Overview

A pool that is implemented by forwarding calls to another pool.

This type can be used as a generic base type for forwarding pools that provide additional behavior to another pool. It provides default implementations of the virtual methods from Deallocator and Pool, allowing authors of derived types to avoid boilerplate.

Note: It is an error for a derived type to override any of the methods below with an implementation that calls any of the corresponding public methods. If it does, the public, NVI-style method will dispatch to the derived type's override, leading to an infinite recursion. Instead, use the pool accessor or call this type's implementation methods directly:

class MyPool : public pw::allocator::ForwardingPool {
 private:
  void* Allocate() override {
    // INCORRECT! This will infinitely recurse.
    // return pw::allocator::ForwardingPool::Allocate();
 
    // Correct: This dispatches to the wrapped pool.
    return pool().Allocate();
  }
 
  void Deallocate(void* ptr) override {
    // Also correct: This dispatches to the wrapped pool.
    pw::allocator::ForwardingPool::DoDeallocate(ptr);
  }
}

Inheritance diagram for pw::allocator::ForwardingPool:

Protected Member Functions
constexpr	ForwardingPool (const Capabilities &capabilities, Layout layout) noexcept

constexpr	ForwardingPool (Pool &pool) noexcept

constexpr void	Init (Pool &pool)

constexpr Pool &	pool ()

constexpr const Pool &	pool () const

void *	DoAllocate () override

void	DoDeallocate (void *ptr) override

Result< Layout >	DoGetInfo (InfoType info_type, const void *ptr) const override

Protected Member Functions inherited from pw::allocator::Pool
constexpr	Pool (const Capabilities &capabilities, const Layout &layout)

virtual void *	DoAllocate ()=0

Protected Member Functions inherited from pw::Deallocator
constexpr	Deallocator ()=default
	TODO(b/326509341): Remove when downstream consumers migrate.

constexpr	Deallocator (const Capabilities &capabilities)

Result< Layout >	GetInfo (InfoType info_type, const void *ptr) const

Result< Layout >	GetRequestedLayout (const void *ptr) const

Result< Layout >	GetUsableLayout (const void *ptr) const

Result< Layout >	GetAllocatedLayout (const void *ptr) const

bool	Recognizes (const void *ptr) const

virtual void	DoDeallocate (void *ptr)=0

virtual Result< Layout >	DoGetInfo (InfoType, const void *) const

Additional Inherited Members
Public Types inherited from pw::Deallocator
using	Capabilities = allocator::Capabilities

using	Capability = allocator::Capability

using	Layout = allocator::Layout

Public Member Functions inherited from pw::allocator::Pool
constexpr const Layout &	layout () const

void *	Allocate ()

template<typename T , int &... kExplicitGuard, typename... Args>
std::enable_if_t<!std::is_array_v< T >, T * >	New (Args &&... args)

template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>>
std::enable_if_t< pw::is_bounded_array_v< T >, ElementType * >	New ()

template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>>
std::enable_if_t< pw::is_unbounded_array_v< T >, ElementType * >	New ()

template<typename T , int &... kExplicitGuard, typename... Args>
std::enable_if_t<!std::is_array_v< T >, UniquePtr< T > >	MakeUnique (Args &&... args)

template<typename T >
std::enable_if_t< pw::is_bounded_array_v< T >, UniquePtr< T > >	MakeUnique ()

template<typename T >
std::enable_if_t< pw::is_unbounded_array_v< T >, UniquePtr< T > >	MakeUnique ()

Public Member Functions inherited from pw::Deallocator
constexpr const Capabilities &	capabilities () const

constexpr bool	HasCapability (Capability capability) const
	Returns whether a given capability is enabled for this object.

void	Deallocate (void *ptr)

template<typename ElementType >
void	DeleteArray (ElementType *ptr, size_t count)

template<typename ElementType >
void	Destroy (ElementType *ptr, size_t count)

