@@ -326,7 +326,7 @@ func (a *Driver) Diff(id, parent string) (archive.Archive, error) {

 	})

 }

-func (a *Driver) applyDiff(id string, diff archive.ArchiveReader) error {

+func (a *Driver) applyDiff(id string, diff archive.Reader) error {

 	return chrootarchive.UntarUncompressed(diff, path.Join(a.rootPath(), "diff", id), nil)

 }

@@ -341,7 +341,7 @@ func (a *Driver) DiffSize(id, parent string) (size int64, err error) {

 // 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 (a *Driver) ApplyDiff(id, parent string, diff archive.ArchiveReader) (size int64, err error) {

+func (a *Driver) ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error) {

 	// AUFS doesn't need the parent id to apply the diff.

 	if err = a.applyDiff(id, diff); err != nil {

 		return

@@ -77,8 +77,8 @@ type Driver interface {

 	// 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.

-	// The archive.ArchiveReader must be an uncompressed stream.

-	ApplyDiff(id, parent string, diff archive.ArchiveReader) (size int64, err error)

+	// The archive.Reader must be an uncompressed stream.

+	ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error)

 	// DiffSize calculates the changes between the specified id

 	// and its parent and returns the size in bytes of the changes

 	// relative to its base filesystem directory.

@@ -11,7 +11,7 @@ type WindowsGraphDriver interface {

 	LayerIdsToPaths(ids []string) []string

 	Info() hcsshim.DriverInfo

 	Export(id string, parentLayerPaths []string) (archive.Archive, error)

-	Import(id string, layerData archive.ArchiveReader, parentLayerPaths []string) (int64, error)

+	Import(id string, layerData archive.Reader, parentLayerPaths []string) (int64, error)

 }

 var (

@@ -25,7 +25,7 @@ type naiveDiffDriver struct {

 // it may or may not support on its own:

 //     Diff(id, parent string) (archive.Archive, error)

 //     Changes(id, parent string) ([]archive.Change, error)

-//     ApplyDiff(id, parent string, diff archive.ArchiveReader) (size int64, err error)

+//     ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error)

 //     DiffSize(id, parent string) (size int64, err error)

 func NaiveDiffDriver(driver ProtoDriver) Driver {

 	return &naiveDiffDriver{ProtoDriver: driver}

@@ -109,7 +109,7 @@ func (gdw *naiveDiffDriver) Changes(id, parent string) ([]archive.Change, error)

 // 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) (size int64, err error) {

+func (gdw *naiveDiffDriver) ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error) {

 	driver := gdw.ProtoDriver

 	// Mount the root filesystem so we can apply the diff/layer.

@@ -28,7 +28,7 @@ var (

 type ApplyDiffProtoDriver interface {

 	graphdriver.ProtoDriver

-	ApplyDiff(id, parent string, diff archive.ArchiveReader) (size int64, err error)

+	ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error)

 }

 type naiveDiffDriverWithApply struct {

@@ -43,7 +43,7 @@ func NaiveDiffDriverWithApply(driver ApplyDiffProtoDriver) graphdriver.Driver {

 	}

 }

-func (d *naiveDiffDriverWithApply) ApplyDiff(id, parent string, diff archive.ArchiveReader) (int64, error) {

+func (d *naiveDiffDriverWithApply) ApplyDiff(id, parent string, diff archive.Reader) (int64, error) {

 	b, err := d.applyDiff.ApplyDiff(id, parent, diff)

 	if err == ErrApplyDiffFallback {

 		return d.Driver.ApplyDiff(id, parent, diff)

@@ -373,7 +373,7 @@ func (d *Driver) Put(id string) error {

 	return nil

 }

-func (d *Driver) ApplyDiff(id string, parent string, diff archive.ArchiveReader) (size int64, err error) {

+func (d *Driver) ApplyDiff(id string, parent string, diff archive.Reader) (size int64, err error) {

 	dir := d.dir(id)

 	if parent == "" {

@@ -171,7 +171,7 @@ func (d *WindowsGraphDriver) Changes(id, parent string) ([]archive.Change, error

