sensor_logger.h

//  Copyright 2020-2021 Herald Project Contributors
//  SPDX-License-Identifier: Apache-2.0
//
 
#ifndef HERALD_SENSOR_LOGGER_H
#define HERALD_SENSOR_LOGGER_H
 
#include "../datatype/bluetooth_state.h"
 
#include <string>
#include <memory>
#include <ostream>
#include <sstream>
 
// Zephyr compile workaround. Not ideal.
// #ifndef HERALD_LOG_LEVEL
// #define HERALD_LOG_LEVEL 4
// #endif
 
#ifdef HERALD_LOG_LEVEL
 
// Defines for within Impl class definitions
#if HERALD_LOG_LEVEL != 0
#define HLOGGER(_ctxT) \
  herald::data::SensorLogger<typename _ctxT::logging_sink_type> logger;
#define HLOGGERINIT(_ctx,_subsystem,_category) ,logger(_ctx.getLoggingSink(),_subsystem,_category)
#endif
 
// HDBG Defines for within main class (more common)
// HTDBG Defines for within Impl class
#if HERALD_LOG_LEVEL == 4
#define HDBG(_msg, ...) mImpl->logger.debug(_msg, ##__VA_ARGS__);
#define HTDBG(_msg, ...) logger.debug(_msg, ##__VA_ARGS__);
#define HLOG(_msg, ...) mImpl->logger.info(_msg, ##__VA_ARGS__);
#define HTLOG(_msg, ...) logger.info(_msg, ##__VA_ARGS__);
#define HERR(_msg, ...) mImpl->logger.fault(_msg, ##__VA_ARGS__);
#define HTERR(_msg, ...) logger.fault(_msg, ##__VA_ARGS__);
#endif
 
#if HERALD_LOG_LEVEL == 3
#define HDBG(...) /* No debug log */
#define HTDBG(...) /* No debug log */
#define HLOG(_msg, ...) mImpl->logger.info(_msg, ##__VA_ARGS__);
#define HTLOG(_msg, ...) logger.info(_msg, ##__VA_ARGS__);
#define HERR(_msg, ...) mImpl->logger.fault(_msg, ##__VA_ARGS__);
#define HTERR(_msg, ...) logger.fault(_msg, ##__VA_ARGS__);
#endif
 
// This 'WARN' exists for runtime valid logging. E.g. contacts.log to RTT on Zephyr
#if HERALD_LOG_LEVEL == 2
#define HDBG(...) /* No debug log */
#define HTDBG(...) /* No debug log */
#define HLOG(_msg, ...) mImpl->logger.info(_msg, ##__VA_ARGS__);
#define HTLOG(_msg, ...) logger.info(_msg, ##__VA_ARGS__);
#define HERR(_msg, ...) mImpl->logger.fault(_msg, ##__VA_ARGS__);
#define HTERR(_msg, ...) logger.fault(_msg, ##__VA_ARGS__);
#endif
 
#if HERALD_LOG_LEVEL == 1
#define HDBG(...) /* No debug log */
#define HTDBG(...) /* No debug log */
#define HLOG(...) /* No info log */
#define HTLOG(...) /* No info log */
#define HERR(_msg, ...) mImpl->logger.fault(_msg, ##__VA_ARGS__);
#define HTERR(_msg, ...) logger.fault(_msg, ##__VA_ARGS__);
#endif
 
#if HERALD_LOG_LEVEL == 0
 
#define HLOGGER(_ctxT) /* No logger instance */
#define HLOGGERINIT(...) /* No logger init */
#define HDBG(...) /* No debug log */
#define HERR(...) /* No error log */
#define HLOG(...) /* No info log */
#define HTDBG(...) /* No debug log */
#define HTERR(...) /* No error log */
#define HTLOG(...) /* No info log */
 
#endif
 
#else
 
#define HLOGGER(_ctxT) /* No logger instance */
#define HLOGGERINIT(...) /* No logger init */
#define HDBG(...) /* No debug log */
#define HERR(...) /* No error log */
#define HLOG(...) /* No info log */
#define HTDBG(...) /* No debug log */
#define HTERR(...) /* No error log */
#define HTLOG(...) /* No info log */
 