StatusWithSize	GetCapacity () const

bool	IsEqual (const Deallocator &other) const

template<typename T , int &... kExplicitGuard, std::enable_if_t<!std::is_array_v< T >, int > = 0>
void	Delete (T *ptr)

template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_bounded_array_v< T >, int > = 0>
void	Delete (ElementType *ptr)

template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
void	Delete (ElementType *ptr, size_t count)

Protected Types inherited from pw::Deallocator
enum class	InfoType { kRequestedLayoutOf , kUsableLayoutOf , kAllocatedLayoutOf , kCapacity , kRecognizes }

Static Protected Member Functions inherited from pw::Deallocator
static Result< Layout >	GetInfo (const Deallocator &deallocator, InfoType info_type, const void *ptr)

static Result< Layout >	GetRequestedLayout (const Deallocator &deallocator, const void *ptr)

static Result< Layout >	GetUsableLayout (const Deallocator &deallocator, const void *ptr)

static Result< Layout >	GetAllocatedLayout (const Deallocator &deallocator, const void *ptr)

static bool	Recognizes (const Deallocator &deallocator, const void *ptr)

Static Protected Attributes inherited from pw::Deallocator
template<typename T >
static constexpr bool	is_bounded_array_v = ::pw::is_bounded_array_v<T>

template<typename T >
static constexpr bool	is_unbounded_array_v = ::pw::is_unbounded_array_v<T>

Constructor & Destructor Documentation

◆ ForwardingPool() [1/2]

constexpr pw::allocator::ForwardingPool::ForwardingPool	(	const Capabilities &	capabilities,
		Layout	layout
	)

inlineconstexprprotectednoexcept

Creates a forwarding pool without setting its wrapped pool.

This constructor should be used when the forwarding pool needs to be created before the pool being wrapped. The pool must be set using Init before any other method is called. The given capabilities and layout must match those of the pool subsequently provided to Init.

◆ ForwardingPool() [2/2]

constexpr pw::allocator::ForwardingPool::ForwardingPool ( Pool & pool )

inlineexplicitconstexprprotectednoexcept

Creates a forwarding pool that wraps a given pool.

This constructor should be used when the forwarding pool is created after the pool being wrapped.

The pool must remain valid for the lifetime of this object.

Member Function Documentation

◆ DoAllocate()

void * pw::allocator::ForwardingPool::DoAllocate ( )

inlineoverrideprotectedvirtual

Returns a chunk of memory with this object's fixed layout.

Like pw::allocator::Allocate, returns null if memory is exhausted.

Return values

The	allocated memory.

Implements pw::allocator::Pool.

◆ DoDeallocate()

void pw::allocator::ForwardingPool::DoDeallocate ( void * ptr )

inlineoverrideprotectedvirtual

Releases a previously-allocated block of memory.

The given pointer must have been previously provided by this memory resource; otherwise the behavior is undefined.

Parameters

[in] ptr Pointer to previously-allocated memory.

Implements pw::Deallocator.

◆ DoGetInfo()

Result< Layout > pw::allocator::ForwardingPool::DoGetInfo	(	InfoType	info_type,
		const void *	ptr
	)		const

inlineoverrideprotectedvirtual

Returns deallocator-specific information about allocations.

Deallocators may support any number of InfoTypes. See that type for what each supported type returns. For unsupported types, this method returns UNIMPLEMENTED.

Reimplemented from pw::Deallocator.

◆ Init()

constexpr void pw::allocator::ForwardingPool::Init ( Pool & pool )

inlineconstexprprotected

Sets the pool being wrapped.

It is an error to call this method if a pool was provided to the constructor. The capabilities of the given pool must match those of previously provided to the constructor.

The pool must remain valid for the lifetime of this object.

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

pw_allocator/public/pw_allocator/forwarding_pool.h

Overview

Protected Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

◆ ForwardingPool() [1/2]

◆ ForwardingPool() [2/2]

Member Function Documentation

◆ DoAllocate()

◆ DoDeallocate()

◆ DoGetInfo()

◆ Init()