 // 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 (d *WindowsGraphDriver) ApplyDiff(id, parent string, diff archive.ArchiveReader) (size int64, err error) {

+func (d *WindowsGraphDriver) ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error) {

 	start := time.Now().UTC()

 	logrus.Debugf("WindowsGraphDriver ApplyDiff: Start untar layer")

@@ -289,7 +289,7 @@ func (d *WindowsGraphDriver) Export(id string, parentLayerPaths []string) (arch

 }

-func (d *WindowsGraphDriver) Import(id string, layerData archive.ArchiveReader, parentLayerPaths []string) (size int64, err error) {

+func (d *WindowsGraphDriver) Import(id string, layerData archive.Reader, parentLayerPaths []string) (size int64, err error) {

 	layerFs, err := d.Get(id, "")

 	if err != nil {

 		return

@@ -198,7 +198,7 @@ func (graph *Graph) Get(name string) (*image.Image, error) {

 }

 // Create creates a new image and registers it in the graph.

-func (graph *Graph) Create(layerData archive.ArchiveReader, containerID, containerImage, comment, author string, containerConfig, config *runconfig.Config) (*image.Image, error) {

+func (graph *Graph) Create(layerData archive.Reader, containerID, containerImage, comment, author string, containerConfig, config *runconfig.Config) (*image.Image, error) {

 	img := &image.Image{

 		ID:            stringid.GenerateRandomID(),

 		Comment:       comment,

@@ -223,7 +223,7 @@ func (graph *Graph) Create(layerData archive.ArchiveReader, containerID, contain

 }

 // Register imports a pre-existing image into the graph.

-func (graph *Graph) Register(img *image.Image, layerData archive.ArchiveReader) (err error) {

+func (graph *Graph) Register(img *image.Image, layerData archive.Reader) (err error) {

 	if err := image.ValidateID(img.ID); err != nil {

 		return err

@@ -535,7 +535,7 @@ func jsonPath(root string) string {

 	return filepath.Join(root, jsonFileName)

 }

-func (graph *Graph) disassembleAndApplyTarLayer(img *image.Image, layerData archive.ArchiveReader, root string) error {

+func (graph *Graph) disassembleAndApplyTarLayer(img *image.Image, layerData archive.Reader, root string) error {

 	// this is saving the tar-split metadata

 	mf, err := os.OpenFile(filepath.Join(root, tarDataFileName), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(0600))

 	if err != nil {

@@ -558,7 +558,7 @@ func (graph *Graph) disassembleAndApplyTarLayer(img *image.Image, layerData arch

 		return err

 	}

-	if img.Size, err = graph.driver.ApplyDiff(img.ID, img.Parent, archive.ArchiveReader(rdr)); err != nil {

+	if img.Size, err = graph.driver.ApplyDiff(img.ID, img.Parent, archive.Reader(rdr)); err != nil {

 		return err

 	}

@@ -73,7 +73,7 @@ func SetupInitLayer(initLayer string) error {

 	return nil

 }

-func createRootFilesystemInDriver(graph *Graph, img *image.Image, layerData archive.ArchiveReader) error {

+func createRootFilesystemInDriver(graph *Graph, img *image.Image, layerData archive.Reader) error {

 	if err := graph.driver.Create(img.ID, img.Parent); err != nil {

 		return fmt.Errorf("Driver %s failed to create image rootfs %s: %s", graph.driver, img.ID, err)

 	}

@@ -87,7 +87,7 @@ func (graph *Graph) restoreBaseImages() ([]string, error) {

 // storeImage stores file system layer data for the given image to the

 // graph's storage driver. Image metadata is stored in a file

 // at the specified root directory.