#endif
 
namespace herald {
 
namespace data {
 
enum class SensorLoggerLevel : int {
  debug, info, fault
};
 
/*
class LoggingSink {
public:
  LoggingSink() = default;
  ~LoggingSink() = default;
 
  void log(const std::string& subsystem, const std::string& category, SensorLoggerLevel level, std::string message);
};
*/
 
// NOTE: HEADER ONLY CLASS AS IT USES VARIABLE TEMPLATE ARGS FOR LOGGING
 
// class SensorLoggingSink {
// public:
//   SensorLoggingSink() = default;
//   virtual ~SensorLoggingSink() = default;
 
//   virtual void log(SensorLoggerLevel level, std::string message) = 0;
// };
 
namespace {
  
  [[maybe_unused]]
  void tprintf(std::stringstream& os, const std::string& format) // base function
  {
    std::size_t pos = 0;
    for ( auto c : format ) {
      if ( c == '{' ) {
        if (format.size() > pos + 1 && format.at(pos + 1) == '}') {
          tprintf(os, format.substr(pos + 2)); // recursive call
        } else {
          tprintf(os, format.substr(pos + 1)); // recursive call
        }
        return;
      }
      os << c;
      ++pos;
    }
  }
 
  template<typename... Targs>
  void tprintf(std::stringstream& os, const std::string& format, std::uint8_t value, Targs... Fargs) // recursive variadic function
  {
    std::size_t pos = 0;
    for ( auto c : format ) {
      if ( c == '{' ) {
        os << std::uint16_t(value);
        if (format.size() > pos + 1 && format.at(pos + 1) == '}') {
          tprintf(os, format.substr(pos + 2), Fargs...); // recursive call
        } else {
          tprintf(os, format.substr(pos + 1), Fargs...); // recursive call
        }
        return;
      }
      os << c;
      ++pos;
    }
  }
 
  template<typename... Targs>
  void tprintf(std::stringstream& os, const std::string& format, std::int8_t value, Targs... Fargs) // recursive variadic function
  {
    std::size_t pos = 0;
    for ( auto c : format ) {
      if ( c == '{' ) {
        os << std::int16_t(value);
        if (format.size() > pos + 1 && format.at(pos + 1) == '}') {
          tprintf(os, format.substr(pos + 2), Fargs...); // recursive call
        } else {
          tprintf(os, format.substr(pos + 1), Fargs...); // recursive call
        }
        return;
      }
      os << c;
      ++pos;
    }
  }
 
  // template<typename... Targs>
  // void tprintf(std::stringstream& os, const std::string& format, const std::string& value, Targs... Fargs) // recursive variadic function
  // {
  //   std::size_t pos = 0;
  //   for ( auto c : format ) {
  //     if ( c == '{' ) {
  //       os << value;
  //       if (format.size() > pos + 1 && format.at(pos + 1) == '}') {
  //         tprintf(os, format.substr(pos + 2), Fargs...); // recursive call
  //       } else {
  //         tprintf(os, format.substr(pos + 1), Fargs...); // recursive call
  //       }
  //       return;
  //     }
  //     os << c;
  //     pos++;
  //   }
  // }
 
  // typename std::enable_if_t<std::is_convertible<T, std::string>::value, std::string>
 
  template<typename T>
  void tprintf(std::stringstream& os, const std::string& format, T value) // recursive variadic function
  {
    std::size_t pos = 0;
    for ( auto c : format ) {
      if ( c == '{' ) {
        os << value;
        if (format.size() > pos + 1 && format.at(pos + 1) == '}') {
          tprintf(os, format.substr(pos + 2)); // recursive call
        } else {
          tprintf(os, format.substr(pos + 1)); // recursive call
        }
        return;
      }
      os << c;
      ++pos;
    }
  }
 
  template<typename FirstT, typename SecondT, typename... RestT>
  void tprintf(std::stringstream& os, const std::string& format, FirstT first, SecondT second, RestT... rest)
  {
    std::size_t pos = 0;
    for ( auto c : format ) {
      if ( c == '{' ) {
        os << first;
        if (format.size() > pos + 1 && format.at(pos + 1) == '}') {
          tprintf(os, format.substr(pos + 2), second, rest...); // recursive call
        } else {
          tprintf(os, format.substr(pos + 1), second, rest...); // recursive call
        }
        return;
      }
      os << c;
      ++pos;
    }
  }
 
