Merge pull request #546 from stevvooe/resumable-digest-refactor

Remove digest package's dependency on external sha implementation

Godeps/Godeps.json

@@ -85,8 +85,8 @@
 			"Rev": "e444e69cbd2e2e3e0749a2f3c717cec491552bbf"
 		},
 		{
-			"ImportPath": "github.com/jlhawn/go-crypto",
-			"Rev": "cd738dde20f0b3782516181b0866c9bb9db47401"
+			"ImportPath": "github.com/stevvooe/resumable",
+			"Rev": "51ad44105773cafcbe91927f70ac68e1bf78f8b4"
 		},
 		{
 			"ImportPath": "github.com/yvasiyarov/go-metrics",

Godeps/_workspace/src/github.com/jlhawn/go-crypto/crypto.go

@@ -1,87 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package crypto is a Subset of the Go `crypto` Package with a Resumable Hash
-package crypto
-
-import (
-	"hash"
-	"strconv"
-)
-
-// Hash identifies a cryptographic hash function that is implemented in another
-// package.
-type Hash uint
-
-// HashFunc simply returns the value of h so that Hash implements SignerOpts.
-func (h Hash) HashFunc() Hash {
-	return h
-}
-
-const (
-	SHA224 Hash = 1 + iota // import crypto/sha256
-	SHA256                 // import crypto/sha256
-	SHA384                 // import crypto/sha512
-	SHA512                 // import crypto/sha512
-	maxHash
-)
-
-var digestSizes = []uint8{
-	SHA224: 28,
-	SHA256: 32,
-	SHA384: 48,
-	SHA512: 64,
-}
-
-// Size returns the length, in bytes, of a digest resulting from the given hash
-// function. It doesn't require that the hash function in question be linked
-// into the program.
-func (h Hash) Size() int {
-	if h > 0 && h < maxHash {
-		return int(digestSizes[h])
-	}
-	panic("crypto: Size of unknown hash function")
-}
-
-// ResumableHash is the common interface implemented by all resumable hash
-// functions.
-type ResumableHash interface {
-	// ResumableHash is a superset of hash.Hash
-	hash.Hash
-	// Len returns the number of bytes written to the Hash so far.
-	Len() uint64
-	// State returns a snapshot of the state of the Hash.
-	State() ([]byte, error)
-	// Restore resets the Hash to the given state.
-	Restore(state []byte) error
-}
-
-var hashes = make([]func() ResumableHash, maxHash)
-
-// New returns a new ResumableHash calculating the given hash function. New panics
-// if the hash function is not linked into the binary.
-func (h Hash) New() ResumableHash {
-	if h > 0 && h < maxHash {
-		f := hashes[h]
-		if f != nil {
-			return f()
-		}
-	}
-	panic("crypto: requested hash function #" + strconv.Itoa(int(h)) + " is unavailable")
-}
-
-// Available reports whether the given hash function is linked into the binary.
-func (h Hash) Available() bool {
-	return h < maxHash && hashes[h] != nil
-}
-
-// RegisterHash registers a function that returns a new instance of the given
-// hash function. This is intended to be called from the init function in
-// packages that implement hash functions.
-func RegisterHash(h Hash, f func() ResumableHash) {
-	if h >= maxHash {
-		panic("crypto: RegisterHash of unknown hash function")
-	}
-	hashes[h] = f
-}

Godeps/_workspace/src/github.com/jlhawn/go-crypto/textflag.h

@@ -1,23 +0,0 @@
-// Copyright 2013 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file defines flags attached to various functions
-// and data objects.  The compilers, assemblers, and linker must
-// all agree on these values.
-
-// Don't profile the marked routine.  This flag is deprecated.
-#define NOPROF	1
-// It is ok for the linker to get multiple of these symbols.  It will
-// pick one of the duplicates to use.
-#define DUPOK	2
-// Don't insert stack check preamble.
-#define NOSPLIT	4
-// Put this data in a read-only section.
-#define RODATA	8
-// This data contains no pointers.
-#define NOPTR	16
-// This is a wrapper function and should not count as disabling 'recover'.
-#define WRAPPER 32
-// This function uses its incoming context register.
-#define NEEDCTXT 64

Godeps/_workspace/src/github.com/stevvooe/resumable/README.md

@@ -3,4 +3,4 @@ A Subset of the Go `crypto` Package with a Resumable Hash Interface
 
 ### Documentation
 
-GoDocs: http://godoc.org/github.com/jlhawn/go-crypto
+GoDocs: http://godoc.org/github.com/stevvooe/resumable

Godeps/_workspace/src/github.com/stevvooe/resumable/resumable.go

@@ -0,0 +1,43 @@
+// Package resumable registers resumable versions of hash functions. Resumable
+// varieties of hash functions are available via the standard crypto package.
+// Support can be checked by type assertion against the resumable.Hash
+// interface.
+//
+// While one can use these sub-packages directly, it makes more sense to
+// register them using side-effect imports:
+//
+// 	import _ "github.com/stevvooe/resumable/sha256"
+//
+// This will make the resumable hashes available to the application through
+// the standard crypto package. For example, if a new sha256 is required, one
+// should use the following:
+//
+// 	h := crypto.SHA256.New()
+//
+// Such a features allows one to control the inclusion of resumable hash
+// support in a single file. Applications that require the resumable hash
+// implementation can type switch to detect support, while other parts of the
+// application can be completely oblivious to the presence of the alternative
+// hash functions.
+//
+// Also note that the implementations available in this package are completely
+// untouched from their Go counterparts in the standard library. Only an extra
+// file is added to each package to implement the extra resumable hash
+// functions.
+package resumable
+
+import "hash"
+
+// Hash is the common interface implemented by all resumable hash functions.
+type Hash interface {
+	hash.Hash
+
+	// Len returns the number of bytes written to the Hash so far.
+	Len() int64
+
+	// State returns a snapshot of the state of the Hash.
+	State() ([]byte, error)
+
+	// Restore resets the Hash to the given state.
+	Restore(state []byte) error
+}

Godeps/_workspace/src/github.com/stevvooe/resumable/sha256/resume.go

@@ -3,11 +3,14 @@ package sha256
 import (
 	"bytes"
 	"encoding/gob"
+
+	// import to ensure that our init function runs after the standard package
+	_ "crypto/sha256"
 )
 
 // Len returns the number of bytes which have been written to the digest.
-func (d *digest) Len() uint64 {
-	return d.len
+func (d *digest) Len() int64 {
+	return int64(d.len)
 }
 
 // State returns a snapshot of the state of the digest.

