@@ -62,6 +62,7 @@ RUN apt-get update && apt-get install -y \

 	libudev-dev \

 	mercurial \

 	net-tools \

+	pigz \

 	pkg-config \

 	protobuf-compiler \

 	protobuf-c-compiler \

@@ -52,6 +52,7 @@ RUN apt-get update && apt-get install -y \

 	libudev-dev \

 	mercurial \

 	net-tools \

+	pigz \

 	pkg-config \

 	protobuf-compiler \

 	protobuf-c-compiler \

@@ -45,6 +45,7 @@ RUN apt-get update && apt-get install -y \

 	libtool \

 	libudev-dev \

 	mercurial \

+	pigz \

 	pkg-config \

 	python-backports.ssl-match-hostname \

 	python-dev \

@@ -47,6 +47,7 @@ RUN apk add --update \

     g++ \

     git \

     iptables \

+    pigz \

     tar \

     xz \

     && rm -rf /var/cache/apk/*

@@ -46,6 +46,7 @@ RUN apt-get update && apt-get install -y \

 	libtool \

 	libudev-dev \

 	mercurial \

+	pigz \

 	pkg-config \

 	python-backports.ssl-match-hostname \

 	python-dev \

@@ -42,6 +42,7 @@ RUN apt-get update && apt-get install -y \

 	libtool \

 	libudev-dev \

 	mercurial \

+	pigz \

 	pkg-config \

 	python-backports.ssl-match-hostname \

 	python-dev \

@@ -28,6 +28,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \

 		e2fsprogs \

 		iptables \

 		pkg-config \

+		pigz \

 		procps \

 		xfsprogs \

 		xz-utils \

@@ -6,6 +6,7 @@ import (

 	"bytes"

 	"compress/bzip2"

 	"compress/gzip"

+	"context"

 	"fmt"

 	"io"

 	"io/ioutil"

@@ -13,6 +14,7 @@ import (

 	"os/exec"

 	"path/filepath"

 	"runtime"

+	"strconv"

 	"strings"

 	"syscall"

@@ -24,6 +26,17 @@ import (

 	"github.com/sirupsen/logrus"

 )

+var unpigzPath string

+

+func init() {

+	if path, err := exec.LookPath("unpigz"); err != nil {

+		logrus.Debug("unpigz binary not found in PATH, falling back to go gzip library")

+	} else {

+		logrus.Debugf("Using unpigz binary found at path %s", path)

+		unpigzPath = path

+	}

+}

+

 type (

 	// Compression is the state represents if compressed or not.

 	Compression int

@@ -136,10 +149,34 @@ func DetectCompression(source []byte) Compression {

 	return Uncompressed

 }

-func xzDecompress(archive io.Reader) (io.ReadCloser, <-chan struct{}, error) {

+func xzDecompress(ctx context.Context, archive io.Reader) (io.ReadCloser, error) {

 	args := []string{"xz", "-d", "-c", "-q"}

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

+	return cmdStream(exec.CommandContext(ctx, args[0], args[1:]...), archive)

+}

+

+func gzDecompress(ctx context.Context, buf io.Reader) (io.ReadCloser, error) {

+	if unpigzPath == "" {

+		return gzip.NewReader(buf)

+	}

+

+	disablePigzEnv := os.Getenv("MOBY_DISABLE_PIGZ")

+	if disablePigzEnv != "" {

+		if disablePigz, err := strconv.ParseBool(disablePigzEnv); err != nil {

+			return nil, err

+		} else if disablePigz {

+			return gzip.NewReader(buf)

+		}

+	}

+

+	return cmdStream(exec.CommandContext(ctx, unpigzPath, "-d", "-c"), buf)

+}

+

+func wrapReadCloser(readBuf io.ReadCloser, cancel context.CancelFunc) io.ReadCloser {

+	return ioutils.NewReadCloserWrapper(readBuf, func() error {

+		cancel()

+		return readBuf.Close()

+	})

 }

 // DecompressStream decompresses the archive and returns a ReaderCloser with the decompressed archive.