  // template<typename T, typename... Targs>
  // void tprintf(std::stringstream& os, const std::string& format, T value, Targs... Fargs) // recursive variadic function
  // {
  //   std::size_t pos = 0;
  //   for ( auto c : format ) {
  //     if ( c == '{' ) {
  //       os << value;
  //       if (format.size() > pos + 1 && format.at(pos + 1) == '}') {
  //         tprintf(os, format.substr(pos + 2), Fargs...); // recursive call
  //       } else {
  //         tprintf(os, format.substr(pos + 1), Fargs...); // recursive call
  //       }
  //       return;
  //     }
  //     os << c;
  //     pos++;
  //   }
  // }
 
  // // G++ deduction guide workaround - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80438
  // template<typename T, typename... Targs>
  // void tprintf(std::stringstream& os, const std::string& format, Targs... Fargs)
  // {
  //   tprintf(os, format, Fargs...);
  // }
  
}
 
template <typename LoggingSinkT>
class SensorLogger {
public:
  SensorLogger(LoggingSinkT& sink, std::string subsystem, std::string category) 
    : mSink(sink), mSubsystem(subsystem), mCategory(category)
  {
    ;
  }
 
  SensorLogger(const SensorLogger& other)
    : mSink(other.mSink), mSubsystem(other.mSubsystem), mCategory(other.mCategory)
  {
    ;
  }
 
  SensorLogger(SensorLogger&& other)
    : mSink(other.mSink), mSubsystem(other.mSubsystem), mCategory(other.mCategory)
  {
    ;
  }
 
  SensorLogger& operator=(const SensorLogger& other)
  {
    mSink = other.mSink;
    mSubsystem = other.mSubsystem;
    mCategory = other.mCategory;
    return *this;
  }
 
  SensorLogger& operator=(SensorLogger&& other)
  {
    mSink = other.mSink;
    mSubsystem = other.mSubsystem;
    mCategory = other.mCategory;
    return *this;
  }
  
  // TODO consider supporting multiple sinks in the context - E.g. USB UART and log file
 
  ~SensorLogger() = default;
 
  // use std::format to generate the string
  // std::format in C++20, fmt::format library before that
  // Note: C++11 Variadic template parameter pack expansion
  template <typename ... Types>
  void debug(const std::string& message, const Types&... args) {
    const int size = sizeof...(args);
    if (0 == size) {
      log(SensorLoggerLevel::debug,message);
    } else {
      std::stringstream os;
      tprintf(os,message,args...);
      os << std::ends;
      log(SensorLoggerLevel::debug, os.str());
    }
  }
 
  template <typename ... Types>
  void info(const std::string& message, const Types&... args) {
    const int size = sizeof...(args);
    if (0 == size) {
      log(SensorLoggerLevel::debug,message);
    } else {
      std::stringstream os;
      tprintf(os,message,args...);
      os << std::ends;
      log(SensorLoggerLevel::info, os.str());
    }
  }
 
  template <typename ... Types>
  void fault(const std::string& message, const Types&... args) {
    const int size = sizeof...(args);
    if (0 == size) {
      log(SensorLoggerLevel::debug,message);
    } else {
      std::stringstream os;
      tprintf(os,message,args...);
      os << std::ends;
      log(SensorLoggerLevel::fault, os.str());
    }
  }
 
private:
  inline void log(SensorLoggerLevel lvl, std::string msg) {
    mSink.log(mSubsystem, mCategory, lvl, msg);
  }
 
  LoggingSinkT& mSink;
  std::string mSubsystem;
  std::string mCategory;
};
 
} // end namespace
} // end namespace
 
#endif