765e5842cd
# Objective Make it easier to short-circuit system parameter validation. Simplify the API surface by combining `ValidationOutcome` with `SystemParamValidationError`. ## Solution Replace `ValidationOutcome` with `Result<(), SystemParamValidationError>`. Move the docs from `ValidationOutcome` to `SystemParamValidationError`. Add a `skipped` field to `SystemParamValidationError` to distinguish the `Skipped` and `Invalid` variants. Use the `?` operator to short-circuit validation in tuples of system params.
1032 lines
39 KiB
Rust
1032 lines
39 KiB
Rust
use crate::{
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archetype::{ArchetypeComponentId, ArchetypeGeneration},
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component::{ComponentId, Tick},
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prelude::FromWorld,
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query::{Access, FilteredAccessSet},
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schedule::{InternedSystemSet, SystemSet},
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system::{
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check_system_change_tick, ReadOnlySystemParam, System, SystemIn, SystemInput, SystemParam,
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SystemParamItem,
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},
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world::{unsafe_world_cell::UnsafeWorldCell, DeferredWorld, World, WorldId},
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};
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use alloc::{borrow::Cow, vec, vec::Vec};
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use core::marker::PhantomData;
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use variadics_please::all_tuples;
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#[cfg(feature = "trace")]
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use tracing::{info_span, Span};
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use super::{IntoSystem, ReadOnlySystem, SystemParamBuilder, SystemParamValidationError};
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/// The metadata of a [`System`].
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#[derive(Clone)]
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pub struct SystemMeta {
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pub(crate) name: Cow<'static, str>,
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/// The set of component accesses for this system. This is used to determine
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/// - soundness issues (e.g. multiple [`SystemParam`]s mutably accessing the same component)
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/// - ambiguities in the schedule (e.g. two systems that have some sort of conflicting access)
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pub(crate) component_access_set: FilteredAccessSet<ComponentId>,
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/// This [`Access`] is used to determine which systems can run in parallel with each other
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/// in the multithreaded executor.
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///
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/// We use a [`ArchetypeComponentId`] as it is more precise than just checking [`ComponentId`]:
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/// for example if you have one system with `Query<&mut T, With<A>>` and one system with `Query<&mut T, With<B>>`
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/// they conflict if you just look at the [`ComponentId`] of `T`; but if there are no archetypes with
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/// both `A`, `B` and `T` then in practice there's no risk of conflict. By using [`ArchetypeComponentId`]
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/// we can be more precise because we can check if the existing archetypes of the [`World`]
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/// cause a conflict
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pub(crate) archetype_component_access: Access<ArchetypeComponentId>,
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// NOTE: this must be kept private. making a SystemMeta non-send is irreversible to prevent
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// SystemParams from overriding each other
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is_send: bool,
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has_deferred: bool,
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pub(crate) last_run: Tick,
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#[cfg(feature = "trace")]
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pub(crate) system_span: Span,
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#[cfg(feature = "trace")]
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pub(crate) commands_span: Span,
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}
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impl SystemMeta {
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pub(crate) fn new<T>() -> Self {
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let name = core::any::type_name::<T>();
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Self {
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name: name.into(),
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archetype_component_access: Access::default(),
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component_access_set: FilteredAccessSet::default(),
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is_send: true,
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has_deferred: false,
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last_run: Tick::new(0),
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#[cfg(feature = "trace")]
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system_span: info_span!("system", name = name),
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#[cfg(feature = "trace")]
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commands_span: info_span!("system_commands", name = name),
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}
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}
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/// Returns the system's name
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#[inline]
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pub fn name(&self) -> &str {
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&self.name
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}
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/// Sets the name of this system.
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///
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/// Useful to give closure systems more readable and unique names for debugging and tracing.
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#[inline]
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pub fn set_name(&mut self, new_name: impl Into<Cow<'static, str>>) {
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let new_name: Cow<'static, str> = new_name.into();
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#[cfg(feature = "trace")]
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{
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let name = new_name.as_ref();
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self.system_span = info_span!("system", name = name);
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self.commands_span = info_span!("system_commands", name = name);
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}
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self.name = new_name;
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}
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/// Returns true if the system is [`Send`].
