mintdb get_known_coin(): Do not allocate memory for return paramter.

Instead populate the fields of the placeholder return variable.

src/include/taler_mintdb_plugin.h

@@ -332,7 +332,7 @@ struct TALER_MINTDB_RefreshMelt
    */
   struct TALER_Amount amount_with_fee;
 
-  /**
+  /** FIXME: This can be retrieved from the Denomination? Do we need this?
    * Melting fee charged by the mint.  This must match the Mint's
    * denomination key's melting fee.  If the client puts in an invalid
    * melting fee (too high or too low) that does not match the Mint's
@@ -848,7 +848,7 @@ struct TALER_MINTDB_Plugin
    * @param cls the plugin closure
    * @param session the database session handle
    * @param coin_pub the public key of the coin to search for
-   * @param ret_coin_info place holder for the returned coin information object
+   * @param coin_info place holder for the returned coin information object
    * @return #GNUNET_SYSERR upon error; #GNUNET_NO if no coin is found; #GNUNET_OK
    *           if upon succesfullying retrieving the record data info @a
    *           ret_coin_info
@@ -857,7 +857,7 @@ struct TALER_MINTDB_Plugin
   (*get_known_coin) (void *cls,
                      struct TALER_MINTDB_Session *session,
                      const struct TALER_CoinSpendPublicKeyP *coin_pub,
-                     struct TALER_CoinPublicInfo **ret_coin_info);
+                     struct TALER_CoinPublicInfo *coin_info);
 
 
   /**

src/mintdb/plugin_mintdb_postgres.c

@@ -1641,23 +1641,24 @@ postgres_insert_known_coin (void *cls,
  * @param cls the plugin closure
  * @param session the database session handle
  * @param coin_pub the public key of the coin to search for
- * @param ret_coin_info place holder for the returned coin information object
+ * @param coin_info place holder for the returned coin information object
  * @return #GNUNET_SYSERR upon error; #GNUNET_NO if no coin is found; #GNUNET_OK
  *           if upon succesfullying retrieving the record data info @a
- *           ret_coin_info
+ *           coin_info
  */
 static int
 postgres_get_known_coin (void *cls,
                          struct TALER_MINTDB_Session *session,
                          const struct TALER_CoinSpendPublicKeyP *coin_pub,
-                         struct TALER_CoinPublicInfo **ret_coin_info)
+                         struct TALER_CoinPublicInfo *coin_info)
 {
   PGresult *result;
   struct TALER_PQ_QueryParam params[] = {
     TALER_PQ_query_param_auto_from_type (coin_pub),
     TALER_PQ_query_param_end
   };
-  struct TALER_CoinPublicInfo *coin_info;
+  int nrows;
+
   result = TALER_PQ_exec_prepared (session->conn,
                                    "get_known_coin",
                                    params);
@@ -1667,17 +1668,13 @@ postgres_get_known_coin (void *cls,
     PQclear (result);
     return GNUNET_SYSERR;
   }
-  if (0 == PQntuples (result))
+  nrows = PQntuples (result);
+  if (0 == nrows)
   {
     PQclear (result);
     return GNUNET_NO;
   }
-  if ((NULL == ret_coin_info) && (1 == PQntuples (result)))
+  GNUNET_assert (1 == nrows);   /* due to primary key */
-  {
-    PQclear (result);
-    return GNUNET_OK;
-  }
-  coin_info = GNUNET_new (struct TALER_CoinPublicInfo);
   struct TALER_PQ_ResultSpec rs[] = {
     TALER_PQ_result_spec_rsa_public_key ("denom_pub", &coin_info->denom_pub.rsa_public_key),
     TALER_PQ_result_spec_rsa_signature ("denom_sig", &coin_info->denom_sig.rsa_signature),
@@ -1691,10 +1688,11 @@ postgres_get_known_coin (void *cls,
     return GNUNET_SYSERR;
   }
   PQclear (result);
+  /* no need to copy if the src and dest are same */
+  if (coin_pub != &coin_info->coin_pub)
     (void) memcpy (&coin_info->coin_pub,
                    coin_pub,
                    sizeof (struct TALER_CoinSpendPublicKeyP));
-  *ret_coin_info = coin_info;
   return GNUNET_OK;
 }
 

src/mintdb/test_mintdb.c

@@ -180,7 +180,7 @@ static int
 test_known_coins (struct TALER_MINTDB_Session *session)
 {
   struct TALER_CoinPublicInfo coin_info;
-  struct TALER_CoinPublicInfo *ret_coin_info;
+  struct TALER_CoinPublicInfo ret_coin_info;
   struct DenomKeyPair *dkp;
   int ret = GNUNET_SYSERR;
 
@@ -190,13 +190,11 @@ test_known_coins (struct TALER_MINTDB_Session *session)
   coin_info.denom_sig.rsa_signature =
       GNUNET_CRYPTO_rsa_sign (dkp->priv.rsa_private_key,
                               "foobar", 6);
-  ret_coin_info = NULL;
   FAILIF (GNUNET_NO !=
           plugin->get_known_coin (plugin->cls,
                                   session,
                                   &coin_info.coin_pub,
                                   &ret_coin_info));
-  FAILIF (NULL != ret_coin_info);
   FAILIF (GNUNET_OK !=
           plugin->insert_known_coin (plugin->cls,
                                      session,
@@ -206,23 +204,18 @@ test_known_coins (struct TALER_MINTDB_Session *session)
                                   session,
                                   &coin_info.coin_pub,
                                   &ret_coin_info));
-  FAILIF (NULL == ret_coin_info);
   FAILIF (0 != GNUNET_CRYPTO_rsa_public_key_cmp
-          (ret_coin_info->denom_pub.rsa_public_key,
+          (ret_coin_info.denom_pub.rsa_public_key,
            coin_info.denom_pub.rsa_public_key));
   FAILIF (0 != GNUNET_CRYPTO_rsa_signature_cmp
-          (ret_coin_info->denom_sig.rsa_signature,
+          (ret_coin_info.denom_sig.rsa_signature,
            coin_info.denom_sig.rsa_signature));
+  GNUNET_CRYPTO_rsa_public_key_free (ret_coin_info.denom_pub.rsa_public_key);
+  GNUNET_CRYPTO_rsa_signature_free (ret_coin_info.denom_sig.rsa_signature);
   ret = GNUNET_OK;
  drop:
   destroy_denom_key_pair (dkp);
   GNUNET_CRYPTO_rsa_signature_free (coin_info.denom_sig.rsa_signature);
-  if (NULL != ret_coin_info)
-  {
-    GNUNET_CRYPTO_rsa_public_key_free (ret_coin_info->denom_pub.rsa_public_key);
-    GNUNET_CRYPTO_rsa_signature_free (ret_coin_info->denom_sig.rsa_signature);
-    GNUNET_free (ret_coin_info);
-  }
   return ret;
 }