return taler-specific error codes from C API as well

(#4497/4705)

14 files changed, 199 insertions, 7 deletions

diff --git a/src/exchange-lib/exchange_api_admin.c b/src/exchange-lib/exchange_api_admin.c
index 524916e68..e17cd780a 100644
--- a/src/exchange-lib/exchange_api_admin.c
+++ b/src/exchange-lib/exchange_api_admin.c
@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2014, 2015 GNUnet e.V.
+  Copyright (C) 2014, 2015, 2016 GNUnet e.V.
 
   TALER is free software; you can redistribute it and/or modify it under the
   terms of the GNU General Public License as published by the Free Software
@@ -29,6 +29,7 @@
 #include "taler_json_lib.h"
 #include "taler_exchange_service.h"
 #include "exchange_api_handle.h"
+#include "exchange_api_common.h"
 #include "taler_signatures.h"
 
 
@@ -129,6 +130,7 @@ handle_admin_add_incoming_finished (void *cls,
   }
   aai->cb (aai->cb_cls,
            response_code,
+	   TALER_EXCHANGE_json_get_error_code (json),
            json);
   TALER_EXCHANGE_admin_add_incoming_cancel (aai);
 }
diff --git a/src/exchange-lib/exchange_api_common.c b/src/exchange-lib/exchange_api_common.c
index e6ab2cbc2..445e2f131 100644
--- a/src/exchange-lib/exchange_api_common.c
+++ b/src/exchange-lib/exchange_api_common.c
@@ -28,6 +28,33 @@
 
 
 /**
+ * Extract the Taler error code from the given @a json object.
+ * Note that #TALER_EC_NONE is returned if no "code" is present.
+ *
+ * @param json response to extract the error code from
+ * @return the "code" value from @a json
+ */
+enum TALER_ErrorCode
+TALER_EXCHANGE_json_get_error_code (const json_t *json)
+{
+  const json_t *jc;
+
+  if (NULL == json)
+  {
+    GNUNET_break_op (0);
+    return TALER_EC_INVALID_RESPONSE;
+  }
+  jc = json_object_get (json, "code");
+  if (NULL == jc)
+    return TALER_EC_NONE;
+  if (json_is_integer (jc))
+    return (enum TALER_ErrorCode) json_integer_value (jc);
+  GNUNET_break_op (0);
+  return TALER_EC_INVALID;
+}
+
+
+/**
  * Verify a coins transaction history as returned by the exchange.
  *
  * @param currency expected currency for the coin
diff --git a/src/exchange-lib/exchange_api_common.h b/src/exchange-lib/exchange_api_common.h
index 5655f5d3b..bea36258e 100644
--- a/src/exchange-lib/exchange_api_common.h
+++ b/src/exchange-lib/exchange_api_common.h
@@ -23,6 +23,18 @@
 #include <gnunet/gnunet_util_lib.h>
 #include "taler_exchange_service.h"
 
