Function copyOneFile

sync/copy.go:95–161

(src fs.FS, dst filesystem.FileSystem, p string, info fs.FileInfo)

}

func copyOneFile(src fs.FS, dst filesystem.FileSystem, p string, info fs.FileInfo) error {
	in, err := src.Open(p)
	if err != nil {
		return err
	}
	defer func() { _ = in.Close() }()

	out, err := dst.OpenFile(p, os.O_CREATE|os.O_TRUNC|os.O_RDWR)
	if err != nil {
		return err
	}
	defer func() { _ = out.Close() }()

	if info.Size() <= maxCopyAllSize {
		data, err := io.ReadAll(in)
		if err != nil {
			return err
		}
		n, err := out.Write(data)
		if err != nil {
			return err
		}
		if n != len(data) {
			return io.ErrShortWrite
		}
	} else {
		buf := make([]byte, 32*1024)
		for {
			n, rerr := in.Read(buf)
			if n > 0 {
				written := 0
				for written < n {
					w, werr := out.Write(buf[written:n])
					if werr != nil {
						return werr
					}
					if w == 0 {
						return io.ErrShortWrite
					}
					written += w
				}
			}
			if rerr == io.EOF {
				break
			}
			if rerr != nil {
				return rerr
			}
		}
	}

	// Restore timestamps *after* data is written (tar semantics)
	atime := getAccessTime(info)
	if atime.IsZero() {
		atime = info.ModTime() // fallback
	}
	if err := dst.Chtimes(
		p,