Godeps/_workspace/src/github.com/stevvooe/resumable/sha256/sha256.go

@@ -7,7 +7,8 @@
 package sha256
 
 import (
-	"github.com/jlhawn/go-crypto"
+	"crypto"
+	"hash"
 )
 
 func init() {
@@ -77,15 +78,15 @@ func (d *digest) Reset() {
 	d.len = 0
 }
 
-// New returns a new crypto.ResumableHash computing the SHA256 checksum.
-func New() crypto.ResumableHash {
+// New returns a new hash.Hash computing the SHA256 checksum.
+func New() hash.Hash {
 	d := new(digest)
 	d.Reset()
 	return d
 }
 
-// New224 returns a new crypto.ResumableHash computing the SHA224 checksum.
-func New224() crypto.ResumableHash {
+// New224 returns a new hash.Hash computing the SHA224 checksum.
+func New224() hash.Hash {
 	d := new(digest)
 	d.is224 = true
 	d.Reset()

Godeps/_workspace/src/github.com/stevvooe/resumable/sha256/sha256block_amd64.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-#include "../textflag.h"
+#include "textflag.h"
 
 // SHA256 block routine. See sha256block.go for Go equivalent.
 //

Godeps/_workspace/src/github.com/stevvooe/resumable/sha256/sha256resume_test.go

@@ -2,15 +2,17 @@ package sha256
 
 import (
 	"bytes"
-	stdlib "crypto"
+	"crypto"
 	"crypto/rand"
-	_ "crypto/sha256" // To register the stdlib sha224 and sha256 algs.
-	resumable "github.com/jlhawn/go-crypto"
+	"crypto/sha256" // To register the stdlib sha224 and sha256 algs.
+	"hash"
 	"io"
 	"testing"
+
+	"github.com/stevvooe/resumable"
 )
 
-func compareResumableHash(t *testing.T, r resumable.Hash, h stdlib.Hash) {
+func compareResumableHash(t *testing.T, newResumable func() hash.Hash, newStdlib func() hash.Hash) {
 	// Read 3 Kilobytes of random data into a buffer.
 	buf := make([]byte, 3*1024)
 	if _, err := io.ReadFull(rand.Reader, buf); err != nil {
@@ -20,8 +22,8 @@ func compareResumableHash(t *testing.T, r resumable.Hash, h stdlib.Hash) {
 	// Use two Hash objects to consume prefixes of the data. One will be
 	// snapshotted and resumed with each additional byte, then both will write
 	// that byte. The digests should be equal after each byte is digested.
-	resumableHasher := r.New()
-	stdlibHasher := h.New()
+	resumableHasher := newResumable().(resumable.Hash)
+	stdlibHasher := newStdlib()
 
 	// First, assert that the initial distest is the same.
 	if !bytes.Equal(resumableHasher.Sum(nil), stdlibHasher.Sum(nil)) {
@@ -52,6 +54,21 @@ func compareResumableHash(t *testing.T, r resumable.Hash, h stdlib.Hash) {
 }
 
 func TestResumable(t *testing.T) {
-	compareResumableHash(t, resumable.SHA224, stdlib.SHA224)
-	compareResumableHash(t, resumable.SHA256, stdlib.SHA256)
+	compareResumableHash(t, New224, sha256.New224)
+	compareResumableHash(t, New, sha256.New)
+}
+
+func TestResumableRegistered(t *testing.T) {
+
+	for _, hf := range []crypto.Hash{crypto.SHA224, crypto.SHA256} {
+		// make sure that the hash gets the resumable version from the global
+		// registry in crypto library.
+		h := hf.New()
+
+		if rh, ok := h.(resumable.Hash); !ok {
+			t.Fatalf("non-resumable hash function registered: %#v %#v", rh, crypto.SHA256)
+		}
+
+	}
+
 }

Godeps/_workspace/src/github.com/stevvooe/resumable/sha512/resume.go

@@ -3,11 +3,14 @@ package sha512
 import (
 	"bytes"
 	"encoding/gob"
+
+	// import to ensure that our init function runs after the standard package
+	_ "crypto/sha512"
 )
 
 // Len returns the number of bytes which have been written to the digest.
-func (d *digest) Len() uint64 {
-	return d.len
+func (d *digest) Len() int64 {
+	return int64(d.len)
 }
 
 // State returns a snapshot of the state of the digest.

Godeps/_workspace/src/github.com/stevvooe/resumable/sha512/sha512.go

@@ -7,7 +7,8 @@
 package sha512
 
 import (
-	"github.com/jlhawn/go-crypto"
+	"crypto"
+	"hash"
 )
 
 func init() {
@@ -77,15 +78,15 @@ func (d *digest) Reset() {
 	d.len = 0
 }
 
-// New returns a new crypto.ResumableHash computing the SHA512 checksum.
-func New() crypto.ResumableHash {
+// New returns a new hash.Hash computing the SHA512 checksum.
+func New() hash.Hash {
 	d := new(digest)
 	d.Reset()
 	return d
 }
 
-// New384 returns a new crypto.ResumableHash computing the SHA384 checksum.
-func New384() crypto.ResumableHash {
+// New384 returns a new hash.Hash computing the SHA384 checksum.
+func New384() hash.Hash {
 	d := new(digest)
 	d.is384 = true
 	d.Reset()

Godeps/_workspace/src/github.com/stevvooe/resumable/sha512/sha512block_amd64.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-#include "../textflag.h"
+#include "textflag.h"
 
 // SHA512 block routine. See sha512block.go for Go equivalent.
 //

Godeps/_workspace/src/github.com/stevvooe/resumable/sha512/sha512resume_test.go

@@ -2,15 +2,17 @@ package sha512
 
 import (
 	"bytes"
-	stdlib "crypto"
-	"crypto/rand"
-	_ "crypto/sha512" // To register the stdlib sha224 and sha256 algs.
-	resumable "github.com/jlhawn/go-crypto"
+	"crypto"
+	"crypto/rand" // To register the stdlib sha224 and sha256 algs.
+	"crypto/sha512"
+	"hash"
 	"io"
 	"testing"
+
+	"github.com/stevvooe/resumable"
 )
 
