Add BLAKE3 support

This adds support for the BLAKE3 hash family with a default output
size of 256-bit.

Signed-off-by: Sargun Dhillon <sargun@sargun.me>

blake3/blake3.go

@@ -0,0 +1,44 @@
+// Copyright 2021 OCI Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package blake3
+
+import (
+	"hash"
+
+	"github.com/opencontainers/go-digest"
+	"github.com/zeebo/blake3"
+)
+
+const (
+	// BLAKE3 is the blake3 algorithm with the default 256-bit output size
+	BLAKE3 digest.Algorithm = "blake3"
+)
+
+func init() {
+	digest.RegisterAlgorithm(BLAKE3, &blake3hash{})
+}
+
+type blake3hash struct{}
+
+func (blake3hash) Available() bool {
+	return true
+}
+
+func (blake3hash) Size() int {
+	return blake3.New().Size()
+}
+
+func (blake3hash) New() hash.Hash {
+	return blake3.New()
+}

blake3/blake3_test.go

@@ -0,0 +1,38 @@
+// Copyright 2021 OCI Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package blake3
+
+import (
+	"testing"
+
+	"github.com/opencontainers/go-digest/testdigest"
+	_ "github.com/zeebo/blake3"
+)
+
+func TestBLAKE3(t *testing.T) {
+	testdigest.RunTestCase(t, testdigest.TestCase{
+		Input:     "blake3:af1349b9f5f9a1a6a0404dea36dcc9499bcb25c9adc112b7cc9a93cae41f3262",
+		Algorithm: "blake3",
+		Encoded:   "af1349b9f5f9a1a6a0404dea36dcc9499bcb25c9adc112b7cc9a93cae41f3262",
+	})
+}
+
+func TestBLAKE3Vector(t *testing.T) {
+	// From the BLAKE3 test vectors.
+	testvector := BLAKE3.FromBytes([]byte{0, 1, 2, 3, 4})
+	expected := "blake3:b40b44dfd97e7a84a996a91af8b85188c66c126940ba7aad2e7ae6b385402aa2"
+	if string(testvector) != expected {
+		t.Fatalf("Expected: %s; Got: %s", expected, testvector)
+	}
+}

blake3/go.mod

@@ -0,0 +1,12 @@
+module github.com/opencontainers/go-digest/blake3
+
+go 1.15
+
+require (
+	github.com/opencontainers/go-digest v0.0.0
+	github.com/zeebo/blake3 v0.1.1
+)
+
+replace (
+ github.com/opencontainers/go-digest => ../
+)

testdigest/testdigest.go

@@ -0,0 +1,80 @@
+// Copyright 2021 OCI Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// testdigest is a separate package, because it has some testing utilities in it that may be useful
+// to other internal Algorithm implementors.
+//
+// It is not a stable interface and not meant for consumption outside of digest developers.
+
+package testdigest
+
+import (
+	"testing"
+
+	pkgdigest "github.com/opencontainers/go-digest"
+)
+
+type TestCase struct {
+	// Input the formal format of the hash, for example sha256:e58fcf7418d4390dec8e8fb69d88c06ec07039d651fedd3aa72af9972e7d046b
+	Input     string
+	// If err is non-nil, then the parsing of Input is expected to return this error
+	Err       error
+	// Algorithm should be an available or registered algorithm
+	Algorithm pkgdigest.Algorithm
+	// Encoded is the the encoded portion of the digest to expect, for example e58fcf7418d4390dec8e8fb69d88c06ec07039d651fedd3aa72af9972e7d046b
+	Encoded   string
+}
+
+func RunTestCase(t *testing.T, testcase TestCase) {
+		digest, err := pkgdigest.Parse(testcase.Input)
+		if err != testcase.Err {
+			t.Fatalf("error differed from expected while parsing %q: %v != %v", testcase.Input, err, testcase.Err)
+		}
+
+		if testcase.Err != nil {
+			return
+		}
+
+		if digest.Algorithm() != testcase.Algorithm {
+			t.Fatalf("incorrect Algorithm for parsed digest: %q != %q", digest.Algorithm(), testcase.Algorithm)
+		}
+
+		if digest.Encoded() != testcase.Encoded {
+			t.Fatalf("incorrect hex for parsed digest: %q != %q", digest.Encoded(), testcase.Encoded)
+		}
+
+		// Parse string return value and check equality
+		newParsed, err := pkgdigest.Parse(digest.String())
+
+		if err != nil {
+			t.Fatalf("unexpected error parsing Input %q: %v", testcase.Input, err)
+		}
+
+		if newParsed != digest {
+			t.Fatalf("expected equal: %q != %q", newParsed, digest)
+		}
+
+		newFromHex := pkgdigest.NewDigestFromEncoded(newParsed.Algorithm(), newParsed.Encoded())
+		if newFromHex != digest {
+			t.Fatalf("%v != %v", newFromHex, digest)
+		}
+}
+
+func RunTestCases(t *testing.T, testcases []TestCase) {
+	for _, testcase := range testcases {
+		t.Run(testcase.Input, func(t *testing.T) {
+			RunTestCase(t, testcase)
+		})
+	}
+}