@@ -1,7 +1,10 @@

 package fscache

 import (

+	"archive/tar"

+	"crypto/sha256"

 	"encoding/json"

+	"hash"

 	"os"

 	"path/filepath"

 	"sort"

@@ -11,8 +14,10 @@ import (

 	"github.com/boltdb/bolt"

 	"github.com/docker/docker/builder"

 	"github.com/docker/docker/builder/remotecontext"

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

 	"github.com/docker/docker/pkg/directory"

 	"github.com/docker/docker/pkg/stringid"

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

 	"github.com/moby/buildkit/session/filesync"

 	"github.com/pkg/errors"

 	"github.com/sirupsen/logrus"

@@ -578,6 +583,10 @@ func (dc *detectChanges) MarkSupported(v bool) {

 	dc.supported = v

 }

+func (dc *detectChanges) ContentHasher() fsutil.ContentHasher {

+	return newTarsumHash

+}

+

 type wrappedContext struct {

 	builder.Source

 	closer func() error

@@ -607,3 +616,40 @@ func (s sortableCacheSources) Less(i, j int) bool {

 func (s sortableCacheSources) Swap(i, j int) {

 	s[i], s[j] = s[j], s[i]

 }

+

+func newTarsumHash(stat *fsutil.Stat) (hash.Hash, error) {

+	fi := &fsutil.StatInfo{stat}

+	p := stat.Path

+	if fi.IsDir() {

+		p += string(os.PathSeparator)

+	}

+	h, err := archive.FileInfoHeader(p, fi, stat.Linkname)

+	if err != nil {

+		return nil, err

+	}

+	h.Name = p

+	h.Uid = int(stat.Uid)

+	h.Gid = int(stat.Gid)

+	h.Linkname = stat.Linkname

+	if stat.Xattrs != nil {

+		h.Xattrs = make(map[string]string)

+		for k, v := range stat.Xattrs {

+			h.Xattrs[k] = string(v)

+		}

+	}

+

+	tsh := &tarsumHash{h: h, Hash: sha256.New()}

+	tsh.Reset()

+	return tsh, nil

+}

+

+// Reset resets the Hash to its initial state.

+func (tsh *tarsumHash) Reset() {

+	tsh.Hash.Reset()

+	tarsum.WriteV1Header(tsh.h, tsh.Hash)

+}

+

+type tarsumHash struct {

+	hash.Hash

+	h *tar.Header

+}

@@ -5,15 +5,15 @@ import (

 	"os"

 	"sync"

-	iradix "github.com/hashicorp/go-immutable-radix"

-

 	"github.com/docker/docker/pkg/containerfs"

+	iradix "github.com/hashicorp/go-immutable-radix"

+	digest "github.com/opencontainers/go-digest"

 	"github.com/pkg/errors"

 	"github.com/tonistiigi/fsutil"

 )

 type hashed interface {

-	Hash() string

+	Digest() digest.Digest

 }

 // CachableSource is a source that contains cache records for its contents

@@ -110,7 +110,7 @@ func (cs *CachableSource) HandleChange(kind fsutil.ChangeKind, p string, fi os.F

 	}

 	hfi := &fileInfo{

-		sum: h.Hash(),

+		sum: h.Digest().Hex(),

 	}

 	cs.txn.Insert([]byte(p), hfi)

 	cs.mu.Unlock()

@@ -586,7 +586,9 @@ func testBuildWithSession(c *check.C, dir, dockerfile string) (outStr string) {

 	sess, err := session.NewSession("foo1", "foo")

 	assert.Nil(c, err)

-	fsProvider := filesync.NewFSSyncProvider(dir, nil)

+	fsProvider := filesync.NewFSSyncProvider([]filesync.SyncedDir{

+		{Dir: dir},

+	})

 	sess.Allow(fsProvider)

 	g, ctx := errgroup.WithContext(context.Background())

@@ -596,7 +598,7 @@ func testBuildWithSession(c *check.C, dir, dockerfile string) (outStr string) {

 	})

 	g.Go(func() error {

-		res, body, err := request.Post("/build?remote=client-session&session="+sess.UUID(), func(req *http.Request) error {

+		res, body, err := request.Post("/build?remote=client-session&session="+sess.ID(), func(req *http.Request) error {

 			req.Body = ioutil.NopCloser(strings.NewReader(dockerfile))

 			return nil

 		})

@@ -27,7 +27,7 @@ github.com/imdario/mergo 0.2.1

 golang.org/x/sync de49d9dcd27d4f764488181bea099dfe6179bcf0

 github.com/containerd/continuity 22694c680ee48fb8f50015b44618517e2bde77e8

-github.com/moby/buildkit c2dbdeb457ea665699a5d97f79eebfac4ab4726f https://github.com/tonistiigi/buildkit.git

+github.com/moby/buildkit aaff9d591ef128560018433fe61beb802e149de8

 github.com/tonistiigi/fsutil 1dedf6e90084bd88c4c518a15e68a37ed1370203

 #get libnetwork packages