-func (graph *Graph) storeImage(img *image.Image, layerData archive.ArchiveReader, root string) (err error) {

+func (graph *Graph) storeImage(img *image.Image, layerData archive.Reader, root string) (err error) {

 	// Store the layer. If layerData is not nil, unpack it into the new layer

 	if layerData != nil {

 		if err := graph.disassembleAndApplyTarLayer(img, layerData, root); err != nil {

@@ -19,7 +19,7 @@ func SetupInitLayer(initLayer string) error {

 	return nil

 }

-func createRootFilesystemInDriver(graph *Graph, img *image.Image, layerData archive.ArchiveReader) error {

+func createRootFilesystemInDriver(graph *Graph, img *image.Image, layerData archive.Reader) error {

 	if wd, ok := graph.driver.(*windows.WindowsGraphDriver); ok {

 		if img.Container != "" && layerData == nil {

 			logrus.Debugf("Copying from container %s.", img.Container)

@@ -71,7 +71,7 @@ func (graph *Graph) ParentLayerIds(img *image.Image) (ids []string, err error) {

 // storeImage stores file system layer data for the given image to the

 // graph's storage driver. Image metadata is stored in a file

 // at the specified root directory.

-func (graph *Graph) storeImage(img *image.Image, layerData archive.ArchiveReader, root string) (err error) {

+func (graph *Graph) storeImage(img *image.Image, layerData archive.Reader, root string) (err error) {

 	if wd, ok := graph.driver.(*windows.WindowsGraphDriver); ok {

 		// Store the layer. If layerData is not nil and this isn't a base image,

@@ -20,7 +20,7 @@ import (

 func (s *TagStore) Import(src string, repo string, tag string, inConfig io.ReadCloser, outStream io.Writer, containerConfig *runconfig.Config) error {

 	var (

 		sf      = streamformatter.NewJSONStreamFormatter()

-		archive archive.ArchiveReader

+		archive archive.Reader

 		resp    *http.Response

 	)

@@ -37,6 +37,7 @@ packages=(

 	graph

 	image

 	integration-cli

+	pkg/archive

 	pkg/broadcastwriter

 	pkg/chrootarchive

 	pkg/directory

@@ -25,12 +25,17 @@ import (

 )

 type (

-	Archive         io.ReadCloser

-	ArchiveReader   io.Reader

-	Compression     int

+	// Archive is a type of io.ReadCloser which has two interfaces Read and Closer.

+	Archive io.ReadCloser

+	// Reader is a type of io.Reader.

+	Reader io.Reader

+	// Compression is the state represtents if compressed or not.

+	Compression int

+	// TarChownOptions wraps the chown options UID and GID.

 	TarChownOptions struct {

 		UID, GID int

 	}

+	// TarOptions wraps the tar options.

 	TarOptions struct {

 		IncludeFiles     []string

 		ExcludePatterns  []string

@@ -59,17 +64,23 @@ type (

 )

 var (

+	// ErrNotImplemented is the error message of function not implemented.

 	ErrNotImplemented = errors.New("Function not implemented")

 	defaultArchiver   = &Archiver{Untar}

 )

 const (

+	// Uncompressed represents the uncompressed.

 	Uncompressed Compression = iota

+	// Bzip2 is bzip2 compression algorithm.

 	Bzip2

+	// Gzip is gzip compression algorithm.

 	Gzip

+	// Xz is xz compression algorithm.

 	Xz

 )

+// IsArchive checks if it is a archive by the header.

 func IsArchive(header []byte) bool {

 	compression := DetectCompression(header)

 	if compression != Uncompressed {

@@ -80,6 +91,7 @@ func IsArchive(header []byte) bool {

 	return err == nil

 }

+// DetectCompression detects the compression algorithm of the source.

 func DetectCompression(source []byte) Compression {

 	for compression, m := range map[Compression][]byte{

 		Bzip2: {0x42, 0x5A, 0x68},

@@ -103,6 +115,7 @@ func xzDecompress(archive io.Reader) (io.ReadCloser, error) {

 	return CmdStream(exec.Command(args[0], args[1:]...), archive)

 }

+// DecompressStream decompress the archive and returns a ReaderCloser with the decompressed archive.

 func DecompressStream(archive io.Reader) (io.ReadCloser, error) {

 	p := pools.BufioReader32KPool

 	buf := p.Get(archive)

@@ -139,6 +152,7 @@ func DecompressStream(archive io.Reader) (io.ReadCloser, error) {

 	}

 }

+// CompressStream compresses the dest with specified compression algorithm.