@@ -163,26 +200,29 @@ func DecompressStream(archive io.Reader) (io.ReadCloser, error) {

 		readBufWrapper := p.NewReadCloserWrapper(buf, buf)

 		return readBufWrapper, nil

 	case Gzip:

-		gzReader, err := gzip.NewReader(buf)

+		ctx, cancel := context.WithCancel(context.Background())

+

+		gzReader, err := gzDecompress(ctx, buf)

 		if err != nil {

+			cancel()

 			return nil, err

 		}

 		readBufWrapper := p.NewReadCloserWrapper(buf, gzReader)

-		return readBufWrapper, nil

+		return wrapReadCloser(readBufWrapper, cancel), nil

 	case Bzip2:

 		bz2Reader := bzip2.NewReader(buf)

 		readBufWrapper := p.NewReadCloserWrapper(buf, bz2Reader)

 		return readBufWrapper, nil

 	case Xz:

-		xzReader, chdone, err := xzDecompress(buf)

+		ctx, cancel := context.WithCancel(context.Background())

+

+		xzReader, err := xzDecompress(ctx, buf)

 		if err != nil {

+			cancel()

 			return nil, err

 		}

 		readBufWrapper := p.NewReadCloserWrapper(buf, xzReader)

-		return ioutils.NewReadCloserWrapper(readBufWrapper, func() error {

-			<-chdone

-			return readBufWrapper.Close()

-		}), nil

+		return wrapReadCloser(readBufWrapper, cancel), nil

 	default:

 		return nil, fmt.Errorf("Unsupported compression format %s", (&compression).Extension())

 	}

@@ -1163,8 +1203,7 @@ func remapIDs(idMappings *idtools.IDMappings, hdr *tar.Header) error {

 // cmdStream executes a command, and returns its stdout as a stream.

 // If the command fails to run or doesn't complete successfully, an error

 // will be returned, including anything written on stderr.

-func cmdStream(cmd *exec.Cmd, input io.Reader) (io.ReadCloser, <-chan struct{}, error) {

-	chdone := make(chan struct{})

+func cmdStream(cmd *exec.Cmd, input io.Reader) (io.ReadCloser, error) {

 	cmd.Stdin = input

 	pipeR, pipeW := io.Pipe()

 	cmd.Stdout = pipeW

@@ -1173,7 +1212,7 @@ func cmdStream(cmd *exec.Cmd, input io.Reader) (io.ReadCloser, <-chan struct{},

 	// Run the command and return the pipe

 	if err := cmd.Start(); err != nil {

-		return nil, nil, err

+		return nil, err

 	}

 	// Copy stdout to the returned pipe

@@ -1183,10 +1222,9 @@ func cmdStream(cmd *exec.Cmd, input io.Reader) (io.ReadCloser, <-chan struct{},

 		} else {

 			pipeW.Close()

 		}

-		close(chdone)

 	}()

-	return pipeR, chdone, nil

+	return pipeR, nil

 }

 // NewTempArchive reads the content of src into a temporary file, and returns the contents

@@ -3,6 +3,7 @@ package archive

 import (

 	"archive/tar"

 	"bytes"

+	"compress/gzip"

 	"fmt"

 	"io"

 	"io/ioutil"

@@ -15,6 +16,7 @@ import (

 	"time"

 	"github.com/docker/docker/pkg/idtools"

+	"github.com/docker/docker/pkg/ioutils"

 	"github.com/stretchr/testify/assert"

 	"github.com/stretchr/testify/require"

 )

@@ -87,7 +89,7 @@ func TestIsArchivePathTar(t *testing.T) {

 	}

 }

-func testDecompressStream(t *testing.T, ext, compressCommand string) {

+func testDecompressStream(t *testing.T, ext, compressCommand string) io.Reader {

 	cmd := exec.Command("sh", "-c",

 		fmt.Sprintf("touch /tmp/archive && %s /tmp/archive", compressCommand))

 	output, err := cmd.CombinedOutput()

@@ -111,6 +113,8 @@ func testDecompressStream(t *testing.T, ext, compressCommand string) {

 	if err = r.Close(); err != nil {

 		t.Fatalf("Failed to close the decompressed stream: %v ", err)

