简单的wostream日志类（使用自定义流操纵器） [英] Simple wostream logging class (with custom stream manipulators)
问题描述
我一直在读大量的问题，文章和文档，但我没有找到解决我的问题。
我想创建一个用于调试的简单类。最终结果将允许我做这样的事情：
logger<错误< L这是一个问题！ << endl
logger<<警告< L这可能是一个问题！ << endl
logger<<信息< L这不是问题，但我认为你应该知道它< endl
有了这样的想法，在logger类中，我可以切换是否这些东西到控制台/ debug file。
logger.setLevel（ERROR）;
我有一个骨架，但我不能让操作符重载操作器工作。
这里是Logger.h：
class LoggerBuffer：public wfilebuf {
//函数
public：
LoggerBuffer（）{wfilebuf :: open（NUL，ios :: out）; currentState = 1;}
〜LoggerBuffer（）{wcout<< DELETED！ << endl;}
void open（const char fname []）;
void close（）{wfilebuf :: close（）;}
virtual int sync（）;
void setState（int newState）;
//变量
private：
int currentState;
};
class LoggerStream：public wostream {
//函数
public：
LoggerStream（）：wostream（new LoggerBuffer（）），wios（0）{}
〜LoggerStream（）{delete rdbuf（）; }
void open（const char fname [] = 0）{
wcout< 流开放< fname<< endl;（（LoggerBuffer *）rdbuf（）） - > open（fname）; }
void close（）{（（LoggerBuffer *）rdbuf（）） - > close（） }
void setState（int newState）;
};
和Logger.cpp：
void LoggerBuffer :: open（const char fname []）{
wcout< 缓冲器打开< fname<< endl
close（）;
wfilebuf * temp = wfilebuf :: open（fname，ios :: out）;
wcout<< Temp：<温度< endl
}
int LoggerBuffer :: sync（）{
wcout<< 当前状态：< currentState<< ，数据：< pbase（）;
return wfilebuf :: sync（）;
}
void LoggerBuffer :: setState（int newState）{
wcout<< New buffer state =< newState<< endl
currentState = newState;
}
void LoggerStream :: setState（int newState）{
wcout< New stream state =<< newState<< endl
（（LoggerBuffer *）rdbuf（）） - > setState（newState）;
}
和main.cpp：
struct doSetState {
int _l;
doSetState（int l）：_l（l）{}
friend LoggerStream&运算符<< （LoggerStream& os，doSetState fb）{
os.setState（3）;
return（os）;
}
};
...
LoggerStream test;
test.open（debug.txt）;
test<< 设置状态！ << doSetState（1）<< endl
...
这种混乱在VS2005中产生以下错误：
错误C2679：binary'<<'：no
操作符找到一个
类型$的右手操作数b $ b'doSetState'（或没有
可接受的转换）
任何帮助是非常感谢。 p>
谢谢！
/ p>
而不是继承 std :: wostream ，我会有一个 std :: wfostream 成员在我的logger类。然后你可以有一个通用的模板运算符<< 选择性地转发到嵌入的流。
class Logger;
template< class T>记录器& operator<<（Logger& const T&）;
enum LogLevel
{
debug，
info，
warning，
error
}
class Logger
{
public：
void open（const char * file）{stream.open（file）; }
void close（）{stream.close（）; }
void passLevel（Loglevel level）{pass = level; }
void logLevel（LogLevel level）{current = level; }
private：
bool passThrough（）{return current> = pass; }
std :: wofstream stream;
LogLevel pass
LogLevel current;
friend template< class T>记录器& operator<<（Logger& const T&）;
};
template< class T>
Logger& <<<（Logger& log，const T& rhs）
{
if（log.passthrough（））
{
log.stream< rhs;
}
return log;
}
Logger& operator<<<（Logger& LogLevel level）
{
log.logLevel（level）;
return log;
}
struct setLogLevel {
setLogLevel（LogLevel l）：level（l）{}
LogLevel level;
};
Logger& operator<<<（Logger& const setLogLevel setter）
{
log.passLevel（setter.level）;
return log;
}
I've been reading tons of questions, articles, and documentation, but I've not found a solution to my problem.