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#[inline]
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pub fn is_send(&self) -> bool {
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self.is_send
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}
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/// Sets the system to be not [`Send`].
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///
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/// This is irreversible.
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#[inline]
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pub fn set_non_send(&mut self) {
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self.is_send = false;
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}
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/// Returns true if the system has deferred [`SystemParam`]'s
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#[inline]
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pub fn has_deferred(&self) -> bool {
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self.has_deferred
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}
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/// Marks the system as having deferred buffers like [`Commands`](`super::Commands`)
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/// This lets the scheduler insert [`ApplyDeferred`](`crate::prelude::ApplyDeferred`) systems automatically.
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#[inline]
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pub fn set_has_deferred(&mut self) {
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self.has_deferred = true;
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}
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/// Archetype component access that is used to determine which systems can run in parallel with each other
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/// in the multithreaded executor.
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///
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/// We use an [`ArchetypeComponentId`] as it is more precise than just checking [`ComponentId`]:
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/// for example if you have one system with `Query<&mut A, With<B>`, and one system with `Query<&mut A, Without<B>`,
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/// they conflict if you just look at the [`ComponentId`];
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/// but no archetype that matches the first query will match the second and vice versa,
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/// which means there's no risk of conflict.
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#[inline]
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pub fn archetype_component_access(&self) -> &Access<ArchetypeComponentId> {
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&self.archetype_component_access
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}
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/// Returns a mutable reference to the [`Access`] for [`ArchetypeComponentId`].
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/// This is used to determine which systems can run in parallel with each other
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/// in the multithreaded executor.
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///
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/// We use an [`ArchetypeComponentId`] as it is more precise than just checking [`ComponentId`]:
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/// for example if you have one system with `Query<&mut A, With<B>`, and one system with `Query<&mut A, Without<B>`,
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/// they conflict if you just look at the [`ComponentId`];
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/// but no archetype that matches the first query will match the second and vice versa,
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/// which means there's no risk of conflict.
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///
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/// # Safety
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///
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/// No access can be removed from the returned [`Access`].
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#[inline]
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pub unsafe fn archetype_component_access_mut(&mut self) -> &mut Access<ArchetypeComponentId> {
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&mut self.archetype_component_access
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}
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/// Returns a reference to the [`FilteredAccessSet`] for [`ComponentId`].
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/// Used to check if systems and/or system params have conflicting access.
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#[inline]
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pub fn component_access_set(&self) -> &FilteredAccessSet<ComponentId> {
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&self.component_access_set
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}
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/// Returns a mutable reference to the [`FilteredAccessSet`] for [`ComponentId`].
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/// Used internally to statically check if systems have conflicting access.
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///
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/// # Safety
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///
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/// No access can be removed from the returned [`FilteredAccessSet`].
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#[inline]
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pub unsafe fn component_access_set_mut(&mut self) -> &mut FilteredAccessSet<ComponentId> {
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&mut self.component_access_set
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}
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}
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// TODO: Actually use this in FunctionSystem. We should probably only do this once Systems are constructed using a World reference
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// (to avoid the need for unwrapping to retrieve SystemMeta)
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/// Holds on to persistent state required to drive [`SystemParam`] for a [`System`].
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///
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/// This is a powerful and convenient tool for working with exclusive world access,
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/// allowing you to fetch data from the [`World`] as if you were running a [`System`].
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/// However, simply calling `world::run_system(my_system)` using a [`World::run_system`](World::run_system)
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/// can be significantly simpler and ensures that change detection and command flushing work as expected.
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///
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/// Borrow-checking is handled for you, allowing you to mutably access multiple compatible system parameters at once,
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/// and arbitrary system parameters (like [`EventWriter`](crate::event::EventWriter)) can be conveniently fetched.
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///
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/// For an alternative approach to split mutable access to the world, see [`World::resource_scope`].
