util: logging facility
refs #3562
Change-Id: I61d934c5306e1a73b41c81aeb3524d6bf581af3c
diff --git a/src/util/logger.hpp b/src/util/logger.hpp
new file mode 100644
index 0000000..58e7b2a
--- /dev/null
+++ b/src/util/logger.hpp
@@ -0,0 +1,167 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2016 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library 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 Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#ifndef NDN_UTIL_LOGGER_HPP
+#define NDN_UTIL_LOGGER_HPP
+
+#include "../common.hpp"
+
+#include <boost/log/common.hpp>
+#include <boost/log/sources/logger.hpp>
+#include <atomic>
+
+namespace ndn {
+namespace util {
+
+/** \brief indicates the severity level of a log message
+ */
+enum class LogLevel {
+ FATAL = -1, ///< fatal (will be logged unconditionally)
+ NONE = 0, ///< no messages
+ ERROR = 1, ///< serious error messages
+ WARN = 2, ///< warning messages
+ INFO = 3, ///< informational messages
+ DEBUG = 4, ///< debug messages
+ TRACE = 5, ///< trace messages (most verbose)
+ ALL = 255 ///< all messages
+};
+
+/** \brief output LogLevel as string
+ * \throw std::invalid_argument unknown \p level
+ */
+std::ostream&
+operator<<(std::ostream& os, LogLevel level);
+
+/** \brief parse LogLevel from string
+ * \throw std::invalid_argument unknown level name
+ */
+LogLevel
+parseLogLevel(const std::string& s);
+
+/** \brief represents a logger in logging facility
+ * \note User should declare a new logger with \p NDN_CXX_LOG_INIT macro.
+ */
+class Logger : public boost::log::sources::logger_mt
+{
+public:
+ explicit
+ Logger(const std::string& name);
+
+ const std::string&
+ getModuleName() const
+ {
+ return m_moduleName;
+ }
+
+ bool
+ isLevelEnabled(LogLevel level) const
+ {
+ return m_currentLevel.load(std::memory_order_relaxed) >= level;
+ }
+
+ void
+ setLevel(LogLevel level)
+ {
+ m_currentLevel.store(level, std::memory_order_relaxed);
+ }
+
+private:
+ const std::string m_moduleName;
+ std::atomic<LogLevel> m_currentLevel;
+};
+
+/** \brief declare a log module
+ */
+#define NDN_CXX_LOG_INIT(name) \
+ namespace { \
+ inline ::ndn::util::Logger& getNdnCxxLogger() \
+ { \
+ static ::ndn::util::Logger logger(BOOST_STRINGIZE(name)); \
+ return logger; \
+ } \
+ } \
+ struct ndn_cxx__allow_trailing_semicolon
+
+/** \brief a tag that writes a timestamp upon stream output
+ * \code
+ * std::clog << LoggerTimestamp();
+ * \endcode
+ */
+struct LoggerTimestamp
+{
+};
+
+/** \brief write a timestamp to \p os
+ * \note This function is thread-safe.
+ */
+std::ostream&
+operator<<(std::ostream& os, const LoggerTimestamp&);
+
+#if (BOOST_VERSION >= 105900) && (BOOST_VERSION < 106000)
+// workaround Boost bug 11549
+#define NDN_CXX_BOOST_LOG(x) BOOST_LOG(x) << ""
+#else
+#define NDN_CXX_BOOST_LOG(x) BOOST_LOG(x)
+#endif
+
+#define NDN_CXX_LOG(lvl, lvlstr, expression) \
+ do { \
+ if (getNdnCxxLogger().isLevelEnabled(::ndn::util::LogLevel::lvl)) { \
+ NDN_CXX_BOOST_LOG(getNdnCxxLogger()) << ::ndn::util::LoggerTimestamp{} \
+ << " " BOOST_STRINGIZE(lvlstr) ": [" << getNdnCxxLogger().getModuleName() << "] " \
+ << expression; \
+ } \
+ } while (false)
+
+/** \brief log at TRACE level
+ * \pre A log module must be declared in the same translation unit.
+ */
+#define NDN_CXX_LOG_TRACE(expression) NDN_CXX_LOG(TRACE, TRACE, expression)
+
+/** \brief log at DEBUG level
+ * \pre A log module must be declared in the same translation unit.
+ */
+#define NDN_CXX_LOG_DEBUG(expression) NDN_CXX_LOG(DEBUG, DEBUG, expression)
+
+/** \brief log at INFO level
+ * \pre A log module must be declared in the same translation unit.
+ */
+#define NDN_CXX_LOG_INFO(expression) NDN_CXX_LOG(INFO, INFO, expression)
+
+/** \brief log at WARN level
+ * \pre A log module must be declared in the same translation unit.
+ */
+#define NDN_CXX_LOG_WARN(expression) NDN_CXX_LOG(WARN, WARNING, expression)
+
+/** \brief log at ERROR level
+ * \pre A log module must be declared in the same translation unit.
+ */
+#define NDN_CXX_LOG_ERROR(expression) NDN_CXX_LOG(ERROR, ERROR, expression)
+
+/** \brief log at FATAL level
+ * \pre A log module must be declared in the same translation unit.
+ */
+#define NDN_CXX_LOG_FATAL(expression) NDN_CXX_LOG(FATAL, FATAL, expression)
+
+} // namespace util
+} // namespace ndn
+
+#endif // NDN_UTIL_LOGGER_HPP