 	}

+

+	return r

 }

 func TestDecompressStreamGzip(t *testing.T) {

@@ -206,7 +210,7 @@ func TestExtensionXz(t *testing.T) {

 func TestCmdStreamLargeStderr(t *testing.T) {

 	cmd := exec.Command("sh", "-c", "dd if=/dev/zero bs=1k count=1000 of=/dev/stderr; echo hello")

-	out, _, err := cmdStream(cmd, nil)

+	out, err := cmdStream(cmd, nil)

 	if err != nil {

 		t.Fatalf("Failed to start command: %s", err)

 	}

@@ -231,7 +235,7 @@ func TestCmdStreamBad(t *testing.T) {

 		t.Skip("Failing on Windows CI machines")

 	}

 	badCmd := exec.Command("sh", "-c", "echo hello; echo >&2 error couldn\\'t reverse the phase pulser; exit 1")

-	out, _, err := cmdStream(badCmd, nil)

+	out, err := cmdStream(badCmd, nil)

 	if err != nil {

 		t.Fatalf("Failed to start command: %s", err)

 	}

@@ -246,7 +250,7 @@ func TestCmdStreamBad(t *testing.T) {

 func TestCmdStreamGood(t *testing.T) {

 	cmd := exec.Command("sh", "-c", "echo hello; exit 0")

-	out, _, err := cmdStream(cmd, nil)

+	out, err := cmdStream(cmd, nil)

 	if err != nil {

 		t.Fatal(err)

 	}

@@ -1318,3 +1322,38 @@ func readFileFromArchive(t *testing.T, archive io.ReadCloser, name string, expec

 	assert.NoError(t, err)

 	return string(content)

 }

+

+func TestDisablePigz(t *testing.T) {

+	_, err := exec.LookPath("unpigz")

+	if err != nil {

+		t.Log("Test will not check full path when Pigz not installed")

+	}

+

+	os.Setenv("MOBY_DISABLE_PIGZ", "true")

+	defer os.Unsetenv("MOBY_DISABLE_PIGZ")

+

+	r := testDecompressStream(t, "gz", "gzip -f")

+	// For the bufio pool

+	outsideReaderCloserWrapper := r.(*ioutils.ReadCloserWrapper)

+	// For the context canceller

+	contextReaderCloserWrapper := outsideReaderCloserWrapper.Reader.(*ioutils.ReadCloserWrapper)

+

+	assert.IsType(t, &gzip.Reader{}, contextReaderCloserWrapper.Reader)

+}

+

+func TestPigz(t *testing.T) {

+	r := testDecompressStream(t, "gz", "gzip -f")

+	// For the bufio pool

+	outsideReaderCloserWrapper := r.(*ioutils.ReadCloserWrapper)

+	// For the context canceller

+	contextReaderCloserWrapper := outsideReaderCloserWrapper.Reader.(*ioutils.ReadCloserWrapper)

+

+	_, err := exec.LookPath("unpigz")

+	if err == nil {

+		t.Log("Tested whether Pigz is used, as it installed")

+		assert.IsType(t, &io.PipeReader{}, contextReaderCloserWrapper.Reader)

+	} else {

+		t.Log("Tested whether Pigz is not used, as it not installed")

+		assert.IsType(t, &gzip.Reader{}, contextReaderCloserWrapper.Reader)

+	}

+}

@@ -8,18 +8,22 @@ import (

 	"golang.org/x/net/context"

 )

-type readCloserWrapper struct {

+// ReadCloserWrapper wraps an io.Reader, and implements an io.ReadCloser

+// It calls the given callback function when closed. It should be constructed

+// with NewReadCloserWrapper

+type ReadCloserWrapper struct {

 	io.Reader

 	closer func() error

 }

-func (r *readCloserWrapper) Close() error {

+// Close calls back the passed closer function

+func (r *ReadCloserWrapper) Close() error {

 	return r.closer()

 }

 // NewReadCloserWrapper returns a new io.ReadCloser.

 func NewReadCloserWrapper(r io.Reader, closer func() error) io.ReadCloser {

-	return &readCloserWrapper{

+	return &ReadCloserWrapper{

 		Reader: r,

 		closer: closer,

 	}