Sentry class for managing the need to create and dispose of a local THD instance. More...

#include <rpl_utility.h>

Public Member Functions
	THD_instance_guard (THD *thd)
	If the given `THD` object pointer is `nullptr`, a new instance will be initialized within the constructor and disposed of in the destructor. More...

virtual	~THD_instance_guard ()
	If a new instance of `THD` was created in the constructor, it will be disposed here. More...

	operator THD * ()
	Returns the active `THD` object pointer. More...

Private Attributes
THD *	m_target {nullptr}
	The active `THD` object pointer. More...

bool	m_is_locally_initialized {false}
	Tells whether or not the active `THD` object was created in this object constructor. More...

Detailed Description

Sentry class for managing the need to create and dispose of a local THD instance.

If the given THD object pointer passed on the constructor is nullptr, a new instance will be initialized within the constructor and disposed of in the destructor.

If the given THD object pointer passed on the constructor is not nullptr, the reference is kept and nothing is disposed on the destructor.

Casting operator to THD* is also provided, to easy code replacemente.

Usage example:

 THD_instance_guard thd{current_thd != nullptr ? current_thd :
                                                 this->info_thd};
 Acl_cache_lock_guard guard{thd, Acl_cache_lock_mode::READ_MODE};
 if (guard.lock())
   ...

Constructor & Destructor Documentation

◆ THD_instance_guard()

THD_instance_guard::THD_instance_guard ( THD * thd )

If the given THD object pointer is nullptr, a new instance will be initialized within the constructor and disposed of in the destructor.

If the given THD object pointer is not nullptr, the reference is kept and nothing is disposed on the destructor.

Parameters

thd	`THD` object reference that determines if an existence instance is used or a new instance of `THD` must be created.

◆ ~THD_instance_guard()

THD_instance_guard::~THD_instance_guard ( )

virtual

If a new instance of THD was created in the constructor, it will be disposed here.

Member Function Documentation

◆ operator THD *()

THD_instance_guard::operator THD * ( )

Returns the active THD object pointer.

Returns: a not-nullptr THD object pointer.

Member Data Documentation

◆ m_is_locally_initialized

bool THD_instance_guard::m_is_locally_initialized {false}

private

Tells whether or not the active THD object was created in this object constructor.

◆ m_target

THD* THD_instance_guard::m_target {nullptr}