Define event consumption interface for the application side event service

implementation.
Implement event pass-through to the applicaiton.

Refs codership/wsrep-lib#174

src/event_service_v1.hpp

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2020 Codership Oy <info@codership.com>
+ *
+ * This file is part of wsrep-lib.
+ *
+ * Wsrep-lib 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Wsrep-lib 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 wsrep-lib.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef WSREP_EVENT_SERVICE_V1_HPP
+#define WSREP_EVENT_SERVICE_V1_HPP
+
+namespace wsrep
+{
+    class event_service;
+    /**
+     * Probe event_service_v1 support in loaded library.
+     *
+     * @param dlh Handle returned by dlopen().
+     *
+     * @return Zero on success, non-zero system error code on failure.
+     */
+    int event_service_v1_probe(void *dlh);
+
+    /**
+     * Initialize event service.
+     *
+     * @param dlh Handle returned by dlopen().
+     * @params event_service Pointer to wsrep::event_service implementation.
+     *
+     * @return Zero on success, non-zero system error code on failure.
+     */
+    int event_service_v1_init(void* dlh,
+                              wsrep::event_service* event_service);
+
+    /**
+     * Deinitialize event service.
+     *
+     * @param dlh Handler returned by dlopen().
+     */
+    void event_service_v1_deinit(void* dlh);
+}
+
+#endif // WSREP_EVENT_SERVICE_V1_HPP