Struct CMMemoryPool 

pub struct CMMemoryPool { /* private fields */ }

Available on crate feature CMMemoryPool only.

CMMemoryPool.h

Memory pool for optimizing repeated large block allocation.

CMMemoryPool is a memory allocation service that holds onto a pool of recently deallocated memory so as to speed up subsequent allocations of the same size. It’s intended for cases where large memory blocks need to be repeatedly allocated – for example, the compressed data output by a video encoder.

All of its allocations are on the granularity of page sizes; it does not suballocate memory within pages, so it is a poor choice for allocating tiny blocks. For example, it’s appropriate to use as the blockAllocator argument to CMBlockBufferCreateWithMemoryBlock, but not the structureAllocator argument – use kCFAllocatorDefault instead.

When you no longer need to allocate memory from the pool, call CMMemoryPoolInvalidate and CFRelease. Calling CMMemoryPoolInvalidate tells the pool to stop holding onto memory for reuse. Note that the pool’s CFAllocator can outlive the pool, owing to the way that CoreFoundation is designed: CFAllocators are themselves CF objects, and every object allocated with a CFAllocator implicitly retains the CFAllocator until it is finalized. After the CMMemoryPool is invalidated or finalized, its CFAllocator allocates and deallocates with no pooling behavior.

CMMemoryPool deallocates memory if it has not been recycled in 0.5 second, so that short-term peak usage does not cause persistent bloat. (This period may be overridden by specifying kCMMemoryPoolOption_AgeOutPeriod.) Such “aging out” is done during the pool’s CFAllocatorAllocate and CFAllocatorDeallocate methods.

See also Apple’s documentation

Implementations

impl CMMemoryPool

pub unsafe fn new(options: Option<&CFDictionary>) -> CFRetained<CMMemoryPool>

Creates a new CMMemoryPool.

Safety

options generics must be of the correct type.

pub unsafe fn allocator(&self) -> CFRetained<CFAllocator>

Returns the pool’s CFAllocator.

pub unsafe fn flush(&self)

Deallocates all memory the pool was holding for recycling.

pub unsafe fn invalidate(&self)

Stops the pool from recycling.

When CMMemoryPoolInvalidate is called the pool’s allocator stops recycling memory. The pool deallocates any memory it was holding for recycling. This also happens when the retain count of the CMMemoryPool drops to zero, except that under GC it may be delayed.

Methods from Deref<Target = CFType>

pub fn downcast_ref<T>(&self) -> Option<&T>

where T: ConcreteType,

Available on crate feature CMAttachment only.

Attempt to downcast the type to that of type T.

This is the reference-variant. Use CFRetained::downcast if you want to convert a retained type. See also ConcreteType for more details on which types support being converted to.

pub fn retain_count(&self) -> usize

Available on crate feature CMAttachment only.

Get the reference count of the object.

This function may be useful for debugging. You normally do not use this function otherwise.

Beware that some things (like CFNumbers, small CFStrings etc.) may not have a normal retain count for optimization purposes, and can return usize::MAX in that case.

Trait Implementations

impl AsRef<AnyObject> for CMMemoryPool

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<CFType> for CMMemoryPool

fn as_ref(&self) -> &CFType

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<CMMemoryPool> for CMMemoryPool

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<AnyObject> for CMMemoryPool

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<CFType> for CMMemoryPool

fn borrow(&self) -> &CFType

Immutably borrows from an owned value.

impl ConcreteType for CMMemoryPool

fn type_id() -> CFTypeID

Get the unique CFTypeID identifier for the type.

impl Debug for CMMemoryPool

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for CMMemoryPool

type Target = CFType

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Hash for CMMemoryPool

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for CMMemoryPool

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl PartialEq for CMMemoryPool

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RefEncode for CMMemoryPool

const ENCODING_REF: Encoding

The Objective-C type-encoding for a reference of this type.

impl Type for CMMemoryPool

fn retain(&self) -> CFRetained<Self>

where Self: Sized,

Increment the reference count of the receiver.

fn as_concrete_TypeRef(&self) -> &Self

👎Deprecated: this is redundant

Helper for easier transition from the core-foundation crate.

unsafe fn wrap_under_get_rule(ptr: *const Self) -> CFRetained<Self>

where Self: Sized,

👎Deprecated: use CFRetained::retain

Helper for easier transition from the core-foundation crate.

fn as_CFTypeRef(&self) -> &CFType

where Self: AsRef<CFType>,

👎Deprecated: this is redundant (CF types deref to CFType)

Helper for easier transition from the core-foundation crate.

unsafe fn wrap_under_create_rule(ptr: *const Self) -> CFRetained<Self>

where Self: Sized,

👎Deprecated: use CFRetained::from_raw

Helper for easier transition from the core-foundation crate.

impl Eq for CMMemoryPool

impl Send for CMMemoryPool

impl Sync for CMMemoryPool