-func compareResumableHash(t *testing.T, r resumable.Hash, h stdlib.Hash) {
+func compareResumableHash(t *testing.T, newResumable func() hash.Hash, newStdlib func() hash.Hash) {
 	// Read 3 Kilobytes of random data into a buffer.
 	buf := make([]byte, 3*1024)
 	if _, err := io.ReadFull(rand.Reader, buf); err != nil {
@@ -20,8 +22,8 @@ func compareResumableHash(t *testing.T, r resumable.Hash, h stdlib.Hash) {
 	// Use two Hash objects to consume prefixes of the data. One will be
 	// snapshotted and resumed with each additional byte, then both will write
 	// that byte. The digests should be equal after each byte is digested.
-	resumableHasher := r.New()
-	stdlibHasher := h.New()
+	resumableHasher := newResumable().(resumable.Hash)
+	stdlibHasher := newStdlib()
 
 	// First, assert that the initial distest is the same.
 	if !bytes.Equal(resumableHasher.Sum(nil), stdlibHasher.Sum(nil)) {
@@ -52,6 +54,21 @@ func compareResumableHash(t *testing.T, r resumable.Hash, h stdlib.Hash) {
 }
 
 func TestResumable(t *testing.T) {
-	compareResumableHash(t, resumable.SHA384, stdlib.SHA384)
-	compareResumableHash(t, resumable.SHA512, stdlib.SHA512)
+	compareResumableHash(t, New384, sha512.New384)
+	compareResumableHash(t, New, sha512.New)
+}
+
+func TestResumableRegistered(t *testing.T) {
+
+	for _, hf := range []crypto.Hash{crypto.SHA384, crypto.SHA512} {
+		// make sure that the hash gets the resumable version from the global
+		// registry in crypto library.
+		h := hf.New()
+
+		if rh, ok := h.(resumable.Hash); !ok {
+			t.Fatalf("non-resumable hash function registered: %#v %#v", rh, crypto.SHA256)
+		}
+
+	}
+
 }

digest/digest.go

@@ -15,6 +15,7 @@ import (
 const (
 	// DigestTarSumV1EmptyTar is the digest for the empty tar file.
 	DigestTarSumV1EmptyTar = "tarsum.v1+sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+
 	// DigestSha256EmptyTar is the canonical sha256 digest of empty data
 	DigestSha256EmptyTar = "sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
 )
@@ -38,7 +39,7 @@ const (
 type Digest string
 
 // NewDigest returns a Digest from alg and a hash.Hash object.
-func NewDigest(alg string, h hash.Hash) Digest {
+func NewDigest(alg Algorithm, h hash.Hash) Digest {
 	return Digest(fmt.Sprintf("%s:%x", alg, h.Sum(nil)))
 }
 
@@ -71,9 +72,9 @@ func ParseDigest(s string) (Digest, error) {
 
 // FromReader returns the most valid digest for the underlying content.
 func FromReader(rd io.Reader) (Digest, error) {
-	digester := NewCanonicalDigester()
+	digester := Canonical.New()
 
-	if _, err := io.Copy(digester, rd); err != nil {
+	if _, err := io.Copy(digester.Hash(), rd); err != nil {
 		return "", err
 	}
 
@@ -130,8 +131,8 @@ func (d Digest) Validate() error {
 		return ErrDigestInvalidFormat
 	}
 
-	switch s[:i] {
-	case "sha256", "sha384", "sha512":
+	switch Algorithm(s[:i]) {
+	case SHA256, SHA384, SHA512:
 		break
 	default:
 		return ErrDigestUnsupported
@@ -142,8 +143,8 @@ func (d Digest) Validate() error {
 
 // Algorithm returns the algorithm portion of the digest. This will panic if
 // the underlying digest is not in a valid format.
-func (d Digest) Algorithm() string {
-	return string(d[:d.sepIndex()])
+func (d Digest) Algorithm() Algorithm {
+	return Algorithm(d[:d.sepIndex()])
 }
 
 // Hex returns the hex digest portion of the digest. This will panic if the

digest/digest_test.go

@@ -10,7 +10,7 @@ func TestParseDigest(t *testing.T) {
 	for _, testcase := range []struct {
 		input     string
 		err       error
-		algorithm string
+		algorithm Algorithm
 		hex       string
 	}{
 		{

digest/digester.go

@@ -1,54 +1,95 @@
 package digest
 
 import (
-	"crypto/sha256"
+	"crypto"
 	"hash"
 )
 
-// Digester calculates the digest of written data. It is functionally
-// equivalent to hash.Hash but provides methods for returning the Digest type
-// rather than raw bytes.
-type Digester struct {
-	alg string
-	hash.Hash
+// Algorithm identifies and implementation of a digester by an identifier.
+// Note the that this defines both the hash algorithm used and the string
+// encoding.
+type Algorithm string
+
+// supported digest types
+const (
+	SHA256         Algorithm = "sha256"           // sha256 with hex encoding
+	SHA384         Algorithm = "sha384"           // sha384 with hex encoding
+	SHA512         Algorithm = "sha512"           // sha512 with hex encoding
+	TarsumV1SHA256 Algorithm = "tarsum+v1+sha256" // supported tarsum version, verification only
+
+	// Canonical is the primary digest algorithm used with the distribution
+	// project. Other digests may be used but this one is the primary storage
+	// digest.
+	Canonical = SHA256
+)
+
+var (
+	// TODO(stevvooe): Follow the pattern of the standard crypto package for
+	// registration of digests. Effectively, we are a registerable set and
+	// common symbol access.
+
+	// algorithms maps values to hash.Hash implementations. Other algorithms
+	// may be available but they cannot be calculated by the digest package.
+	algorithms = map[Algorithm]crypto.Hash{
+		SHA256: crypto.SHA256,
+		SHA384: crypto.SHA384,
+		SHA512: crypto.SHA512,
+	}
+)
+
+// Available returns true if the digest type is available for use. If this
+// returns false, New and Hash will return nil.
+func (a Algorithm) Available() bool {
+	h, ok := algorithms[a]
+	if !ok {
+		return false
 	}
 
-// NewDigester create a new Digester with the given hashing algorithm and instance
-// of that algo's hasher.
-func NewDigester(alg string, h hash.Hash) Digester {
-	return Digester{
-		alg:  alg,
-		Hash: h,
+	// check availability of the hash, as well
+	return h.Available()
+}
+
+// New returns a new digester for the specified algorithm. If the algorithm
+// does not have a digester implementation, nil will be returned. This can be
+// checked by calling Available before calling New.
+func (a Algorithm) New() Digester {
+	return &digester{
+		alg:  a,
+		hash: a.Hash(),
 	}
 }
 
