fixing #3814 by removing ability to melt multiple oldcoins at the same time

2 files changed, 63 insertions, 116 deletions

diff --git a/src/include/taler_exchange_service.h b/src/include/taler_exchange_service.h
index 09cbd786..fd09b528 100644
--- a/src/include/taler_exchange_service.h
+++ b/src/include/taler_exchange_service.h
@@ -711,12 +711,12 @@ typedef void
  */
 struct TALER_EXCHANGE_ReserveWithdrawHandle *
 TALER_EXCHANGE_reserve_withdraw (struct TALER_EXCHANGE_Handle *exchange,
-                             const struct TALER_EXCHANGE_DenomPublicKey *pk,
-                             const struct TALER_ReservePrivateKeyP *reserve_priv,
-                             const struct TALER_CoinSpendPrivateKeyP *coin_priv,
-                             const struct TALER_DenominationBlindingKey *blinding_key,
-                             TALER_EXCHANGE_ReserveWithdrawResultCallback res_cb,
-                             void *res_cb_cls);
+                                 const struct TALER_EXCHANGE_DenomPublicKey *pk,
+                                 const struct TALER_ReservePrivateKeyP *reserve_priv,
+                                 const struct TALER_CoinSpendPrivateKeyP *coin_priv,
+                                 const struct TALER_DenominationBlindingKey *blinding_key,
+                                 TALER_EXCHANGE_ReserveWithdrawResultCallback res_cb,
+                                 void *res_cb_cls);
 
 
 /**
@@ -745,8 +745,8 @@ TALER_EXCHANGE_reserve_withdraw_cancel (struct TALER_EXCHANGE_ReserveWithdrawHan
  * to #TALER_EXCHANGE_refresh_melt() that will generate the request.
  *
  * This function does verify that the given request data is internally
- * consistent.  However, the @a melts_sigs are only verified if @a
- * check_sigs is set to #GNUNET_YES, as this may be relatively
+ * consistent.  However, the @a melts_sig is only verified if @a
+ * check_sig is set to #GNUNET_YES, as this may be relatively
  * expensive and should be redundant.
  *
  * Aside from some non-trivial cryptographic operations that might
@@ -754,17 +754,16 @@ TALER_EXCHANGE_reserve_withdraw_cancel (struct TALER_EXCHANGE_ReserveWithdrawHan
  * its result immediately and does not start any asynchronous
  * processing.  This function is also thread-safe.
  *
- * @param num_melts number of coins that are being melted (typically 1)
- * @param melt_privs array of @a num_melts private keys of the coins to melt
- * @param melt_amounts array of @a num_melts amounts specifying how much
- *                     each coin will contribute to the melt (including fee)
- * @param melt_sigs array of @a num_melts signatures affirming the
+ * @param melt_priv private keys of the coin to melt
+ * @param melt_amount amount specifying how much
+ *                     the coin will contribute to the melt (including fee)
+ * @param melt_sig signatures affirming the
  *                   validity of the public keys corresponding to the
- *                   @a melt_privs private keys
- * @param melt_pks array of @a num_melts denomination key information
- *                   records corresponding to the @a melt_sigs
+ *                   @a melt_priv private key
+ * @param melt_pk denomination key information
+ *                   record corresponding to the @a melt_sig
  *                   validity of the keys
- * @param check_sigs verify the validity of the signatures of @a melt_sigs
+ * @param check_sig verify the validity of the signatures of @a melt_sig
  * @param fresh_pks_len length of the @a pks array
  * @param fresh_pks array of @a pks_len denominations of fresh coins to create
  * @param[out] res_size set to the size of the return value, or 0 on error
@@ -775,12 +774,11 @@ TALER_EXCHANGE_reserve_withdraw_cancel (struct TALER_EXCHANGE_ReserveWithdrawHan
  *         Non-null results should be freed using #GNUNET_free().
  */
 char *
-TALER_EXCHANGE_refresh_prepare (unsigned int num_melts,
-                                const struct TALER_CoinSpendPrivateKeyP *melt_privs,
-                                const struct TALER_Amount *melt_amounts,
-                                const struct TALER_DenominationSignature *melt_sigs,
-                                const struct TALER_EXCHANGE_DenomPublicKey *melt_pks,
-                                int check_sigs,
+TALER_EXCHANGE_refresh_prepare (const struct TALER_CoinSpendPrivateKeyP *melt_priv,
+                                const struct TALER_Amount *melt_amount,
+                                const struct TALER_DenominationSignature *melt_sig,
+                                const struct TALER_EXCHANGE_DenomPublicKey *melt_pk,
+                                int check_sig,
                                 unsigned int fresh_pks_len,
                                 const struct TALER_EXCHANGE_DenomPublicKey *fresh_pks,
                                 size_t *res_size);
diff --git a/src/include/taler_exchangedb_plugin.h b/src/include/taler_exchangedb_plugin.h
index fff6e251..2cc3b439 100644
--- a/src/include/taler_exchangedb_plugin.h
+++ b/src/include/taler_exchangedb_plugin.h
@@ -359,33 +359,6 @@ struct TALER_EXCHANGEDB_Refund
 
