Add rnp_signature_get_features

include/rnp/rnp.h

@@ -143,6 +143,13 @@ typedef uint32_t rnp_result_t;
  */
 #define RNP_REVOKER_SENSITIVE (1U << 0)
 
+/**
+ * Key feature flags.
+ */
+#define RNP_KEY_FEATURE_MDC (1U << 0)
+#define RNP_KEY_FEATURE_AEAD (1U << 1)
+#define RNP_KEY_FEATURE_V5 (1U << 2)
+
 /**
  * Return a constant string describing the result code
  */
@@ -1721,6 +1728,9 @@ RNP_API rnp_result_t rnp_signature_get_creation(rnp_signature_handle_t sig, uint
 RNP_API rnp_result_t rnp_signature_get_expiration(rnp_signature_handle_t sig,
                                                   uint32_t *             expires);
 
+RNP_API rnp_result_t rnp_signature_get_features(rnp_signature_handle_t sig,
+                                                uint32_t *             features);
+
 /** Get signer's key id from the signature.
  *  Note: if key id is not available from the signature then NULL value will
  *        be stored to result.

src/lib/rnp.cpp

@@ -6522,6 +6522,20 @@
 }
 FFI_GUARD
 
+rnp_result_t
+rnp_signature_get_features(rnp_signature_handle_t handle, uint32_t *features)
+try {
+    if (!handle || !features) {
+        return RNP_ERROR_NULL_POINTER;
+    }
+    if (!handle->sig) {
+        return RNP_ERROR_BAD_PARAMETERS;
+    }
+    *features = handle->sig->sig.key_get_features();
+    return RNP_SUCCESS;
+}
+FFI_GUARD
+
 rnp_result_t
 rnp_signature_get_keyid(rnp_signature_handle_t handle, char **result)
 try {

src/librepgp/stream-sig.cpp

@@ -1097,6 +1097,13 @@ pgp_signature_t::set_revocation_reason(pgp_revocation_type_t code, const std::st
     }
 }
 
+pgp_key_feature_t
+pgp_signature_t::key_get_features() const
+{
+    const pgp_sig_subpkt_t *subpkt = get_subpkt(PGP_SIG_SUBPKT_FEATURES);
+    return (pgp_key_feature_t)(subpkt ? subpkt->data[0] : 0);
+}
+
 bool
 pgp_signature_t::key_has_features(pgp_key_feature_t flags) const
 {

src/librepgp/stream-sig.h

@@ -289,6 +289,8 @@ typedef struct pgp_signature_t {
      */
     void set_revocation_reason(pgp_revocation_type_t code, const std::string &reason);
 
+    pgp_key_feature_t key_get_features() const;
+
     /**
      * @brief Check whether signer's key supports certain feature(s). Makes sense only for
      *        self-signature, for more details see the RFC 4880bis, 5.2.3.25. If there is

src/tests/ffi-key-sig.cpp

@@ -902,6 +902,11 @@ TEST_F(rnp_tests, test_ffi_sig_validity)
     uint32_t expires = 0;
     assert_rnp_success(rnp_signature_get_expiration(sig, &expires));
     assert_int_equal(expires, 86400);
+    uint32_t features = 0;
+    assert_rnp_failure(rnp_signature_get_features(NULL, &features));
+    assert_rnp_failure(rnp_signature_get_features(sig, NULL));
+    assert_rnp_success(rnp_signature_get_features(sig, &features));
+    assert_int_equal(features, 0);
     rnp_signature_handle_destroy(sig);
     rnp_uid_handle_destroy(uid);
     rnp_key_handle_destroy(key);