I'd like to create a simple class for use in debugging. The end result of which would allow me to do something like this:
logger << error << L"This is a problem!" << endl;
logger << warning << L"This might be a problem!" << endl;
logger << info << L"This isn't a problem but I thought you should know about it" << endl;
With the idea that within the logger class I can toggle whether or not these things make it to the console/debug file.
logger.setLevel(ERROR);
I've got a skeleton together but I can't get the operator overloading for the manipulators to work.
Here's Logger.h:
class LoggerBuffer : public wfilebuf {
// Functions
public:
LoggerBuffer() { wfilebuf::open("NUL", ios::out); currentState = 1;}
~LoggerBuffer() {wcout << "DELETED!" << endl;}
void open(const char fname[]);
void close() {wfilebuf::close();}
virtual int sync();
void setState(int newState);
// Variables
private:
int currentState;
};
class LoggerStream : public wostream {
// Functions
public:
LoggerStream() : wostream(new LoggerBuffer()), wios(0) {}
~LoggerStream() { delete rdbuf(); }
void open(const char fname[] = 0) {
wcout << "Stream Opening " << fname << endl;((LoggerBuffer*)rdbuf())->open(fname); }
void close() { ((LoggerBuffer*)rdbuf())->close(); }
void setState(int newState);
};
And Logger.cpp:
void LoggerBuffer::open(const char fname[]) {
wcout << "Buffer Opening " << fname << endl;
close();
wfilebuf* temp = wfilebuf::open(fname, ios::out);
wcout << "Temp: " << temp << endl;
}
int LoggerBuffer::sync() {
wcout << "Current State: " << currentState << ", Data: " << pbase();
return wfilebuf::sync();
}
void LoggerBuffer::setState(int newState) {
wcout << "New buffer state = " << newState << endl;
currentState = newState;
}
void LoggerStream::setState(int newState) {
wcout << "New stream state = " << newState << endl;
((LoggerBuffer*)rdbuf())->setState(newState);
}
And main.cpp:
struct doSetState {
int _l;
doSetState ( int l ): _l ( l ) {}
friend LoggerStream& operator<< (LoggerStream& os, doSetState fb ) {
os.setState(3);
return (os);
}
};
...
LoggerStream test;
test.open("debug.txt");
test << "Setting state!" << doSetState(1) << endl;
...
This mess produces the following error in VS2005:
"error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'doSetState' (or there is no acceptable conversion)"
Any help is GREATLY appreciated.
Thanks!
I would go for a slightly different approach.
Instead of inheriting from std::wostream, I would have a std::wfostream member in my logger class. Then you can have a generic templated operator<< that selectively forwards to the embedded stream.
For example:
class Logger;
template<class T> Logger& operator<<(Logger&, const T&);
enum LogLevel
{
debug,
info,
warning,
error
};
class Logger
{
public:
void open(const char* file) { stream.open(file); }
void close() { stream.close(); }
void passLevel(Loglevel level) { pass = level; }
void logLevel(LogLevel level) { current = level; }
private:
bool passThrough() { return current >= pass; }
std::wofstream stream;
LogLevel pass;
LogLevel current;
friend template<class T> Logger& operator<<(Logger&, const T&);
};
template<class T>
Logger& operator<<(Logger& log, const T& rhs)
{
if (log.passthrough())
{
log.stream << rhs;
}
return log;
}
Logger& operator<<(Logger&, LogLevel level)
{
log.logLevel(level);
return log;
}
struct setLogLevel {
setLogLevel(LogLevel l) : level(l) { }
LogLevel level;
};
Logger& operator<<(Logger&, const setLogLevel setter)
{
log.passLevel(setter.level);
return log;
}
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