+
+/**
+ * Extract the Taler error code from the given @a json object.
+ * Note that #TALER_EC_NONE is returned if no "code" is present.
+ *
+ * @param json response to extract the error code from
+ * @return the "code" value from @a json
+ */
+enum TALER_ErrorCode
+TALER_EXCHANGE_json_get_error_code (const json_t *json);
+
+
 /**
  * Verify a coins transaction history as returned by the exchange.
  *
diff --git a/src/exchange-lib/exchange_api_deposit.c b/src/exchange-lib/exchange_api_deposit.c
index aa7e07ed8..63ae87d05 100644
--- a/src/exchange-lib/exchange_api_deposit.c
+++ b/src/exchange-lib/exchange_api_deposit.c
@@ -262,6 +262,7 @@ handle_deposit_finished (void *cls,
   }
   dh->cb (dh->cb_cls,
           response_code,
+	  TALER_EXCHANGE_json_get_error_code (json),
           ep,
           json);
   TALER_EXCHANGE_deposit_cancel (dh);
diff --git a/src/exchange-lib/exchange_api_refresh.c b/src/exchange-lib/exchange_api_refresh.c
index 6d12a718c..e185ef98b 100644
--- a/src/exchange-lib/exchange_api_refresh.c
+++ b/src/exchange-lib/exchange_api_refresh.c
@@ -1115,6 +1115,7 @@ handle_refresh_melt_finished (void *cls,
     {
       rmh->melt_cb (rmh->melt_cb_cls,
                     response_code,
+		    TALER_EXCHANGE_json_get_error_code (json),
                     noreveal_index,
                     (0 == response_code) ? NULL : &exchange_pub,
                     json);
@@ -1160,6 +1161,7 @@ handle_refresh_melt_finished (void *cls,
   if (NULL != rmh->melt_cb)
     rmh->melt_cb (rmh->melt_cb_cls,
                   response_code,
+		  TALER_EXCHANGE_json_get_error_code (json),
                   UINT16_MAX,
                   NULL,
                   json);
@@ -1598,6 +1600,7 @@ handle_refresh_reveal_finished (void *cls,
       {
         rrh->reveal_cb (rrh->reveal_cb_cls,
                         MHD_HTTP_OK,
+			TALER_EC_NONE,
                         rrh->md->num_fresh_coins,
                         coin_privs,
                         sigs,
@@ -1634,7 +1637,10 @@ handle_refresh_reveal_finished (void *cls,
   if (NULL != rrh->reveal_cb)
     rrh->reveal_cb (rrh->reveal_cb_cls,
                     response_code,
-                    0, NULL, NULL,
+		    TALER_EXCHANGE_json_get_error_code (json),
+		    0,
+		    NULL,
+		    NULL,
                     json);
   TALER_EXCHANGE_refresh_reveal_cancel (rrh);
 }
diff --git a/src/exchange-lib/exchange_api_refresh_link.c b/src/exchange-lib/exchange_api_refresh_link.c
index a1dba9938..c5dbc389a 100644
--- a/src/exchange-lib/exchange_api_refresh_link.c
+++ b/src/exchange-lib/exchange_api_refresh_link.c
@@ -27,6 +27,7 @@
 #include "taler_exchange_service.h"
 #include "taler_json_lib.h"
 #include "exchange_api_handle.h"
+#include "exchange_api_common.h"
 #include "taler_signatures.h"
 
 
@@ -265,6 +266,7 @@ parse_refresh_link_ok (struct TALER_EXCHANGE_RefreshLinkHandle *rlh,
     {
       rlh->link_cb (rlh->link_cb_cls,
 		    MHD_HTTP_OK,
+		    TALER_EC_NONE,
 		    num_coins,
 		    coin_privs,
 		    sigs,
@@ -345,7 +347,11 @@ handle_refresh_link_finished (void *cls,
   if (NULL != rlh->link_cb)
     rlh->link_cb (rlh->link_cb_cls,
                   response_code,
-                  0, NULL, NULL, NULL,
+		  TALER_EXCHANGE_json_get_error_code (json),
+                  0,
+		  NULL,
+		  NULL,
+		  NULL,
                   json);
   TALER_EXCHANGE_refresh_link_cancel (rlh);
 }
diff --git a/src/exchange-lib/exchange_api_refund.c b/src/exchange-lib/exchange_api_refund.c
index f712f126a..73dd6ce51 100644
--- a/src/exchange-lib/exchange_api_refund.c
+++ b/src/exchange-lib/exchange_api_refund.c
@@ -196,6 +196,7 @@ handle_refund_finished (void *cls,
   }
   rh->cb (rh->cb_cls,
           response_code,
+	  TALER_EXCHANGE_json_get_error_code (json),
           ep,
           json);
   TALER_EXCHANGE_refund_cancel (rh);
diff --git a/src/exchange-lib/exchange_api_reserve.c b/src/exchange-lib/exchange_api_reserve.c
index 9de2b268f..bcf372580 100644
--- a/src/exchange-lib/exchange_api_reserve.c
+++ b/src/exchange-lib/exchange_api_reserve.c
@@ -29,6 +29,7 @@
 #include "taler_exchange_service.h"
 #include "taler_json_lib.h"
 #include "exchange_api_handle.h"
+#include "exchange_api_common.h"
 #include "taler_signatures.h"
 
