Add Commit::extract_signature

This returns the signature and the signed data so the user can compare
them.

Author: carlosmn

ext/rugged/rugged_commit.c

@@ -612,11 +612,58 @@ static VALUE rb_git_commit_header(VALUE self)
 	return rb_str_new_utf8(raw_header);
 }
 
+/*
+ *  call-seq:
+ *    Rugged::Commit.extract_signature(repo, commit, field_name) -> [str, str]
+ *
+ *  Returns +commit+'s signature in 'field' and the signed data
+ *
+ *  The signature is done over the contents of the commit without the
+ *  signature block in the header, which is the data in the second
+ *  element in the return array.
+ */
+static VALUE rb_git_commit_extract_signature(int argc, VALUE *argv, VALUE self)
+{
+	int error;
+	VALUE ret_arr;
+	git_oid commit_id;
+	const char *field;
+	git_repository *repo;
+	git_buf signature = {0}, signed_data = {0};
+	VALUE rb_repo, rb_commit, rb_field = Qnil;
+
+	rb_scan_args(argc, argv, "21", &rb_repo, &rb_commit, &rb_field);
+
+	rugged_check_repo(rb_repo);
+	Data_Get_Struct(rb_repo, git_repository, repo);
+
+	error = git_oid_fromstr(&commit_id, StringValueCStr(rb_commit));
+	rugged_exception_check(error);
+
+	field = NIL_P(rb_field) ? NULL : StringValueCStr(rb_field);
+	error = git_commit_extract_signature(&signature, &signed_data, repo, &commit_id, field);
+	if (error < 0) {
+		git_buf_free(&signature);
+		git_buf_free(&signed_data);
+	}
+
+	rugged_exception_check(error);
+
+	ret_arr = rb_ary_new3(2, rb_str_new(signature.ptr, signature.size),
+			         rb_str_new(signed_data.ptr, signed_data.size));
+
+	git_buf_free(&signature);
+	git_buf_free(&signed_data);
+
+	return ret_arr;
+}
+
 void Init_rugged_commit(void)
 {
 	rb_cRuggedCommit = rb_define_class_under(rb_mRugged, "Commit", rb_cRuggedObject);
 
 	rb_define_singleton_method(rb_cRuggedCommit, "create", rb_git_commit_create, 2);
+	rb_define_singleton_method(rb_cRuggedCommit, "extract_signature", rb_git_commit_extract_signature, -1);
 
 	rb_define_method(rb_cRuggedCommit, "message", rb_git_commit_message_GET, 0);
 	rb_define_method(rb_cRuggedCommit, "epoch_time", rb_git_commit_epoch_time_GET, 0);

test/commit_test.rb

@@ -204,6 +204,74 @@ def test_header
 
     assert_equal expected_header, obj.header
   end
+
+  def test_extract_signature
+
+    raw_commit = <<-COMMIT
+tree 6b79e22d69bf46e289df0345a14ca059dfc9bdf6
+parent 34734e478d6cf50c27c9d69026d93974d052c454
+author Ben Burkert <[email protected]> 1358451456 -0800
+committer Ben Burkert <[email protected]> 1358451456 -0800
+gpgsig -----BEGIN PGP SIGNATURE-----
+ Version: GnuPG v1.4.12 (Darwin)
+ 
+ iQIcBAABAgAGBQJQ+FMIAAoJEH+LfPdZDSs1e3EQAJMjhqjWF+WkGLHju7pTw2al
+ o6IoMAhv0Z/LHlWhzBd9e7JeCnanRt12bAU7yvYp9+Z+z+dbwqLwDoFp8LVuigl8
+ JGLcnwiUW3rSvhjdCp9irdb4+bhKUnKUzSdsR2CK4/hC0N2i/HOvMYX+BRsvqweq
+ AsAkA6dAWh+gAfedrBUkCTGhlNYoetjdakWqlGL1TiKAefEZrtA1TpPkGn92vbLq
+ SphFRUY9hVn1ZBWrT3hEpvAIcZag3rTOiRVT1X1flj8B2vGCEr3RrcwOIZikpdaW
+ who/X3xh/DGbI2RbuxmmJpxxP/8dsVchRJJzBwG+yhwU/iN3MlV2c5D69tls/Dok
+ 6VbyU4lm/ae0y3yR83D9dUlkycOnmmlBAHKIZ9qUts9X7mWJf0+yy2QxJVpjaTGG
+ cmnQKKPeNIhGJk2ENnnnzjEve7L7YJQF6itbx5VCOcsGh3Ocb3YR7DMdWjt7f8pu
+ c6j+q1rP7EpE2afUN/geSlp5i3x8aXZPDj67jImbVCE/Q1X9voCtyzGJH7MXR0N9
+ ZpRF8yzveRfMH8bwAJjSOGAFF5XkcR/RNY95o+J+QcgBLdX48h+ZdNmUf6jqlu3J
+ 7KmTXXQcOVpN6dD3CmRFsbjq+x6RHwa8u1iGn+oIkX908r97ckfB/kHKH7ZdXIJc
+ cpxtDQQMGYFpXK/71stq
+ =ozeK
+ -----END PGP SIGNATURE-----
+
+a simple commit which works
+COMMIT
+
+    exp_signature = <<-SIGNATURE.strip
+-----BEGIN PGP SIGNATURE-----
+Version: GnuPG v1.4.12 (Darwin)
+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+=ozeK
+-----END PGP SIGNATURE-----
+SIGNATURE
+
+    exp_signed_data = <<-SIGNEDDATA
+tree 6b79e22d69bf46e289df0345a14ca059dfc9bdf6
+parent 34734e478d6cf50c27c9d69026d93974d052c454
+author Ben Burkert <[email protected]> 1358451456 -0800
+committer Ben Burkert <[email protected]> 1358451456 -0800
+
+a simple commit which works
+SIGNEDDATA
+
+    commit_sha = @repo.write(raw_commit, :commit)
+
+    signature, signed_data = Rugged::Commit.extract_signature(@repo, commit_sha, "gpgsig")
+    assert_equal exp_signature, signature
+    assert_equal exp_signed_data, signed_data
+
+    signature, signed_data = Rugged::Commit.extract_signature(@repo, commit_sha)
+    assert_equal exp_signature, signature
+    assert_equal exp_signed_data, signed_data
+  end
 end
 
 class CommitWriteTest < Rugged::TestCase