/
copy.go
131 lines (116 loc) · 2.99 KB
/
copy.go
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// Copyright 2019 CUE 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 copy provides utilities to copy files and directories.
package copy
import (
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
)
// File creates dst and copies the contents src to it.
func File(src, dst string) error {
src = filepath.Clean(src)
dst = filepath.Clean(dst)
stat, err := os.Stat(src)
if err != nil {
return fmt.Errorf("copy file: %v", err)
}
err = copyFile(stat, src, dst)
if err != nil {
return fmt.Errorf("copy file: %v", err)
}
return nil
}
// Dir copies a src directory to its destination.
func Dir(src, dst string) error {
src = filepath.Clean(src)
dst = filepath.Clean(dst)
stat, err := os.Stat(src)
if err != nil {
return fmt.Errorf("copy failed: %v", err)
} else if !stat.IsDir() {
return fmt.Errorf("copy failed: source is not a directory")
}
err = copyDir(stat, src, dst)
if err != nil {
return fmt.Errorf("copy failed: %v", err)
}
return nil
}
func copyDir(info os.FileInfo, src, dst string) error {
if _, err := os.Stat(dst); err != nil {
if !os.IsNotExist(err) {
return fmt.Errorf("dest err %s: %v", dst, err)
}
if err := os.MkdirAll(dst, info.Mode()); err != nil {
return fmt.Errorf("making dest %s: %v", dst, err)
}
}
entries, err := ioutil.ReadDir(src)
if err != nil {
return fmt.Errorf("reading dir %s: %v", src, err)
}
for _, e := range entries {
srcPath := filepath.Join(src, e.Name())
dstPath := filepath.Join(dst, e.Name())
switch mode := e.Mode(); mode & os.ModeType {
case os.ModeSymlink:
err = copySymLink(e, srcPath, dstPath)
case os.ModeDir:
err = copyDir(e, srcPath, dstPath)
default:
err = copyFile(e, srcPath, dstPath)
}
if err != nil {
return err
}
}
return nil
}
func copySymLink(info os.FileInfo, src, dst string) error {
mode := info.Mode()
link, err := os.Readlink(src)
if err != nil {
return err
}
err = os.Symlink(link, dst)
if err != nil {
return err
}
return os.Chmod(dst, mode)
}
func copyFile(info os.FileInfo, src, dst string) (err error) {
in, err := os.Open(src)
if err != nil {
return fmt.Errorf("error reading %s: %v", src, err)
}
defer in.Close()
out, err := os.OpenFile(dst, os.O_RDWR|os.O_CREATE|os.O_TRUNC, info.Mode())
if err != nil {
return fmt.Errorf("error creating %s: %v", dst, err)
}
defer func() {
cErr := out.Close()
if err == nil {
err = cErr
}
}()
_, err = io.Copy(out, in)
if err != nil {
return fmt.Errorf("error copying %s: %v", dst, err)
}
return err
}