 
@@ -314,7 +315,8 @@ handle_reserve_status_finished (void *cls,
       if (GNUNET_OK !=
           GNUNET_JSON_parse (json,
                              spec,
-                             NULL, NULL))
+                             NULL,
+			     NULL))
       {
         GNUNET_break_op (0);
         response_code = 0;
@@ -355,6 +357,7 @@ handle_reserve_status_finished (void *cls,
         }
         wsh->cb (wsh->cb_cls,
                  response_code,
+		 TALER_EC_NONE,
                  json,
                  &balance,
                  len,
@@ -387,6 +390,7 @@ handle_reserve_status_finished (void *cls,
   if (NULL != wsh->cb)
     wsh->cb (wsh->cb_cls,
              response_code,
+	     TALER_EXCHANGE_json_get_error_code (json),
              json,
              NULL,
              0, NULL);
@@ -589,6 +593,7 @@ reserve_withdraw_ok (struct TALER_EXCHANGE_ReserveWithdrawHandle *wsh,
   dsig.rsa_signature = sig;
   wsh->cb (wsh->cb_cls,
            MHD_HTTP_OK,
+	   TALER_EC_NONE,
            &dsig,
            json);
   /* make sure callback isn't called again after return */
@@ -762,6 +767,7 @@ handle_reserve_withdraw_finished (void *cls,
   if (NULL != wsh->cb)
     wsh->cb (wsh->cb_cls,
              response_code,
+	     TALER_EXCHANGE_json_get_error_code (json),
              NULL,
              json);
   TALER_EXCHANGE_reserve_withdraw_cancel (wsh);
diff --git a/src/exchange-lib/exchange_api_track_transaction.c b/src/exchange-lib/exchange_api_track_transaction.c
index c05115d57..cf0685733 100644
--- a/src/exchange-lib/exchange_api_track_transaction.c
+++ b/src/exchange-lib/exchange_api_track_transaction.c
@@ -239,6 +239,7 @@ handle_deposit_wtid_finished (void *cls,
   }
   dwh->cb (dwh->cb_cls,
            response_code,
+	   TALER_EXCHANGE_json_get_error_code (json),
            ep,
            json,
            wtid,
diff --git a/src/exchange-lib/exchange_api_track_transfer.c b/src/exchange-lib/exchange_api_track_transfer.c
index ffcb19b59..0b45ecfc5 100644
--- a/src/exchange-lib/exchange_api_track_transfer.c
+++ b/src/exchange-lib/exchange_api_track_transfer.c
@@ -183,6 +183,7 @@ check_track_transfer_response_ok (struct TALER_EXCHANGE_TrackTransferHandle *wdh
     }
     wdh->cb (wdh->cb_cls,
              MHD_HTTP_OK,
+	     TALER_EC_NONE,
              &exchange_pub,
              json,
              &h_wire,
@@ -253,6 +254,7 @@ handle_track_transfer_finished (void *cls,
   }
   wdh->cb (wdh->cb_cls,
            response_code,
+	   TALER_EXCHANGE_json_get_error_code (json),
            NULL,
            json,
            NULL,
diff --git a/src/exchange-lib/exchange_api_wire.c b/src/exchange-lib/exchange_api_wire.c
index cb8df4944..60e9113ab 100644
--- a/src/exchange-lib/exchange_api_wire.c
+++ b/src/exchange-lib/exchange_api_wire.c
@@ -210,6 +210,7 @@ handle_wire_finished (void *cls,
   }
   wh->cb (wh->cb_cls,
           response_code,
+	  TALER_EXCHANGE_json_get_error_code (json),
           (NULL != keep) ? keep : json);
   if (NULL != keep)
     json_decref (keep);
diff --git a/src/exchange-lib/test_exchange_api.c b/src/exchange-lib/test_exchange_api.c
index 80007c66f..39b8becef 100644
--- a/src/exchange-lib/test_exchange_api.c
+++ b/src/exchange-lib/test_exchange_api.c
@@ -761,11 +761,13 @@ next_command (struct InterpreterState *is)
  * @param cls closure with the interpreter state
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param full_response full response from the exchange (for logging, in case of errors)
  */
 static void
 add_incoming_cb (void *cls,
                  unsigned int http_status,