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///
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/// # Warning
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///
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/// [`SystemState`] values created can be cached to improve performance,
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/// and *must* be cached and reused in order for system parameters that rely on local state to work correctly.
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/// These include:
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/// - [`Added`](crate::query::Added) and [`Changed`](crate::query::Changed) query filters
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/// - [`Local`](crate::system::Local) variables that hold state
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/// - [`EventReader`](crate::event::EventReader) system parameters, which rely on a [`Local`](crate::system::Local) to track which events have been seen
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///
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/// Note that this is automatically handled for you when using a [`World::run_system`](World::run_system).
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///
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/// # Example
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///
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/// Basic usage:
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/// ```
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/// # use bevy_ecs::prelude::*;
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/// # use bevy_ecs::system::SystemState;
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/// # use bevy_ecs::event::Events;
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/// #
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/// # #[derive(Event)]
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/// # struct MyEvent;
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/// # #[derive(Resource)]
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/// # struct MyResource(u32);
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/// #
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/// # #[derive(Component)]
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/// # struct MyComponent;
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/// #
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/// // Work directly on the `World`
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/// let mut world = World::new();
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/// world.init_resource::<Events<MyEvent>>();
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///
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/// // Construct a `SystemState` struct, passing in a tuple of `SystemParam`
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/// // as if you were writing an ordinary system.
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/// let mut system_state: SystemState<(
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/// EventWriter<MyEvent>,
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/// Option<ResMut<MyResource>>,
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/// Query<&MyComponent>,
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/// )> = SystemState::new(&mut world);
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///
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/// // Use system_state.get_mut(&mut world) and unpack your system parameters into variables!
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/// // system_state.get(&world) provides read-only versions of your system parameters instead.
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/// let (event_writer, maybe_resource, query) = system_state.get_mut(&mut world);
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///
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/// // If you are using `Commands`, you can choose when you want to apply them to the world.
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/// // You need to manually call `.apply(world)` on the `SystemState` to apply them.
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/// ```
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/// Caching:
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/// ```
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/// # use bevy_ecs::prelude::*;
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/// # use bevy_ecs::system::SystemState;
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/// # use bevy_ecs::event::Events;
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/// #
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/// # #[derive(Event)]
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/// # struct MyEvent;
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/// #[derive(Resource)]
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/// struct CachedSystemState {
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/// event_state: SystemState<EventReader<'static, 'static, MyEvent>>,
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/// }
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///
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/// // Create and store a system state once
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/// let mut world = World::new();
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/// world.init_resource::<Events<MyEvent>>();
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/// let initial_state: SystemState<EventReader<MyEvent>> = SystemState::new(&mut world);
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///
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/// // The system state is cached in a resource
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/// world.insert_resource(CachedSystemState {
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/// event_state: initial_state,
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/// });
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///
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/// // Later, fetch the cached system state, saving on overhead
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/// world.resource_scope(|world, mut cached_state: Mut<CachedSystemState>| {
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/// let mut event_reader = cached_state.event_state.get_mut(world);
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///
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/// for events in event_reader.read() {
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/// println!("Hello World!");
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/// }
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/// });
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/// ```
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pub struct SystemState<Param: SystemParam + 'static> {
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meta: SystemMeta,
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param_state: Param::State,
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world_id: WorldId,
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archetype_generation: ArchetypeGeneration,
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}
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// Allow closure arguments to be inferred.
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// For a closure to be used as a `SystemParamFunction`, it needs to be generic in any `'w` or `'s` lifetimes.
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// Rust will only infer a closure to be generic over lifetimes if it's passed to a function with a Fn constraint.
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// So, generate a function for each arity with an explicit `FnMut` constraint to enable higher-order lifetimes,
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// along with a regular `SystemParamFunction` constraint to allow the system to be built.
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macro_rules! impl_build_system {
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($(#[$meta:meta])* $($param: ident),*) => {
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$(#[$meta])*
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impl<$($param: SystemParam),*> SystemState<($($param,)*)> {
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/// Create a [`FunctionSystem`] from a [`SystemState`].
