Make RunOnce not a manual system implementation

Can we make `System` sealed please?
bevyengine · Feb 14, 2022 · edd2c67 · edd2c67
1 parent 29419a3
commit edd2c67
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Showing 2 changed files with 9 additions and 44 deletions.
diff --git a/crates/bevy_app/src/app.rs b/crates/bevy_app/src/app.rs
@@ -5,8 +5,8 @@ pub use bevy_derive::AppLabel;
 use bevy_ecs::{
     prelude::{FromWorld, IntoExclusiveSystem},
     schedule::{
-        IntoSystemDescriptor, RunOnce, Schedule, Stage, StageLabel, State, StateData, SystemSet,
-        SystemStage,
+        run_once_criteria, IntoSystemDescriptor, Schedule, Stage, StageLabel, State, StateData,
+        SystemSet, SystemStage,
     },
     system::Resource,
     world::World,
@@ -594,7 +594,7 @@ impl App {
             .add_stage(
                 StartupSchedule,
                 Schedule::default()
-                    .with_run_criteria(RunOnce::default())
+                    .with_run_criteria(run_once_criteria())
                     .with_stage(StartupStage::PreStartup, SystemStage::parallel())
                     .with_stage(StartupStage::Startup, SystemStage::parallel())
                     .with_stage(StartupStage::PostStartup, SystemStage::parallel()),

diff --git a/crates/bevy_ecs/src/schedule/run_criteria.rs b/crates/bevy_ecs/src/schedule/run_criteria.rs
@@ -1,7 +1,5 @@
 use crate::{
-    archetype::{Archetype, ArchetypeComponentId, ArchetypeGeneration},
-    component::ComponentId,
-    query::Access,
+    archetype::ArchetypeGeneration,
     schedule::{BoxedRunCriteriaLabel, GraphNode, RunCriteriaLabel},
     system::{BoxedSystem, IntoSystem, System},
     world::World,
@@ -399,47 +397,14 @@ where
     }
 }
 
-#[derive(Default)]
-pub struct RunOnce {
-    ran: bool,
-    archetype_component_access: Access<ArchetypeComponentId>,
-    component_access: Access<ComponentId>,
-}
-
-impl System for RunOnce {
-    type In = ();
-    type Out = ShouldRun;
-
-    fn name(&self) -> Cow<'static, str> {
-        Cow::Borrowed(std::any::type_name::<RunOnce>())
-    }
-
-    fn new_archetype(&mut self, _archetype: &Archetype) {}
-
-    fn component_access(&self) -> &Access<ComponentId> {
-        &self.component_access
-    }
-
-    fn archetype_component_access(&self) -> &Access<ArchetypeComponentId> {
-        &self.archetype_component_access
-    }
-
-    fn is_send(&self) -> bool {
-        true
-    }
-
-    unsafe fn run_unsafe(&mut self, _input: (), _world: &World) -> ShouldRun {
-        if self.ran {
+pub fn run_once_criteria() -> impl FnMut() -> ShouldRun {
+    let mut ran = false;
+    move || {
+        if ran {
             ShouldRun::No
         } else {
-            self.ran = true;
+            ran = true;
             ShouldRun::Yes
         }
     }
-
-    fn apply_buffers(&mut self, _world: &mut World) {}
-
-    fn initialize(&mut self, _world: &mut World) {}
-
-    fn check_change_tick(&mut self, _change_tick: u32) {}
 }