+		 enum TALER_ErrorCode ec,
                  const json_t *full_response)
 {
   struct InterpreterState *is = cls;
@@ -857,6 +859,7 @@ compare_reserve_withdraw_history (const struct TALER_EXCHANGE_ReserveHistory *h,
  * @param cls closure with the interpreter state
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param[in] json original response in JSON format (useful only for diagnostics)
  * @param balance current balance in the reserve, NULL on error
  * @param history_length number of entries in the transaction history, 0 on error
@@ -865,6 +868,7 @@ compare_reserve_withdraw_history (const struct TALER_EXCHANGE_ReserveHistory *h,
 static void
 reserve_status_cb (void *cls,
                    unsigned int http_status,
+		   enum TALER_ErrorCode ec,
                    const json_t *json,
                    const struct TALER_Amount *balance,
                    unsigned int history_length,
@@ -973,12 +977,14 @@ reserve_status_cb (void *cls,
  * @param cls closure with the interpreter state
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param sig signature over the coin, NULL on error
  * @param full_response full response from the exchange (for logging, in case of errors)
  */
 static void
 reserve_withdraw_cb (void *cls,
                      unsigned int http_status,
+		     enum TALER_ErrorCode ec,
                      const struct TALER_DenominationSignature *sig,
                      const json_t *full_response)
 {
@@ -1027,6 +1033,7 @@ reserve_withdraw_cb (void *cls,
  * @param cls closure with the interpreter state
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful deposit;
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param exchange_pub public key the exchange used for signing
  * @param obj the received JSON reply, should be kept as proof (and, in case of errors,
  *            be forwarded to the customer)
@@ -1034,6 +1041,7 @@ reserve_withdraw_cb (void *cls,
 static void
 deposit_cb (void *cls,
             unsigned int http_status,
+	    enum TALER_ErrorCode ec,
             const struct TALER_ExchangePublicKeyP *exchange_pub,
             const json_t *obj)
 {
@@ -1061,6 +1069,7 @@ deposit_cb (void *cls,
  * @param cls closure with the interpreter state
  * @param http_status HTTP response code, never #MHD_HTTP_OK (200) as for successful intermediate response this callback is skipped.
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param noreveal_index choice by the exchange in the cut-and-choose protocol,
  *                    UINT16_MAX on error
  * @param exchange_pub public key the exchange used for signing
@@ -1069,6 +1078,7 @@ deposit_cb (void *cls,
 static void
 melt_cb (void *cls,
          unsigned int http_status,
+	 enum TALER_ErrorCode ec,
          uint16_t noreveal_index,
          const struct TALER_ExchangePublicKeyP *exchange_pub,
          const json_t *full_response)
@@ -1098,6 +1108,7 @@ melt_cb (void *cls,
  * @param cls closure with the interpreter state
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param num_coins number of fresh coins created, length of the @a sigs and @a coin_privs arrays, 0 if the operation failed
  * @param coin_privs array of @a num_coins private keys for the coins that were created, NULL on error
  * @param sigs array of signature over @a num_coins coins, NULL on error
@@ -1106,6 +1117,7 @@ melt_cb (void *cls,
 static void
 reveal_cb (void *cls,
            unsigned int http_status,
+	   enum TALER_ErrorCode ec,
            unsigned int num_coins,
            const struct TALER_CoinSpendPrivateKeyP *coin_privs,
            const struct TALER_DenominationSignature *sigs,
