func (c *DaemonClient) ImageBuild(ctx context.Context, context io.Reader, options types.ImageBuildOptions) (types.ImageBuildResponse, error) {
	if c.imageName != "" {
		if len(options.Tags) != 1 || options.Tags[0] != c.imageName {
			return types.ImageBuildResponse{}, fmt.Errorf("expected image %q, got %v", c.imageName, options.Tags)
		}
	}
	if c.contextDir != "" {
		tmp, err := ioutil.TempDir("", "image-build-test")
		if err != nil {
			return types.ImageBuildResponse{}, err
		}
		if err := archive.Untar(context, tmp, nil); err != nil {
			return types.ImageBuildResponse{}, err
		}
		changes, err := archive.ChangesDirs(tmp, c.contextDir)
		if err != nil {
			return types.ImageBuildResponse{}, err
		}
		if len(changes) != c.changes {
			return types.ImageBuildResponse{}, fmt.Errorf("expected %d changes, got %v", c.changes, changes)
		}
		b, err := json.Marshal(c.message)
		if err != nil {
			return types.ImageBuildResponse{}, err
		}
		return types.ImageBuildResponse{
			Body: ioutil.NopCloser(bytes.NewReader(b)),
		}, nil
	}
	return c.NopClient.ImageBuild(ctx, context, options)
}

// ApplyDiff extracts the changeset from the given diff into the
// layer with the specified id and parent, returning the size of the
// new layer in bytes.
func (gdw *naiveDiffDriver) ApplyDiff(id, parent string, diff archive.ArchiveReader) (bytes int64, err error) {
	driver := gdw.ProtoDriver

	// Mount the root filesystem so we can apply the diff/layer.
	layerFs, err := driver.Get(id, "")
	if err != nil {
		return
	}
	defer driver.Put(id)

	start := time.Now().UTC()
	log.Debugf("Start untar layer")
	if err = archive.ApplyLayer(layerFs, diff); err != nil {
		return
	}
	log.Debugf("Untar time: %vs", time.Now().UTC().Sub(start).Seconds())

	if parent == "" {
		return utils.TreeSize(layerFs)
	}

	parentFs, err := driver.Get(parent, "")
	if err != nil {
		err = fmt.Errorf("Driver %s failed to get image parent %s: %s", driver, parent, err)
		return
	}
	defer driver.Put(parent)

	changes, err := archive.ChangesDirs(layerFs, parentFs)
	if err != nil {
		return
	}

	return archive.ChangesSize(layerFs, changes), nil
}

func diff(id, parent string) (diff archive.Archive, err error) {

	// create pod

	// start or replace pod
	glog.Infof("Diff between %s and %s", id, parent)
	layerFs := "/tmp/test1"
	if parent == "" {
		archive, err := archive.Tar(layerFs, archive.Uncompressed)
		if err != nil {
			return nil, err
		}
		return ioutils.NewReadCloserWrapper(archive, func() error {
			err := archive.Close()
			return err
		}), nil
	}

	parentFs := "/tmp/test2"

	changes, err := archive.ChangesDirs(layerFs, parentFs)
	if err != nil {
		return nil, err
	}

	archive, err := archive.ExportChanges(layerFs, changes)
	if err != nil {
		return nil, err
	}

	return ioutils.NewReadCloserWrapper(archive, func() error {
		err := archive.Close()
		return err
	}), nil
}

// ApplyDiff applies the new layer on top of the root, if parent does not exist with will return a ErrApplyDiffFallback error.
func (d *Driver) ApplyDiff(id string, parent string, diff archive.ArchiveReader) (size int64, err error) {
	dir := d.dir(id)

	if parent == "" {
		return 0, ErrApplyDiffFallback
	}

	parentRootDir := path.Join(d.dir(parent), "root")
	if _, err := os.Stat(parentRootDir); err != nil {
		return 0, ErrApplyDiffFallback
	}