 func CompressStream(dest io.WriteCloser, compression Compression) (io.WriteCloser, error) {

 	p := pools.BufioWriter32KPool

 	buf := p.Get(dest)

@@ -159,6 +173,7 @@ func CompressStream(dest io.WriteCloser, compression Compression) (io.WriteClose

 	}

 }

+// Extension returns the extension of a file that uses the specified compression algorithm.

 func (compression *Compression) Extension() string {

 	switch *compression {

 	case Uncompressed:

@@ -530,6 +545,7 @@ func TarWithOptions(srcPath string, options *TarOptions) (io.ReadCloser, error)

 	return pipeReader, nil

 }

+// Unpack unpacks the decompressedArchive to dest with options.

 func Unpack(decompressedArchive io.Reader, dest string, options *TarOptions) error {

 	tr := tar.NewReader(decompressedArchive)

 	trBuf := pools.BufioReader32KPool.Get(nil)

@@ -643,7 +659,7 @@ func Untar(tarArchive io.Reader, dest string, options *TarOptions) error {

 	return untarHandler(tarArchive, dest, options, true)

 }

-// Untar reads a stream of bytes from `archive`, parses it as a tar archive,

+// UntarUncompressed reads a stream of bytes from `archive`, parses it as a tar archive,

 // and unpacks it into the directory at `dest`.

 // The archive must be an uncompressed stream.

 func UntarUncompressed(tarArchive io.Reader, dest string, options *TarOptions) error {

@@ -663,7 +679,7 @@ func untarHandler(tarArchive io.Reader, dest string, options *TarOptions, decomp

 		options.ExcludePatterns = []string{}

 	}

-	var r io.Reader = tarArchive

+	r := tarArchive

 	if decompress {

 		decompressedArchive, err := DecompressStream(tarArchive)

 		if err != nil {

@@ -676,6 +692,8 @@ func untarHandler(tarArchive io.Reader, dest string, options *TarOptions, decomp

 	return Unpack(r, dest, options)

 }

+// TarUntar is a convenience function which calls Tar and Untar, with the output of one piped into the other.

+// If either Tar or Untar fails, TarUntar aborts and returns the error.

 func (archiver *Archiver) TarUntar(src, dst string) error {

 	logrus.Debugf("TarUntar(%s %s)", src, dst)

 	archive, err := TarWithOptions(src, &TarOptions{Compression: Uncompressed})

@@ -692,6 +710,7 @@ func TarUntar(src, dst string) error {

 	return defaultArchiver.TarUntar(src, dst)

 }

+// UntarPath untar a file from path to a destination, src is the source tar file path.

 func (archiver *Archiver) UntarPath(src, dst string) error {

 	archive, err := os.Open(src)

 	if err != nil {

@@ -710,6 +729,10 @@ func UntarPath(src, dst string) error {

 	return defaultArchiver.UntarPath(src, dst)

 }

+// CopyWithTar creates a tar archive of filesystem path `src`, and

+// unpacks it at filesystem path `dst`.

+// The archive is streamed directly with fixed buffering and no

+// intermediary disk IO.

 func (archiver *Archiver) CopyWithTar(src, dst string) error {

 	srcSt, err := os.Stat(src)

 	if err != nil {

@@ -735,6 +758,9 @@ func CopyWithTar(src, dst string) error {

 	return defaultArchiver.CopyWithTar(src, dst)

 }

+// CopyFileWithTar emulates the behavior of the 'cp' command-line

+// for a single file. It copies a regular file from path `src` to

+// path `dst`, and preserves all its metadata.

 func (archiver *Archiver) CopyFileWithTar(src, dst string) (err error) {

 	logrus.Debugf("CopyFileWithTar(%s, %s)", src, dst)

 	srcSt, err := os.Stat(src)

@@ -878,6 +904,8 @@ func NewTempArchive(src Archive, dir string) (*TempArchive, error) {

 	return &TempArchive{File: f, Size: size}, nil

 }

+// TempArchive is a temporary archive. The archive can only be read once - as soon as reading completes,

+// the file will be deleted.

 type TempArchive struct {

 	*os.File

 	Size   int64 // Pre-computed from Stat().Size() as a convenience

@@ -18,14 +18,22 @@ import (

 	"github.com/docker/docker/pkg/system"

 )

+// ChangeType represents the change type.

 type ChangeType int

 const (

+	// ChangeModify represents the modify operation.