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/// This method signature allows type inference of closure parameters for a system with no input.
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/// You can use [`SystemState::build_system_with_input()`] if you have input, or [`SystemState::build_any_system()`] if you don't need type inference.
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pub fn build_system<
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Out: 'static,
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Marker,
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F: FnMut($(SystemParamItem<$param>),*) -> Out
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+ SystemParamFunction<Marker, Param = ($($param,)*), In = (), Out = Out>
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>
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(
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self,
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func: F,
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) -> FunctionSystem<Marker, F>
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{
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self.build_any_system(func)
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}
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/// Create a [`FunctionSystem`] from a [`SystemState`].
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/// This method signature allows type inference of closure parameters for a system with input.
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/// You can use [`SystemState::build_system()`] if you have no input, or [`SystemState::build_any_system()`] if you don't need type inference.
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pub fn build_system_with_input<
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Input: SystemInput,
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Out: 'static,
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Marker,
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F: FnMut(Input, $(SystemParamItem<$param>),*) -> Out
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+ SystemParamFunction<Marker, Param = ($($param,)*), In = Input, Out = Out>,
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>(
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self,
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func: F,
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) -> FunctionSystem<Marker, F> {
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self.build_any_system(func)
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}
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}
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}
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}
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all_tuples!(
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#[doc(fake_variadic)]
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impl_build_system,
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0,
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16,
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P
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);
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impl<Param: SystemParam> SystemState<Param> {
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/// Creates a new [`SystemState`] with default state.
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///
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/// ## Note
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/// For users of [`SystemState::get_manual`] or [`get_manual_mut`](SystemState::get_manual_mut):
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///
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/// `new` does not cache any of the world's archetypes, so you must call [`SystemState::update_archetypes`]
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/// manually before calling `get_manual{_mut}`.
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pub fn new(world: &mut World) -> Self {
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let mut meta = SystemMeta::new::<Param>();
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meta.last_run = world.change_tick().relative_to(Tick::MAX);
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let param_state = Param::init_state(world, &mut meta);
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Self {
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meta,
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param_state,
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world_id: world.id(),
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archetype_generation: ArchetypeGeneration::initial(),
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}
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}
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/// Create a [`SystemState`] from a [`SystemParamBuilder`]
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pub(crate) fn from_builder(world: &mut World, builder: impl SystemParamBuilder<Param>) -> Self {
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let mut meta = SystemMeta::new::<Param>();
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meta.last_run = world.change_tick().relative_to(Tick::MAX);
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let param_state = builder.build(world, &mut meta);
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Self {
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meta,
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param_state,
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world_id: world.id(),
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archetype_generation: ArchetypeGeneration::initial(),
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}
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}
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/// Create a [`FunctionSystem`] from a [`SystemState`].
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/// This method signature allows any system function, but the compiler will not perform type inference on closure parameters.
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/// You can use [`SystemState::build_system()`] or [`SystemState::build_system_with_input()`] to get type inference on parameters.
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pub fn build_any_system<Marker, F: SystemParamFunction<Marker, Param = Param>>(
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self,
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func: F,
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) -> FunctionSystem<Marker, F> {
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FunctionSystem {
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func,
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state: Some(FunctionSystemState {
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param: self.param_state,
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world_id: self.world_id,
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}),
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system_meta: self.meta,
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archetype_generation: self.archetype_generation,
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marker: PhantomData,
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}
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}
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/// Gets the metadata for this instance.
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#[inline]
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pub fn meta(&self) -> &SystemMeta {
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&self.meta
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}
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/// Gets the metadata for this instance.
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#[inline]
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pub fn meta_mut(&mut self) -> &mut SystemMeta {
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&mut self.meta
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}
|
|
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/// Retrieve the [`SystemParam`] values. This can only be called when all parameters are read-only.
