55 lines
1.3 KiB
Rust
55 lines
1.3 KiB
Rust
use bevy::{
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ecs::{
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system::{IntoSystem, Resource, SystemId},
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world::World,
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},
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utils::HashMap,
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};
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use std::sync::Arc;
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#[derive(Resource, Default)]
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pub struct DeferredSystemRegistry {
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// TODO: Replace ref_counts with Box<Vec<SystemId>> and insert SystemId into it on unmount
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pub ref_counts: HashMap<SystemId, Arc<()>>,
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pub run_queue: Box<Vec<SystemId>>,
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}
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#[derive(Clone, Copy)]
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struct DeferredSystem {
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id: SystemId,
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run_queue: *mut Vec<SystemId>,
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}
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impl DeferredSystem {
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fn schedule(&self) {
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unsafe { &mut *self.run_queue }.push(self.id);
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}
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}
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unsafe impl Send for DeferredSystem {}
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unsafe impl Sync for DeferredSystem {}
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pub fn new_deferred_system<S, M>(
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system: S,
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world: &mut World,
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) -> (impl Fn() + Send + Sync + Copy, Arc<()>)
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where
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S: IntoSystem<(), (), M> + 'static,
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M: 'static,
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{
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let id = world.register_system(system);
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let ref_count = Arc::new(());
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let mut system_registry = world.resource_mut::<DeferredSystemRegistry>();
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system_registry
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.ref_counts
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.insert(id, Arc::clone(&ref_count));
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let deferred_system = DeferredSystem {
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id,
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run_queue: Box::as_mut(&mut system_registry.run_queue),
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};
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(move || deferred_system.schedule(), ref_count)
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}
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