-// NewCanonicalDigester is a convenience function to create a new Digester with
-// our default settings.
-func NewCanonicalDigester() Digester {
-	return NewDigester("sha256", sha256.New())
+// Hash returns a new hash as used by the algorithm. If not available, nil is
+// returned. Make sure to check Available before calling.
+func (a Algorithm) Hash() hash.Hash {
+	if !a.Available() {
+		return nil
 	}
 
-// Digest returns the current digest for this digester.
-func (d *Digester) Digest() Digest {
-	return NewDigest(d.alg, d.Hash)
+	return algorithms[a].New()
 }
 
-// ResumableHash is the common interface implemented by all resumable hash
-// functions.
-type ResumableHash interface {
-	// ResumableHash is a superset of hash.Hash
-	hash.Hash
-	// Len returns the number of bytes written to the Hash so far.
-	Len() uint64
-	// State returns a snapshot of the state of the Hash.
-	State() ([]byte, error)
-	// Restore resets the Hash to the given state.
-	Restore(state []byte) error
-}
+// TODO(stevvooe): Allow resolution of verifiers using the digest type and
+// this registration system.
 
-// ResumableDigester is a digester that can export its internal state and be
-// restored from saved state.
-type ResumableDigester interface {
-	ResumableHash
+// Digester calculates the digest of written data. Writes should go directly
+// to the return value of Hash, while calling Digest will return the current
+// value of the digest.
+type Digester interface {
+	Hash() hash.Hash // provides direct access to underlying hash instance.
 	Digest() Digest
 }
+
+// digester provides a simple digester definition that embeds a hasher.
+type digester struct {
+	alg  Algorithm
+	hash hash.Hash
+}
+
+func (d *digester) Hash() hash.Hash {
+	return d.hash
+}
+
+func (d *digester) Digest() Digest {
+	return NewDigest(d.alg, d.hash)
+}

digest/digester_resumable.go

@@ -1,52 +0,0 @@
-// +build !noresumabledigest
-
-package digest
-
-import (
-	"fmt"
-
-	"github.com/jlhawn/go-crypto"
-	// For ResumableHash
-	_ "github.com/jlhawn/go-crypto/sha256" // For Resumable SHA256
-	_ "github.com/jlhawn/go-crypto/sha512" // For Resumable SHA384, SHA512
-)
-
-// resumableDigester implements ResumableDigester.
-type resumableDigester struct {
-	alg string
-	crypto.ResumableHash
-}
-
-var resumableHashAlgs = map[string]crypto.Hash{
-	"sha256": crypto.SHA256,
-	"sha384": crypto.SHA384,
-	"sha512": crypto.SHA512,
-}
-
-// NewResumableDigester creates a new ResumableDigester with the given hashing
-// algorithm.
-func NewResumableDigester(alg string) (ResumableDigester, error) {
-	hash, supported := resumableHashAlgs[alg]
-	if !supported {
-		return resumableDigester{}, fmt.Errorf("unsupported resumable hash algorithm: %s", alg)
-	}
-
-	return resumableDigester{
-		alg:           alg,
-		ResumableHash: hash.New(),
-	}, nil
-}
-
-// NewCanonicalResumableDigester creates a ResumableDigester using the default
-// digest algorithm.
-func NewCanonicalResumableDigester() ResumableDigester {
-	return resumableDigester{
-		alg:           "sha256",
-		ResumableHash: crypto.SHA256.New(),
-	}
-}
-
-// Digest returns the current digest for this resumable digester.
-func (d resumableDigester) Digest() Digest {
-	return NewDigest(d.alg, d.ResumableHash)
-}

digest/digester_resumable_test.go

@@ -0,0 +1,21 @@
+// +build !noresumabledigest
+
+package digest
+
+import (
+	"testing"
+
+	"github.com/stevvooe/resumable"
+	_ "github.com/stevvooe/resumable/sha256"
+)
+
+// TestResumableDetection just ensures that the resumable capability of a hash
+// is exposed through the digester type, which is just a hash plus a Digest
+// method.
+func TestResumableDetection(t *testing.T) {
+	d := Canonical.New()
+
+	if _, ok := d.Hash().(resumable.Hash); !ok {
+		t.Fatalf("expected digester to implement resumable.Hash: %#v, %v", d, d.Hash())
+	}
+}

digest/set.go

@@ -42,17 +42,17 @@ func NewSet() *Set {
 // values or short values. This function does not test equality,
 // rather whether the second value could match against the first
 // value.
-func checkShortMatch(alg, hex, shortAlg, shortHex string) bool {
+func checkShortMatch(alg Algorithm, hex, shortAlg, shortHex string) bool {
 	if len(hex) == len(shortHex) {
 		if hex != shortHex {
 			return false
 		}
-		if len(shortAlg) > 0 && alg != shortAlg {
+		if len(shortAlg) > 0 && string(alg) != shortAlg {
 			return false
 		}
 	} else if !strings.HasPrefix(hex, shortHex) {
 		return false
-	} else if len(shortAlg) > 0 && alg != shortAlg {
+	} else if len(shortAlg) > 0 && string(alg) != shortAlg {
 		return false
 	}
 	return true
@@ -68,7 +68,7 @@ func (dst *Set) Lookup(d string) (Digest, error) {
 	}
 	var (
 		searchFunc func(int) bool
-		alg        string
+		alg        Algorithm
 		hex        string
 	)
 	dgst, err := ParseDigest(d)
@@ -88,13 +88,13 @@ func (dst *Set) Lookup(d string) (Digest, error) {
 		}
 	}
 	idx := sort.Search(len(dst.entries), searchFunc)
-	if idx == len(dst.entries) || !checkShortMatch(dst.entries[idx].alg, dst.entries[idx].val, alg, hex) {
+	if idx == len(dst.entries) || !checkShortMatch(dst.entries[idx].alg, dst.entries[idx].val, string(alg), hex) {
 		return "", ErrDigestNotFound
 	}
 	if dst.entries[idx].alg == alg && dst.entries[idx].val == hex {
 		return dst.entries[idx].digest, nil
 	}
-	if idx+1 < len(dst.entries) && checkShortMatch(dst.entries[idx+1].alg, dst.entries[idx+1].val, alg, hex) {
+	if idx+1 < len(dst.entries) && checkShortMatch(dst.entries[idx+1].alg, dst.entries[idx+1].val, string(alg), hex) {
 		return "", ErrDigestAmbiguous
 	}
 
