2 files changed, 170 insertions, 0 deletions
diff --git a/src/logger/logger.cpp b/src/logger/logger.cpp
new file mode 100644
index 0000000..92a3d9b
--- /dev/null
+++ b/src/logger/logger.cpp
@@ -0,0 +1,42 @@
+#include <logger/logger.hpp>
+#include <config/config.hpp>
+
+Logger::Logger(const int log_level):
+  log_level(log_level),
+  stream(std::cout.rdbuf()),
+  null_buffer{},
+  null_stream{&null_buffer}
+{
+}
+
+Logger::Logger(const int log_level, const std::string& log_file):
+  log_level(log_level),
+  ofstream(log_file.data(), std::ios_base::app),
+  stream(ofstream.rdbuf()),
+  null_buffer{},
+  null_stream{&null_buffer}
+{
+}
+
+std::unique_ptr<Logger>& Logger::instance()
+{
+  static std::unique_ptr<Logger> instance;
+
+  if (!instance)
+    {
+      const std::string log_file = Config::get("log_file", "");
+      const int log_level = Config::get_int("log_level", 0);
+      if (log_file.empty())
+        instance = std::make_unique<Logger>(log_level);
+      else
+        instance = std::make_unique<Logger>(log_level, log_file);
+    }
+  return instance;
+}
+
+std::ostream& Logger::get_stream(const int lvl)
+{
+  if (lvl >= this->log_level)
+    return this->stream;
+  return this->null_stream;
+}
diff --git a/src/logger/logger.hpp b/src/logger/logger.hpp
new file mode 100644
index 0000000..ff6a82b
--- /dev/null
+++ b/src/logger/logger.hpp
@@ -0,0 +1,128 @@
+#pragma once
+
+
+/**
+ * Singleton used in logger macros to write into files or stdout, with
+ * various levels of severity.
+ * Only the macros should be used.
+ * @class Logger
+ */
+
+#include <memory>
+#include <iostream>
+#include <fstream>
+
+#define debug_lvl 0
+#define info_lvl 1
+#define warning_lvl 2
+#define error_lvl 3
+
+#include "biboumi.h"
+#ifdef SYSTEMD_FOUND
+# include <systemd/sd-daemon.h>
+#else
+# define SD_DEBUG    "[DEBUG]: "
+# define SD_INFO     "[INFO]: "
+# define SD_WARNING  "[WARNING]: "
+# define SD_ERR      "[ERROR]: "
+#endif
+
+// Macro defined to get the filename instead of the full path. But if it is
+// not properly defined by the build system, we fallback to __FILE__
+#ifndef __FILENAME__
+# define __FILENAME__ __FILE__
+#endif
+
+
+/**
+ * A buffer, used to construct an ostream that does nothing
+ * when we output data in it
+ */
+class NullBuffer: public std::streambuf
+{
+ public:
+  int overflow(int c) { return c; }
+};
+
+class Logger
+{
+public:
+  static std::unique_ptr<Logger>& instance();
+  std::ostream& get_stream(const int);
+  Logger(const int log_level, const std::string& log_file);
+  Logger(const int log_level);
+
+  Logger(const Logger&) = delete;
+  Logger& operator=(const Logger&) = delete;
+  Logger(Logger&&) = delete;
+  Logger& operator=(Logger&&) = delete;
+
+private:
+  const int log_level;
+  std::ofstream ofstream{};
+  std::ostream stream;
+
+  NullBuffer null_buffer;
+  std::ostream null_stream;
+};
+
+#define WHERE __FILENAME__, ":", __LINE__, ":\t"
+
+namespace logging_details
+{
+  template <typename T>
+  void log(std::ostream& os, const T& arg)
+  {
+    os << arg << std::endl;
+  }
+
+  template <typename T, typename... U>
+  void log(std::ostream& os, const T& first, U&&... rest)
+  {
+    os << first;
+    log(os, std::forward<U>(rest)...);
+  }
+
+  template <typename... U>
+  void log_debug(U&&... args)
+  {
+    auto& os = Logger::instance()->get_stream(debug_lvl);
+    os << SD_DEBUG;
+    log(os, std::forward<U>(args)...);
+  }
+
+  template <typename... U>
+  void log_info(U&&... args)
+  {
+    auto& os = Logger::instance()->get_stream(info_lvl);
+    os << SD_INFO;
+    log(os, std::forward<U>(args)...);
+  }
+
+  template <typename... U>
+  void log_warning(U&&... args)
+  {
+    auto& os = Logger::instance()->get_stream(warning_lvl);
+    os << SD_WARNING;
+    log(os, std::forward<U>(args)...);
+  }
+
+  template <typename... U>
+  void log_error(U&&... args)
+  {
+    auto& os = Logger::instance()->get_stream(error_lvl);
+    os << SD_ERR;
+    log(os, std::forward<U>(args)...);
+  }
+}
+
+#define log_info(...) logging_details::log_info(WHERE, __VA_ARGS__)
+
+#define log_warning(...) logging_details::log_warning(WHERE, __VA_ARGS__)
+
+#define log_error(...) logging_details::log_error(WHERE, __VA_ARGS__)
+
+#define log_debug(...) logging_details::log_debug(WHERE, __VA_ARGS__)
+
+
+