1 files changed, 106 insertions, 0 deletions
diff --git a/wsrep-lib/src/service_helpers.hpp b/wsrep-lib/src/service_helpers.hpp
new file mode 100644
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+++ b/wsrep-lib/src/service_helpers.hpp
@@ -0,0 +1,106 @@
+/*
+ * 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_SERVICE_HELPERS_HPP
+#define WSREP_SERVICE_HELPERS_HPP
+
+#include "wsrep/logger.hpp"
+
+#include <dlfcn.h>
+#include <cerrno>
+
+namespace wsrep_impl
+{
+    template <typename InitFn>
+    int service_probe(void* dlh, const char* symbol, const char* service_name)
+    {
+        union {
+            InitFn dlfun;
+            void* obj;
+        } alias;
+        // Clear previous errors
+        (void)dlerror();
+        alias.obj = dlsym(dlh, symbol);
+        if (alias.obj)
+        {
+            return 0;
+        }
+        else
+        {
+            wsrep::log_warning() << "Support for " << service_name
+                                 << " " << symbol
+                                 << " not found from provider: "
+                                 << dlerror();
+            return ENOTSUP;
+        }
+    }
+
+
+    template <typename InitFn, typename ServiceCallbacks>
+    int service_init(void* dlh,
+                     const char* symbol,
+                     ServiceCallbacks service_callbacks,
+                     const char* service_name)
+    {
+        union {
+            InitFn dlfun;
+            void* obj;
+        } alias;
+        // Clear previous errors
+        (void)dlerror();
+        alias.obj = dlsym(dlh, symbol);
+        if (alias.obj)
+        {
+            wsrep::log_info() << "Initializing " << service_name;
+            return (*alias.dlfun)(service_callbacks);
+        }
+        else
+        {
+            wsrep::log_info()
+                << "Provider does not support " << service_name;
+            return ENOTSUP;
+        }
+    }
+
+    template <typename DeinitFn>
+    void service_deinit(void* dlh, const char* symbol, const char* service_name)
+    {
+        union {
+            DeinitFn dlfun;
+            void* obj;
+        } alias;
+        // Clear previous errors
+        (void)dlerror();
+        alias.obj = dlsym(dlh, symbol);
+        if (alias.obj)
+        {
+            wsrep::log_info() << "Deinitializing " << service_name;
+            (*alias.dlfun)();
+        }
+        else
+        {
+            wsrep::log_info()
+                << "Provider does not support deinitializing of "
+                << service_name;
+        }
+    }
+}
+
+#endif // WSREP_SERVICE_HELPERS_HPP
+