GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope Class Reference

RAII guard for temporary installation of a value; movable. More...

#include <GlobalVariable.h>

Public Member Functions
	Scope (mutable_type value)
	Scope (Scope &&other)=default
Scope &	operator= (Scope &&other)=default
	~Scope ()
void	Commit ()
bool	HasValue () const

Private Attributes
std::conditional_t< ScopedOnly, mutable_type, std::optional< mutable_type > >	m_previous

Detailed Description

template<typename Tag, typename Type, auto initializer = nullptr, bool ScopedOnly = true>
class GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope

RAII guard for temporary installation of a value; movable.

Constructor captures previous value, installs a new value; destructor restores the previous value, unless moved-from or Committed

Not required to have stack-like lifetime. Non-nested lifetimes for distinct Scope objects is not prevented and may have surprising results.

Definition at line 70 of file GlobalVariable.h.

Constructor & Destructor Documentation

Scope() [1/2]

template<typename Tag , typename Type , auto initializer = nullptr, bool ScopedOnly = true>

GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::Scope ( mutable_type  value )

inlineexplicit

Definition at line 73 of file GlobalVariable.h.

         : m_previous{ Assign(std::move(value)) }
      {}

Scope() [2/2]

template<typename Tag , typename Type , auto initializer = nullptr, bool ScopedOnly = true>

GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::Scope ( Scope &&  other )

default

~Scope()

template<typename Tag , typename Type , auto initializer = nullptr, bool ScopedOnly = true>

GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::~Scope ( )

inline

Definition at line 78 of file GlobalVariable.h.

      {
         if constexpr (ScopedOnly)
            Assign(std::move(m_previous));
         else if (m_previous)
            Assign(std::move(*m_previous));
      }

References GlobalVariable< Tag, Type, initializer, ScopedOnly >::Assign(), and GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::m_previous.

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Member Function Documentation

Commit()

template<typename Tag , typename Type , auto initializer = nullptr, bool ScopedOnly = true>

void GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::Commit ( )

inline

Won't compile unless ScopedOnly is false

Definition at line 86 of file GlobalVariable.h.

      {
         static_assert(!ScopedOnly);
         m_previous.reset();
      }

References GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::m_previous.

HasValue()

template<typename Tag , typename Type , auto initializer = nullptr, bool ScopedOnly = true>

bool GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::HasValue ( ) const

inline

Definition at line 91 of file GlobalVariable.h.

      {
         if constexpr (ScopedOnly)
            return true;
         else
            return m_previous.has_value();
      }

References GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::m_previous.

operator=()

template<typename Tag , typename Type , auto initializer = nullptr, bool ScopedOnly = true>

Scope & GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::operator= ( Scope &&  other )

default

Member Data Documentation

m_previous

template<typename Tag , typename Type , auto initializer = nullptr, bool ScopedOnly = true>

std::conditional_t<ScopedOnly, mutable_type, std::optional<mutable_type> > GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::m_previous

private

Definition at line 101 of file GlobalVariable.h.

Referenced by GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::Commit(), GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::HasValue(), and GlobalVariable< Tag, Type, initializer, ScopedOnly >::Scope::~Scope().

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The documentation for this class was generated from the following file:

• GlobalVariable.h