even cleaner separation of PostGres-specific logic, and nicer libtalerutil headers

3 files changed, 188 insertions, 2 deletions

diff --git a/src/pq/Makefile.am b/src/pq/Makefile.am
index cd7a5c93f..532d2909b 100644
--- a/src/pq/Makefile.am
+++ b/src/pq/Makefile.am
@@ -4,7 +4,7 @@ lib_LTLIBRARIES = \
   libtalerpq.la
 
 libtalerpq_la_SOURCES = \
-  db_pq.c
+  db_pq.c db_pq.h
 
 libtalerpq_la_LIBADD = \
   -lgnunetutil \
diff --git a/src/pq/db_pq.c b/src/pq/db_pq.c
index 2864f3475..069827579 100644
--- a/src/pq/db_pq.c
+++ b/src/pq/db_pq.c
@@ -22,7 +22,7 @@
  */
 #include "platform.h"
 #include <gnunet/gnunet_util_lib.h>
-#include "taler_db_lib.h"
+#include "db_pq.h"
 
 
 /**
diff --git a/src/pq/db_pq.h b/src/pq/db_pq.h
new file mode 100644
index 000000000..6e2b2b2c0
--- /dev/null
+++ b/src/pq/db_pq.h
@@ -0,0 +1,186 @@
+/*
+  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 include/taler_db_lib.h
+ * @brief helper functions for DB interactions
+ * @author Sree Harsha Totakura <sreeharsha@totakura.in>
+ * @author Florian Dold
+ * @author Christian Grothoff
+ */
+
+#ifndef TALER_DB_LIB_H_
+#define TALER_DB_LIB_H_
+
+#include <libpq-fe.h>
+#include "taler_util.h"
+
+/**
+ * Description of a DB query parameter.
+ */
+struct TALER_DB_QueryParam
+{
+  /**
+   * Data or NULL
+   */
+  const void *data;
+
+  /**
+   * Size of @e data
+   */
+  size_t size;
+
+  /**
+   * Non-null if this is not the last parameter.
+   * This allows for null as sentinal value.
+   */
+  int more;
+};
+
+/**
+ * End of query parameter specification.
+ */
+#define TALER_DB_QUERY_PARAM_END { NULL, 0, 0 }
+
+/**
+ * Generate fixed-size query parameter with size given explicitly.
+ *
+ * @param x pointer to the query parameter to pass
+ * @param s number of bytes of @a x to use for the query
+ */
+#define TALER_DB_QUERY_PARAM_PTR_SIZED(x, s) { (x), (s), 1 }
+
+/**
+ * Generate fixed-size query parameter with size determined
+ * by variable type.
+ *
+ * @param x pointer to the query parameter to pass.
+ */
+#define TALER_DB_QUERY_PARAM_PTR(x) TALER_DB_QUERY_PARAM_PTR_SIZED(x, sizeof (*(x)))
+
+
+/**
+ * Description of a DB result cell.
+ */
+struct TALER_DB_ResultSpec
+{
+  /**
+   * Destination for the data.
+   */
+  void *dst;
+
+  /**
+   * Allowed size for the data, 0 for variable-size
+   * (in this case, the type of @e dst is a `void **`
+   * and we need to allocate a buffer of the right size).
+   */
+  size_t dst_size;
+
+  /**
+   * Field name of the desired result.
+   */
+  char *fname;
+
+  /**
+   * Actual size of the result.
+   */
+  size_t *result_size;
+
+};
+
+
+/**
+ * End of result parameter specification.
+ */
+#define TALER_DB_RESULT_SPEC_END { NULL, 0, NULL, NULL }
+
+/**
+ * We expect a fixed-size result, with size given explicitly
+ *
+ * @param name name of the field in the table
+ * @param dst point to where to store the result
+ * @param s number of bytes we should use in @a dst
+ */
+#define TALER_DB_RESULT_SPEC_SIZED(name, dst, s) { (void *) (dst), (s), (name), NULL }
+
+/**
+ * We expect a fixed-size result, with size determined by the type of `* dst`
+ *
+ * @param name name of the field in the table
+ * @param dst point to where to store the result, type fits expected result size
+ */
+#define TALER_DB_RESULT_SPEC(name, dst) TALER_DB_RESULT_SPEC_SIZED(name, dst, sizeof (*(dst)))
+
+/**
+ * Variable-size result expected.
+ *
+ * @param name name of the field in the table
+ * @param dst where to store the result (of type void **), to be allocated
+ * @param sptr pointer to a `size_t` for where to store the size of @a dst
+ */
+#define TALER_DB_RESULT_SPEC_VAR(name, dst, sptr) { (void *) (dst), 0, (name), sptr }
+
+
+/**
+ * Execute a prepared statement.
+ */
+PGresult *
+TALER_DB_exec_prepared (PGconn *db_conn,
+                        const char *name,
+                        const struct TALER_DB_QueryParam *params);
+
+
+/**
+ * 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
+TALER_DB_field_isnull (PGresult *result,
+                       int row,
+                       const char *fname);
+
+
+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
+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);
+
+#endif  /* TALER_DB_LIB_H_ */
+
+/* end of include/taler_db_lib.h */