plumbing/hash: Add SHA256 as a supported algorithm

Relates to #706.

Signed-off-by: Paulo Gomes <pjbgf@linux.com>

3 files changed, 33 insertions, 0 deletions

diff --git a/plumbing/hash/hash.go b/plumbing/hash/hash.go
index 80e4b5f..82d1856 100644
--- a/plumbing/hash/hash.go
+++ b/plumbing/hash/hash.go
@@ -21,6 +21,7 @@ func init() {
 // that registers new algorithms to avoid side effects.
 func reset() {
 	algos[crypto.SHA1] = sha1cd.New
+	algos[crypto.SHA256] = crypto.SHA256.New
 }
 
 // RegisterHash allows for the hash algorithm used to be overriden.
@@ -34,6 +35,8 @@ func RegisterHash(h crypto.Hash, f func() hash.Hash) error {
 	switch h {
 	case crypto.SHA1:
 		algos[h] = f
+	case crypto.SHA256:
+		algos[h] = f
 	default:
 		return fmt.Errorf("unsupported hash function: %v", h)
 	}
diff --git a/plumbing/hash/hash_sha1.go b/plumbing/hash/hash_sha1.go
new file mode 100644
index 0000000..e3cb60f
--- /dev/null
+++ b/plumbing/hash/hash_sha1.go
@@ -0,0 +1,15 @@
+//go:build !sha256
+// +build !sha256
+
+package hash
+
+import "crypto"
+
+const (
+	// CryptoType defines what hash algorithm is being used.
+	CryptoType = crypto.SHA1
+	// Size defines the amount of bytes the hash yields.
+	Size = 20
+	// HexSize defines the strings size of the hash when represented in hexadecimal.
+	HexSize = 40
+)
diff --git a/plumbing/hash/hash_sha256.go b/plumbing/hash/hash_sha256.go
new file mode 100644
index 0000000..1c52b89
--- /dev/null
+++ b/plumbing/hash/hash_sha256.go
@@ -0,0 +1,15 @@
+//go:build sha256
+// +build sha256
+
+package hash
+
+import "crypto"
+
+const (
+	// CryptoType defines what hash algorithm is being used.
+	CryptoType = crypto.SHA256
+	// Size defines the amount of bytes the hash yields.
+	Size = 32
+	// HexSize defines the strings size of the hash when represented in hexadecimal.
+	HexSize = 64
+)