 	ChangeModify = iota

+	// ChangeAdd represents the add operation.

 	ChangeAdd

+	// ChangeDelete represents the delete operation.

 	ChangeDelete

 )

+// Change represents a change, it wraps the change type and path.

+// It describes changes of the files in the path respect to the

+// parent layers. The change could be modify, add, delete.

+// This is used for layer diff.

 type Change struct {

 	Path string

 	Kind ChangeType

@@ -161,6 +169,7 @@ func Changes(layers []string, rw string) ([]Change, error) {

 	return changes, nil

 }

+// FileInfo describes the information of a file.

 type FileInfo struct {

 	parent     *FileInfo

 	name       string

@@ -170,11 +179,12 @@ type FileInfo struct {

 	added      bool

 }

-func (root *FileInfo) LookUp(path string) *FileInfo {

+// LookUp looks up the file information of a file.

+func (info *FileInfo) LookUp(path string) *FileInfo {

 	// As this runs on the daemon side, file paths are OS specific.

-	parent := root

+	parent := info

 	if path == string(os.PathSeparator) {

-		return root

+		return info

 	}

 	pathElements := strings.Split(path, string(os.PathSeparator))

@@ -275,6 +285,7 @@ func (info *FileInfo) addChanges(oldInfo *FileInfo, changes *[]Change) {

 }

+// Changes add changes to file information.

 func (info *FileInfo) Changes(oldInfo *FileInfo) []Change {

 	var changes []Change

@@ -246,7 +246,7 @@ func CopyInfoDestinationPath(path string) (info CopyInfo, err error) {

 // contain the archived resource described by srcInfo, to the destination

 // described by dstInfo. Returns the possibly modified content archive along

 // with the path to the destination directory which it should be extracted to.

-func PrepareArchiveCopy(srcContent ArchiveReader, srcInfo, dstInfo CopyInfo) (dstDir string, content Archive, err error) {

+func PrepareArchiveCopy(srcContent Reader, srcInfo, dstInfo CopyInfo) (dstDir string, content Archive, err error) {

 	// Separate the destination path between its directory and base

 	// components in case the source archive contents need to be rebased.

 	dstDir, dstBase := SplitPathDirEntry(dstInfo.Path)

@@ -296,7 +296,7 @@ func PrepareArchiveCopy(srcContent ArchiveReader, srcInfo, dstInfo CopyInfo) (ds

 // rebaseArchiveEntries rewrites the given srcContent archive replacing

 // an occurance of oldBase with newBase at the beginning of entry names.

-func rebaseArchiveEntries(srcContent ArchiveReader, oldBase, newBase string) Archive {

+func rebaseArchiveEntries(srcContent Reader, oldBase, newBase string) Archive {

 	if oldBase == "/" {

 		// If oldBase specifies the root directory, use an empty string as

 		// oldBase instead so that newBase doesn't replace the path separator

@@ -368,7 +368,7 @@ func CopyResource(srcPath, dstPath string) error {

 // CopyTo handles extracting the given content whose

 // entries should be sourced from srcInfo to dstPath.

-func CopyTo(content ArchiveReader, srcInfo CopyInfo, dstPath string) error {

+func CopyTo(content Reader, srcInfo CopyInfo, dstPath string) error {

 	// The destination path need not exist, but CopyInfoDestinationPath will

 	// ensure that at least the parent directory exists.

 	dstInfo, err := CopyInfoDestinationPath(dstPath)

@@ -16,7 +16,10 @@ import (

 	"github.com/docker/docker/pkg/system"

 )

-func UnpackLayer(dest string, layer ArchiveReader) (size int64, err error) {

+// UnpackLayer unpack `layer` to a `dest`. The stream `layer` can be

+// compressed or uncompressed.

+// Returns the size in bytes of the contents of the layer.

