[pq] added helper to load oids of composite types

- TALER_PQ_load_oids_for_composite_types added
- Called during postgres-initialization

src/exchangedb/plugin_exchangedb_postgres.c

@@ -293,6 +293,15 @@ TEH_PG_internal_setup (struct PostgresClosure *pg)
                                           NULL);
     if (NULL == db_conn)
       return GNUNET_SYSERR;
+
+    if (GNUNET_OK != TALER_PQ_load_oids_for_composite_types (db_conn))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "Failed to load OIDs for composite types\n");
+      GNUNET_PQ_disconnect (db_conn);
+      return GNUNET_SYSERR;
+    }
+
     pg->prep_gen++;
     pg->conn = db_conn;
   }

src/include/taler_exchangedb_lib.h

@@ -46,7 +46,6 @@ TALER_EXCHANGEDB_plugin_load (const struct GNUNET_CONFIGURATION_Handle *cfg);
 void
 TALER_EXCHANGEDB_plugin_unload (struct TALER_EXCHANGEDB_Plugin *plugin);
 
-
 /**
  * Information about an account from the configuration.
  */

src/include/taler_pq_lib.h

@@ -19,15 +19,42 @@
  * @author Sree Harsha Totakura <sreeharsha@totakura.in>
  * @author Florian Dold
  * @author Christian Grothoff
+ * @author Özgür Kesim
  */
 #ifndef TALER_PQ_LIB_H_
 #define TALER_PQ_LIB_H_
 
 #include <libpq-fe.h>
 #include <jansson.h>
+#include <gnunet/gnunet_common.h>
 #include <gnunet/gnunet_pq_lib.h>
 #include "taler_util.h"
 
+/**
+ * Enumerates the composite types that Taler defines in Postgres.
+ * The corresponding OIDs (which are assigned by postgres at time of
+ * declaration) are stored in TALER_PQ_CompositeOIDs.
+ */
+enum TALER_PQ_CompositeType
+{
+  TALER_PQ_CompositeAmount,
+  TALER_PQ_CompositeMAX /* MUST be last */
+};
+
+/**
+ * The correspondence of the Composite types and their OID in Postgres
+ */
+extern Oid TALER_PQ_CompositeOIDs[TALER_PQ_CompositeMAX];
+
+/**
+ * Initialize the list of OIDs in TALER_PQ_CompositeOIDs.  MUST be called
+ * before any composite type is used in arrays-specs/-params.
+ *
+ * @return GNUNET_SYSERR on failure
+ */
+enum GNUNET_GenericReturnValue
+TALER_PQ_load_oids_for_composite_types (struct GNUNET_PQ_Context *db);
+
 /**
  * Generate query parameter for a currency, consisting of the three
  * components "value", "fraction" and "currency" in this order. The

src/pq/Makefile.am

@@ -10,6 +10,8 @@ lib_LTLIBRARIES = \
   libtalerpq.la
 
 libtalerpq_la_SOURCES = \
+  pq_common.h \
+  pq_composite_types.c \
   pq_query_helper.c \
   pq_result_helper.c
 libtalerpq_la_LIBADD = \

src/pq/pq_common.h

@@ -47,20 +47,6 @@ enum TALER_PQ_ArrayType
   TALER_PQ_array_of_MAX,       /* must be last */
 };
 
-/**
- * The header for a postgresql array in binary format. note that this a
- * simplified special case of the general structure (which contains pointers),
- * as we only support one-dimensional arrays.
- */
-struct TALER_PQ_ArrayHeader_P
-{
-  uint32_t ndim;     /* number of dimensions. we only support ndim = 1 */
-  uint32_t has_null;
-  uint32_t oid;
-  uint32_t dim;      /* size of the array */
-  uint32_t lbound;   /* index value of first element in the db (default: 1). */
-} __attribute__((packed));
-
 /**
  * Memory representation of an taler amount record for Postgres.
  *
@@ -92,5 +78,6 @@ struct TALER_PQ_Amount_P
     .f = htonl ((amount)->fraction) \
   }
 
