1 files changed, 158 insertions, 0 deletions
diff --git a/src/backenddb/pg_helper.h b/src/backenddb/pg_helper.h
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+/*
+   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 pg_helper.h
+ * @brief shared internal definitions for postgres DB plugin
+ * @author Christian Grothoff
+ */
+#ifndef PG_HELPER_H
+#define PG_HELPER_H
+
+#include <gnunet/gnunet_db_lib.h>
+
+/**
+ * Type of the "cls" argument given to each of the functions in
+ * our API.
+ */
+struct PostgresClosure
+{
+
+  /**
+   * Postgres connection handle.
+   */
+  struct GNUNET_PQ_Context *conn;
+
+  /**
+   * Directory with SQL statements to run to create tables.
+   */
+  char *sql_dir;
+
+  /**
+   * Underlying configuration.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Name of the currently active transaction, NULL if none is active.
+   */
+  const char *transaction_name;
+
+  /**
+   * How many times have we connected to the DB.
+   */
+  uint64_t prep_gen;
+
+};
+
+
+/**
+ * Prepares SQL statement @a sql under @a name for
+ * connection @a pg once.
+ * Returns with #GNUNET_DB_STATUS_HARD_ERROR on failure.
+ *
+ * @param pg a `struct PostgresClosure`
+ * @param name name to prepare the statement under
+ * @param sql actual SQL text
+ */
+#define PREPARE(pg,name,sql)                      \
+  do {                                            \
+    static unsigned long long gen;                \
+                                                  \
+    if (gen < pg->prep_gen)                       \
+    {                                             \
+      struct GNUNET_PQ_PreparedStatement ps[] = { \
+        GNUNET_PQ_make_prepare (name, sql),       \
+        GNUNET_PQ_PREPARED_STATEMENT_END          \
+      };                                          \
+                                                  \
+      if (GNUNET_OK !=                            \
+          GNUNET_PQ_prepare_statements (pg->conn, \
+                                        ps))      \
+      {                                           \
+        GNUNET_break (0);                         \
+        return GNUNET_DB_STATUS_HARD_ERROR;       \
+      }                                           \
+      gen = pg->prep_gen;                         \
+    }                                             \
+  } while (0)
+
+
+/**
+ * Check that the database connection is still up
+ * and automatically reconnects unless we are
+ * already inside of a transaction.
+ *
+ * @param pg connection to check
+ */
+void
+check_connection (struct PostgresClosure *pg);
+
+
+/**
+ * Do a pre-flight check that we are not in an uncommitted transaction.
+ * If we are, die.
+ * Does not return anything, as we will continue regardless of the outcome.
+ *
+ * @param cls the `struct PostgresClosure` with the plugin-specific state
+ */
+void
+postgres_preflight (void *cls);
+
+/**
+ * Start a transaction.
+ *
+ * @param cls the `struct PostgresClosure` with the plugin-specific state
+ * @param name unique name identifying the transaction (for debugging),
+ *             must point to a constant
+ * @return #GNUNET_OK on success
+ */
+enum GNUNET_GenericReturnValue
+TMH_PG_start (void *cls,
+              const char *name);
+
+
+/**
+ * Start a transaction in 'read committed' mode.
+ *
+ * @param cls the `struct PostgresClosure` with the plugin-specific state
+ * @param name unique name identifying the transaction (for debugging),
+ *             must point to a constant
+ * @return #GNUNET_OK on success
+ */
+enum GNUNET_GenericReturnValue
+TMH_PG_start_read_committed (void *cls,
+                             const char *name);
+
+/**
+ * Roll back the current transaction of a database connection.
+ *
+ * @param cls the `struct PostgresClosure` with the plugin-specific state
+ */
+void
+TMH_PG_rollback (void *cls);
+
+
+/**
+ * Commit the current transaction of a database connection.
+ *
+ * @param cls the `struct PostgresClosure` with the plugin-specific state
+ * @return transaction status code
+ */
+enum GNUNET_DB_QueryStatus
+TMH_PG_commit (void *cls);
+
+
+#endif