Update vendor

vendor/github.com/google/go-containerregistry/pkg/v1/hash.go

@@ -0,0 +1,123 @@
+// Copyright 2018 Google LLC All Rights Reserved.
+//
+// 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
+//
+//    http://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 v1
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"hash"
+	"io"
+	"strconv"
+	"strings"
+)
+
+// Hash is an unqualified digest of some content, e.g. sha256:deadbeef
+type Hash struct {
+	// Algorithm holds the algorithm used to compute the hash.
+	Algorithm string
+
+	// Hex holds the hex portion of the content hash.
+	Hex string
+}
+
+// String reverses NewHash returning the string-form of the hash.
+func (h Hash) String() string {
+	return fmt.Sprintf("%s:%s", h.Algorithm, h.Hex)
+}
+
+// NewHash validates the input string is a hash and returns a strongly type Hash object.
+func NewHash(s string) (Hash, error) {
+	h := Hash{}
+	if err := h.parse(s); err != nil {
+		return Hash{}, err
+	}
+	return h, nil
+}
+
+// MarshalJSON implements json.Marshaler
+func (h Hash) MarshalJSON() ([]byte, error) {
+	return json.Marshal(h.String())
+}
+
+// UnmarshalJSON implements json.Unmarshaler
+func (h *Hash) UnmarshalJSON(data []byte) error {
+	s, err := strconv.Unquote(string(data))
+	if err != nil {
+		return err
+	}
+	return h.parse(s)
+}
+
+// MarshalText implements encoding.TextMarshaler. This is required to use
+// v1.Hash as a key in a map when marshalling JSON.
+func (h Hash) MarshalText() (text []byte, err error) {
+	return []byte(h.String()), nil
+}
+
+// UnmarshalText implements encoding.TextUnmarshaler. This is required to use
+// v1.Hash as a key in a map when unmarshalling JSON.
+func (h *Hash) UnmarshalText(text []byte) error {
+	return h.parse(string(text))
+}
+
+// Hasher returns a hash.Hash for the named algorithm (e.g. "sha256")
+func Hasher(name string) (hash.Hash, error) {
+	switch name {
+	case "sha256":
+		return sha256.New(), nil
+	default:
+		return nil, fmt.Errorf("unsupported hash: %q", name)
+	}
+}
+
+func (h *Hash) parse(unquoted string) error {
+	parts := strings.Split(unquoted, ":")
+	if len(parts) != 2 {
+		return fmt.Errorf("too many parts in hash: %s", unquoted)
+	}
+
+	rest := strings.TrimLeft(parts[1], "0123456789abcdef")
+	if len(rest) != 0 {
+		return fmt.Errorf("found non-hex character in hash: %c", rest[0])
+	}
+
+	hasher, err := Hasher(parts[0])
+	if err != nil {
+		return err
+	}
+	// Compare the hex to the expected size (2 hex characters per byte)
+	if len(parts[1]) != hasher.Size()*2 {
+		return fmt.Errorf("wrong number of hex digits for %s: %s", parts[0], parts[1])
+	}
+
+	h.Algorithm = parts[0]
+	h.Hex = parts[1]
+	return nil
+}
+
+// SHA256 computes the Hash of the provided io.Reader's content.
+func SHA256(r io.Reader) (Hash, int64, error) {
+	hasher := sha256.New()
+	n, err := io.Copy(hasher, r)
+	if err != nil {
+		return Hash{}, 0, err
+	}
+	return Hash{
+		Algorithm: "sha256",
+		Hex:       hex.EncodeToString(hasher.Sum(make([]byte, 0, hasher.Size()))),
+	}, n, nil
+}