@@ -172,7 +172,7 @@ func ShortCodeTable(dst *Set, length int) map[Digest]string {
 }
 
 type digestEntry struct {
-	alg    string
+	alg    Algorithm
 	val    string
 	digest Digest
 }

digest/verifiers.go

@@ -1,8 +1,6 @@
 package digest
 
 import (
-	"crypto/sha256"
-	"crypto/sha512"
 	"hash"
 	"io"
 	"io/ioutil"
@@ -33,7 +31,7 @@ func NewDigestVerifier(d Digest) (Verifier, error) {
 	switch alg {
 	case "sha256", "sha384", "sha512":
 		return hashVerifier{
-			hash:   newHash(alg),
+			hash:   alg.Hash(),
 			digest: d,
 		}, nil
 	default:
@@ -95,19 +93,6 @@ func (lv *lengthVerifier) Verified() bool {
 	return lv.expected == lv.len
 }
 
-func newHash(name string) hash.Hash {
-	switch name {
-	case "sha256":
-		return sha256.New()
-	case "sha384":
-		return sha512.New384()
-	case "sha512":
-		return sha512.New()
-	default:
-		panic("unsupport algorithm: " + name)
-	}
-}
-
 type hashVerifier struct {
 	digest Digest
 	hash   hash.Hash

registry/client/repository.go

@@ -322,8 +322,8 @@ func (bs *blobs) Put(ctx context.Context, mediaType string, p []byte) (distribut
 	if err != nil {
 		return distribution.Descriptor{}, err
 	}
-	dgstr := digest.NewCanonicalDigester()
-	n, err := io.Copy(writer, io.TeeReader(bytes.NewReader(p), dgstr))
+	dgstr := digest.Canonical.New()
+	n, err := io.Copy(writer, io.TeeReader(bytes.NewReader(p), dgstr.Hash()))
 	if err != nil {
 		return distribution.Descriptor{}, err
 	}

registry/handlers/api_test.go

@@ -213,8 +213,8 @@ func TestBlobAPI(t *testing.T) {
 	// Now, push just a chunk
 	layerFile.Seek(0, 0)
 
-	canonicalDigester := digest.NewCanonicalDigester()
-	if _, err := io.Copy(canonicalDigester, layerFile); err != nil {
+	canonicalDigester := digest.Canonical.New()
+	if _, err := io.Copy(canonicalDigester.Hash(), layerFile); err != nil {
 		t.Fatalf("error copying to digest: %v", err)
 	}
 	canonicalDigest := canonicalDigester.Digest()
@@ -637,9 +637,9 @@ func doPushLayer(t *testing.T, ub *v2.URLBuilder, name string, dgst digest.Diges
 
 // pushLayer pushes the layer content returning the url on success.
 func pushLayer(t *testing.T, ub *v2.URLBuilder, name string, dgst digest.Digest, uploadURLBase string, body io.Reader) string {
-	digester := digest.NewCanonicalDigester()
+	digester := digest.Canonical.New()
 
-	resp, err := doPushLayer(t, ub, name, dgst, uploadURLBase, io.TeeReader(body, &digester))
+	resp, err := doPushLayer(t, ub, name, dgst, uploadURLBase, io.TeeReader(body, digester.Hash()))
 	if err != nil {
 		t.Fatalf("unexpected error doing push layer request: %v", err)
 	}
@@ -702,9 +702,9 @@ func doPushChunk(t *testing.T, uploadURLBase string, body io.Reader) (*http.Resp
 
 	uploadURL := u.String()
 
-	digester := digest.NewCanonicalDigester()
+	digester := digest.Canonical.New()
 
-	req, err := http.NewRequest("PATCH", uploadURL, io.TeeReader(body, digester))
+	req, err := http.NewRequest("PATCH", uploadURL, io.TeeReader(body, digester.Hash()))
 	if err != nil {
 		t.Fatalf("unexpected error creating new request: %v", err)
 	}

registry/storage/blobwriter.go

@@ -1,11 +1,9 @@
 package storage
 
 import (
+	"errors"
 	"fmt"
 	"io"
-	"os"
-	"path"
-	"strconv"
 	"time"
 
 	"github.com/Sirupsen/logrus"
@@ -15,6 +13,10 @@ import (
 	storagedriver "github.com/docker/distribution/registry/storage/driver"
 )
 
+var (
+	errResumableDigestNotAvailable = errors.New("resumable digest not available")
+)
+
 // layerWriter is used to control the various aspects of resumable
 // layer upload. It implements the LayerUpload interface.
 type blobWriter struct {
@@ -22,7 +24,8 @@ type blobWriter struct {
 
 	id        string
 	startedAt time.Time
-	resumableDigester digest.ResumableDigester
+	digester  digest.Digester
+	written   int64 // track the contiguous write
 
 	// implementes io.WriteSeeker, io.ReaderFrom and io.Closer to satisfy
 	// LayerUpload Interface
@@ -82,33 +85,31 @@ func (bw *blobWriter) Cancel(ctx context.Context) error {
 }
 
 func (bw *blobWriter) Write(p []byte) (int, error) {
-	if bw.resumableDigester == nil {
-		return bw.bufferedFileWriter.Write(p)
-	}
-
 	// Ensure that the current write offset matches how many bytes have been
 	// written to the digester. If not, we need to update the digest state to
 	// match the current write position.
-	if err := bw.resumeHashAt(bw.blobStore.ctx, bw.offset); err != nil {
+	if err := bw.resumeDigestAt(bw.blobStore.ctx, bw.offset); err != nil && err != errResumableDigestNotAvailable {
 		return 0, err
 	}
 