@@ -1160,6 +1172,7 @@ reveal_cb (void *cls,
  * @param cls closure with the interpreter state
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param num_coins number of fresh coins created, length of the @a sigs and @a coin_privs arrays, 0 if the operation failed
  * @param coin_privs array of @a num_coins private keys for the coins that were created, NULL on error
  * @param sigs array of signature over @a num_coins coins, NULL on error
@@ -1169,6 +1182,7 @@ reveal_cb (void *cls,
 static void
 link_cb (void *cls,
          unsigned int http_status,
+	 enum TALER_ErrorCode ec,
          unsigned int num_coins,
          const struct TALER_CoinSpendPrivateKeyP *coin_privs,
          const struct TALER_DenominationSignature *sigs,
@@ -1336,12 +1350,14 @@ find_pk (const struct TALER_EXCHANGE_Keys *keys,
  * @param cls closure with the interpreter state
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful request;
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param obj the received JSON reply, if successful this should be the wire
  *            format details as provided by /wire.
  */
 static void
 wire_cb (void *cls,
          unsigned int http_status,
+	 enum TALER_ErrorCode ec,
          const json_t *obj)
 {
   struct InterpreterState *is = cls;
@@ -1391,6 +1407,7 @@ wire_cb (void *cls,
  *
  * @param cls closure
  * @param http_status HTTP status code we got, 0 on exchange protocol violation
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param exchange_pub public key the exchange used for signing
  * @param json original json reply (may include signatures, those have then been
  *        validated already)
@@ -1404,6 +1421,7 @@ wire_cb (void *cls,
 static void
 wire_deposits_cb (void *cls,
                   unsigned int http_status,
+		  enum TALER_ErrorCode ec,
                   const struct TALER_ExchangePublicKeyP *exchange_pub,
                   const json_t *json,
                   const struct GNUNET_HashCode *h_wire,
@@ -1521,6 +1539,7 @@ wire_deposits_cb (void *cls,
  *
  * @param cls closure
  * @param http_status HTTP status code we got, 0 on exchange protocol violation
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param exchange_pub public key the exchange used for signing
  * @param json original json reply (may include signatures, those have then been
  *        validated already)
@@ -1534,6 +1553,7 @@ wire_deposits_cb (void *cls,
 static void
 deposit_wtid_cb (void *cls,
                  unsigned int http_status,
+		 enum TALER_ErrorCode ec,
                  const struct TALER_ExchangePublicKeyP *exchange_pub,
                  const json_t *json,
                  const struct TALER_WireTransferIdentifierRawP *wtid,
@@ -1588,6 +1608,7 @@ deposit_wtid_cb (void *cls,
  * @param cls closure
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful deposit;
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param exchange_pub public key the exchange used for signing @a obj
  * @param obj the received JSON reply, should be kept as proof (and, in particular,
  *            be forwarded to the customer)
@@ -1595,6 +1616,7 @@ deposit_wtid_cb (void *cls,
 static void
 refund_cb (void *cls,
            unsigned int http_status,
+	   enum TALER_ErrorCode ec,
            const struct TALER_ExchangePublicKeyP *exchange_pub,
            const json_t *obj)
 {
diff --git a/src/include/taler_error_codes.h b/src/include/taler_error_codes.h
index dbe189936..632c160a1 100644
--- a/src/include/taler_error_codes.h
+++ b/src/include/taler_error_codes.h
@@ -33,10 +33,22 @@ enum TALER_ErrorCode
 {
 