+
 #endif  /* TALER_PQ_COMMON_H_ */
 /* end of pg/pq_common.h */

src/pq/pq_composite_types.c

@@ -0,0 +1,57 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2023 Taler Systems SA
+
+  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 <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file pq/pq_composite_types.c
+ * @brief helper functions for Taler-specific libpq (PostGres) interactions with composite types
+ * @author Özgür Kesim
+ */
+#include "platform.h"
+#include <gnunet/gnunet_common.h>
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_pq_lib.h>
+#include "taler_pq_lib.h"
+#include "pq_common.h"
+
+Oid TALER_PQ_CompositeOIDs[TALER_PQ_CompositeMAX] = {0};
+
+enum GNUNET_GenericReturnValue
+TALER_PQ_load_oids_for_composite_types (
+  struct GNUNET_PQ_Context *db)
+{
+  static char *names[] = {
+    [TALER_PQ_CompositeAmount] = "taler_amount"
+  };
+  size_t num = sizeof(names) / sizeof(names[0]);
+
+  GNUNET_static_assert (num == TALER_PQ_CompositeMAX);
+
+  for (size_t i = 0; i < num; i++)
+  {
+    enum GNUNET_GenericReturnValue ret;
+    enum TALER_PQ_CompositeType typ = i;
+    ret = GNUNET_PQ_get_oid_by_name (db,
+                                     names[i],
+                                     &TALER_PQ_CompositeOIDs[typ]);
+    if (GNUNET_OK != ret)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "Failed to load OID for type %s\n",
+                  names[i]);
+      return GNUNET_SYSERR;
+    }
+  }
+  return GNUNET_OK;
+}

src/pq/pq_query_helper.c

@@ -872,7 +872,7 @@ qconv_array (
     RETURN_UNLESS ((0 == num) || (y / num == x));
 
     /* size of header */
-    total_size  = x = sizeof(struct TALER_PQ_ArrayHeader_P);
+    total_size  = x = sizeof(struct GNUNET_PQ_ArrayHeader_P);
     total_size += y;
     RETURN_UNLESS (total_size >= x);
 
@@ -941,7 +941,7 @@ qconv_array (
   /* Write data */
   {
     char *out = elements;
-    struct TALER_PQ_ArrayHeader_P h = {
+    struct GNUNET_PQ_ArrayHeader_P h = {
       .ndim = htonl (1),        /* We only support one-dimensional arrays */
       .has_null = htonl (0),    /* We do not support NULL entries in arrays */
       .lbound = htonl (1),      /* Default start index value */

src/pq/pq_result_helper.c

@@ -1166,7 +1166,7 @@ extract_array_generic (
   int data_sz;
   char *data;
   void *out = NULL;
-  struct TALER_PQ_ArrayHeader_P header;
+  struct GNUNET_PQ_ArrayHeader_P header;
   int col_num;
 
   GNUNET_assert (NULL != dst);
@@ -1192,8 +1192,8 @@ extract_array_generic (
   FAIL_IF (NULL == data);
 
   {
-    struct TALER_PQ_ArrayHeader_P *h =
+    struct GNUNET_PQ_ArrayHeader_P *h =
-      (struct TALER_PQ_ArrayHeader_P *) data;
+      (struct GNUNET_PQ_ArrayHeader_P *) data;
 
     header.ndim = ntohl (h->ndim);
     header.has_null = ntohl (h->has_null);

src/pq/test_pq.c

@@ -194,6 +194,16 @@ main (int argc,
     GNUNET_PQ_disconnect (conn);
     return 1;
   }
+
+  ret = TALER_PQ_load_oids_for_composite_types (conn);
+  if (GNUNET_OK != ret)
+  {
+    fprintf (stderr,
+             "Failed to load oids for composites\n");
+    GNUNET_PQ_disconnect (conn);
+    return 1;
+  }
+
   ret = run_queries (conn);
   {
     struct GNUNET_PQ_ExecuteStatement ds[] = {