text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2018 The Bitcoin Core developers
  // Copyright (c) 2021 The Bitcoin3 Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #ifndef BITCOIN3_LOGGING_H
  #define BITCOIN3_LOGGING_H
  
  #include <fs.h>
  #include <tinyformat.h>
  
  #include <atomic>
  #include <cstdint>
  #include <list>
  #include <mutex>
  #include <string>
  #include <vector>
  
  static const bool DEFAULT_LOGTIMEMICROS = false;
  static const bool DEFAULT_LOGIPS        = false;
  static const bool DEFAULT_LOGTIMESTAMPS = true;
  extern const char * const DEFAULT_DEBUGLOGFILE;
  
  extern bool fLogIPs;
  
  struct CLogCategoryActive
  {
      std::string category;
      bool active;
  };
  
  namespace BCLog {
      enum LogFlags : uint32_t {
          NONE        = 0,
          NET         = (1 <<  0),
          TOR         = (1 <<  1),
          MEMPOOL     = (1 <<  2),
          HTTP        = (1 <<  3),
          BENCH       = (1 <<  4),
          ZMQ         = (1 <<  5),
          DB          = (1 <<  6),
          RPC         = (1 <<  7),
          ESTIMATEFEE = (1 <<  8),
          ADDRMAN     = (1 <<  9),
          SELECTCOINS = (1 << 10),
          REINDEX     = (1 << 11),
          CMPCTBLOCK  = (1 << 12),
          RAND        = (1 << 13),
          PRUNE       = (1 << 14),
          PROXY       = (1 << 15),
          MEMPOOLREJ  = (1 << 16),
          LIBEVENT    = (1 << 17),
          COINDB      = (1 << 18),
          QT          = (1 << 19),
          LEVELDB     = (1 << 20),
          ALL         = ~(uint32_t)0,
      };
  
      class Logger
      {
      private:
          FILE* m_fileout = nullptr;
          std::mutex m_file_mutex;
          std::list<std::string> m_msgs_before_open;
  
          /**
           * m_started_new_line is a state variable that will suppress printing of
           * the timestamp when multiple calls are made that don't end in a
           * newline.
           */
          std::atomic_bool m_started_new_line{true};
  
          /** Log categories bitfield. */
          std::atomic<uint32_t> m_categories{0};
  
          std::string LogTimestampStr(const std::string& str);
  
      public:
          bool m_print_to_console = false;
          bool m_print_to_file = false;
  
          bool m_log_timestamps = DEFAULT_LOGTIMESTAMPS;
          bool m_log_time_micros = DEFAULT_LOGTIMEMICROS;
  
          fs::path m_file_path;
          std::atomic<bool> m_reopen_file{false};
  
          /** Send a string to the log output */
          void LogPrintStr(const std::string &str);
  
          /** Returns whether logs will be written to any output */
          bool Enabled() const { return m_print_to_console || m_print_to_file; }
  
          bool OpenDebugLog();
          void ShrinkDebugFile();
  
          uint32_t GetCategoryMask() const { return m_categories.load(); }
  
          void EnableCategory(LogFlags flag);
          bool EnableCategory(const std::string& str);
          void DisableCategory(LogFlags flag);
          bool DisableCategory(const std::string& str);
  
          bool WillLogCategory(LogFlags category) const;
  
          bool DefaultShrinkDebugFile() const;
      };
  
  } // namespace BCLog
  
  extern BCLog::Logger* const g_logger;
  
  /** Return true if log accepts specified category */
  static inline bool LogAcceptCategory(BCLog::LogFlags category)
  {
      return g_logger->WillLogCategory(category);
  }
  
  /** Returns a string with the log categories. */
  std::string ListLogCategories();
  
  /** Returns a vector of the active log categories. */
  std::vector<CLogCategoryActive> ListActiveLogCategories();
  
  /** Return true if str parses as a log category and set the flag */
  bool GetLogCategory(BCLog::LogFlags& flag, const std::string& str);
  
  /** Get format string from VA_ARGS for error reporting */
  template<typename... Args> std::string FormatStringFromLogArgs(const char *fmt, const Args&... args) { return fmt; }
  
  static inline void MarkUsed() {}
  template<typename T, typename... Args> static inline void MarkUsed(const T& t, const Args&... args)
  {
      (void)t;
      MarkUsed(args...);
  }
  
  // Be conservative when using LogPrintf/error or other things which
  // unconditionally log to debug.log! It should not be the case that an inbound
  // peer can fill up a user's disk with debug.log entries.
  
  #ifdef USE_COVERAGE
  #define LogPrintf(...) do { MarkUsed(__VA_ARGS__); } while(0)
  #define LogPrint(category, ...) do { MarkUsed(__VA_ARGS__); } while(0)
  #else
  #define LogPrintf(...) do { \
      if (g_logger->Enabled()) { \
          std::string _log_msg_; /* Unlikely name to avoid shadowing variables */ \
          try { \
              _log_msg_ = tfm::format(__VA_ARGS__); \
          } catch (tinyformat::format_error &fmterr) { \
              /* Original format string will have newline so don't add one here */ \
              _log_msg_ = "Error \"" + std::string(fmterr.what()) + "\" while formatting log message: " + FormatStringFromLogArgs(__VA_ARGS__); \
          } \
          g_logger->LogPrintStr(_log_msg_); \
      } \
  } while(0)
  
  #define LogPrint(category, ...) do { \
      if (LogAcceptCategory((category))) { \
          LogPrintf(__VA_ARGS__); \
      } \
  } while(0)
  #endif
  
  #endif // BITCOIN3_LOGGING_H
  