 
 /**
- * @brief Global information for a refreshing session.  Includes
- * dimensions of the operation, security parameters and
- * client signatures from "/refresh/melt" and "/refresh/commit".
- */
-struct TALER_EXCHANGEDB_RefreshSession
-{
-
-  /**
-   * Number of coins we are melting.
-   */
-  uint16_t num_oldcoins;
-
-  /**
-   * Number of new coins we are creating.
-   */
-  uint16_t num_newcoins;
-
-  /**
-   * Index (smaller #TALER_CNC_KAPPA) which the exchange has chosen to not
-   * have revealed during cut and choose.
-   */
-  uint16_t noreveal_index;
-
-};
-
-
-/**
  * @brief Specification for coin in a /refresh/melt operation.
  */
 struct TALER_EXCHANGEDB_RefreshMelt
@@ -430,6 +403,33 @@ struct TALER_EXCHANGEDB_RefreshMelt
 
 
 /**
+ * @brief Global information for a refreshing session.  Includes
+ * dimensions of the operation, security parameters and
+ * client signatures from "/refresh/melt" and "/refresh/commit".
+ */
+struct TALER_EXCHANGEDB_RefreshSession
+{
+
+  /**
+   * Melt operation details.
+   */
+  struct TALER_EXCHANGEDB_RefreshMelt melt;
+
+  /**
+   * Number of new coins we are creating.
+   */
+  uint16_t num_newcoins;
+
+  /**
+   * Index (smaller #TALER_CNC_KAPPA) which the exchange has chosen to not
+   * have revealed during cut and choose.
+   */
+  uint16_t noreveal_index;
+
+};
+
+
+/**
  * @brief We have as many `struct TALER_EXCHANGEDB_RefreshCommitCoin` as there are new
  * coins being created by the refresh (for each of the #TALER_CNC_KAPPA
  * sets).  These are the coins we ask the exchange to sign if the
@@ -558,21 +558,11 @@ struct TALER_EXCHANGEDB_MeltCommitment
 {
 
   /**
-   * Number of coins we are melting.
-   */
-  uint16_t num_oldcoins;
-
-  /**
    * Number of new coins we are creating.
    */
   uint16_t num_newcoins;
 
   /**
-   * Array of @e num_oldcoins melt operation details.
-   */
-  struct TALER_EXCHANGEDB_RefreshMelt *melts;
-
-  /**
    * Array of @e num_newcoins denomination keys
    */
   struct TALER_DenominationPublicKey *denom_pubs;
@@ -583,9 +573,9 @@ struct TALER_EXCHANGEDB_MeltCommitment
   struct TALER_EXCHANGEDB_RefreshCommitCoin *commit_coins[TALER_CNC_KAPPA];
 
   /**
-   * 2D-Array of #TALER_CNC_KAPPA and @e new_oldcoins links.
+   * Array of #TALER_CNC_KAPPA links.
    */
-  struct TALER_RefreshCommitLinkP *commit_links[TALER_CNC_KAPPA];
+  struct TALER_RefreshCommitLinkP commit_links[TALER_CNC_KAPPA];
 };
 
