2 files changed, 29 insertions, 0 deletions
diff --git a/commons/hash.go b/commons/hash.go
new file mode 100644
index 0000000..03fa53f
--- /dev/null
+++ b/commons/hash.go
@@ -0,0 +1,17 @@
+package commons
+
+import (
+	"crypto/sha1"
+	"fmt"
+	"strconv"
+)
+
+func GitHash(t string, b []byte) string {
+	h := []byte(t)
+	h = append(h, ' ')
+	h = strconv.AppendInt(h, int64(len(b)), 10)
+	h = append(h, 0)
+	h = append(h, b...)
+
+	return fmt.Sprintf("%x", sha1.Sum(h))
+}
diff --git a/commons/hash_test.go b/commons/hash_test.go
new file mode 100644
index 0000000..79a22ea
--- /dev/null
+++ b/commons/hash_test.go
@@ -0,0 +1,12 @@
+package commons
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCalculateHash(t *testing.T) {
+	assert.Equal(t, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391", GitHash("blob", []byte("")))
+	assert.Equal(t, "8ab686eafeb1f44702738c8b0f24f2567c36da6d", GitHash("blob", []byte("Hello, World!\n")))
+}