   /**
-   * Special code to indicate no error.
+   * Special code to indicate no error (or no "code" present).
    */
   TALER_EC_NONE = 0,
 
+  /**
+   * Special code to indicate that a non-integer error code was
+   * returned in the JSON response.
+   */
+  TALER_EC_INVALID = 1,
+
+  /**
+   * The response we got from the server was not even in JSON format.
+   */
+  TALER_EC_INVALID_RESPONSE = 2,
+
+  
   /* ********** generic error codes ************* */
   
   /**
@@ -975,6 +987,33 @@ enum TALER_ErrorCode
   TALER_EC_TRACK_TRANSACTION_DB_NO_DEPOSITS_ERROR = 2305,
 
   /**
+   * We failed to obtain a wire transfer identifier for one
+   * of the coins in the transaction.  The response is
+   * provided with HTTP status code MHD_HTTP_FAILED_DEPENDENCY if
+   * the exchange had a hard error, or MHD_HTTP_ACCEPTED if the
+   * exchange signaled that the transfer was in progress.
+   */
+  TALER_EC_TRACK_TRANSACTION_COIN_TRACE_ERROR = 2306,
+
+  /**
+   * We failed to obtain the full wire transfer identifier for the
+   * transfer one of the coins was aggregated into.
+   * The response is
+   * provided with HTTP status code MHD_HTTP_FAILED_DEPENDENCY.
+   */
+  TALER_EC_TRACK_TRANSACTION_WIRE_TRANSFER_TRACE_ERROR = 2307,
+  
+  /**
+   * We got conflicting reports from the exhange with 
+   * respect to which transfers are included in which
+   * aggregate.
+   * The response is
+   * provided with HTTP status code MHD_HTTP_FAILED_DEPENDENCY.
+   */
+  TALER_EC_TRACK_TRANSACTION_CONFLICTING_REPORTS = 2308,
+
+  
+  /**
    * We failed to contact the exchange for the /track/transfer
    * request.  This response is provided with HTTP status code
    * MHD_HTTP_SERVICE_UNAVAILABLE.
@@ -986,8 +1025,52 @@ enum TALER_ErrorCode
    * in the request.   This response is
    * provided with HTTP status code MHD_HTTP_NOT_FOUND.
    */
-  TALER_EC_TRACK_TRANSFER_INSTANCE_UNKNOWN = 2000,
+  TALER_EC_TRACK_TRANSFER_INSTANCE_UNKNOWN = 2401,
+
+  /**
+   * We failed to persist coin wire transfer information in
+   * our merchant database.
+   * The response is
+   * provided with HTTP status code MHD_HTTP_INTERNAL_SERVER_ERROR.
+   */
+  TALER_EC_TRACK_TRANSFER_DB_STORE_COIN_ERROR = 2402,
 
+  /**
+   * We internally failed to execute the /track/transfer request.
+   * The response is
+   * provided with HTTP status code MHD_HTTP_INTERNAL_SERVER_ERROR.
+   */
+  TALER_EC_TRACK_TRANSFER_REQUEST_ERROR = 2403,
+
+  /**
+   * We failed to persist wire transfer information in
+   * our merchant database.
+   * The response is
+   * provided with HTTP status code MHD_HTTP_INTERNAL_SERVER_ERROR.
+   */
+  TALER_EC_TRACK_TRANSFER_DB_STORE_TRANSER_ERROR = 2404,
+  
+  /**
+   * The exchange returned an error from /track/transfer.
+   * The response is
+   * provided with HTTP status code MHD_HTTP_FAILED_DEPENDENCY.
+   */
+  TALER_EC_TRACK_TRANSFER_EXCHANGE_ERROR = 2405,
+
+  /**
+   * We failed to fetch deposit information from
+   * our merchant database.
+   * The response is
+   * provided with HTTP status code MHD_HTTP_INTERNAL_SERVER_ERROR.
+   */
+  TALER_EC_TRACK_TRANSFER_DB_FETCH_DEPOSIT_ERROR = 2406,
+
+  /**
+   * We encountered an internal logic error.
+   * The response is
+   * provided with HTTP status code MHD_HTTP_INTERNAL_SERVER_ERROR.
+   */
+  TALER_EC_TRACK_TRANSFER_DB_INTERNAL_LOGIC_ERROR = 2407,
 
   
   /* ********** /test API error codes ************* */
diff --git a/src/include/taler_exchange_service.h b/src/include/taler_exchange_service.h
index 9e3c48c4c..d1f6dbbe3 100644
--- a/src/include/taler_exchange_service.h
+++ b/src/include/taler_exchange_service.h
@@ -24,6 +24,7 @@
 
 #include <jansson.h>
 #include "taler_util.h"
+#include "taler_error_codes.h"
 #include <gnunet/gnunet_curl_lib.h>
 
 
@@ -355,6 +356,7 @@ struct TALER_EXCHANGE_WireHandle;
  * @param cls closure
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful request;
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param obj the received JSON reply, if successful this should be the wire
  *            format details as provided by /wire, or NULL if the
  *            reply was not in JSON format.
@@ -362,6 +364,7 @@ struct TALER_EXCHANGE_WireHandle;
 typedef void
 (*TALER_EXCHANGE_WireResultCallback) (void *cls,
                                       unsigned int http_status,
+				      enum TALER_ErrorCode ec,
                                       const json_t *obj);
 
 
@@ -423,6 +426,7 @@ struct TALER_EXCHANGE_DepositHandle;
 typedef void
 (*TALER_EXCHANGE_DepositResultCallback) (void *cls,
                                          unsigned int http_status,
+					 enum TALER_ErrorCode ec,
                                          const struct TALER_ExchangePublicKeyP *sign_key,
                                          const json_t *obj);
 
@@ -504,6 +508,7 @@ struct TALER_EXCHANGE_RefundHandle;
  * @param cls closure
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful deposit;
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param sign_key exchange key used to sign @a obj, or NULL
  * @param obj the received JSON reply, should be kept as proof (and, in particular,
  *            be forwarded to the customer)
@@ -511,6 +516,7 @@ struct TALER_EXCHANGE_RefundHandle;
 typedef void
 (*TALER_EXCHANGE_RefundResultCallback) (void *cls,
 					unsigned int http_status,
+					enum TALER_ErrorCode ec,
                                         const struct TALER_ExchangePublicKeyP *sign_key,
 					const json_t *obj);
 
@@ -650,6 +656,7 @@ struct TALER_EXCHANGE_ReserveHistory
  * @param cls closure
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param[in] json original response in JSON format (useful only for diagnostics)
  * @param balance current balance in the reserve, NULL on error
  * @param history_length number of entries in the transaction history, 0 on error
@@ -658,6 +665,7 @@ struct TALER_EXCHANGE_ReserveHistory
 typedef void
 (*TALER_EXCHANGE_ReserveStatusResultCallback) (void *cls,
                                                unsigned int http_status,
+					       enum TALER_ErrorCode ec,
                                                const json_t *json,
                                                const struct TALER_Amount *balance,
                                                unsigned int history_length,
@@ -713,12 +721,14 @@ struct TALER_EXCHANGE_ReserveWithdrawHandle;
  * @param cls closure
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param sig signature over the coin, NULL on error
  * @param full_response full response from the exchange (for logging, in case of errors)
  */
 typedef void
 (*TALER_EXCHANGE_ReserveWithdrawResultCallback) (void *cls,
                                                  unsigned int http_status,
+						 enum TALER_ErrorCode ec,
                                                  const struct TALER_DenominationSignature *sig,
                                                  const json_t *full_response);
 
@@ -835,6 +845,7 @@ struct TALER_EXCHANGE_RefreshMeltHandle;
  * @param cls closure
  * @param http_status HTTP response code, never #MHD_HTTP_OK (200) as for successful intermediate response this callback is skipped.
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param noreveal_index choice by the exchange in the cut-and-choose protocol,
  *                    UINT16_MAX on error
  * @param sign_key exchange key used to sign @a full_response, or NULL
@@ -843,7 +854,8 @@ struct TALER_EXCHANGE_RefreshMeltHandle;
 typedef void
 (*TALER_EXCHANGE_RefreshMeltCallback) (void *cls,
                                        unsigned int http_status,
-                                       uint16_t noreveal_index,
+				       enum TALER_ErrorCode ec,
+				       uint16_t noreveal_index,
                                        const struct TALER_ExchangePublicKeyP *sign_key,
                                        const json_t *full_response);
 