	// We now know there is a parent, and it has a "root" directory containing
	// the full root filesystem. We can just hardlink it and apply the
	// layer. This relies on two things:
	// 1) ApplyDiff is only run once on a clean (no writes to upper layer) container
	// 2) ApplyDiff doesn't do any in-place writes to files (would break hardlinks)
	// These are all currently true and are not expected to break

	tmpRootDir, err := ioutil.TempDir(dir, "tmproot")
	if err != nil {
		return 0, err
	}
	defer func() {
		if err != nil {
			os.RemoveAll(tmpRootDir)
		} else {
			os.RemoveAll(path.Join(dir, "upper"))
			os.RemoveAll(path.Join(dir, "work"))
			os.RemoveAll(path.Join(dir, "merged"))
			os.RemoveAll(path.Join(dir, "lower-id"))
		}
	}()

	if err = copyDir(parentRootDir, tmpRootDir, copyHardlink); err != nil {
		return 0, err
	}

	start := time.Now().UTC()
	log.Debugf("Start untar layer")
	if err = chrootarchive.ApplyLayer(tmpRootDir, diff); err != nil {
		return 0, err
	}
	log.Debugf("Untar time: %vs", time.Now().UTC().Sub(start).Seconds())

	changes, err := archive.ChangesDirs(tmpRootDir, parentRootDir, nil)
	if err != nil {
		return 0, err
	}

	size = archive.ChangesSize(tmpRootDir, changes)

	rootDir := path.Join(dir, "root")
	if err := os.Rename(tmpRootDir, rootDir); err != nil {
		return 0, err
	}

	return
}

func Diff(mainPath, parentPath string) (arch io.ReadCloser, err error) {
	changes, err := archive.ChangesDirs(mainPath, parentPath)
	if err != nil {
		return nil, err
	}

	return archive.ExportChanges(mainPath, changes, nil, nil)
}

func compareDirectories(src string, dest string) error {
	changes, err := archive.ChangesDirs(dest, src)
	if err != nil {
		return err
	}
	if len(changes) > 0 {
		return fmt.Errorf("Unexpected differences after untar: %v", changes)
	}
	return nil
}

// Diff produces an archive of the changes between the specified
// layer and its parent layer which may be "".
func (gdw *NaiveDiffDriver) Diff(id, parent string) (arch archive.Archive, err error) {
	startTime := time.Now()
	driver := gdw.ProtoDriver

	layerFs, err := driver.Get(id, "")
	if err != nil {
		return nil, err
	}

	defer func() {
		if err != nil {
			driver.Put(id)
		}
	}()

	if parent == "" {
		archive, err := archive.Tar(layerFs, archive.Uncompressed)
		if err != nil {
			return nil, err
		}
		return ioutils.NewReadCloserWrapper(archive, func() error {
			err := archive.Close()
			driver.Put(id)
			return err
		}), nil
	}

	parentFs, err := driver.Get(parent, "")
	if err != nil {
		return nil, err
	}
	defer driver.Put(parent)

	changes, err := archive.ChangesDirs(layerFs, parentFs)
	if err != nil {
		return nil, err
	}

	archive, err := archive.ExportChanges(layerFs, changes, gdw.uidMaps, gdw.gidMaps)
	if err != nil {
		return nil, err
	}

	return ioutils.NewReadCloserWrapper(archive, func() error {
		err := archive.Close()
		driver.Put(id)

		// NaiveDiffDriver compares file metadata with parent layers. Parent layers
		// are extracted from tar's with full second precision on modified time.
		// We need this hack here to make sure calls within same second receive
		// correct result.
		time.Sleep(startTime.Truncate(time.Second).Add(time.Second).Sub(time.Now()))
		return err
	}), nil
}

func main() {
	flag.Usage = func() {
		fmt.Println("Produce a tar from comparing two directory paths. By default a demo tar is created of around 200 files (including hardlinks)")
		fmt.Printf("%s [OPTIONS]\n", os.Args[0])
		flag.PrintDefaults()
	}
	flag.Parse()
	log.Out = os.Stderr
	if (len(os.Getenv("DEBUG")) > 0) || *flDebug {
		logrus.SetLevel(logrus.DebugLevel)
	}
	var newDir, oldDir string