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#[inline]
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pub fn get<'w, 's>(&'s mut self, world: &'w World) -> SystemParamItem<'w, 's, Param>
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where
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Param: ReadOnlySystemParam,
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{
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self.validate_world(world.id());
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self.update_archetypes(world);
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// SAFETY: Param is read-only and doesn't allow mutable access to World.
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// It also matches the World this SystemState was created with.
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unsafe { self.get_unchecked_manual(world.as_unsafe_world_cell_readonly()) }
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}
|
|
|
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/// Retrieve the mutable [`SystemParam`] values.
|
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#[inline]
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pub fn get_mut<'w, 's>(&'s mut self, world: &'w mut World) -> SystemParamItem<'w, 's, Param> {
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self.validate_world(world.id());
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self.update_archetypes(world);
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// SAFETY: World is uniquely borrowed and matches the World this SystemState was created with.
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unsafe { self.get_unchecked_manual(world.as_unsafe_world_cell()) }
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}
|
|
|
|
/// Applies all state queued up for [`SystemParam`] values. For example, this will apply commands queued up
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/// by a [`Commands`](`super::Commands`) parameter to the given [`World`].
|
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/// This function should be called manually after the values returned by [`SystemState::get`] and [`SystemState::get_mut`]
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/// are finished being used.
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pub fn apply(&mut self, world: &mut World) {
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Param::apply(&mut self.param_state, &self.meta, world);
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}
|
|
|
|
/// Wrapper over [`SystemParam::validate_param`].
|
|
///
|
|
/// # Safety
|
|
///
|
|
/// - The passed [`UnsafeWorldCell`] must have read-only access to
|
|
/// world data in `archetype_component_access`.
|
|
/// - `world` must be the same [`World`] that was used to initialize [`state`](SystemParam::init_state).
|
|
pub unsafe fn validate_param(
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|
state: &Self,
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|
world: UnsafeWorldCell,
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|
) -> Result<(), SystemParamValidationError> {
|
|
// SAFETY: Delegated to existing `SystemParam` implementations.
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unsafe { Param::validate_param(&state.param_state, &state.meta, world) }
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|
}
|
|
|
|
/// Returns `true` if `world_id` matches the [`World`] that was used to call [`SystemState::new`].
|
|
/// Otherwise, this returns false.
|
|
#[inline]
|
|
pub fn matches_world(&self, world_id: WorldId) -> bool {
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self.world_id == world_id
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|
}
|
|
|
|
/// Asserts that the [`SystemState`] matches the provided world.
|
|
#[inline]
|
|
#[track_caller]
|
|
fn validate_world(&self, world_id: WorldId) {
|
|
#[inline(never)]
|
|
#[track_caller]
|
|
#[cold]
|
|
fn panic_mismatched(this: WorldId, other: WorldId) -> ! {
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|
panic!("Encountered a mismatched World. This SystemState was created from {this:?}, but a method was called using {other:?}.");
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|
}
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|
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if !self.matches_world(world_id) {
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panic_mismatched(self.world_id, world_id);
|
|
}
|
|
}
|
|
|
|
/// Updates the state's internal view of the [`World`]'s archetypes. If this is not called before fetching the parameters,
|
|
/// the results may not accurately reflect what is in the `world`.
|
|
///
|
|
/// This is only required if [`SystemState::get_manual`] or [`SystemState::get_manual_mut`] is being called, and it only needs to
|
|
/// be called if the `world` has been structurally mutated (i.e. added/removed a component or resource). Users using
|
|
/// [`SystemState::get`] or [`SystemState::get_mut`] do not need to call this as it will be automatically called for them.
|
|
#[inline]
|
|
pub fn update_archetypes(&mut self, world: &World) {
|
|
self.update_archetypes_unsafe_world_cell(world.as_unsafe_world_cell_readonly());
|
|
}
|
|
|
|
/// Updates the state's internal view of the `world`'s archetypes. If this is not called before fetching the parameters,
|
|
/// the results may not accurately reflect what is in the `world`.
