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@@ -1,252 +0,0 @@
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-package docker
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-
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-import (
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- "errors"
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- "fmt"
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- "io"
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- "io/ioutil"
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- "os"
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- "path/filepath"
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- "strings"
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- "syscall"
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- "time"
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-)
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-
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-type Filesystem struct {
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- RootFS string
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- RWPath string
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- // The layers to be mounted on top of each other via aufs.
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- // Layers are ordered top-to-bottom: the first layer in the list will be mounted on top of the others.
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- // In other words, THE BASE IMAGE SHOULD BE LAST!
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- Layers []string
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-}
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-
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-func (fs *Filesystem) createMountPoints() error {
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- if err := os.Mkdir(fs.RootFS, 0755); err != nil && !os.IsExist(err) {
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- return err
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- }
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- if err := os.Mkdir(fs.RWPath, 0755); err != nil && !os.IsExist(err) {
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- return err
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- }
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- return nil
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-}
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-
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-func (fs *Filesystem) Mount() error {
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- if fs.IsMounted() {
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- return errors.New("Mount: Filesystem already mounted")
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- }
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- if err := fs.createMountPoints(); err != nil {
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- return err
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- }
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- rwBranch := fmt.Sprintf("%v=rw", fs.RWPath)
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- roBranches := ""
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- for _, layer := range fs.Layers {
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- roBranches += fmt.Sprintf("%v=ro:", layer)
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- }
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- branches := fmt.Sprintf("br:%v:%v", rwBranch, roBranches)
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- if err := mount("none", fs.RootFS, "aufs", 0, branches); err != nil {
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- return err
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- }
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- if !fs.IsMounted() {
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- return errors.New("Mount failed")
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- }
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- return nil
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-}
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-
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-func (fs *Filesystem) Umount() error {
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- if !fs.IsMounted() {
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- return errors.New("Umount: Filesystem not mounted")
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- }
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- if err := syscall.Unmount(fs.RootFS, 0); err != nil {
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- return err
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- }
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- if fs.IsMounted() {
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- return fmt.Errorf("Umount: Filesystem still mounted after calling umount(%v)", fs.RootFS)
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- }
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- // Even though we just unmounted the filesystem, AUFS will prevent deleting the mntpoint
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- // for some time. We'll just keep retrying until it succeeds.
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- for retries := 0; retries < 1000; retries++ {
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- err := os.Remove(fs.RootFS)
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- if err == nil {
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- // rm mntpoint succeeded
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- return nil
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- }
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- if os.IsNotExist(err) {
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- // mntpoint doesn't exist anymore. Success.
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- return nil
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- }
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- // fmt.Printf("(%v) Remove %v returned: %v\n", retries, fs.RootFS, err)
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- time.Sleep(10 * time.Millisecond)
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- }
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- return fmt.Errorf("Umount: Failed to umount %v", fs.RootFS)
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-}
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-
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-func (fs *Filesystem) IsMounted() bool {
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- mntpoint, err := os.Stat(fs.RootFS)
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- if err != nil {
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- if os.IsNotExist(err) {
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- return false
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- }
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- panic(err)
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- }
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- parent, err := os.Stat(filepath.Join(fs.RootFS, ".."))
