--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/github.com/spf13/afero/copyOnWriteFs.go Sat Sep 29 18:09:54 2018 +0200
@@ -0,0 +1,292 @@
+package afero
+
+import (
+ "fmt"
+ "os"
+ "path/filepath"
+ "syscall"
+ "time"
+)
+
+var _ Lstater = (*CopyOnWriteFs)(nil)
+
+// The CopyOnWriteFs is a union filesystem: a read only base file system with
+// a possibly writeable layer on top. Changes to the file system will only
+// be made in the overlay: Changing an existing file in the base layer which
+// is not present in the overlay will copy the file to the overlay ("changing"
+// includes also calls to e.g. Chtimes() and Chmod()).
+//
+// Reading directories is currently only supported via Open(), not OpenFile().
+type CopyOnWriteFs struct {
+ base Fs
+ layer Fs
+}
+
+func NewCopyOnWriteFs(base Fs, layer Fs) Fs {
+ return &CopyOnWriteFs{base: base, layer: layer}
+}
+
+// Returns true if the file is not in the overlay
+func (u *CopyOnWriteFs) isBaseFile(name string) (bool, error) {
+ if _, err := u.layer.Stat(name); err == nil {
+ return false, nil
+ }
+ _, err := u.base.Stat(name)
+ if err != nil {
+ if oerr, ok := err.(*os.PathError); ok {
+ if oerr.Err == os.ErrNotExist || oerr.Err == syscall.ENOENT || oerr.Err == syscall.ENOTDIR {
+ return false, nil
+ }
+ }
+ if err == syscall.ENOENT {
+ return false, nil
+ }
+ }
+ return true, err
+}
+
+func (u *CopyOnWriteFs) copyToLayer(name string) error {
+ return copyToLayer(u.base, u.layer, name)
+}
+
+func (u *CopyOnWriteFs) Chtimes(name string, atime, mtime time.Time) error {
+ b, err := u.isBaseFile(name)
+ if err != nil {
+ return err
+ }
+ if b {
+ if err := u.copyToLayer(name); err != nil {
+ return err
+ }
+ }
+ return u.layer.Chtimes(name, atime, mtime)
+}
+
+func (u *CopyOnWriteFs) Chmod(name string, mode os.FileMode) error {
+ b, err := u.isBaseFile(name)
+ if err != nil {
+ return err
+ }
+ if b {
+ if err := u.copyToLayer(name); err != nil {
+ return err
+ }
+ }
+ return u.layer.Chmod(name, mode)
+}
+
+func (u *CopyOnWriteFs) Stat(name string) (os.FileInfo, error) {
+ fi, err := u.layer.Stat(name)
+ if err != nil {
+ isNotExist := u.isNotExist(err)
+ if isNotExist {
+ return u.base.Stat(name)
+ }
+ return nil, err
+ }
+ return fi, nil
+}
+
+func (u *CopyOnWriteFs) LstatIfPossible(name string) (os.FileInfo, bool, error) {
+ llayer, ok1 := u.layer.(Lstater)
+ lbase, ok2 := u.base.(Lstater)
+
+ if ok1 {
+ fi, b, err := llayer.LstatIfPossible(name)
+ if err == nil {
+ return fi, b, nil
+ }
+
+ if !u.isNotExist(err) {
+ return nil, b, err
+ }
+ }
+
+ if ok2 {
+ fi, b, err := lbase.LstatIfPossible(name)
+ if err == nil {
+ return fi, b, nil
+ }
+ if !u.isNotExist(err) {
+ return nil, b, err
+ }
+ }
+
+ fi, err := u.Stat(name)
+
+ return fi, false, err
+}
+
+func (u *CopyOnWriteFs) isNotExist(err error) bool {
+ if e, ok := err.(*os.PathError); ok {
+ err = e.Err
+ }
+ if err == os.ErrNotExist || err == syscall.ENOENT || err == syscall.ENOTDIR {
+ return true
+ }
+ return false
+}
+
+// Renaming files present only in the base layer is not permitted
+func (u *CopyOnWriteFs) Rename(oldname, newname string) error {
+ b, err := u.isBaseFile(oldname)
+ if err != nil {
+ return err
+ }
+ if b {
+ return syscall.EPERM
+ }
+ return u.layer.Rename(oldname, newname)
+}
+
+// Removing files present only in the base layer is not permitted. If
+// a file is present in the base layer and the overlay, only the overlay
+// will be removed.
