DockerCLI/vendor/github.com/containerd/continuity/fs/copy.go

122 lines
3.1 KiB
Go

package fs
import (
"io/ioutil"
"os"
"path/filepath"
"sync"
"github.com/pkg/errors"
)
var bufferPool = &sync.Pool{
New: func() interface{} {
buffer := make([]byte, 32*1024)
return &buffer
},
}
// CopyDir copies the directory from src to dst.
// Most efficient copy of files is attempted.
func CopyDir(dst, src string) error {
inodes := map[uint64]string{}
return copyDirectory(dst, src, inodes)
}
func copyDirectory(dst, src string, inodes map[uint64]string) error {
stat, err := os.Stat(src)
if err != nil {
return errors.Wrapf(err, "failed to stat %s", src)
}
if !stat.IsDir() {
return errors.Errorf("source is not directory")
}
if st, err := os.Stat(dst); err != nil {
if err := os.Mkdir(dst, stat.Mode()); err != nil {
return errors.Wrapf(err, "failed to mkdir %s", dst)
}
} else if !st.IsDir() {
return errors.Errorf("cannot copy to non-directory: %s", dst)
} else {
if err := os.Chmod(dst, stat.Mode()); err != nil {
return errors.Wrapf(err, "failed to chmod on %s", dst)
}
}
fis, err := ioutil.ReadDir(src)
if err != nil {
return errors.Wrapf(err, "failed to read %s", src)
}
if err := copyFileInfo(stat, dst); err != nil {
return errors.Wrapf(err, "failed to copy file info for %s", dst)
}
for _, fi := range fis {
source := filepath.Join(src, fi.Name())
target := filepath.Join(dst, fi.Name())
switch {
case fi.IsDir():
if err := copyDirectory(target, source, inodes); err != nil {
return err
}
continue
case (fi.Mode() & os.ModeType) == 0:
link, err := getLinkSource(target, fi, inodes)
if err != nil {
return errors.Wrap(err, "failed to get hardlink")
}
if link != "" {
if err := os.Link(link, target); err != nil {
return errors.Wrap(err, "failed to create hard link")
}
} else if err := CopyFile(target, source); err != nil {
return errors.Wrap(err, "failed to copy files")
}
case (fi.Mode() & os.ModeSymlink) == os.ModeSymlink:
link, err := os.Readlink(source)
if err != nil {
return errors.Wrapf(err, "failed to read link: %s", source)
}
if err := os.Symlink(link, target); err != nil {
return errors.Wrapf(err, "failed to create symlink: %s", target)
}
case (fi.Mode() & os.ModeDevice) == os.ModeDevice:
if err := copyDevice(target, fi); err != nil {
return errors.Wrapf(err, "failed to create device")
}
default:
// TODO: Support pipes and sockets
return errors.Wrapf(err, "unsupported mode %s", fi.Mode())
}
if err := copyFileInfo(fi, target); err != nil {
return errors.Wrap(err, "failed to copy file info")
}
if err := copyXAttrs(target, source); err != nil {
return errors.Wrap(err, "failed to copy xattrs")
}
}
return nil
}
// CopyFile copies the source file to the target.
// The most efficient means of copying is used for the platform.
func CopyFile(target, source string) error {
src, err := os.Open(source)
if err != nil {
return errors.Wrapf(err, "failed to open source %s", source)
}
defer src.Close()
tgt, err := os.Create(target)
if err != nil {
return errors.Wrapf(err, "failed to open target %s", target)
}
defer tgt.Close()
return copyFileContent(tgt, src)
}