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- if err != nil {
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- panic(err)
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- }
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-
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- mntpointSt := mntpoint.Sys().(*syscall.Stat_t)
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- parentSt := parent.Sys().(*syscall.Stat_t)
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- return mntpointSt.Dev != parentSt.Dev
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-}
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-
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-// Tar returns the contents of the filesystem as an uncompressed tar stream
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-func (fs *Filesystem) Tar() (io.Reader, error) {
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- if err := fs.EnsureMounted(); err != nil {
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- return nil, err
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- }
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- return Tar(fs.RootFS)
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-}
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-
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-func (fs *Filesystem) EnsureMounted() error {
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- if !fs.IsMounted() {
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- if err := fs.Mount(); err != nil {
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- return err
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- }
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- }
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- return nil
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-}
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-
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-type ChangeType int
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-
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-const (
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- ChangeModify = iota
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- ChangeAdd
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- ChangeDelete
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-)
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-
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-type Change struct {
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- Path string
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- Kind ChangeType
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-}
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-
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-func (change *Change) String() string {
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- var kind string
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- switch change.Kind {
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- case ChangeModify:
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- kind = "C"
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- case ChangeAdd:
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- kind = "A"
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- case ChangeDelete:
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- kind = "D"
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- }
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- return fmt.Sprintf("%s %s", kind, change.Path)
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-}
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-
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-func (fs *Filesystem) Changes() ([]Change, error) {
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- var changes []Change
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- err := filepath.Walk(fs.RWPath, func(path string, f os.FileInfo, err error) error {
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- if err != nil {
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- return err
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- }
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-
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- // Rebase path
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- path, err = filepath.Rel(fs.RWPath, path)
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- if err != nil {
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- return err
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- }
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- path = filepath.Join("/", path)
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-
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- // Skip root
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- if path == "/" {
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- return nil
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- }
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-
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- // Skip AUFS metadata
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- if matched, err := filepath.Match("/.wh..wh.*", path); err != nil || matched {
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- return err
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- }
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-
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- change := Change{
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- Path: path,
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- }
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-
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- // Find out what kind of modification happened
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- file := filepath.Base(path)
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- // If there is a whiteout, then the file was removed
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- if strings.HasPrefix(file, ".wh.") {
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- originalFile := strings.TrimLeft(file, ".wh.")
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- change.Path = filepath.Join(filepath.Dir(path), originalFile)
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- change.Kind = ChangeDelete
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- } else {
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- // Otherwise, the file was added
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- change.Kind = ChangeAdd
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-
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- // ...Unless it already existed in a top layer, in which case, it's a modification
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- for _, layer := range fs.Layers {
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- stat, err := os.Stat(filepath.Join(layer, path))
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- if err != nil && !os.IsNotExist(err) {
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- return err
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- }
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- if err == nil {
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- // The file existed in the top layer, so that's a modification
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-
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- // However, if it's a directory, maybe it wasn't actually modified.
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- // If you modify /foo/bar/baz, then /foo will be part of the changed files only because it's the parent of bar
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- if stat.IsDir() && f.IsDir() {
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- if f.Size() == stat.Size() && f.Mode() == stat.Mode() && f.ModTime() == stat.ModTime() {
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- // Both directories are the same, don't record the change
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- return nil
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- }
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- }
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- change.Kind = ChangeModify
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- break
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- }
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- }
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- }
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-
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- // Record change
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- changes = append(changes, change)
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- return nil
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- })
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- if err != nil {
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- return nil, err
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- }
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- return changes, nil
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-}
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-
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-// Reset removes all changes to the filesystem, reverting it to its initial state.
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-func (fs *Filesystem) Reset() error {
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- if err := os.RemoveAll(fs.RWPath); err != nil {
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- return err
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- }
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- // We removed the RW directory itself along with its content: let's re-create an empty one.
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- if err := fs.createMountPoints(); err != nil {
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- return err
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- }
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- return nil
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-}
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-
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-// Open opens the named file for reading.
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-func (fs *Filesystem) OpenFile(path string, flag int, perm os.FileMode) (*os.File, error) {
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- if err := fs.EnsureMounted(); err != nil {
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- return nil, err
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- }
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- return os.OpenFile(filepath.Join(fs.RootFS, path), flag, perm)
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-}
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-
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-// ReadDir reads the directory named by dirname, relative to the Filesystem's root,
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-// and returns a list of sorted directory entries
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-func (fs *Filesystem) ReadDir(dirname string) ([]os.FileInfo, error) {
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- if err := fs.EnsureMounted(); err != nil {
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- return nil, err
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- }
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- return ioutil.ReadDir(filepath.Join(fs.RootFS, dirname))
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-}
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-
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-func newFilesystem(rootfs string, rwpath string, layers []string) *Filesystem {
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- return &Filesystem{
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- RootFS: rootfs,
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- RWPath: rwpath,
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- Layers: layers,
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- }
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-}
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