bench_custom_cell.rs

//! Custom cell impl, internal use only
use std::{cell::UnsafeCell, fmt, rc::Rc};
use criterion::{black_box, criterion_group, criterion_main, Criterion};
use std::cell::RefCell;

pub(crate) struct Cell<T> {
    inner: Rc<UnsafeCell<T>>,
}

impl<T> Clone for Cell<T> {
    fn clone(&self) -> Self {
        Self {
            inner: self.inner.clone(),
        }
    }
}

impl<T: fmt::Debug> fmt::Debug for Cell<T> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.inner.fmt(f)
    }
}

impl<T> Cell<T> {
    pub(crate) fn new(inner: T) -> Self {
        Self {
            inner: Rc::new(UnsafeCell::new(inner)),
        }
    }

    pub(crate) fn get_ref(&self) -> &T {
        unsafe { &*self.inner.as_ref().get() }
    }

    pub(crate) fn get_mut(&mut self) -> &mut T {
        unsafe { &mut *self.inner.as_ref().get() }
    }
}

fn bench_get_ref(c: &mut Criterion) {
    c.bench_function(
        "custom cell get_ref",
        |b| {
            let to_clone = Cell::new(black_box(20));
            b.iter_with_setup(
                || to_clone.clone(),
                |cell| cell.get_ref().clone()
            )
        }
    );
}

fn bench_get_mut(c: &mut Criterion) {
    c.bench_function(
        "custom cell get_mut",
        |b| {
            let to_clone = Cell::new(black_box(20));
            b.iter_with_setup(
                || to_clone.clone(),
                |mut cell| cell.get_mut().clone()
            )
        }
    );
}

fn bench_borrow_rc_refcell(c: &mut Criterion) {
    c.bench_function(
        "rc refcell borrow",
        |b| {
            let to_clone = Rc::new(RefCell::new(black_box(20)));
            b.iter_with_setup(
                || to_clone.clone(),
                |cell| cell.borrow().clone()
            )
        }
    );
}

fn bench_borrow_mut_rc_refcell(c: &mut Criterion) {
    c.bench_function(
        "rc refcell borrow_mut",
        |b| {
            let to_clone = Rc::new(RefCell::new(black_box(20)));
            b.iter_with_setup(
                || to_clone.clone(),
                |cell| cell.borrow_mut().clone()
            )
        }
    );
}


criterion_group!(benches, bench_get_ref, bench_get_mut, bench_borrow_rc_refcell, bench_borrow_mut_rc_refcell);
criterion_main!(benches);