
		} else {
			// Skip symlinks.
			if entry.Mode()&os.ModeSymlink != 0 {
				continue
			}

			err = CopyFile(srcPath, dstPath)
			if err != nil {
				return err
			}
		}
	}

	return err
}

// CopyFile copies the contents of the file named src to the file named by dst.
func CopyFile(src, dst string) error {
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()

	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer func() {
		if e := out.Close(); e != nil {
			err = e
		}
	}()

	_, err = io.Copy(out, in)
	if err != nil {
		return err
	}

	err = out.Sync()
	if err != nil {
		return err
	}

	si, err := os.Stat(src)
	if err != nil {
		return err
	}
	err = os.Chmod(dst, si.Mode())
	if err != nil {
		return err
	}

	return err
}