Struct RawPinnedPool

Source

pub struct RawPinnedPool<T: 'static> { /* private fields */ }

Expand description

A pool of objects of type T.

All values in the pool remain pinned for their entire lifetime.

The pool automatically expands its capacity when needed.

§Thread safety

If T: Send then the pool is thread-safe (Send and Sync).

§Example: unique object ownership

use std::fmt::Display;

use infinity_pool::RawPinnedPool;

let mut pool = RawPinnedPool::<String>::new();

// Insert an object into the pool, returning a unique handle to it.
let mut handle = pool.insert("Hello, world!".to_string());

// A unique handle allows us to create exclusive references to the target object.
// SAFETY: We promise to keep the pool alive for the duration of this reference.
let value_mut = unsafe { handle.as_mut() };
value_mut.push_str(" Welcome to Infinity Pool!");

println!("Updated value: {value_mut}");

// This is optional - we could also just drop the pool.
// SAFETY: We promise that this handle really is for an object present in this pool.
unsafe {
    pool.remove(handle);
}

§Example: shared object ownership

use std::fmt::Display;

use infinity_pool::RawPinnedPool;

let mut pool = RawPinnedPool::<String>::new();

// Insert an object into the pool, returning a unique handle to it.
let handle = pool.insert("Hello, world!".to_string());

// The unique handle can be converted into a shared handle,
// allowing multiple copies of the handle to be created.
let shared_handle = handle.into_shared();
let shared_handle_copy = shared_handle;

// Shared handles allow only shared references to be created.
// SAFETY: We promise to keep the pool alive for the duration of this reference.
let value_ref = unsafe { shared_handle.as_ref() };

println!("Shared access to value: {value_ref}");

// This is optional - we could also just drop the pool.
// SAFETY: We promise that the object has not already been removed
// via a different shared handle - look up to verify that.
unsafe {
    pool.remove(shared_handle);
}

Implementations§

Source §

impl<T: 'static> RawPinnedPool<T>

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pub fn builder() -> RawPinnedPoolBuilder<T>

Starts configuring and creating a new instance of the pool.

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pub fn new() -> Self

Creates a new pool with the default configuration.

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pub fn len(&self) -> usize

The number of objects currently in the pool.

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pub fn capacity(&self) -> usize

The total capacity of the pool.

This is the maximum number of objects (including current contents) that the pool can contain without capacity extension. The pool will automatically extend its capacity if more than this many objects are inserted.

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pub fn is_empty(&self) -> bool

Whether the pool contains zero objects.

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pub fn reserve(&mut self, additional: usize)

Ensures that the pool has capacity for at least additional more objects.

§Panics

Panics if the new capacity would exceed the size of virtual memory (usize::MAX).

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pub fn shrink_to_fit(&mut self)

Drops unused pool capacity to reduce memory usage.

There is no guarantee that any unused capacity can be dropped. The exact outcome depends on the specific pool structure and which objects remain in the pool.

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pub fn insert(&mut self, value: T) -> RawPooledMut<T>

Inserts an object into the pool and returns a handle to it.

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pub unsafe fn insert_with<F>(&mut self, f: F) -> RawPooledMut<T>
where F: FnOnce(&mut MaybeUninit<T>),

Inserts an object into the pool via closure and returns a handle to it.

This method allows the caller to partially initialize the object, skipping any MaybeUninit fields that are intentionally not initialized at insertion time. This can make insertion of objects containing MaybeUninit fields faster, although requires unsafe code to implement.

This method is NOT faster than insert() for fully initialized objects. Prefer insert() for a better safety posture if you do not intend to skip initialization of any MaybeUninit fields.

§Example

use std::mem::MaybeUninit;
use std::ptr;

use infinity_pool::RawPinnedPool;

struct DataBuffer {
    id: u32,
    data: MaybeUninit<[u8; 1024]>,
}

let mut pool = RawPinnedPool::<DataBuffer>::new();

// Initialize only the id, leaving data uninitialized for performance.
let handle = unsafe {
    pool.insert_with(|uninit: &mut MaybeUninit<DataBuffer>| {
        let ptr = uninit.as_mut_ptr();

        // SAFETY: We are writing to a correctly located field within the object.
        unsafe {
            ptr::addr_of_mut!((*ptr).id).write(42);
        }
    })
};

// SAFETY: We promise that the pool is not dropped while we hold this reference.
let item = unsafe { handle.as_ref() };
assert_eq!(item.id, 42);