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|
package cp
import (
"errors"
"fmt"
"io"
"io/fs"
"os"
"path/filepath"
)
type Progress interface {
Max(int64)
Progress(int64)
FileStart(string)
FileDone(string, error)
}
func size(files []string) int64 {
var n int64 = 0
for _, f := range files {
filepath.WalkDir(f, func(path string, d fs.DirEntry, err error) error {
if err != nil {
return nil
}
switch d.Type() {
case 0: // regular file
stat, err := d.Info()
if err != nil {
return nil
}
n += 1 + stat.Size()
case os.ModeSymlink, os.ModeDir:
n++
}
return nil
})
}
return n
}
func fileExists(path string) bool {
_, err := os.Lstat(path)
return !errors.Is(err, os.ErrNotExist)
}
func copyRegularFile(src, dst string, force bool, progress Progress) (err error) {
progress.FileStart(src)
in, err := os.Open(src)
if err != nil {
return err
}
defer in.Close()
stat, err := in.Stat()
if err != nil {
return err
}
out, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, stat.Mode().Perm())
if err != nil {
if !force || !fileExists(dst) {
return err
}
if err := os.RemoveAll(dst); err != nil {
return err
}
out, err = os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, stat.Mode().Perm())
if err != nil {
return err
}
}
defer out.Close()
for {
n, err := io.CopyN(out, in, 1024*1024)
if n > 0 {
progress.Progress(n)
}
if err != nil {
if err == io.EOF {
break
}
return err
}
}
if err := out.Close(); err != nil {
return err
}
progress.Progress(1)
return nil
}
func copySpecialFile(src string, d fs.DirEntry, dst string, force bool, progress Progress) error {
switch d.Type() {
case fs.ModeSymlink:
target, err := os.Readlink(src)
if err != nil {
return err
}
if err := os.Symlink(target, dst); err != nil {
if !force || !fileExists(dst) {
return err
}
if err := os.RemoveAll(dst); err != nil {
return err
}
if err := os.Symlink(target, dst); err != nil {
return err
}
}
progress.Progress(1)
case fs.ModeDir:
stat, err := d.Info()
if err != nil {
return err
}
if err := os.Mkdir(dst, stat.Mode().Perm()); err != nil {
if !force || !fileExists(dst) {
return err
}
if err := os.RemoveAll(dst); err != nil {
return err
}
if err := os.Mkdir(dst, stat.Mode().Perm()); err != nil {
return err
}
}
progress.Progress(1)
default:
return fmt.Errorf("%s: unknown file type %s", src, d.Type())
}
return nil
}
func Copy(srcs []string, dstRoot string, force bool, progress Progress) {
go func() {
progress.Max(size(srcs))
}()
const maxConcurrency = 10
// sem acts as a semaphore to limit the number of concurrent file copies
sem := make(chan struct{}, maxConcurrency)
for _, srcRoot := range srcs {
filepath.WalkDir(srcRoot, func(src string, d fs.DirEntry, err error) error {
if err != nil {
progress.FileDone(src, err)
return nil
}
relPath, err := filepath.Rel(srcRoot, src)
if err != nil {
progress.FileDone(src, err)
return nil
}
dst := filepath.Join(dstRoot, relPath)
if d.Type().IsRegular() {
sem <- struct{}{}
go func() {
defer func() { <-sem }()
err := copyRegularFile(src, dst, force, progress)
progress.FileDone(src, err)
}()
} else {
if err := copySpecialFile(src, d, dst, force, progress); err != nil {
progress.FileDone(src, err)
return nil
}
}
return nil
})
}
for range maxConcurrency {
sem <- struct{}{}
}
}
|
