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Diffstat (limited to 'src/util/db.c')
| -rw-r--r-- | src/util/db.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/src/util/db.c b/src/util/db.c new file mode 100644 index 000000000..a0b234a06 --- /dev/null +++ b/src/util/db.c @@ -0,0 +1,196 @@ +/* + This file is part of TALER + (C) 2014 Christian Grothoff (and other contributing authors) + + 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, If not, see <http://www.gnu.org/licenses/> +*/ + + +/** + * @file util/db.c + * @brief helper functions for DB interactions + * @author Sree Harsha Totakura <sreeharsha@totakura.in> + * @author Florian Dold + */ + +#include "platform.h" +#include <gnunet/gnunet_util_lib.h> +#include "taler_db_lib.h" + + +/** + * Execute a prepared statement. + */ +PGresult * +TALER_DB_exec_prepared (PGconn *db_conn, + const char *name, + const struct TALER_DB_QueryParam *params) +{ + unsigned len; + unsigned i; + + /* count the number of parameters */ + + { + const struct TALER_DB_QueryParam *x; + for (len = 0, x = params; + x->more; + len +=1, x += 1); + } + + /* new scope to allow stack allocation without alloca */ + + { + void *param_values[len]; + int param_lengths[len]; + int param_formats[len]; + + for (i = 0; i < len; i += 1) + { + param_values[i] = (void *) params[i].data; + param_lengths[i] = params[i].size; + param_formats[i] = 1; + } + return PQexecPrepared (db_conn, name, len, + (const char **) param_values, param_lengths, param_formats, 1); + } +} + + +/** + * Extract results from a query result according to the given specification. + * If colums are NULL, the destination is not modified, and GNUNET_NO + * is returned. + * + * @return + * GNUNET_YES if all results could be extracted + * GNUNET_NO if at least one result was NULL + * GNUNET_SYSERR if a result was invalid (non-existing field) + */ +int +TALER_DB_extract_result (PGresult *result, + struct TALER_DB_ResultSpec *rs, + int row) +{ + int had_null = GNUNET_NO; + + for (; NULL != rs->fname; rs += 1) + { + int fnum; + fnum = PQfnumber (result, rs->fname); + if (fnum < 0) + { + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "field '%s' does not exist in result\n", rs->fname); + return GNUNET_SYSERR; + } + + /* if a field is null, continue but + * remember that we now return a different result */ + + if (PQgetisnull (result, row, fnum)) + { + had_null = GNUNET_YES; + continue; + } + const char *res; + if (rs->dst_size != PQgetlength (result, row, fnum)) + { + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "field '%s' has wrong size (got %u, expected %u)\n", + rs->fname, (int) PQgetlength (result, row, fnum), (int) rs->dst_size); + return GNUNET_SYSERR; + } + res = PQgetvalue (result, row, fnum); + GNUNET_assert (NULL != res); + memcpy (rs->dst, res, rs->dst_size); + } + if (GNUNET_YES == had_null) + return GNUNET_NO; + return GNUNET_YES; +} + + +int +TALER_DB_field_isnull (PGresult *result, + int row, + const char *fname) +{ + int fnum; + fnum = PQfnumber (result, fname); + GNUNET_assert (fnum >= 0); + if (PQgetisnull (result, row, fnum)) + return GNUNET_YES; + return GNUNET_NO; +} + + +int +TALER_DB_extract_amount_nbo (PGresult *result, + int row, + const char *val_name, + const char *frac_name, + const char *curr_name, + struct TALER_AmountNBO *r_amount_nbo) +{ + int val_num; + int frac_num; + int curr_num; + int len; + + GNUNET_assert (NULL != strstr (val_name, "_val")); + GNUNET_assert (NULL != strstr (frac_name, "_frac")); + GNUNET_assert (NULL != strstr (curr_name, "_curr")); + + val_num = PQfnumber (result, val_name); + GNUNET_assert (val_num >= 0); + frac_num = PQfnumber (result, frac_name); + GNUNET_assert (frac_num >= 0); + curr_num = PQfnumber (result, curr_name); + GNUNET_assert (curr_num >= 0); + + r_amount_nbo->value = *(uint32_t *) PQgetvalue (result, row, val_num); + r_amount_nbo->fraction = *(uint32_t *) PQgetvalue (result, row, frac_num); + memset (r_amount_nbo->currency, 0, TALER_CURRENCY_LEN); + // FIXME: overflow? + len = PQgetlength (result, row, curr_num); + len = GNUNET_MIN (TALER_CURRENCY_LEN, len); + memcpy (r_amount_nbo->currency, PQgetvalue (result, row, curr_num), len); + r_amount_nbo->currency[TALER_CURRENCY_LEN - 1] = '\0'; + + return GNUNET_OK; +} + + +int +TALER_DB_extract_amount (PGresult *result, + int row, + const char *val_name, + const char *frac_name, + const char *curr_name, + struct TALER_Amount *r_amount) +{ + struct TALER_AmountNBO amount_nbo; + + (void) + TALER_DB_extract_amount_nbo (result, + row, + val_name, + frac_name, + curr_name, + &amount_nbo); + r_amount->value = ntohl (amount_nbo.value); + r_amount->fraction = ntohl (amount_nbo.fraction); + (void) strncpy (r_amount->currency, amount_nbo.currency, TALER_CURRENCY_LEN); + + return GNUNET_OK; +} + +/* end of util/db.c */ |