include/threadcontext.h

#pragma once
// std
#include <string>
namespace osdev {
namespace components {
namespace mqtt {
/**
 * @brief   Set the current thread context
 * The context is restored to the previous context when this object goes out of scope.
 * @note This object is meat to be used on the stack.
 */
class ThreadContextScope
{
public:
    /**
     * @brief   Construct a scoped object that sets the current thread context.
     * @param   context The context that will be used by the loggin framework.
     */
    explicit ThreadContextScope( const std::string &context );
    ~ThreadContextScope();
    // Non copyable and non movable
    ThreadContextScope( const ThreadContextScope& ) = delete;
    ThreadContextScope& operator=( const ThreadContextScope& ) = delete;
    ThreadContextScope( ThreadContextScope&& ) = delete;
    ThreadContextScope& operator=( ThreadContextScope&& ) = delete;
private:
    std::string m_previousContext;  ///< Copy of the previous context.
};
/**
 * @brief   Add context to a thread.
 * For every thread only one specific instance of this object will exist.
 * @note Contexts can only be set by using a ThreadContextScope object.
 */
class ThreadContext
{
    // Contexts can only be set by using the ThreadContextScope object.
    friend class ThreadContextScope;
public:
    static ThreadContext& instance();
    const std::string& context() const
    {
        return m_context;
    }
private:
    /**
     * @brief Set the thread context.
     */
    void setContext( const std::string &contextString )
    {
        m_context = contextString;
    }
    /**
     * Construct a ThreadContext object.
     * The context is set to "default"
     */
    ThreadContext();
    // Non copyable and non moveable
    ThreadContext(const ThreadContext&) = delete;
    ThreadContext& operator=(const ThreadContext&) = delete;
    ThreadContext(ThreadContext&&) = delete;
    ThreadContext& operator=(ThreadContext&&) = delete;
    std::string m_context;  ///< The context string
};
}   // End namespace mqtt
}   // End namespace components
}   // End namespace osdev