[age restriction] progress 8/n

More work towards support for extensions and age restriction

- updated gana
- added handler for DB-Event
- added TEH_extensions_init() and _done()
- added global for age restriction
- added stub for post handler
- added SQL-table for extension metadata
- added enum type for extensions and other data structures

Also:
- fixed some warnings -Wmaybe-unitialized

1 files changed, 110 insertions, 0 deletions

diff --git a/src/exchange/taler-exchange-httpd_extensions.c b/src/exchange/taler-exchange-httpd_extensions.c
new file mode 100644
index 000000000..98092bd09
--- /dev/null
+++ b/src/exchange/taler-exchange-httpd_extensions.c
@@ -0,0 +1,110 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2021 Taler Systems SA
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Affero 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 Affero General Public License for more details.
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file taler-exchange-httpd_extensions.c
+ * @brief Handle extensions (age-restriction, peer2peer)
+ * @author Özgür Kesim
+ */
+#include "platform.h"
+#include <gnunet/gnunet_json_lib.h>
+#include "taler_dbevents.h"
+#include "taler-exchange-httpd_responses.h"
+#include "taler-exchange-httpd_extensions.h"
+#include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
+#include <jansson.h>
+
+
+/**
+ * Handler listening for extensions updates by other exchange
+ * services.
+ */
+static struct GNUNET_DB_EventHandler *extensions_eh;
+
+
+/**
+ * Function called whenever another exchange process has updated
+ * the extensions data in the database.
+ *
+ * @param cls NULL
+ * @param extra unused
+ * @param extra_size number of bytes in @a extra unused
+ */
+static void
+extension_update_event_cb (void *cls,
+                           const void *extra,
+                           size_t extra_size)
+{
+  (void) cls;
+  (void) extra;
+  (void) extra_size;
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Received /management/extensions update event\n");
+}
+
+
+enum GNUNET_GenericReturnValue
+TEH_extensions_init ()
+{
+  struct GNUNET_DB_EventHeaderP es = {
+    .size = htons (sizeof (es)),
+    .type = htons (TALER_DBEVENT_EXCHANGE_EXTENSIONS_UPDATED),
+  };
+
+  extensions_eh = TEH_plugin->event_listen (TEH_plugin->cls,
+                                            GNUNET_TIME_UNIT_FOREVER_REL,
+                                            &es,
+                                            &extension_update_event_cb,
+                                            NULL);
+  if (NULL == extensions_eh)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+void
+TEH_extensions_done ()
+{
+  if (NULL != extensions_eh)
+  {
+    TEH_plugin->event_listen_cancel (TEH_plugin->cls,
+                                     extensions_eh);
+    extensions_eh = NULL;
+  }
+}
+
+
+void
+TEH_extensions_update_state (void)
+{
+  /* TODO */
+#if 0
+  struct GNUNET_DB_EventHeaderP es = {
+    .size = htons (sizeof (es)),
+    .type = htons (TALER_DBEVENT_EXCHANGE_WIRE_UPDATED),
+  };
+
+  TEH_plugin->event_notify (TEH_plugin->cls,
+                            &es,
+                            NULL,
+                            0);
+#endif
+}
+
+
+/* end of taler-exchange-httpd_extensions.c */