QwLog.h

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/*!
 * \file   QwLog.h
 * \brief  A logfile class, based on an identical class in the Hermes analyzer
 *
 * \author Wouter Deconinck
 * \date   2009-11-25
 */
 
#pragma once
 
// System headers
#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
using std::string;
 
// Qweak headers
#include "QwTypes.h"
#include "QwColor.h"
 
/*!
 * \note Because QwOptions depends on QwLog, and QwLog depends also on QwOptions,
 * we cannot include QwOptions in the QwLog header file here.  QwLog is treated
 * as more basic than QwOptions.
 */
 
// Forward declarations
class QwOptions;
 
/*! \def QwOut
 *  \brief Predefined log drain for explicit output
 */
#define QwOut      gQwLog(QwLog::kAlways,__PRETTY_FUNCTION__)
 
/*! \def QwError
 *  \brief Predefined log drain for errors
 */
#define QwError    gQwLog(QwLog::kError,__PRETTY_FUNCTION__)
 
/*! \def QwWarning
 *  \brief Predefined log drain for warnings
 */
#define QwWarning  gQwLog(QwLog::kWarning,__PRETTY_FUNCTION__)
 
/*! \def QwMessage
 *  \brief Predefined log drain for regular messages
 */
#define QwMessage  gQwLog(QwLog::kMessage,__PRETTY_FUNCTION__)
 
/*! \def QwVerbose
 *  \brief Predefined log drain for verbose messages
 */
#define QwVerbose  if (gQwLog.GetLogLevel() >= QwLog::kVerbose) gQwLog(QwLog::kVerbose,__PRETTY_FUNCTION__)
 
/*! \def QwDebug
 *  \brief Predefined log drain for debugging output
 */
#define QwDebug    if (gQwLog.GetLogLevel() >= QwLog::kDebug) gQwLog(QwLog::kDebug,__PRETTY_FUNCTION__)
 
 
/**
 *  \class QwLog
 *  \ingroup QwAnalysis
 *  \brief Logging and output management system with configurable verbosity levels
 *
 * Provides a hierarchical logging system with multiple output levels
 * (Error, Warning, Message, Verbose, Debug) and predefined log drains
 * (QwError, QwWarning, QwMessage, QwVerbose, QwDebug). Supports output
 * redirection to files, colored output, and function-specific debugging.
 * Should not be used directly; use the predefined macros instead.
 */
class QwLog : public std::ostream {
 
  public:
 
    /// \brief Define available class options for QwOptions
    static void DefineOptions(QwOptions* options);
    /// \brief Process class options for QwOptions
    void ProcessOptions(QwOptions* options);
    // Note: this uses pointers as opposed to references, because as indicated
    // above the QwLog class cannot depend on the QwOptions class.  When using a
    // pointer we only need a forward declaration and we do not need to include
    // the header file QwOptions.h.
 
    //! Loglevels
    /*! enum of possible log levels */
    enum QwLogLevel {
      kAlways    = -1, /*!< Explicit output  */
      kError     =  0, /*!< Error loglevel   */
      kWarning   =  1, /*!< Warning loglevel */
      kMessage   =  2, /*!< Message loglevel */
      kVerbose   =  3, /*!< Verbose loglevel */
      kDebug     =  4  /*!< Debug loglevel   */
    };
 
    //! Log file open modes
    static const std::ios_base::openmode kTruncate;
    static const std::ios_base::openmode kAppend;
 
    /*! \brief The constructor
     */
    QwLog();
 
    /*! \brief The destructor
     */
    ~QwLog() override;
 
    /*! \brief Determine whether the function name matches a specified list of regular expressions
     */
    bool                        IsDebugFunction(const string func_name);
 
    /*! \brief Initialize the log file with name 'name'
     */
    void                        InitLogFile(const std::string name, const std::ios_base::openmode mode = kAppend);
 
    /*! \brief Set the screen color mode
     */
    void                        SetScreenColor(bool flag);
 
    /*! \brief Set the screen log level
     */
    void                        SetScreenThreshold(int thr);
 
    /*! \brief Set the file log level
     */
    void                        SetFileThreshold(int thr);
 
    /*! \brief Get highest log level 
     */
    QwLogLevel                  GetLogLevel() const {
      return std::max(fScreenThreshold, fFileThreshold);
    };
 
    /*! \brief Set the stream log level
     */
    QwLog&                      operator()(const QwLogLevel level,
                                           const std::string func_sig  = "<unknown>");
 
    /*! \brief Stream an object to the output stream
     */
    template <class T> QwLog&   operator<<(const T &t) {
      if (fScreen && fLogLevel <= fScreenThreshold) {
        *(fScreen) << t;
      }
      if (fFile && fLogLevel <= fFileThreshold) {
        *(fFile) << t;
      }
      return *this;
    }
 
    /*! \brief Pass the ios_base manipulators
     */
#if (__GNUC__ >= 3)
    QwLog&                      operator<<(std::ios_base & (*manip) (std::ios_base &));
#endif
    QwLog&                      operator<<(std::ostream & (*manip) (std::ostream &));
 
    /*! \brief End of the line
     */
    static std::ostream&        endl(std::ostream&);
 
    /*! \brief Flush the streams
     */
    static std::ostream&        flush(std::ostream&);
 
  private:
 
    /*! \brief Get the local time
     */
    const char*                 GetTime();
    char                        fTimeString[128];
 
    //! Screen thresholds and stream
    QwLogLevel    fScreenThreshold;
    std::ostream *fScreen;
    //! File thresholds and stream
    QwLogLevel    fFileThreshold;
    std::ostream *fFile;
    //! Log level of this stream
    QwLogLevel fLogLevel;
 
    //! Flag to print function signature on warning or error
    bool fPrintFunctionSignature;
 
    //! List of regular expressions for functions that will have increased log level
    std::map<std::string,bool> fIsDebugFunction;
    std::vector<std::string> fDebugFunctionRegexString;
 
    //! Flag to disable color
    bool fUseColor;
 
    //! Flags only relevant for current line, but static for use in static function
    static bool fFileAtNewLine;
    static bool fScreenInColor;
    static bool fScreenAtNewLine;
 
};
 
extern QwLog gQwLog;