|
|
///
|
|
/// This is only required if [`SystemState::get_manual`] or [`SystemState::get_manual_mut`] is being called, and it only needs to
|
|
/// be called if the `world` has been structurally mutated (i.e. added/removed a component or resource). Users using
|
|
/// [`SystemState::get`] or [`SystemState::get_mut`] do not need to call this as it will be automatically called for them.
|
|
///
|
|
/// # Note
|
|
///
|
|
/// This method only accesses world metadata.
|
|
#[inline]
|
|
pub fn update_archetypes_unsafe_world_cell(&mut self, world: UnsafeWorldCell) {
|
|
assert_eq!(self.world_id, world.id(), "Encountered a mismatched World. A System cannot be used with Worlds other than the one it was initialized with.");
|
|
|
|
let archetypes = world.archetypes();
|
|
let old_generation =
|
|
core::mem::replace(&mut self.archetype_generation, archetypes.generation());
|
|
|
|
for archetype in &archetypes[old_generation..] {
|
|
// SAFETY: The assertion above ensures that the param_state was initialized from `world`.
|
|
unsafe { Param::new_archetype(&mut self.param_state, archetype, &mut self.meta) };
|
|
}
|
|
}
|
|
|
|
/// Retrieve the [`SystemParam`] values. This can only be called when all parameters are read-only.
|
|
/// This will not update the state's view of the world's archetypes automatically nor increment the
|
|
/// world's change tick.
|
|
///
|
|
/// For this to return accurate results, ensure [`SystemState::update_archetypes`] is called before this
|
|
/// function.
|
|
///
|
|
/// Users should strongly prefer to use [`SystemState::get`] over this function.
|
|
#[inline]
|
|
pub fn get_manual<'w, 's>(&'s mut self, world: &'w World) -> SystemParamItem<'w, 's, Param>
|
|
where
|
|
Param: ReadOnlySystemParam,
|
|
{
|
|
self.validate_world(world.id());
|
|
let change_tick = world.read_change_tick();
|
|
// SAFETY: Param is read-only and doesn't allow mutable access to World.
|
|
// It also matches the World this SystemState was created with.
|
|
unsafe { self.fetch(world.as_unsafe_world_cell_readonly(), change_tick) }
|
|
}
|
|
|
|
/// Retrieve the mutable [`SystemParam`] values. This will not update the state's view of the world's archetypes
|
|
/// automatically nor increment the world's change tick.
|
|
///
|
|
/// For this to return accurate results, ensure [`SystemState::update_archetypes`] is called before this
|
|
/// function.
|
|
///
|
|
/// Users should strongly prefer to use [`SystemState::get_mut`] over this function.
|
|
#[inline]
|
|
pub fn get_manual_mut<'w, 's>(
|
|
&'s mut self,
|
|
world: &'w mut World,
|
|
) -> SystemParamItem<'w, 's, Param> {
|
|
self.validate_world(world.id());
|
|
let change_tick = world.change_tick();
|
|
// SAFETY: World is uniquely borrowed and matches the World this SystemState was created with.
|
|
unsafe { self.fetch(world.as_unsafe_world_cell(), change_tick) }
|
|
}
|
|
|
|
/// Retrieve the [`SystemParam`] values. This will not update archetypes automatically.
|
|
///
|
|
/// # Safety
|
|
/// This call might access any of the input parameters in a way that violates Rust's mutability rules. Make sure the data
|
|
/// access is safe in the context of global [`World`] access. The passed-in [`World`] _must_ be the [`World`] the [`SystemState`] was
|
|
/// created with.
|
|
#[inline]
|
|
pub unsafe fn get_unchecked_manual<'w, 's>(
|
|
&'s mut self,
|
|
world: UnsafeWorldCell<'w>,
|
|
) -> SystemParamItem<'w, 's, Param> {
|
|
let change_tick = world.increment_change_tick();
|
|
// SAFETY: The invariants are upheld by the caller.