-	return io.MultiWriter(&bw.bufferedFileWriter, bw.resumableDigester).Write(p)
+	n, err := io.MultiWriter(&bw.bufferedFileWriter, bw.digester.Hash()).Write(p)
+	bw.written += int64(n)
+
+	return n, err
 }
 
 func (bw *blobWriter) ReadFrom(r io.Reader) (n int64, err error) {
-	if bw.resumableDigester == nil {
-		return bw.bufferedFileWriter.ReadFrom(r)
-	}
-
 	// Ensure that the current write offset matches how many bytes have been
 	// written to the digester. If not, we need to update the digest state to
 	// match the current write position.
-	if err := bw.resumeHashAt(bw.blobStore.ctx, bw.offset); err != nil {
+	if err := bw.resumeDigestAt(bw.blobStore.ctx, bw.offset); err != nil && err != errResumableDigestNotAvailable {
 		return 0, err
 	}
 
-	return bw.bufferedFileWriter.ReadFrom(io.TeeReader(r, bw.resumableDigester))
+	nn, err := bw.bufferedFileWriter.ReadFrom(io.TeeReader(r, bw.digester.Hash()))
+	bw.written += nn
+
+	return nn, err
 }
 
 func (bw *blobWriter) Close() error {
@@ -116,11 +117,9 @@ func (bw *blobWriter) Close() error {
 		return bw.err
 	}
 
-	if bw.resumableDigester != nil {
 	if err := bw.storeHashState(bw.blobStore.ctx); err != nil {
 		return err
 	}
-	}
 
 	return bw.bufferedFileWriter.Close()
 }
@@ -171,13 +170,11 @@ func (bw *blobWriter) validateBlob(ctx context.Context, desc distribution.Descri
 		desc.Length = bw.size
 	}
 
-	if bw.resumableDigester != nil {
-		// Restore the hasher state to the end of the upload.
-		if err := bw.resumeHashAt(ctx, bw.size); err != nil {
-			return distribution.Descriptor{}, err
-		}
+	// TODO(stevvooe): This section is very meandering. Need to be broken down
+	// to be a lot more clear.
 
-		canonical = bw.resumableDigester.Digest()
+	if err := bw.resumeDigestAt(ctx, bw.size); err == nil {
+		canonical = bw.digester.Digest()
 
 		if canonical.Algorithm() == desc.Digest.Algorithm() {
 			// Common case: client and server prefer the same canonical digest
@@ -189,13 +186,28 @@ func (bw *blobWriter) validateBlob(ctx context.Context, desc distribution.Descri
 			// uploaded content using that digest algorithm.
 			fullHash = true
 		}
-	} else {
+	} else if err == errResumableDigestNotAvailable {
 		// Not using resumable digests, so we need to hash the entire layer.
 		fullHash = true
+	} else {
+		return distribution.Descriptor{}, err
 	}
 
 	if fullHash {
-		digester := digest.NewCanonicalDigester()
+		// a fantastic optimization: if the the written data and the size are
+		// the same, we don't need to read the data from the backend. This is
+		// because we've written the entire file in the lifecycle of the
+		// current instance.
+		if bw.written == bw.size && digest.Canonical == desc.Digest.Algorithm() {
+			canonical = bw.digester.Digest()
+			verified = desc.Digest == canonical
+		}
+
+		// If the check based on size fails, we fall back to the slowest of
+		// paths. We may be able to make the size-based check a stronger
+		// guarantee, so this may be defensive.
+		if !verified {
+			digester := digest.Canonical.New()
 
 			digestVerifier, err := digest.NewDigestVerifier(desc.Digest)
 			if err != nil {
@@ -208,7 +220,7 @@ func (bw *blobWriter) validateBlob(ctx context.Context, desc distribution.Descri
 				return distribution.Descriptor{}, err
 			}
 
-		tr := io.TeeReader(fr, digester)
+			tr := io.TeeReader(fr, digester.Hash())
 
 			if _, err := io.Copy(digestVerifier, tr); err != nil {
 				return distribution.Descriptor{}, err
@@ -217,6 +229,7 @@ func (bw *blobWriter) validateBlob(ctx context.Context, desc distribution.Descri
 			canonical = digester.Digest()
 			verified = digestVerifier.Verified()
 		}
+	}
 
 	if !verified {
 		context.GetLoggerWithFields(ctx,
@@ -298,172 +311,3 @@ func (bw *blobWriter) moveBlob(ctx context.Context, desc distribution.Descriptor
 
