package polyfill import ( "os" "path/filepath" "gopkg.in/src-d/go-billy.v4" ) // Polyfill is a helper that implements all missing method from billy.Filesystem. type Polyfill struct { billy.Basic c capabilities } type capabilities struct{ tempfile, dir, symlink, chroot bool } // New creates a new filesystem wrapping up 'fs' the intercepts all the calls // made and errors if fs doesn't implement any of the billy interfaces. func New(fs billy.Basic) billy.Filesystem { if original, ok := fs.(billy.Filesystem); ok { return original } h := &Polyfill{Basic: fs} _, h.c.tempfile = h.Basic.(billy.TempFile) _, h.c.dir = h.Basic.(billy.Dir) _, h.c.symlink = h.Basic.(billy.Symlink) _, h.c.chroot = h.Basic.(billy.Chroot) return h } func (h *Polyfill) TempFile(dir, prefix string) (billy.File, error) { if !h.c.tempfile { return nil, billy.ErrNotSupported } return h.Basic.(billy.TempFile).TempFile(dir, prefix) } func (h *Polyfill) ReadDir(path string) ([]os.FileInfo, error) { if !h.c.dir { return nil, billy.ErrNotSupported } return h.Basic.(billy.Dir).ReadDir(path) } func (h *Polyfill) MkdirAll(filename string, perm os.FileMode) error { if !h.c.dir { return billy.ErrNotSupported } return h.Basic.(billy.Dir).MkdirAll(filename, perm) } func (h *Polyfill) Symlink(target, link string) error { if !h.c.symlink { return billy.ErrNotSupported } return h.Basic.(billy.Symlink).Symlink(target, link) } func (h *Polyfill) Readlink(link string) (string, error) { if !h.c.symlink { return "", billy.ErrNotSupported } return h.Basic.(billy.Symlink).Readlink(link) } func (h *Polyfill) Lstat(path string) (os.FileInfo, error) { if !h.c.symlink { return nil, billy.ErrNotSupported } return h.Basic.(billy.Symlink).Lstat(path) } func (h *Polyfill) Chroot(path string) (billy.Filesystem, error) { if !h.c.chroot { return nil, billy.ErrNotSupported } return h.Basic.(billy.Chroot).Chroot(path) } func (h *Polyfill) Root() string { if !h.c.chroot { return string(filepath.Separator) } return h.Basic.(billy.Chroot).Root() } func (h *Polyfill) Underlying() billy.Basic { return h.Basic } // Capabilities implements the Capable interface. func (h *Polyfill) Capabilities() billy.Capability { return billy.Capabilities(h.Basic) }