dioxus/packages/signals/tests/memo.rs

#![allow(unused, non_upper_case_globals, non_snake_case)]
use dioxus::html::p;
use dioxus::prelude::*;
use dioxus_core::{generation, ElementId};
use dioxus_core::{NoOpMutations, ScopeState};
use dioxus_signals::*;
use std::cell::RefCell;
use std::collections::HashMap;
use std::rc::Rc;
use std::sync::atomic::{AtomicBool, Ordering};

#[test]
fn memos_rerun() {
    tracing_subscriber::fmt::init();

    #[derive(Default)]
    struct RunCounter {
        component: usize,
        effect: usize,
    }

    let counter = Rc::new(RefCell::new(RunCounter::default()));
    let mut dom = VirtualDom::new_with_props(
        |counter: Rc<RefCell<RunCounter>>| {
            counter.borrow_mut().component += 1;

            let mut signal = use_signal(|| 0);
            let memo = use_memo({
                to_owned![counter];
                move || {
                    counter.borrow_mut().effect += 1;
                    println!("Signal: {:?}", signal);
                    signal()
                }
            });
            assert_eq!(memo(), 0);
            signal += 1;
            assert_eq!(memo(), 1);

            rsx! {
                div {}
            }
        },
        counter.clone(),
    );

    dom.rebuild_in_place();

    let current_counter = counter.borrow();
    assert_eq!(current_counter.component, 1);
    assert_eq!(current_counter.effect, 2);
}

#[test]
fn memos_prevents_component_rerun() {
    #[derive(Default)]
    struct RunCounter {
        component: usize,
        memo: usize,
    }

    let counter = Rc::new(RefCell::new(RunCounter::default()));
    let mut dom = VirtualDom::new_with_props(
        |props: Rc<RefCell<RunCounter>>| {
            let mut signal = use_signal(|| 0);

            if generation() == 1 {
                *signal.write() = 0;
            }
            if generation() == 2 {
                println!("Writing to signal");
                *signal.write() = 1;
            }

            rsx! {
                Child {
                    signal: signal,
                    counter: props.clone(),
                }
            }
        },
        counter.clone(),
    );

    #[derive(Default, Props, Clone)]
    struct ChildProps {
        signal: Signal<usize>,
        counter: Rc<RefCell<RunCounter>>,
    }

    impl PartialEq for ChildProps {
        fn eq(&self, other: &Self) -> bool {
            self.signal == other.signal
        }
    }

    fn Child(props: ChildProps) -> Element {
        let counter = &props.counter;
        let signal = props.signal;
        counter.borrow_mut().component += 1;

        let memo = use_memo({
            to_owned![counter];
            move || {
                counter.borrow_mut().memo += 1;
                println!("Signal: {:?}", signal);
                signal()
            }
        });
        match generation() {
            0 => {
                assert_eq!(memo(), 0);
            }
            1 => {
                assert_eq!(memo(), 1);
            }
            _ => panic!("Unexpected generation"),
        }

        rsx! {
            div {}
        }
    }

    dom.rebuild_in_place();
    dom.mark_dirty(ScopeId::APP);
    dom.render_immediate(&mut NoOpMutations);

    {
        let current_counter = counter.borrow();
        assert_eq!(current_counter.component, 1);
        assert_eq!(current_counter.memo, 2);
    }

    dom.mark_dirty(ScopeId::APP);
    dom.render_immediate(&mut NoOpMutations);
    dom.render_immediate(&mut NoOpMutations);

    {
        let current_counter = counter.borrow();
        assert_eq!(current_counter.component, 2);
        assert_eq!(current_counter.memo, 3);
    }

    dom.in_scope(ScopeId(3), || {
        assert!(consume_context::<ErrorContext>().error().is_none())
    });
}

// Regression test for https://github.com/DioxusLabs/dioxus/issues/2990
#[test]
fn memos_sync_rerun_after_unrelated_write() {
    static PASSED: AtomicBool = AtomicBool::new(false);
    let mut dom = VirtualDom::new(|| {
        let mut signal = use_signal(|| 0);
        let memo = use_memo(move || dbg!(signal() < 2));
        if generation() == 0 {
            assert!(memo());
            signal += 1;
        } else {
            // It should be fine to hold the write and read the memo at the same time
            let mut write = signal.write();
            println!("Memo: {:?}", memo());
            assert!(memo());
            *write = 2;
            drop(write);
            assert!(!memo());
            PASSED.store(true, std::sync::atomic::Ordering::SeqCst);
        }

        rsx! {
            div {}
        }
    });

    dom.rebuild_in_place();
    dom.mark_dirty(ScopeId::APP);
    dom.render_immediate(&mut NoOpMutations);
    assert!(PASSED.load(Ordering::SeqCst));
}