 
@@ -1117,43 +1107,6 @@ struct TALER_EXCHANGEDB_Plugin
 
 
   /**
-   * Store the given /refresh/melt request in the database.
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database connection
-   * @param oldcoin_index index of the coin to store
-   * @param melt coin melt operation details to store; includes
-   *             the session hash of the melt
-   * @return #GNUNET_OK on success
-   *         #GNUNET_SYSERR on internal error
-   */
-  int
-  (*insert_refresh_melt) (void *cls,
-                          struct TALER_EXCHANGEDB_Session *session,
-                          uint16_t oldcoin_index,
-                          const struct TALER_EXCHANGEDB_RefreshMelt *melt);
-
-
-  /**
-   * Get information about melted coin details from the database.
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database connection
-   * @param session_hash hash to identify refresh session
-   * @param oldcoin_index index of the coin to retrieve
-   * @param melt melt data to fill in, can be NULL
-   * @return #GNUNET_OK on success
-   *         #GNUNET_SYSERR on internal error
-   */
-  int
-  (*get_refresh_melt) (void *cls,
-                       struct TALER_EXCHANGEDB_Session *session,
-                       const struct GNUNET_HashCode *session_hash,
-                       uint16_t oldcoin_index,
-                       struct TALER_EXCHANGEDB_RefreshMelt *melt);
-
-
-  /**
    * Store in the database which coin(s) we want to create
    * in a given refresh operation.
    *
@@ -1245,18 +1198,16 @@ struct TALER_EXCHANGEDB_Plugin
    * @param cls the @e cls of this struct with the plugin-specific state
    * @param session database connection to use
    * @param session_hash hash to identify refresh session
-   * @param cnc_index cut and choose index (1st dimension), relating to #TALER_CNC_KAPPA
-   * @param num_links size of the @a commit_link array
-   * @param commit_links array of link information to store
+   * @param cnc_index cut and choose index, relating to #TALER_CNC_KAPPA
+   * @param link link information to store
    * @return #GNUNET_SYSERR on internal error, #GNUNET_OK on success
    */
   int
-  (*insert_refresh_commit_links) (void *cls,
-                                  struct TALER_EXCHANGEDB_Session *session,
-                                  const struct GNUNET_HashCode *session_hash,
-                                  uint16_t cnc_index,
-                                  uint16_t num_links,
-                                  const struct TALER_RefreshCommitLinkP *commit_links);
+  (*insert_refresh_commit_link) (void *cls,
+                                 struct TALER_EXCHANGEDB_Session *session,
+                                 const struct GNUNET_HashCode *session_hash,
+                                 uint16_t cnc_index,
+                                 const struct TALER_RefreshCommitLinkP *link);
 
   /**
    * Obtain the commited (encrypted) refresh link data
@@ -1266,19 +1217,17 @@ struct TALER_EXCHANGEDB_Plugin
    * @param session database connection to use
    * @param session_hash hash to identify refresh session
    * @param cnc_index cut and choose index (1st dimension)
-   * @param num_links size of the @a links array to return
-   * @param[out] links array link information to return
+   * @param[out] link information to return
    * @return #GNUNET_SYSERR on internal error,
    *         #GNUNET_NO if commitment was not found
    *         #GNUNET_OK on success
    */
   int
-  (*get_refresh_commit_links) (void *cls,
-                               struct TALER_EXCHANGEDB_Session *session,
-                               const struct GNUNET_HashCode *session_hash,
-                               uint16_t cnc_index,
-                               uint16_t num_links,
-                               struct TALER_RefreshCommitLinkP *links);
+  (*get_refresh_commit_link) (void *cls,
+                              struct TALER_EXCHANGEDB_Session *session,
+                              const struct GNUNET_HashCode *session_hash,
+                              uint16_t cnc_index,
+                              struct TALER_RefreshCommitLinkP *link);
 
 
   /**