 	return bw.blobStore.driver.Move(ctx, bw.path, blobPath)
 }
-
-type hashStateEntry struct {
-	offset int64
-	path   string
-}
-
-// getStoredHashStates returns a slice of hashStateEntries for this upload.
-func (bw *blobWriter) getStoredHashStates(ctx context.Context) ([]hashStateEntry, error) {
-	uploadHashStatePathPrefix, err := bw.blobStore.pm.path(uploadHashStatePathSpec{
-		name: bw.blobStore.repository.Name(),
-		id:   bw.id,
-		alg:  bw.resumableDigester.Digest().Algorithm(),
-		list: true,
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	paths, err := bw.blobStore.driver.List(ctx, uploadHashStatePathPrefix)
-	if err != nil {
-		if _, ok := err.(storagedriver.PathNotFoundError); !ok {
-			return nil, err
-		}
-		// Treat PathNotFoundError as no entries.
-		paths = nil
-	}
-
-	hashStateEntries := make([]hashStateEntry, 0, len(paths))
-
-	for _, p := range paths {
-		pathSuffix := path.Base(p)
-		// The suffix should be the offset.
-		offset, err := strconv.ParseInt(pathSuffix, 0, 64)
-		if err != nil {
-			logrus.Errorf("unable to parse offset from upload state path %q: %s", p, err)
-		}
-
-		hashStateEntries = append(hashStateEntries, hashStateEntry{offset: offset, path: p})
-	}
-
-	return hashStateEntries, nil
-}
-
-// resumeHashAt attempts to restore the state of the internal hash function
-// by loading the most recent saved hash state less than or equal to the given
-// offset. Any unhashed bytes remaining less than the given offset are hashed
-// from the content uploaded so far.
-func (bw *blobWriter) resumeHashAt(ctx context.Context, offset int64) error {
-	if offset < 0 {
-		return fmt.Errorf("cannot resume hash at negative offset: %d", offset)
-	}
-
-	if offset == int64(bw.resumableDigester.Len()) {
-		// State of digester is already at the requested offset.
-		return nil
-	}
-
-	// List hash states from storage backend.
-	var hashStateMatch hashStateEntry
-	hashStates, err := bw.getStoredHashStates(ctx)
-	if err != nil {
-		return fmt.Errorf("unable to get stored hash states with offset %d: %s", offset, err)
-	}
-
-	// Find the highest stored hashState with offset less than or equal to
-	// the requested offset.
-	for _, hashState := range hashStates {
-		if hashState.offset == offset {
-			hashStateMatch = hashState
-			break // Found an exact offset match.
-		} else if hashState.offset < offset && hashState.offset > hashStateMatch.offset {
-			// This offset is closer to the requested offset.
-			hashStateMatch = hashState
-		} else if hashState.offset > offset {
-			// Remove any stored hash state with offsets higher than this one
-			// as writes to this resumed hasher will make those invalid. This
-			// is probably okay to skip for now since we don't expect anyone to
-			// use the API in this way. For that reason, we don't treat an
-			// an error here as a fatal error, but only log it.
-			if err := bw.driver.Delete(ctx, hashState.path); err != nil {
-				logrus.Errorf("unable to delete stale hash state %q: %s", hashState.path, err)
-			}
-		}
-	}
-
-	if hashStateMatch.offset == 0 {
-		// No need to load any state, just reset the hasher.
-		bw.resumableDigester.Reset()
-	} else {
-		storedState, err := bw.driver.GetContent(ctx, hashStateMatch.path)
-		if err != nil {
-			return err
-		}
-
-		if err = bw.resumableDigester.Restore(storedState); err != nil {
-			return err
-		}
-	}
-
-	// Mind the gap.
-	if gapLen := offset - int64(bw.resumableDigester.Len()); gapLen > 0 {
-		// Need to read content from the upload to catch up to the desired offset.
-		fr, err := newFileReader(ctx, bw.driver, bw.path, bw.size)
-		if err != nil {
-			return err
-		}
-
-		if _, err = fr.Seek(int64(bw.resumableDigester.Len()), os.SEEK_SET); err != nil {
-			return fmt.Errorf("unable to seek to layer reader offset %d: %s", bw.resumableDigester.Len(), err)
-		}
-
-		if _, err := io.CopyN(bw.resumableDigester, fr, gapLen); err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-func (bw *blobWriter) storeHashState(ctx context.Context) error {
-	uploadHashStatePath, err := bw.blobStore.pm.path(uploadHashStatePathSpec{
-		name:   bw.blobStore.repository.Name(),
-		id:     bw.id,
-		alg:    bw.resumableDigester.Digest().Algorithm(),
-		offset: int64(bw.resumableDigester.Len()),
-	})
-	if err != nil {
-		return err
-	}
-
-	hashState, err := bw.resumableDigester.State()
-	if err != nil {
-		return err
-	}
-
-	return bw.driver.PutContent(ctx, uploadHashStatePath, hashState)
-}
-
-// removeResources should clean up all resources associated with the upload
-// instance. An error will be returned if the clean up cannot proceed. If the
-// resources are already not present, no error will be returned.
-func (bw *blobWriter) removeResources(ctx context.Context) error {
-	dataPath, err := bw.blobStore.pm.path(uploadDataPathSpec{
-		name: bw.blobStore.repository.Name(),
-		id:   bw.id,
-	})
-
-	if err != nil {
-		return err
-	}
-
-	// Resolve and delete the containing directory, which should include any
-	// upload related files.
-	dirPath := path.Dir(dataPath)
-	if err := bw.blobStore.driver.Delete(ctx, dirPath); err != nil {
-		switch err := err.(type) {
-		case storagedriver.PathNotFoundError:
-			break // already gone!
-		default:
-			// This should be uncommon enough such that returning an error
-			// should be okay. At this point, the upload should be mostly
-			// complete, but perhaps the backend became unaccessible.
-			context.GetLogger(ctx).Errorf("unable to delete layer upload resources %q: %v", dirPath, err)
-			return err
-		}
-	}
-
-	return nil
-}

registry/storage/blobwriter_nonresumable.go

@@ -2,5 +2,16 @@
 
 package storage
 
-func (bw *blobWriter) setupResumableDigester() {
+import (
+	"github.com/docker/distribution/context"
+)
+
+// resumeHashAt is a noop when resumable digest support is disabled.
+func (bw *blobWriter) resumeDigestAt(ctx context.Context, offset int64) error {
+	return errResumableDigestNotAvailable
+}
+
+// storeHashState is a noop when resumable digest support is disabled.
+func (bw *blobWriter) storeHashState(ctx context.Context) error {
+	return errResumableDigestNotAvailable
 }

registry/storage/blobwriter_resumable.go

@@ -2,8 +2,198 @@
 
 package storage
 
-import "github.com/docker/distribution/digest"
+import (
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"strconv"
 