|
|
unsafe { self.fetch(world, change_tick) }
|
|
}
|
|
|
|
/// # Safety
|
|
/// This call might access any of the input parameters in a way that violates Rust's mutability rules. Make sure the data
|
|
/// access is safe in the context of global [`World`] access. The passed-in [`World`] _must_ be the [`World`] the [`SystemState`] was
|
|
/// created with.
|
|
#[inline]
|
|
unsafe fn fetch<'w, 's>(
|
|
&'s mut self,
|
|
world: UnsafeWorldCell<'w>,
|
|
change_tick: Tick,
|
|
) -> SystemParamItem<'w, 's, Param> {
|
|
// SAFETY: The invariants are upheld by the caller.
|
|
let param =
|
|
unsafe { Param::get_param(&mut self.param_state, &self.meta, world, change_tick) };
|
|
self.meta.last_run = change_tick;
|
|
param
|
|
}
|
|
|
|
/// Returns a reference to the current system param states.
|
|
pub fn param_state(&self) -> &Param::State {
|
|
&self.param_state
|
|
}
|
|
|
|
/// Returns a mutable reference to the current system param states.
|
|
/// Marked as unsafe because modifying the system states may result in violation to certain
|
|
/// assumptions made by the [`SystemParam`]. Use with care.
|
|
///
|
|
/// # Safety
|
|
/// Modifying the system param states may have unintended consequences.
|
|
/// The param state is generally considered to be owned by the [`SystemParam`]. Modifications
|
|
/// should respect any invariants as required by the [`SystemParam`].
|
|
/// For example, modifying the system state of [`ResMut`](crate::system::ResMut) without also
|
|
/// updating [`SystemMeta::component_access_set`] will obviously create issues.
|
|
pub unsafe fn param_state_mut(&mut self) -> &mut Param::State {
|
|
&mut self.param_state
|
|
}
|
|
}
|
|
|
|
impl<Param: SystemParam> FromWorld for SystemState<Param> {
|
|
fn from_world(world: &mut World) -> Self {
|
|
Self::new(world)
|
|
}
|
|
}
|
|
|
|
/// The [`System`] counter part of an ordinary function.
|
|
///
|
|
/// You get this by calling [`IntoSystem::into_system`] on a function that only accepts
|
|
/// [`SystemParam`]s. The output of the system becomes the functions return type, while the input
|
|
/// becomes the functions first parameter or `()` if no such parameter exists.
|
|
///
|
|
/// [`FunctionSystem`] must be `.initialized` before they can be run.
|
|
///
|
|
/// The [`Clone`] implementation for [`FunctionSystem`] returns a new instance which
|
|
/// is NOT initialized. The cloned system must also be `.initialized` before it can be run.
|
|
pub struct FunctionSystem<Marker, F>
|
|
where
|
|
F: SystemParamFunction<Marker>,
|
|
{
|
|
func: F,
|
|
state: Option<FunctionSystemState<F::Param>>,
|
|
system_meta: SystemMeta,
|
|
archetype_generation: ArchetypeGeneration,
|
|
// NOTE: PhantomData<fn()-> T> gives this safe Send/Sync impls
|
|
marker: PhantomData<fn() -> Marker>,
|
|
}
|
|
|
|
/// The state of a [`FunctionSystem`], which must be initialized with
|
|
/// [`System::initialize`] before the system can be run. A panic will occur if
|
|
/// the system is run without being initialized.
|
|
struct FunctionSystemState<P: SystemParam> {
|
|
/// The cached state of the system's [`SystemParam`]s.
|
|
param: P::State,
|
|
/// The id of the [`World`] this system was initialized with. If the world
|
|
/// passed to [`System::update_archetype_component_access`] does not match
|
|
/// this id, a panic will occur.
|
|
world_id: WorldId,
|
|
}
|
|
|
|
impl<Marker, F> FunctionSystem<Marker, F>
|
|
where
|
|
F: SystemParamFunction<Marker>,
|
|
{
|
|
/// Return this system with a new name.
|
|
///
|
|
/// Useful to give closure systems more readable and unique names for debugging and tracing.
