add transactions to namestore plugin API

1 files changed, 78 insertions, 1 deletions

diff --git a/src/namestore/plugin_namestore_postgres.c b/src/namestore/plugin_namestore_postgres.c
index 4828cb190..378a88f51 100644
--- a/src/namestore/plugin_namestore_postgres.c
+++ b/src/namestore/plugin_namestore_postgres.c
@@ -243,7 +243,7 @@ namestore_postgres_store_records (void *cls,
                                               data_size,
                                               data);
     if ( (ret < 0) ||
-         (data_size != (size_t) ret) )        
+         (data_size != (size_t) ret) )
     {
       GNUNET_break (0);
       return GNUNET_SYSERR;
@@ -518,6 +518,80 @@ database_shutdown (struct Plugin *plugin)
 
 
 /**
+ * Start a transaction.
+ *
+ * @param cls closure
+ * @return #GNUNET_OK on success, #GNUNET_NO if transactions are not supported,
+ *         #GNUNET_SYSERR on internal errors
+ */
+static int
+namestore_postgres_begin_transaction (void *cls)
+{
+  struct Plugin *plugin = cls;
+  PGresult *result;
+  ExecStatusType ex;
+
+  result = PQexec (plugin->dbh,
+                   "START TRANSACTION ISOLATION LEVEL SERIALIZABLE");
+  if (PGRES_COMMAND_OK !=
+      (ex = PQresultStatus (result)))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to start transaction (%s): %s\n",
+                PQresStatus (ex),
+                PQerrorMessage (plugin->dbh));
+    GNUNET_break (0);
+    PQclear (result);
+    return GNUNET_SYSERR;
+  }
+  PQclear (result);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Try to commit a transaction.
+ *
+ * @param cls closure
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
+ */
+static int
+namestore_postgres_commit_transaction (void *cls)
+{
+  struct Plugin *plugin = cls;
+  PGresult *result;
+  ExecStatusType status;
+  int ret;
+
+  result = PQexec (plugin->dbh,
+                   "COMMIT");
+  status = PQresultStatus (result);
+  ret = (PGRES_COMMAND_OK == status) ? GNUNET_OK : GNUNET_SYSERR;
+  PQclear (result);
+  return ret;
+}
+
+
+/**
+ * Rollback a transaction.
+ *
+ * @param cls closure
+ */
+static void
+namestore_postgres_rollback_transaction (void *cls)
+{
+  struct Plugin *plugin = cls;
+  PGresult *result;
+
+  result = PQexec (plugin->dbh,
+                   "ROLLBACK");
+  GNUNET_break (PGRES_COMMAND_OK ==
+                PQresultStatus (result));
+  PQclear (result);
+}
+
+
+/**
  * Entry point for the plugin.
  *
  * @param cls the `struct GNUNET_NAMESTORE_PluginEnvironment*`
@@ -545,6 +619,9 @@ libgnunet_plugin_namestore_postgres_init (void *cls)
   api->iterate_records = &namestore_postgres_iterate_records;
   api->zone_to_name = &namestore_postgres_zone_to_name;
   api->lookup_records = &namestore_postgres_lookup_records;
+  api->begin_transaction = &namestore_postgres_begin_transaction;
+  api->commit_transaction = &namestore_postgres_commit_transaction;
+  api->rollback_transaction = &namestore_postgres_rollback_transaction;
   LOG (GNUNET_ERROR_TYPE_INFO,
        "Postgres namestore plugin running\n");
   return api;