1package polyfill
  2
  3import (
  4	"os"
  5	"path/filepath"
  6
  7	"github.com/go-git/go-billy/v5"
  8)
  9
 10// Polyfill is a helper that implements all missing method from billy.Filesystem.
 11type Polyfill struct {
 12	billy.Basic
 13	c capabilities
 14}
 15
 16type capabilities struct{ tempfile, dir, symlink, chroot bool }
 17
 18// New creates a new filesystem wrapping up 'fs' the intercepts all the calls
 19// made and errors if fs doesn't implement any of the billy interfaces.
 20func New(fs billy.Basic) billy.Filesystem {
 21	if original, ok := fs.(billy.Filesystem); ok {
 22		return original
 23	}
 24
 25	h := &Polyfill{Basic: fs}
 26
 27	_, h.c.tempfile = h.Basic.(billy.TempFile)
 28	_, h.c.dir = h.Basic.(billy.Dir)
 29	_, h.c.symlink = h.Basic.(billy.Symlink)
 30	_, h.c.chroot = h.Basic.(billy.Chroot)
 31	return h
 32}
 33
 34func (h *Polyfill) TempFile(dir, prefix string) (billy.File, error) {
 35	if !h.c.tempfile {
 36		return nil, billy.ErrNotSupported
 37	}
 38
 39	return h.Basic.(billy.TempFile).TempFile(dir, prefix)
 40}
 41
 42func (h *Polyfill) ReadDir(path string) ([]os.FileInfo, error) {
 43	if !h.c.dir {
 44		return nil, billy.ErrNotSupported
 45	}
 46
 47	return h.Basic.(billy.Dir).ReadDir(path)
 48}
 49
 50func (h *Polyfill) MkdirAll(filename string, perm os.FileMode) error {
 51	if !h.c.dir {
 52		return billy.ErrNotSupported
 53	}
 54
 55	return h.Basic.(billy.Dir).MkdirAll(filename, perm)
 56}
 57
 58func (h *Polyfill) Symlink(target, link string) error {
 59	if !h.c.symlink {
 60		return billy.ErrNotSupported
 61	}
 62
 63	return h.Basic.(billy.Symlink).Symlink(target, link)
 64}
 65
 66func (h *Polyfill) Readlink(link string) (string, error) {
 67	if !h.c.symlink {
 68		return "", billy.ErrNotSupported
 69	}
 70
 71	return h.Basic.(billy.Symlink).Readlink(link)
 72}
 73
 74func (h *Polyfill) Lstat(path string) (os.FileInfo, error) {
 75	if !h.c.symlink {
 76		return nil, billy.ErrNotSupported
 77	}
 78
 79	return h.Basic.(billy.Symlink).Lstat(path)
 80}
 81
 82func (h *Polyfill) Chroot(path string) (billy.Filesystem, error) {
 83	if !h.c.chroot {
 84		return nil, billy.ErrNotSupported
 85	}
 86
 87	return h.Basic.(billy.Chroot).Chroot(path)
 88}
 89
 90func (h *Polyfill) Root() string {
 91	if !h.c.chroot {
 92		return string(filepath.Separator)
 93	}
 94
 95	return h.Basic.(billy.Chroot).Root()
 96}
 97
 98func (h *Polyfill) Underlying() billy.Basic {
 99	return h.Basic
100}
101
102// Capabilities implements the Capable interface.
103func (h *Polyfill) Capabilities() billy.Capability {
104	return billy.Capabilities(h.Basic)
105}