better api for parsing a denomination group

src/exchange/taler-exchange-httpd_keys.c

@@ -2190,6 +2190,8 @@ finish_keys_response (struct TEH_KeyStateHandle *ksh)
           .age_mask = dk->meta.age_mask,
         };
 
+        memset (&meta.hash, 0, sizeof(meta.hash));
+
         /* Search the group/JSON-blob for the key */
         GNUNET_CRYPTO_hash (&meta, sizeof(meta), &key);
 

src/include/taler_json_lib.h

@@ -375,9 +375,6 @@ struct TALER_DenominationGroup
   struct TALER_DenomFeeSet fees;
   struct TALER_AgeMask age_mask;
 
-  // currency must be set prior to calling TALER_JSON_spec_denomination_group
-  const char *currency;
-
   // hash is/should be the XOR of all SHA-512 hashes of the public keys in this
   // group
   struct GNUNET_HashCode hash;
@@ -385,14 +382,15 @@ struct TALER_DenominationGroup
 
 /**
  * Generate a parser for a group of denominations.
- * NOTE: group.currency MUST have been set prior to calling this function.
  *
- * @param field name of the field, maybe NULL
+ * @param[in] field name of the field, maybe NULL
+ * @param[in] currency name of the currency
  * @param[out] group denomination group information
  * @return corresponding field spec
  */
 struct GNUNET_JSON_Specification
 TALER_JSON_spec_denomination_group (const char *field,
+                                    const char *currency,
                                     struct TALER_DenominationGroup *group);
 
 /**

src/json/json_helper.c

@@ -250,16 +250,17 @@ parse_denomination_group (void *cls,
 {
   struct TALER_DenominationGroup *group = spec->ptr;
   const char *cipher;
+  const char *currency = cls;
   bool age_mask_missing = false;
   bool has_age_restricted_suffix = false;
   struct GNUNET_JSON_Specification gspec[] = {
     GNUNET_JSON_spec_string ("cipher",
                              &cipher),
     TALER_JSON_spec_amount ("value",
-                            group->currency,
+                            currency,
                             &group->value),
     TALER_JSON_SPEC_DENOM_FEES ("fee",
-                                group->currency,
+                                currency,
                                 &group->fees),
     GNUNET_JSON_spec_mark_optional (
       GNUNET_JSON_spec_uint32 ("age_mask",
@@ -307,9 +308,11 @@ parse_denomination_group (void *cls,
 
 struct GNUNET_JSON_Specification
 TALER_JSON_spec_denomination_group (const char *name,
+                                    const char *currency,
                                     struct TALER_DenominationGroup *group)
 {
   struct GNUNET_JSON_Specification ret = {
+    .cls = (void *) currency,
     .parser = &parse_denomination_group,
     .cleaner = NULL,
     .field = name,
@@ -318,7 +321,6 @@ TALER_JSON_spec_denomination_group (const char *name,
     .size_ptr = NULL,
   };
 
-
   return ret;
 }
 

src/lib/exchange_api_handle.c

@@ -952,9 +952,9 @@ decode_keys_json (const json_t *resp_obj,
 
       // First, parse { cipher, fees, value, age_mask, hash } of the current
       // group.
-      struct TALER_DenominationGroup group = { .currency = currency };
+      struct TALER_DenominationGroup group = {0};
       struct GNUNET_JSON_Specification group_spec[] = {
-        TALER_JSON_spec_denomination_group (NULL, &group),
+        TALER_JSON_spec_denomination_group (NULL, currency, &group),
         GNUNET_JSON_spec_end ()
       };
       EXITIF (GNUNET_SYSERR ==