From 921818bca208f0c70e85ec670074cb3905cbbc82 Mon Sep 17 00:00:00 2001 From: Niall Sheridan Date: Sat, 27 Aug 2016 01:32:30 +0100 Subject: Update dependencies --- vendor/github.com/spf13/afero/copyOnWriteFs.go | 253 +++++++++++++++++++++++++ 1 file changed, 253 insertions(+) create mode 100644 vendor/github.com/spf13/afero/copyOnWriteFs.go (limited to 'vendor/github.com/spf13/afero/copyOnWriteFs.go') diff --git a/vendor/github.com/spf13/afero/copyOnWriteFs.go b/vendor/github.com/spf13/afero/copyOnWriteFs.go new file mode 100644 index 0000000..ed692ae --- /dev/null +++ b/vendor/github.com/spf13/afero/copyOnWriteFs.go @@ -0,0 +1,253 @@ +package afero + +import ( + "fmt" + "os" + "path/filepath" + "syscall" + "time" +) + +// 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 { + origErr := err + if e, ok := err.(*os.PathError); ok { + err = e.Err + } + if err == syscall.ENOENT || err == syscall.ENOTDIR { + return u.base.Stat(name) + } + return nil, origErr + } + return fi, nil +} + +// 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) +} -- cgit v1.2.3