C++模式:1x基类+Nx派生类，但具有_上一个资源派生类

我正在尝试实现一个具有三个信息级别的记录器：常规（日期/时间）、上下文、消息

为了达到这个目标，我试图实现以下模式：

1. 记录器类（此处不相关）
2. 上下文类
   • 基类LoggerContext，它具有生成一般级别信息的功能
   • 派生类，它添加特定于上下文的信息（特定于应用程序的一部分）

有趣的部分开始于我尝试使用none上下文。也就是说，如果在没有上下文的情况下调用Logger，则应使用单例LoggerContextNone。

在这里，我的代码，无论我如何转换，都不会编译：

#include <string>
#include <iostream>
#include <stdexcept>
using namespace std;
enum class LoggerArea {
        LOGGER_NONE, LOGGER_DOWNLOAD, LOGGER_COMPUTE,
};
class ELoggerContext: std::runtime_error {
        using std::runtime_error::runtime_error;
};
class LoggerContextNone; // forward declaration, only needed for 
                         // the commented version of the code
class LoggerContext {
protected:
        LoggerArea mLA;
public:
        LoggerContext(LoggerArea la);
        virtual ~LoggerContext() = 0;
        /*
        static LoggerContext& getEmptyContext() {
                static LoggerContextNone loggerContextNone = { LoggerArea::LOGGER_NONE };
                return loggerContextNone;
        }
        */
        std::string getGeneral();
        virtual std::string getContext() = 0; // pure virtual
};
string LoggerContext::getGeneral() {
        return "general informations";
}
LoggerContext::LoggerContext(LoggerArea la) :
                mLA(la) {
  if (la == LoggerArea::LOGGER_NONE) {
        throw ELoggerContext("LOGGER_NONE cannot be instantiated");
  }
}
class LoggerContextNone : LoggerContext {
private:
        LoggerContextNone() {
                mLA = LoggerArea::LOGGER_NONE;
        }
public:
        virtual ~LoggerContextNone() override {
        }
        virtual std::string getContext() override {
                return " ";
        }
        static LoggerContextNone& getInstance() {
                static LoggerContextNone instance {};
                return instance;
        }
};
int main() {
  // this should not be compilable:
  LoggerContextNone n{LoggerArea::LOGGER_NONE};
  // this should at least throw an error at run time:
  LoggerContext n{LoggerArea::LOGGER_NONE};
  return 0;
}

目标：

• LoggerContextNone应该从LoggerContext派生，因为我们需要getGeneral()
• LoggerContextNone不应在getInstance（singleton）外部实例化
• 基类不应该有空构造函数，但派生类应该有一个
• LoggerContextNone不应该调用超级构造函数，否则会抛出错误ELoggerContext
• 来自LoggerContext的任何派生类都不应该覆盖getGeneral()

在C++中真的有可能实现这一点吗？我正在寻找一个干净的解决方案（没有工厂，…）

编译器的错误为：

19_virtual_class.cpp: In constructor ‘LoggerContextNone::LoggerContextNone()’:
19_virtual_class.cpp:45:22: error: no matching function for call to ‘LoggerContext::LoggerContext()’
  LoggerContextNone() {
                      ^
[...]
19_virtual_class.cpp: In function ‘int main()’:
19_virtual_class.cpp:62:46: error: no matching function for call to ‘LoggerContextNone::LoggerContextNone(<brace-enclosed initializer list>)’
   LoggerContextNone n{LoggerArea::LOGGER_NONE};
                                              ^

最后一点：这个模式在概念上似乎很简单：许多类都是从一个基类派生而来的，另外还有一个默认类。

编辑：

如果我按照@Angew:调整代码

#include <string>
#include <iostream>
#include <stdexcept>
using namespace std;
enum class LoggerArea {
        LOGGER_NONE, LOGGER_DOWNLOAD, LOGGER_COMPUTE,
};
class ELoggerContext: std::runtime_error {
        using std::runtime_error::runtime_error;
};
class LoggerContextNone;
class LoggerContext {
protected:
        LoggerArea mLA;
        class LoggerContextNone_AccessToken
        {
                friend LoggerContextNone;
                LoggerContextNone_AccessToken() {}
        };
        explicit LoggerContext(LoggerContextNone_AccessToken) : mLA(LoggerArea::LOGGER_NONE) {}
public:
        LoggerContext(LoggerArea la);
        virtual ~LoggerContext() = 0;
        std::string getGeneral();
        virtual std::string getContext() = 0;
};
string LoggerContext::getGeneral() {
        string s = "general informations:";
        if (mLA==LoggerArea::LOGGER_NONE) { s += "LOGGER_NONE"; }
        else if (mLA==LoggerArea::LOGGER_DOWNLOAD) { s += "LOGGER_DOWNLOAD"; }
        else if (mLA==LoggerArea::LOGGER_COMPUTE) { s += "LOGGER_COMPUTE"; }
        else { s += "??????????"; }
        return s;
}
LoggerContext::LoggerContext(LoggerArea la) :
                mLA(la) {
  if (la == LoggerArea::LOGGER_NONE) {
        throw ELoggerContext("LOGGER_NONE cannot be instantiated");
  }
}
class LoggerContextNone : LoggerContext {
private:
        LoggerContextNone(): LoggerContext(LoggerContextNone_AccessToken()) {}
public:
        virtual ~LoggerContextNone() override {
        }
        virtual std::string getContext() override {
                return " ";
        }
        static LoggerContextNone& getInstance() {
                static LoggerContextNone instance {};
                return instance;
        }
};
class LoggerContextDerived : LoggerContext {
public:
        virtual std::string getContext() override {
                return "derived context";
        }
};
int main() {
  LoggerContextDerived n {LoggerArea::LOGGER_DOWNLOAD};
  // cout << "General : " << n.getGeneral() << endl;
  // cout << "Context : " << n.getContext() << endl;
  return 0;
}

我无法实例化派生类。g++说：

9_virtual_class.cpp: In function ‘int main()’:
19_virtual_class.cpp:78:54: error: no matching function for call to ‘LoggerContextDerived::LoggerContextDerived(<brace-enclosed initializer list>)’
   LoggerContextDerived n {LoggerArea::LOGGER_DOWNLOAD};
                                                      ^

它建议我使用复制构造函数或移动构造函数。这对我来说意味着构造函数

LoggerContext(LoggerArea la);

在派生类中不可见。