-func (bw *blobWriter) setupResumableDigester() {
-	bw.resumableDigester = digest.NewCanonicalResumableDigester()
+	"github.com/Sirupsen/logrus"
+	"github.com/docker/distribution/context"
+	storagedriver "github.com/docker/distribution/registry/storage/driver"
+	"github.com/stevvooe/resumable"
+
+	// register resumable hashes with import
+	_ "github.com/stevvooe/resumable/sha256"
+	_ "github.com/stevvooe/resumable/sha512"
+)
+
+// resumeDigestAt attempts to restore the state of the internal hash function
+// by loading the most recent saved hash state less than or equal to the given
+// offset. Any unhashed bytes remaining less than the given offset are hashed
+// from the content uploaded so far.
+func (bw *blobWriter) resumeDigestAt(ctx context.Context, offset int64) error {
+	if offset < 0 {
+		return fmt.Errorf("cannot resume hash at negative offset: %d", offset)
+	}
+
+	h, ok := bw.digester.Hash().(resumable.Hash)
+	if !ok {
+		return errResumableDigestNotAvailable
+	}
+
+	if offset == int64(h.Len()) {
+		// State of digester is already at the requested offset.
+		return nil
+	}
+
+	// List hash states from storage backend.
+	var hashStateMatch hashStateEntry
+	hashStates, err := bw.getStoredHashStates(ctx)
+	if err != nil {
+		return fmt.Errorf("unable to get stored hash states with offset %d: %s", offset, err)
+	}
+
+	// Find the highest stored hashState with offset less than or equal to
+	// the requested offset.
+	for _, hashState := range hashStates {
+		if hashState.offset == offset {
+			hashStateMatch = hashState
+			break // Found an exact offset match.
+		} else if hashState.offset < offset && hashState.offset > hashStateMatch.offset {
+			// This offset is closer to the requested offset.
+			hashStateMatch = hashState
+		} else if hashState.offset > offset {
+			// Remove any stored hash state with offsets higher than this one
+			// as writes to this resumed hasher will make those invalid. This
+			// is probably okay to skip for now since we don't expect anyone to
+			// use the API in this way. For that reason, we don't treat an
+			// an error here as a fatal error, but only log it.
+			if err := bw.driver.Delete(ctx, hashState.path); err != nil {
+				logrus.Errorf("unable to delete stale hash state %q: %s", hashState.path, err)
+			}
+		}
+	}
+
+	if hashStateMatch.offset == 0 {
+		// No need to load any state, just reset the hasher.
+		h.Reset()
+	} else {
+		storedState, err := bw.driver.GetContent(ctx, hashStateMatch.path)
+		if err != nil {
+			return err
+		}
+
+		if err = h.Restore(storedState); err != nil {
+			return err
+		}
+	}
+
+	// Mind the gap.
+	if gapLen := offset - int64(h.Len()); gapLen > 0 {
+		// Need to read content from the upload to catch up to the desired offset.
+		fr, err := newFileReader(ctx, bw.driver, bw.path, bw.size)
+		if err != nil {
+			return err
+		}
+
+		if _, err = fr.Seek(int64(h.Len()), os.SEEK_SET); err != nil {
+			return fmt.Errorf("unable to seek to layer reader offset %d: %s", h.Len(), err)
+		}
+
+		if _, err := io.CopyN(h, fr, gapLen); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// removeResources should clean up all resources associated with the upload
+// instance. An error will be returned if the clean up cannot proceed. If the
+// resources are already not present, no error will be returned.
+func (bw *blobWriter) removeResources(ctx context.Context) error {
+	dataPath, err := bw.blobStore.pm.path(uploadDataPathSpec{
+		name: bw.blobStore.repository.Name(),
+		id:   bw.id,
+	})
+
+	if err != nil {
+		return err
+	}
+
+	// Resolve and delete the containing directory, which should include any
+	// upload related files.
+	dirPath := path.Dir(dataPath)
+	if err := bw.blobStore.driver.Delete(ctx, dirPath); err != nil {
+		switch err := err.(type) {
+		case storagedriver.PathNotFoundError:
+			break // already gone!
+		default:
+			// This should be uncommon enough such that returning an error
+			// should be okay. At this point, the upload should be mostly
+			// complete, but perhaps the backend became unaccessible.
+			context.GetLogger(ctx).Errorf("unable to delete layer upload resources %q: %v", dirPath, err)
+			return err
+		}
+	}
+
+	return nil
+}
+
+type hashStateEntry struct {
+	offset int64
+	path   string
+}
+
+// getStoredHashStates returns a slice of hashStateEntries for this upload.
+func (bw *blobWriter) getStoredHashStates(ctx context.Context) ([]hashStateEntry, error) {
+	uploadHashStatePathPrefix, err := bw.blobStore.pm.path(uploadHashStatePathSpec{
+		name: bw.blobStore.repository.Name(),
+		id:   bw.id,
+		alg:  bw.digester.Digest().Algorithm(),
+		list: true,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	paths, err := bw.blobStore.driver.List(ctx, uploadHashStatePathPrefix)
+	if err != nil {
+		if _, ok := err.(storagedriver.PathNotFoundError); !ok {
+			return nil, err
+		}
+		// Treat PathNotFoundError as no entries.
+		paths = nil
+	}
+
+	hashStateEntries := make([]hashStateEntry, 0, len(paths))
+
+	for _, p := range paths {
+		pathSuffix := path.Base(p)
+		// The suffix should be the offset.
+		offset, err := strconv.ParseInt(pathSuffix, 0, 64)
+		if err != nil {
+			logrus.Errorf("unable to parse offset from upload state path %q: %s", p, err)
+		}
+
+		hashStateEntries = append(hashStateEntries, hashStateEntry{offset: offset, path: p})
+	}
+
+	return hashStateEntries, nil
+}
+
+func (bw *blobWriter) storeHashState(ctx context.Context) error {
+	h, ok := bw.digester.Hash().(resumable.Hash)
+	if !ok {
+		return errResumableDigestNotAvailable
+	}
+
+	uploadHashStatePath, err := bw.blobStore.pm.path(uploadHashStatePathSpec{
+		name:   bw.blobStore.repository.Name(),
+		id:     bw.id,
+		alg:    bw.digester.Digest().Algorithm(),
+		offset: int64(h.Len()),
+	})
+	if err != nil {
+		return err
+	}
+
+	hashState, err := h.State()
+	if err != nil {
+		return err
+	}
+
+	return bw.driver.PutContent(ctx, uploadHashStatePath, hashState)
 }

registry/storage/linkedblobstore.go

@@ -164,11 +164,10 @@ func (lbs *linkedBlobStore) newBlobUpload(ctx context.Context, uuid, path string
 		blobStore:          lbs,
 		id:                 uuid,
 		startedAt:          startedAt,
+		digester:           digest.Canonical.New(),
 		bufferedFileWriter: *fw,
 	}
 
-	bw.setupResumableDigester()
-
 	return bw, nil
 }
 

registry/storage/paths.go

@@ -262,7 +262,7 @@ func (pm *pathMapper) path(spec pathSpec) (string, error) {
 		if v.list {
 			offset = "" // Limit to the prefix for listing offsets.
 		}
-		return path.Join(append(repoPrefix, v.name, "_uploads", v.id, "hashstates", v.alg, offset)...), nil
+		return path.Join(append(repoPrefix, v.name, "_uploads", v.id, "hashstates", string(v.alg), offset)...), nil
 	case repositoriesRootPathSpec:
 		return path.Join(repoPrefix...), nil
 	default:
@@ -447,7 +447,7 @@ func (uploadStartedAtPathSpec) pathSpec() {}
 type uploadHashStatePathSpec struct {
 	name   string
 	id     string
-	alg    string
+	alg    digest.Algorithm
 	offset int64
 	list   bool
 }
@@ -479,7 +479,7 @@ func digestPathComponents(dgst digest.Digest, multilevel bool) ([]string, error)
 		return nil, err
 	}
 
-	algorithm := blobAlgorithmReplacer.Replace(dgst.Algorithm())
+	algorithm := blobAlgorithmReplacer.Replace(string(dgst.Algorithm()))
 	hex := dgst.Hex()
 	prefix := []string{algorithm}