plumbing: object, new Commit.Verify method

plumbing/object/commit.go

@@ -8,6 +8,8 @@ import (
 	"io"
 	"strings"
 
+	"golang.org/x/crypto/openpgp"
+
 	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 	"gopkg.in/src-d/go-git.v4/utils/ioutil"
@@ -311,6 +313,34 @@ func (c *Commit) String() string {
 	)
 }
 
+// Verify performs PGP verification of the commit with a provided armored
+// keyring and returns openpgp.Entity associated with verifying key on success.
+func (c *Commit) Verify(armoredKeyRing string) (*openpgp.Entity, error) {
+	keyRingReader := strings.NewReader(armoredKeyRing)
+	keyring, err := openpgp.ReadArmoredKeyRing(keyRingReader)
+	if err != nil {
+		return nil, err
+	}
+
+	// Extract signature.
+	signature := strings.NewReader(c.PGPSignature)
+
+	// Remove signature. Keep only the commit components.
+	c.PGPSignature = ""
+
+	// Encode commit and get a reader object.
+	encoded := &plumbing.MemoryObject{}
+	if err := c.Encode(encoded); err != nil {
+		return nil, err
+	}
+	er, err := encoded.Reader()
+	if err != nil {
+		return nil, err
+	}
+
+	return openpgp.CheckArmoredDetachedSignature(keyring, er, signature)
+}
+
 func indent(t string) string {
 	var output []string
 	for _, line := range strings.Split(t, "\n") {

plumbing/object/commit_test.go

@@ -296,3 +296,68 @@ func (s *SuiteCommit) TestStat(c *C) {
 	c.Assert(fileStats[1].Deletion, Equals, 0)
 	c.Assert(fileStats[1].String(), Equals, " php/crappy.php | 259 ++++++++++++++++++++++++++++++++++++++++++++++++++++\n")
 }
+
+func (s *SuiteCommit) TestVerify(c *C) {
+	ts := time.Unix(1511197315, 0)
+	commit := &Commit{
+		Hash:      plumbing.NewHash("8a9cea36fe052711fbc42b86e1f99a4fa0065deb"),
+		Author:    Signature{Name: "Sunny", Email: "[email protected]", When: ts},
+		Committer: Signature{Name: "Sunny", Email: "[email protected]", When: ts},
+		Message: `status: simplify template command selection
+`,
+		TreeHash:     plumbing.NewHash("6572ba6df4f1fb323c8aaa24ce07bca0648b161e"),
+		ParentHashes: []plumbing.Hash{plumbing.NewHash("ede5f57ea1280a0065beec96d3e1a3453d010dbd")},
+		PGPSignature: `
+-----BEGIN PGP SIGNATURE-----
+
+iQFHBAABCAAxFiEEoRt6IzxHaZkkUslhQyLeMqcmyU4FAloTCrsTHG1lQGRhcmtv
+d2x6ei5zcGFjZQAKCRBDIt4ypybJTul5CADmVxB4kqlqRZ9fAcSU5LKva3GRXx0+
+leX6vbzoyQztSWYgl7zALh4kB3a3t2C9EnnM6uehlgaORNigyMArCSY1ivWVviCT
+BvldSVi8f8OvnqwbWX0I/5a8KmItthDf5WqZRFjhcRlY1AK5Bo2hUGVRq71euf8F
+rE6wNhDoyBCEpftXuXbq8duD7D6qJ7QiOS4m5+ej1UCssS2WQ60yta7q57odduHY
++txqTKI8MQUpBgoTqh+V4lOkwQQxLiz7hIQ/ZYLUcnp6fan7/kY/G7YoLt9pOG1Y
+vLzAWdidLH2P+EUOqlNMuVScHYWD1FZB0/L5LJ8no5pTowQd2Z+Nggxl
+=0uC8
+-----END PGP SIGNATURE-----
+`,
+	}
+
+	armoredKeyRing := `
+-----BEGIN PGP PUBLIC KEY BLOCK-----
+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+=FPev
+-----END PGP PUBLIC KEY BLOCK-----
+`
+
+	e, err := commit.Verify(armoredKeyRing)
+	c.Assert(err, IsNil)
+
+	_, ok := e.Identities["Sunny <[email protected]>"]
+	c.Assert(ok, Equals, true)
+}