+func UnpackLayer(dest string, layer Reader) (size int64, err error) {

 	tr := tar.NewReader(layer)

 	trBuf := pools.BufioReader32KPool.Get(tr)

 	defer pools.BufioReader32KPool.Put(trBuf)

@@ -177,7 +180,7 @@ func UnpackLayer(dest string, layer ArchiveReader) (size int64, err error) {

 // and applies it to the directory `dest`. The stream `layer` can be

 // compressed or uncompressed.

 // Returns the size in bytes of the contents of the layer.

-func ApplyLayer(dest string, layer ArchiveReader) (int64, error) {

+func ApplyLayer(dest string, layer Reader) (int64, error) {

 	return applyLayerHandler(dest, layer, true)

 }

@@ -185,12 +188,12 @@ func ApplyLayer(dest string, layer ArchiveReader) (int64, error) {

 // `layer`, and applies it to the directory `dest`. The stream `layer`

 // can only be uncompressed.

 // Returns the size in bytes of the contents of the layer.

-func ApplyUncompressedLayer(dest string, layer ArchiveReader) (int64, error) {

+func ApplyUncompressedLayer(dest string, layer Reader) (int64, error) {

 	return applyLayerHandler(dest, layer, false)

 }

 // do the bulk load of ApplyLayer, but allow for not calling DecompressStream

-func applyLayerHandler(dest string, layer ArchiveReader, decompress bool) (int64, error) {

+func applyLayerHandler(dest string, layer Reader, decompress bool) (int64, error) {

 	dest = filepath.Clean(dest)

 	// We need to be able to set any perms

@@ -16,7 +16,7 @@ var testUntarFns = map[string]func(string, io.Reader) error{

 		return Untar(r, dest, nil)

 	},

 	"applylayer": func(dest string, r io.Reader) error {

-		_, err := ApplyLayer(dest, ArchiveReader(r))

+		_, err := ApplyLayer(dest, Reader(r))

 		return err

 	},

 }

@@ -6,7 +6,7 @@ import "github.com/docker/docker/pkg/archive"

 // and applies it to the directory `dest`. The stream `layer` can only be

 // uncompressed.

 // Returns the size in bytes of the contents of the layer.

-func ApplyLayer(dest string, layer archive.ArchiveReader) (size int64, err error) {

+func ApplyLayer(dest string, layer archive.Reader) (size int64, err error) {

 	return applyLayerHandler(dest, layer, true)

 }

@@ -14,6 +14,6 @@ func ApplyLayer(dest string, layer archive.ArchiveReader) (size int64, err error

 // `layer`, and applies it to the directory `dest`. The stream `layer`

 // can only be uncompressed.

 // Returns the size in bytes of the contents of the layer.

-func ApplyUncompressedLayer(dest string, layer archive.ArchiveReader) (int64, error) {

+func ApplyUncompressedLayer(dest string, layer archive.Reader) (int64, error) {

 	return applyLayerHandler(dest, layer, false)

 }

@@ -68,7 +68,7 @@ func applyLayer() {

 // applyLayerHandler parses a diff in the standard layer format from `layer`, and

 // applies it to the directory `dest`. Returns the size in bytes of the

 // contents of the layer.

-func applyLayerHandler(dest string, layer archive.ArchiveReader, decompress bool) (size int64, err error) {

+func applyLayerHandler(dest string, layer archive.Reader, decompress bool) (size int64, err error) {

 	dest = filepath.Clean(dest)

 	if decompress {

 		decompressed, err := archive.DecompressStream(layer)

@@ -12,7 +12,7 @@ import (

 // applyLayerHandler parses a diff in the standard layer format from `layer`, and

 // applies it to the directory `dest`. Returns the size in bytes of the

 // contents of the layer.

-func applyLayerHandler(dest string, layer archive.ArchiveReader, decompress bool) (size int64, err error) {

+func applyLayerHandler(dest string, layer archive.Reader, decompress bool) (size int64, err error) {

 	dest = filepath.Clean(dest)

 	if decompress {

 		decompressed, err := archive.DecompressStream(layer)