	if len(*flNewDir) == 0 {
		var err error
		newDir, err = ioutil.TempDir("", "docker-test-newDir")
		if err != nil {
			log.Fatal(err)
		}
		defer os.RemoveAll(newDir)
		if _, err := prepareUntarSourceDirectory(100, newDir, true); err != nil {
			log.Fatal(err)
		}
	} else {
		newDir = *flNewDir
	}

	if len(*flOldDir) == 0 {
		oldDir, err := ioutil.TempDir("", "docker-test-oldDir")
		if err != nil {
			log.Fatal(err)
		}
		defer os.RemoveAll(oldDir)
	} else {
		oldDir = *flOldDir
	}

	changes, err := archive.ChangesDirs(newDir, oldDir)
	if err != nil {
		log.Fatal(err)
	}

	a, err := archive.ExportChanges(newDir, changes)
	if err != nil {
		log.Fatal(err)
	}
	defer a.Close()

	i, err := io.Copy(os.Stdout, a)
	if err != nil && err != io.EOF {
		log.Fatal(err)
	}
	fmt.Fprintf(os.Stderr, "wrote archive of %d bytes", i)
}

// Diff produces an archive of the changes between the specified
// layer and its parent layer which may be "".
func (gdw *naiveDiffDriver) Diff(id, parent string) (arch archive.Archive, err error) {
	driver := gdw.ProtoDriver

	layerFs, err := driver.Get(id, "")
	if err != nil {
		return nil, err
	}

	defer func() {
		if err != nil {
			driver.Put(id)
		}
	}()

	if parent == "" {
		archive, err := archive.Tar(layerFs, archive.Uncompressed)
		if err != nil {
			return nil, err
		}
		return ioutils.NewReadCloserWrapper(archive, func() error {
			err := archive.Close()
			driver.Put(id)
			return err
		}), nil
	}

	parentFs, err := driver.Get(parent, "")
	if err != nil {
		return nil, err
	}
	defer driver.Put(parent)

	changes, err := archive.ChangesDirs(layerFs, parentFs)
	if err != nil {
		return nil, err
	}

	archive, err := archive.ExportChanges(layerFs, changes)
	if err != nil {
		return nil, err
	}

	return ioutils.NewReadCloserWrapper(archive, func() error {
		err := archive.Close()
		driver.Put(id)
		return err
	}), nil
}

// Changes produces a list of changes between the specified layer
// and its parent layer. If parent is "", then all changes will be ADD changes.
func (gdw *naiveDiffDriver) Changes(id, parent string) ([]archive.Change, error) {
	driver := gdw.ProtoDriver

	layerFs, err := driver.Get(id, "")
	if err != nil {
		return nil, err
	}
	defer driver.Put(id)

	parentFs := ""

	if parent != "" {
		parentFs, err = driver.Get(parent, "")
		if err != nil {
			return nil, err
		}
		defer driver.Put(parent)
	}

	return archive.ChangesDirs(layerFs, parentFs)
}

func (r *gitRepo) exportChangeSet(br branch) (archive.Archive, error) {
	currentBr, err := r.currentBranch()
	if err != nil {
		return nil, err
	}

	_, err = r.checkout(br)
	if err != nil {
		return nil, err
	}

	defer func() {
		r.checkout(currentBr)
	}()

	branches, err := r.branch()
	if err != nil {
		return nil, err
	}

	switch br.number() {
	case 0:
		changes, err := archive.ChangesDirs(r.Path, "")
		if err != nil {
			return nil, err
		}
		var curatedChanges []archive.Change
		for _, ch := range changes {
			if !strings.HasPrefix(ch.Path, "/.git") {
				curatedChanges = append(curatedChanges, ch)
			}
		}
		return archive.ExportChanges(r.Path, curatedChanges)
	default:
		parentBr := branches[br.number()-1]
		diff, _ := r.diff(parentBr, br)
		return exportChanges(r.Path, diff)
	}
}