mysql::allocators::Allocator< T > Class Template Reference

Allocator using a Memory_resource to do the allocation. More...

#include <allocator.h>

Public Types
using	value_type = T
using	size_type = std::size_t
using	difference_type = std::ptrdiff_t
using	propagate_on_container_move_assignment = std::true_type
	On move-assignment for containers using this allocator, make the target container inherit the allocator and reuse the memory from the source container. More...
using	propagate_on_container_copy_assignment = std::false_type
	On copy-assignment for containers using this allocator, make the target container preserve its existing allocator and reuse its own memory if possible. More...

Public Member Functions
	Allocator (Memory_resource memory_resource=Memory_resource()) noexcept
	Construct a new Allocator using the given Memory_resource. More...
template<class U >
constexpr	Allocator (const Allocator< U > &other) noexcept
	Implicit conversion from other instance. More...
constexpr	Allocator (const Allocator &other) noexcept=default
constexpr Allocator &	operator= (const Allocator &other) noexcept=default
constexpr	Allocator (Allocator &&other) noexcept
constexpr Allocator &	operator= (Allocator &&other) noexcept
	~Allocator () noexcept=default
constexpr T *	allocate (size_type n)
	Use the Memory_resource to allocate the given number of elements of type T. More...
constexpr void	deallocate (T *p, size_type size)
	Use the Memory_resource to deallocate the given pointer. More...
std::function< void(T *)>	get_deleter ()
	Return a Deleter function for objects allocated by this class. More...
const Memory_resource &	get_memory_resource () const
	Return a reference to the underlying Memory_resource object. More...

Private Attributes
Memory_resource	m_memory_resource
	The underlying Memory_resource object. More...

Detailed Description

template<class T>
class mysql::allocators::Allocator< T >

Allocator using a Memory_resource to do the allocation.

A library that allocates memory should allow the user to pass a Memory_resource object which defaults to a default-constructed instance, Memory_resource(). Internally it should create the Allocator<T> classes it needs (possibly several, for different classes T), using the given Memory_resource object. Users of the library outside the server should just use the default Memory_resource. Users of the library inside the server should setup a PSI key and pass the result from psi_memory_resource(Key) to the library.

Member Typedef Documentation

difference_type

template<class T >

using mysql::allocators::Allocator< T >::difference_type = std::ptrdiff_t

propagate_on_container_copy_assignment

template<class T >

using mysql::allocators::Allocator< T >::propagate_on_container_copy_assignment = std::false_type

On copy-assignment for containers using this allocator, make the target container preserve its existing allocator and reuse its own memory if possible.

propagate_on_container_move_assignment

template<class T >

using mysql::allocators::Allocator< T >::propagate_on_container_move_assignment = std::true_type

On move-assignment for containers using this allocator, make the target container inherit the allocator and reuse the memory from the source container.

size_type

template<class T >

using mysql::allocators::Allocator< T >::size_type = std::size_t

value_type

template<class T >

using mysql::allocators::Allocator< T >::value_type = T

Constructor & Destructor Documentation

Allocator() [1/4]

template<class T >

mysql::allocators::Allocator< T >::Allocator ( Memory_resource  memory_resource = Memory_resource() )

inlineexplicitnoexcept

Construct a new Allocator using the given Memory_resource.

Parameters

memory_resource

The memory resource. By default, this uses a default-constructed Memory_resource, so it uses std::malloc and std::free for allocations.

Allocator() [2/4]

template<class T >

template<class U >

constexpr mysql::allocators::Allocator< T >::Allocator ( const Allocator< U > &  other )

inlineconstexprnoexcept

Implicit conversion from other instance.

This is required to exist and be implicit by the Windows implementation of std::vector.

Allocator() [3/4]

template<class T >

constexpr mysql::allocators::Allocator< T >::Allocator ( const Allocator< T > &  other )

constexprdefaultnoexcept

Allocator() [4/4]

template<class T >

constexpr mysql::allocators::Allocator< T >::Allocator ( Allocator< T > &&  other )

inlineconstexprnoexcept

~Allocator()

template<class T >

mysql::allocators::Allocator< T >::~Allocator ( )

defaultnoexcept

Member Function Documentation

allocate()

template<class T >

constexpr T * mysql::allocators::Allocator< T >::allocate ( size_type  n )

inlineconstexpr

Use the Memory_resource to allocate the given number of elements of type T.

Parameters

n	The number of elements.

Returns

The new pointer.

Exceptions

std::bad_alloc

on out of memory conditions.

deallocate()

template<class T >

constexpr void mysql::allocators::Allocator< T >::deallocate ( T *  p, size_type  size  )

inlineconstexpr

Use the Memory_resource to deallocate the given pointer.

Parameters

p	The pointer to deallocate.
size	Unused.

get_deleter()

template<class T >

std::function< void(T *)> mysql::allocators::Allocator< T >::get_deleter ( )

inline

Return a Deleter function for objects allocated by this class.

Such a Deleter must be specified when constructing a smart pointer to an object created by this Allocator, for example:

Allocator<T> allocator(some_memory_resource);
T *obj = allocator.allocate(1);
std::shared_ptr<T> ptr(obj, allocator.get_deleter());

Return values

Deleter

function that takes a T* as argument and uses the Memory_resource to deallocate it.

get_memory_resource()

template<class T >

const Memory_resource & mysql::allocators::Allocator< T >::get_memory_resource ( ) const

inline

Return a reference to the underlying Memory_resource object.

operator=() [1/2]

template<class T >

constexpr Allocator & mysql::allocators::Allocator< T >::operator= ( Allocator< T > &&  other )

inlineconstexprnoexcept

operator=() [2/2]

template<class T >

constexpr Allocator & mysql::allocators::Allocator< T >::operator= ( const Allocator< T > &  other )

constexprdefaultnoexcept

Member Data Documentation

m_memory_resource

template<class T >

Memory_resource mysql::allocators::Allocator< T >::m_memory_resource

private

The underlying Memory_resource object.

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

• libs/mysql/allocators/allocator.h