cheat/vendor/github.com/go-git/go-billy/v5/helper/polyfill/polyfill.go
Christopher Allen Lane 80c91cbdee feat(installer): use go-git to clone
Integrate `go-git` into the application, and use it to `git clone`
cheatsheets when the installer runs.

Previously, the installer required that `git` be installed on the system
`PATH`, so this change has to big advantages:

1. It removes that system dependency on `git`
2. It paves the way for implementing the `--update` command

Additionally, `cheat` now performs a `--depth=1` clone when installing
cheatsheets, which should at least somewhat improve installation times
(especially on slow network connections).
2022-08-27 21:00:46 -04:00

106 lines
2.2 KiB
Go

package polyfill
import (
"os"
"path/filepath"
"github.com/go-git/go-billy/v5"
)
// 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)
}