Struct OpaqueFn

#[repr(C)]
pub struct OpaqueFn<'a, A, R, B: Buffer> { /* private fields */ }

A fixed-capacity inline function wrapper without allocation.

OpaqueFn<'a, A, R, N> can store any closure or function pointer that implements Fn(A) -> R and fits into a buffer of size N bytes.

Note

Use call method to invoke the stored callable.

This is intended as a no-alloc alternative to Box<dyn Fn(A) -> R>.

Implementations

impl<'a, A, R, B: Buffer> OpaqueFn<'a, A, R, B>

pub fn new<F>(f: F) -> Self

where F: Fn(A) -> R + 'a,

Constructs a new OpaqueFn wrapping the given callable f.

Panics

Panics if:

• The size of F exceeds the buffer size N.
• The alignment of F exceeds the alignment of the buffer.

pub fn call<'call>(&self, a: A) -> R

where A: 'call,

Invokes the stored callable with argument a.

Trait Implementations

impl<'a, A: Debug, R: Debug, B: Debug + Buffer> Debug for OpaqueFn<'a, A, R, B>

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

Formats the value using the given formatter.

impl<A, R, B: Buffer> Drop for OpaqueFn<'_, A, R, B>

fn drop(&mut self)

Executes the destructor for this type.