Add GPG payload to commit information if present

commit.go

@@ -6,6 +6,7 @@ package git
 
 import (
 	"bufio"
+	"bytes"
 	"container/list"
 	"fmt"
 	"net/http"
@@ -22,11 +23,30 @@ type Commit struct {
 	Author        *Signature
 	Committer     *Signature
 	CommitMessage string
+	Signature     *CommitGPGSignature
 
 	parents        []SHA1 // SHA1 strings
 	submoduleCache *ObjectCache
 }
 
+// CommitGPGSignature represents a git commit signature part.
+type CommitGPGSignature struct {
+	Signature string
+	Payload   string //TODO check if can be reconstruct from the rest of commit information to not have duplicate data
+}
+
+// similar to https://github.com/git/git/blob/3bc53220cb2dcf709f7a027a3f526befd021d858/commit.c#L1128
+func newGPGSignatureFromCommitline(data []byte, signatureStart int) (*CommitGPGSignature, error) {
+	sig := new(CommitGPGSignature)
+	signatureEnd := bytes.LastIndex(data, []byte("-----END PGP SIGNATURE-----"))
+	if signatureEnd == -1 {
+		return nil, fmt.Errorf("end of commit signature not found")
+	}
+	sig.Signature = strings.Replace(string(data[signatureStart:signatureEnd+27]), "\n ", "\n", -1)
+	sig.Payload = string(data[:signatureStart-8]) + string(data[signatureEnd+27:])
+	return sig, nil
+}
+
 // Message returns the commit message. Same as retrieving CommitMessage directly.
 func (c *Commit) Message() string {
 	return c.CommitMessage

repo_commit.go

@@ -78,6 +78,12 @@ l:
 					return nil, err
 				}
 				commit.Committer = sig
+			case "gpgsig":
+				sig, err := newGPGSignatureFromCommitline(data, nextline+spacepos+1)
+				if err != nil {
+					return nil, err
+				}
+				commit.Signature = sig
 			}
 			nextline += eol + 1
 		case eol == 0: