/*
This file is part of TALER
Copyright (C) 2014-2017 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
Foundation; either version 3, or (at your option) any later version.
TALER is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
TALER; see the file COPYING. If not, see
*/
/**
* @file taler-exchange-httpd_db.c
* @brief Generic database operations for the exchange.
* @author Christian Grothoff
*/
#include "platform.h"
#include
#include
#include
#include "taler_json_lib.h"
#include "taler-exchange-httpd_responses.h"
#include "taler-exchange-httpd_keystate.h"
/**
* How often should we retry a transaction before giving up
* (for transactions resulting in serialization/dead locks only).
*/
#define MAX_TRANSACTION_COMMIT_RETRIES 3
/**
* Run a database transaction for @a connection.
* Starts a transaction and calls @a cb. Upon success,
* attempts to commit the transaction. Upon soft failures,
* retries @a cb a few times. Upon hard or persistent soft
* errors, generates an error message for @a connection.
*
* @param connection MHD connection to run @a cb for
* @param name name of the transaction (for debugging)
* @param[out] set to MHD response code, if transaction failed
* @param cb callback implementing transaction logic
* @param cb_cls closure for @a cb, must be read-only!
* @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
*/
int
TEH_DB_run_transaction (struct MHD_Connection *connection,
const char *name,
int *mhd_ret,
TEH_DB_TransactionCallback cb,
void *cb_cls)
{
struct TALER_EXCHANGEDB_Session *session;
if (NULL != mhd_ret)
*mhd_ret = -1; /* invalid value */
if (NULL == (session = TEH_plugin->get_session (TEH_plugin->cls)))
{
GNUNET_break (0);
if (NULL != mhd_ret)
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_DB_SETUP_FAILED);
return GNUNET_SYSERR;
}
TEH_plugin->preflight (TEH_plugin->cls,
session);
for (unsigned int retries = 0;retries < MAX_TRANSACTION_COMMIT_RETRIES; retries++)
{
enum GNUNET_DB_QueryStatus qs;
if (GNUNET_OK !=
TEH_plugin->start (TEH_plugin->cls,
session,
name))
{
GNUNET_break (0);
if (NULL != mhd_ret)
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_DB_START_FAILED);
return GNUNET_SYSERR;
}
qs = cb (cb_cls,
connection,
session,
mhd_ret);
if (0 > qs)
TEH_plugin->rollback (TEH_plugin->cls,
session);
if (GNUNET_DB_STATUS_HARD_ERROR == qs)
return GNUNET_SYSERR;
if (0 <= qs)
qs = TEH_plugin->commit (TEH_plugin->cls,
session);
if (GNUNET_DB_STATUS_HARD_ERROR == qs)
{
if (NULL != mhd_ret)
*mhd_ret = TEH_RESPONSE_reply_commit_error (connection,
TALER_EC_DB_COMMIT_FAILED_HARD);
return GNUNET_SYSERR;
}
/* make sure callback did not violate invariants! */
GNUNET_assert ( (NULL == mhd_ret) ||
(-1 == *mhd_ret) );
if (0 <= qs)
return GNUNET_OK;
}
TALER_LOG_WARNING ("Transaction commit failed %u times\n",
MAX_TRANSACTION_COMMIT_RETRIES);
if (NULL != mhd_ret)
*mhd_ret = TEH_RESPONSE_reply_commit_error (connection,
TALER_EC_DB_COMMIT_FAILED_ON_RETRY);
return GNUNET_SYSERR;
}
/**
* Calculate the total value of all transactions performed.
* Stores @a off plus the cost of all transactions in @a tl
* in @a ret.
*
* @param tl transaction list to process
* @param off offset to use as the starting value
* @param[out] ret where the resulting total is to be stored
* @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
*/
// FIXME: maybe move to another module, i.e. exchangedb???
int
TEH_DB_calculate_transaction_list_totals (struct TALER_EXCHANGEDB_TransactionList *tl,
const struct TALER_Amount *off,
struct TALER_Amount *ret)
{
struct TALER_Amount spent = *off;
struct TALER_EXCHANGEDB_TransactionList *pos;
struct TALER_Amount refunded;
GNUNET_assert (GNUNET_OK ==
TALER_amount_get_zero (spent.currency,
&refunded));
for (pos = tl; NULL != pos; pos = pos->next)
{
switch (pos->type)
{
case TALER_EXCHANGEDB_TT_DEPOSIT:
/* spent += pos->amount_with_fee */
if (GNUNET_OK !=
TALER_amount_add (&spent,
&spent,
&pos->details.deposit->amount_with_fee))
{
GNUNET_break (0);
return GNUNET_SYSERR;
}
break;
case TALER_EXCHANGEDB_TT_REFRESH_MELT:
/* spent += pos->amount_with_fee */
if (GNUNET_OK !=
TALER_amount_add (&spent,
&spent,
&pos->details.melt->session.amount_with_fee))
{
GNUNET_break (0);
return GNUNET_SYSERR;
}
break;
case TALER_EXCHANGEDB_TT_REFUND:
/* refunded += pos->refund_amount - pos->refund_fee */
if (GNUNET_OK !=
TALER_amount_add (&refunded,
&refunded,
&pos->details.refund->refund_amount))
{
GNUNET_break (0);
return GNUNET_SYSERR;
}
if (GNUNET_OK !=
TALER_amount_subtract (&refunded,
&refunded,
&pos->details.refund->refund_fee))
{
GNUNET_break (0);
return GNUNET_SYSERR;
}
break;
case TALER_EXCHANGEDB_TT_PAYBACK:
/* spent += pos->value */
if (GNUNET_OK !=
TALER_amount_add (&spent,
&spent,
&pos->details.payback->value))
{
GNUNET_break (0);
return GNUNET_SYSERR;
}
break;
}
}
/* spent = spent - refunded */
if (GNUNET_SYSERR ==
TALER_amount_subtract (&spent,
&spent,
&refunded))
{
GNUNET_break (0);
return GNUNET_SYSERR;
}
*ret = spent;
return GNUNET_OK;
}
/* end of taler-exchange-httpd_db.c */