1 files changed, 160 insertions, 0 deletions
diff --git a/wsrep-lib/include/wsrep/logger.hpp b/wsrep-lib/include/wsrep/logger.hpp
new file mode 100644
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--- /dev/null
+++ b/wsrep-lib/include/wsrep/logger.hpp
@@ -0,0 +1,160 @@
+/*
+ * Copyright (C) 2018-2019 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_LOGGER_HPP
+#define WSREP_LOGGER_HPP
+
+#include "mutex.hpp"
+#include "lock.hpp"
+#include "atomic.hpp"
+
+#include <iosfwd>
+#include <sstream>
+
+#define WSREP_LOG_DEBUG(debug_level_fn, debug_level, msg)               \
+    do {                                                                \
+        if (debug_level_fn >= debug_level) wsrep::log_debug() << msg;   \
+    } while (0)
+
+namespace wsrep
+{
+    class log
+    {
+    public:
+        enum level
+        {
+            debug,
+            info,
+            warning,
+            error,
+            unknown
+        };
+
+        enum debug_level
+        {
+            debug_level_server_state = 1,
+            debug_level_transaction,
+            debug_level_streaming,
+            debug_level_client_state
+        };
+
+        /**
+         * Signature for user defined logger callback function.
+         *
+         * @param pfx optional internally defined prefix for the message
+         * @param msg message to log
+         */
+        typedef void (*logger_fn_type)(level l,
+                                       const char* pfx, const char* msg);
+
+        static const char* to_c_string(enum level level)
+        {
+            switch (level)
+            {
+            case debug:   return "debug";
+            case info:    return "info";
+            case warning: return "warning";
+            case error:   return "error";
+            case unknown: break;
+            };
+            return "unknown";
+        }
+
+        log(enum wsrep::log::level level, const char* prefix = "L:")
+            : level_(level)
+            , prefix_(prefix)
+            , oss_()
+        { }
+
+        ~log()
+        {
+            if (logger_fn_)
+            {
+                logger_fn_(level_, prefix_, oss_.str().c_str());
+            }
+            else
+            {
+                wsrep::unique_lock<wsrep::mutex> lock(mutex_);
+                os_ << prefix_ << oss_.str() << std::endl;
+            }
+        }
+
+        template <typename T>
+        std::ostream& operator<<(const T& val)
+        {
+            return (oss_ << val);
+        }
+
+        /**
+         * Set user defined logger callback function.
+         */
+        static void logger_fn(logger_fn_type);
+
+        /**
+         * Set debug log level from client
+         */
+        static void debug_log_level(int debug_level);
+
+        /**
+         * Get current debug log level
+         */
+        static int debug_log_level();
+
+    private:
+        log(const log&);
+        log& operator=(const log&);
+        enum level level_;
+        const char* prefix_;
+        std::ostringstream oss_;
+        static wsrep::mutex& mutex_;
+        static std::ostream& os_;
+        static logger_fn_type logger_fn_;
+        static std::atomic_int debug_log_level_;
+    };
+
+    class log_error : public log
+    {
+    public:
+        log_error()
+            : log(error) { }
+    };
+
+    class log_warning : public log
+    {
+    public:
+        log_warning()
+            : log(warning) { }
+    };
+
+    class log_info : public log
+    {
+    public:
+        log_info()
+            : log(info) { }
+    };
+
+    class log_debug : public log
+    {
+    public:
+        log_debug()
+            : log(debug) { }
+    };
+}
+
+#endif // WSREP_LOGGER_HPP