Qt中简单的日志文件实现

#ifndef MUSICLOGGER_H
#define MUSICLOGGER_H

/* =================================================
* This file is part of the TTK Music Player project
* Copyright (c) 2014 - 2016 Greedysky Studio
* All rights reserved!
* Redistribution and use of the source code or any derivative
* works are strictly forbiden.
=================================================*/

#include <QFile>
#include <QTextStream>
#include <QDateTime>
#include "musicglobaldefine.h"

#define CURRENTTIME QTime::currentTime().toString("hh:mm:ss:zzz")
#define CURRENTDATE QDate::currentDate().toString("yyyy-MM-dd")
#define LOG_END     QString("log::npos")

#define M_LOGGER    (*MusicLogger::createInstance())
#define M_MESSAGE(str, msg) \
{ \
M_LOGGER.setLevel(msg); \
M_LOGGER << str << LOG_END;\
}

#ifdef MUSIC_DEBUG
#define M_LOGGER_INFO(str)  M_MESSAGE(str, "[Info]")
#define M_LOGGER_DEBUG(str) M_MESSAGE(str, "[Debug]")
#define M_LOGGER_WARN(str)  M_MESSAGE(str, "[Warn]")
#define M_LOGGER_TRACE(str) M_MESSAGE(str, "[Trace]")
#define M_LOGGER_ERROR(str) M_MESSAGE(str, "[Error]")
#define M_LOGGER_FATAL(str) M_MESSAGE(str, "[Fatal]")
#else
#define M_LOGGER_INFO(str)  Q_UNUSED(str)
#define M_LOGGER_DEBUG(str) Q_UNUSED(str)
#define M_LOGGER_WARN(str)  Q_UNUSED(str)
#define M_LOGGER_TRACE(str) Q_UNUSED(str)
#define M_LOGGER_ERROR(str) Q_UNUSED(str)
#define M_LOGGER_FATAL(str) Q_UNUSED(str)
#endif

/*! @brief The class of the application logger.
* @author Greedysky <greedysky@163.com>
*/
class MUSIC_CORE_EXPORT MusicLogger
{
public:
//通过静态初始化对象实现单例模式
static inline MusicLogger* createInstance()
{
static MusicLogger obj;
return &obj;
}
/*!
* Get object instance ptr.
*/

static QString getClassName()
{
return "MusicLogger";
}
/*!
* Get class object name.
*/
inline void setLevel(const QString &level)
{
m_levelType = level;
}
/*!
* Set logger level.
*/
inline QString level() const
{
return m_levelType;
}
/*!
* Get logger level.
*/

inline MusicLogger &operator <<(bool t)
{
#ifdef MUSIC_DEBUG
m_streamString.append( QString("%1 ").arg(t ? "true" : "false") );
#else
//取消编译器警告信息
Q_UNUSED(t);
#endif
return *this;
}
inline MusicLogger &operator<<(char t) { return debugData<char>(t); }
inline MusicLogger &operator<<(signed short t) { return debugData<short>(t);}
inline MusicLogger &operator<<(unsigned short t) { return debugData<ushort>(t); }
inline MusicLogger &operator<<(signed int t) { return debugData<int>(t); }
inline MusicLogger &operator<<(unsigned int t) { return debugData<uint>(t); }
inline MusicLogger &operator<<(signed long t) { return debugData<long>(t); }
inline MusicLogger &operator<<(unsigned long t) { return debugData<ulong>(t); }
inline MusicLogger &operator<<(qint64 t) { return debugData<qint64>(t); }
inline MusicLogger &operator<<(quint64 t) { return debugData<quint64>(t); }
inline MusicLogger &operator<<(float t) { return debugData<float>(t); }
inline MusicLogger &operator<<(double t) { return debugData<double>(t); }
inline MusicLogger &operator<<(const char *t) { return debugData<const char*>(t); }
inline MusicLogger &operator<<(const QString &t)
{
#ifdef MUSIC_DEBUG
//每次遇到结束符号，导入文件
if(t == LOG_END)
{
m_stream << QString("[%1 %2]:  %3").arg(CURRENTDATE).arg(CURRENTTIME).arg(m_streamString) << endl;
m_streamString.clear();
}
else
{
debugData<QString>(t);
}
#else
Q_UNUSED(t);
#endif
return *this;
}
inline MusicLogger &operator<<(const QStringRef &t) { return debugData<QString>(t.toString()); }
inline MusicLogger &operator<<(const QLatin1String &t) { return debugData<QLatin1String>(t); }
inline MusicLogger &operator<<(const QByteArray &t) { return debugData<QString>(QString(t)); }
/*!
* Operator << override.
*/

private:
MusicLogger()
{
#ifdef MUSIC_DEBUG
m_file.setFileName("logger.txt");
m_file.open(QIODevice::WriteOnly | QIODevice::Append);
m_stream.setDevice(&m_file);
m_stream << QString().rightJustified(70, '=') << endl;
m_levelType = "[Info]";
#endif
}
/*!
* Object contsructor.
*/

~MusicLogger()
{
#ifdef MUSIC_DEBUG
m_file.close();
#endif
}
//用模板实现除str变量之外的所有<<函数的公用操作
template <class T>
MusicLogger &debugData(const T &data)
{
#ifdef MUSIC_DEBUG
m_streamString.append( QString("%1 %2 ").arg(m_levelType).arg(data) );
#else
Q_UNUSED(data);
#endif
return *this;
}
/*!
* Output debug data into local file.
*/

QTextStream m_stream;//关联日志导出文件
QString m_streamString;//每次写内容的时候作为临时缓存，当遇到结束符的时候一并导入文件
QString m_levelType;//日志类别
QFile m_file;

};

#endif // MUSICLOGGER_H