@@ -900,6 +912,7 @@ TALER_EXCHANGE_refresh_melt_cancel (struct TALER_EXCHANGE_RefreshMeltHandle *rmh
  * @param cls closure
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param num_coins number of fresh coins created, length of the @a sigs and @a coin_privs arrays, 0 if the operation failed
  * @param coin_privs array of @a num_coins private keys for the coins that were created, NULL on error
  * @param sigs array of signature over @a num_coins coins, NULL on error
@@ -908,6 +921,7 @@ TALER_EXCHANGE_refresh_melt_cancel (struct TALER_EXCHANGE_RefreshMeltHandle *rmh
 typedef void
 (*TALER_EXCHANGE_RefreshRevealCallback) (void *cls,
                                          unsigned int http_status,
+					 enum TALER_ErrorCode ec,
                                          unsigned int num_coins,
                                          const struct TALER_CoinSpendPrivateKeyP *coin_privs,
                                          const struct TALER_DenominationSignature *sigs,
@@ -979,6 +993,7 @@ struct TALER_EXCHANGE_RefreshLinkHandle;
  * @param cls closure
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param num_coins number of fresh coins created, length of the @a sigs and @a coin_privs arrays, 0 if the operation failed
  * @param coin_privs array of @a num_coins private keys for the coins that were created, NULL on error
  * @param sigs array of signature over @a num_coins coins, NULL on error
@@ -988,6 +1003,7 @@ struct TALER_EXCHANGE_RefreshLinkHandle;
 typedef void
 (*TALER_EXCHANGE_RefreshLinkCallback) (void *cls,
                                        unsigned int http_status,
+				       enum TALER_ErrorCode ec,
                                        unsigned int num_coins,
                                        const struct TALER_CoinSpendPrivateKeyP *coin_privs,
                                        const struct TALER_DenominationSignature *sigs,
@@ -1043,11 +1059,13 @@ struct TALER_EXCHANGE_AdminAddIncomingHandle;
  * @param cls closure
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param full_response full response from the exchange (for logging, in case of errors)
  */
 typedef void
 (*TALER_EXCHANGE_AdminAddIncomingResultCallback) (void *cls,
                                                   unsigned int http_status,
+						  enum TALER_ErrorCode ec,
                                                   const json_t *full_response);
 
 
@@ -1108,6 +1126,7 @@ struct TALER_EXCHANGE_TrackTransferHandle;
  *
  * @param cls closure
  * @param http_status HTTP status code we got, 0 on exchange protocol violation
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param sign_key exchange key used to sign @a json, or NULL
  * @param json original json reply (may include signatures, those have then been
  *        validated already)
@@ -1121,6 +1140,7 @@ struct TALER_EXCHANGE_TrackTransferHandle;
 typedef void
 (*TALER_EXCHANGE_TrackTransferCallback)(void *cls,
                                         unsigned int http_status,
+					enum TALER_ErrorCode ec,
                                         const struct TALER_ExchangePublicKeyP *sign_key,
                                         const json_t *json,
                                         const struct GNUNET_HashCode *h_wire,
@@ -1171,6 +1191,7 @@ struct TALER_EXCHANGE_TrackTransactionHandle;
  *
  * @param cls closure
  * @param http_status HTTP status code we got, 0 on exchange protocol violation
+ * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param sign_key exchange key used to sign @a json, or NULL
  * @param json original json reply (may include signatures, those have then been
  *        validated already)
@@ -1182,6 +1203,7 @@ struct TALER_EXCHANGE_TrackTransactionHandle;
 typedef void
 (*TALER_EXCHANGE_TrackTransactionCallback)(void *cls,
                                            unsigned int http_status,
+					   enum TALER_ErrorCode ec,
                                            const struct TALER_ExchangePublicKeyP *sign_key,
                                            const json_t *json,
                                            const struct TALER_WireTransferIdentifierRawP *wtid,