+func (u *CopyOnWriteFs) Remove(name string) error {
+ err := u.layer.Remove(name)
+ switch err {
+ case syscall.ENOENT:
+ _, err = u.base.Stat(name)
+ if err == nil {
+ return syscall.EPERM
+ }
+ return syscall.ENOENT
+ default:
+ return err
+ }
+}
+
+func (u *CopyOnWriteFs) RemoveAll(name string) error {
+ err := u.layer.RemoveAll(name)
+ switch err {
+ case syscall.ENOENT:
+ _, err = u.base.Stat(name)
+ if err == nil {
+ return syscall.EPERM
+ }
+ return syscall.ENOENT
+ default:
+ return err
+ }
+}
+
+func (u *CopyOnWriteFs) OpenFile(name string, flag int, perm os.FileMode) (File, error) {
+ b, err := u.isBaseFile(name)
+ if err != nil {
+ return nil, err
+ }
+
+ if flag&(os.O_WRONLY|os.O_RDWR|os.O_APPEND|os.O_CREATE|os.O_TRUNC) != 0 {
+ if b {
+ if err = u.copyToLayer(name); err != nil {
+ return nil, err
+ }
+ return u.layer.OpenFile(name, flag, perm)
+ }
+
+ dir := filepath.Dir(name)
+ isaDir, err := IsDir(u.base, dir)
+ if err != nil && !os.IsNotExist(err) {
+ return nil, err
+ }
+ if isaDir {
+ if err = u.layer.MkdirAll(dir, 0777); err != nil {
+ return nil, err
+ }
+ return u.layer.OpenFile(name, flag, perm)
+ }
+
+ isaDir, err = IsDir(u.layer, dir)
+ if err != nil {
+ return nil, err
+ }
+ if isaDir {
+ return u.layer.OpenFile(name, flag, perm)
+ }
+
+ return nil, &os.PathError{Op: "open", Path: name, Err: syscall.ENOTDIR} // ...or os.ErrNotExist?
+ }
+ if b {
+ return u.base.OpenFile(name, flag, perm)
+ }
+ return u.layer.OpenFile(name, flag, perm)
+}
+
+// This function handles the 9 different possibilities caused
+// by the union which are the intersection of the following...
+// layer: doesn't exist, exists as a file, and exists as a directory
+// base: doesn't exist, exists as a file, and exists as a directory
+func (u *CopyOnWriteFs) Open(name string) (File, error) {
+ // Since the overlay overrides the base we check that first
+ b, err := u.isBaseFile(name)
+ if err != nil {
+ return nil, err
+ }
+
+ // If overlay doesn't exist, return the base (base state irrelevant)
+ if b {
+ return u.base.Open(name)
+ }
+
+ // If overlay is a file, return it (base state irrelevant)
+ dir, err := IsDir(u.layer, name)
+ if err != nil {
+ return nil, err
+ }
+ if !dir {
+ return u.layer.Open(name)
+ }
+
+ // Overlay is a directory, base state now matters.
+ // Base state has 3 states to check but 2 outcomes:
+ // A. It's a file or non-readable in the base (return just the overlay)
+ // B. It's an accessible directory in the base (return a UnionFile)
+
+ // If base is file or nonreadable, return overlay
+ dir, err = IsDir(u.base, name)
+ if !dir || err != nil {
+ return u.layer.Open(name)
+ }
+
+ // Both base & layer are directories
+ // Return union file (if opens are without error)
+ bfile, bErr := u.base.Open(name)
+ lfile, lErr := u.layer.Open(name)
+
+ // If either have errors at this point something is very wrong. Return nil and the errors
+ if bErr != nil || lErr != nil {
+ return nil, fmt.Errorf("BaseErr: %v\nOverlayErr: %v", bErr, lErr)
+ }
+
+ return &UnionFile{Base: bfile, Layer: lfile}, nil
+}
+
+func (u *CopyOnWriteFs) Mkdir(name string, perm os.FileMode) error {
+ dir, err := IsDir(u.base, name)
+ if err != nil {
+ return u.layer.MkdirAll(name, perm)
+ }
+ if dir {
+ return syscall.EEXIST
+ }
+ return u.layer.MkdirAll(name, perm)
+}
+
+func (u *CopyOnWriteFs) Name() string {
+ return "CopyOnWriteFs"
+}
+
+func (u *CopyOnWriteFs) MkdirAll(name string, perm os.FileMode) error {
+ dir, err := IsDir(u.base, name)
+ if err != nil {
+ return u.layer.MkdirAll(name, perm)
+ }
+ if dir {
+ return syscall.EEXIST
+ }
+ return u.layer.MkdirAll(name, perm)
+}
+
+func (u *CopyOnWriteFs) Create(name string) (File, error) {
+ return u.OpenFile(name, os.O_CREATE|os.O_TRUNC|os.O_RDWR, 0666)
+}