added logging module and a sandbox project

include/matador/logger/log_sink.hpp

@@ -0,0 +1,47 @@
+#ifndef MATADOR_LOG_SINK_HPP
+#define MATADOR_LOG_SINK_HPP
+
+#include <memory>
+
+namespace matador::logger {
+
+/**
+ * @brief Base class for all log sinks
+ *
+ * This class must be the base class for all
+ * log sinks and provides their interface
+ *
+ * The main interface is the write() interface
+ * defining how the log message is written.
+ *
+ * The close() interface defines a way to close
+ * the concrete log sink
+ */
+class log_sink
+{
+public:
+  /**
+   * Destroys the log sink
+   */
+  virtual ~log_sink() = default;
+
+  /**
+   * Writes the given log message with the given size
+   * to the concrete sink
+   *
+   * @param message The message to log
+   * @param size The size of the message
+   */
+  virtual void write(const char *message, std::size_t size) = 0;
+
+  /**
+   * Closes the log sink if necessary.
+   */
+  virtual void close() = 0;
+};
+
+using sink_ptr = std::shared_ptr<log_sink>; /**< Shortcut to the log sink shared pointer */
+
+}
+
+#endif //MATADOR_LOG_SINK_HPP