Extract GitHash function

Author: klaidliadon

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))
+}

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")))
+}

packfile/objects.go

@@ -2,11 +2,12 @@ package packfile
 
 import (
 	"bytes"
-	"crypto/sha1"
 	"encoding/hex"
 	"fmt"
 	"strconv"
 	"time"
+
+	"github.com/tyba/srcd-crawler/clients/git/commons"
 )
 
 type Object interface {
@@ -30,7 +31,7 @@ type Commit struct {
 }
 
 func NewCommit(b []byte) (*Commit, error) {
-	o := &Commit{hash: calculateHash("commit", b)}
+	o := &Commit{hash: commons.GitHash("commit", b)}
 
 	lines := bytes.Split(b, []byte{'\n'})
 	for i := range lines {
@@ -147,7 +148,7 @@ type TreeEntry struct {
 }
 
 func NewTree(body []byte) (*Tree, error) {
-	o := &Tree{hash: calculateHash("tree", body)}
+	o := &Tree{hash: commons.GitHash("tree", body)}
 
 	if len(body) == 0 {
 		return o, nil
@@ -185,7 +186,7 @@ type Blob struct {
 }
 
 func NewBlob(b []byte) (*Blob, error) {
-	return &Blob{Len: len(b), hash: calculateHash("blob", b)}, nil
+	return &Blob{Len: len(b), hash: commons.GitHash("blob", b)}, nil
 }
 
 func (o *Blob) Type() string {
@@ -196,14 +197,4 @@ func (o *Blob) Hash() string {
 	return o.hash
 }
 
-func calculateHash(objType string, content []byte) string {
-	header := []byte(objType)
-	header = append(header, ' ')
-	header = strconv.AppendInt(header, int64(len(content)), 10)
-	header = append(header, 0)
-	header = append(header, content...)
-
-	return fmt.Sprintf("%x", sha1.Sum(header))
-}
-
 type ContentCallback func(hash string, content []byte)

packfile/objects_test.go

@@ -7,11 +7,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestCalculateHash(t *testing.T) {
-	assert.Equal(t, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391", calculateHash("blob", []byte("")))
-	assert.Equal(t, "8ab686eafeb1f44702738c8b0f24f2567c36da6d", calculateHash("blob", []byte("Hello, World!\n")))
-}
-
 func TestSignature(t *testing.T) {
 	cases := map[string]Signature{
 		`Foo Bar <[email protected]> 1257894000 +0100`: {