|
|
pub fn with_name(mut self, new_name: impl Into<Cow<'static, str>>) -> Self {
|
|
self.system_meta.set_name(new_name.into());
|
|
self
|
|
}
|
|
}
|
|
|
|
// De-initializes the cloned system.
|
|
impl<Marker, F> Clone for FunctionSystem<Marker, F>
|
|
where
|
|
F: SystemParamFunction<Marker> + Clone,
|
|
{
|
|
fn clone(&self) -> Self {
|
|
Self {
|
|
func: self.func.clone(),
|
|
state: None,
|
|
system_meta: SystemMeta::new::<F>(),
|
|
archetype_generation: ArchetypeGeneration::initial(),
|
|
marker: PhantomData,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// A marker type used to distinguish regular function systems from exclusive function systems.
|
|
#[doc(hidden)]
|
|
pub struct IsFunctionSystem;
|
|
|
|
impl<Marker, F> IntoSystem<F::In, F::Out, (IsFunctionSystem, Marker)> for F
|
|
where
|
|
Marker: 'static,
|
|
F: SystemParamFunction<Marker>,
|
|
{
|
|
type System = FunctionSystem<Marker, F>;
|
|
fn into_system(func: Self) -> Self::System {
|
|
FunctionSystem {
|
|
func,
|
|
state: None,
|
|
system_meta: SystemMeta::new::<F>(),
|
|
archetype_generation: ArchetypeGeneration::initial(),
|
|
marker: PhantomData,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<Marker, F> FunctionSystem<Marker, F>
|
|
where
|
|
F: SystemParamFunction<Marker>,
|
|
{
|
|
/// Message shown when a system isn't initialized
|
|
// When lines get too long, rustfmt can sometimes refuse to format them.
|
|
// Work around this by storing the message separately.
|
|
const ERROR_UNINITIALIZED: &'static str =
|
|
"System's state was not found. Did you forget to initialize this system before running it?";
|
|
}
|
|
|
|
impl<Marker, F> System for FunctionSystem<Marker, F>
|
|
where
|
|
Marker: 'static,
|
|
F: SystemParamFunction<Marker>,
|
|
{
|
|
type In = F::In;
|
|
type Out = F::Out;
|
|
|
|
#[inline]
|
|
fn name(&self) -> Cow<'static, str> {
|
|
self.system_meta.name.clone()
|
|
}
|
|
|
|
#[inline]
|
|
fn component_access(&self) -> &Access<ComponentId> {
|
|
self.system_meta.component_access_set.combined_access()
|
|
}
|
|
|
|
#[inline]
|
|
fn archetype_component_access(&self) -> &Access<ArchetypeComponentId> {
|
|
&self.system_meta.archetype_component_access
|
|
}
|
|
|
|
#[inline]
|
|
fn is_send(&self) -> bool {
|
|
self.system_meta.is_send
|
|
}
|
|
|
|
#[inline]
|
|
fn is_exclusive(&self) -> bool {
|
|
false
|
|
}
|
|
|
|
#[inline]
|
|
fn has_deferred(&self) -> bool {
|
|
self.system_meta.has_deferred
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn run_unsafe(
|
|
&mut self,
|
|
input: SystemIn<'_, Self>,
|
|
world: UnsafeWorldCell,
|
|
) -> Self::Out {
|
|
#[cfg(feature = "trace")]
|
|
let _span_guard = self.system_meta.system_span.enter();
|
|
|
|
let change_tick = world.increment_change_tick();
|
|
|
|
let param_state = &mut self.state.as_mut().expect(Self::ERROR_UNINITIALIZED).param;
|
|
// SAFETY:
|
|
// - The caller has invoked `update_archetype_component_access`, which will panic
|
|
// if the world does not match.
|
|
// - All world accesses used by `F::Param` have been registered, so the caller
|
|
// will ensure that there are no data access conflicts.
|
|
let params =
|
|
unsafe { F::Param::get_param(param_state, &self.system_meta, world, change_tick) };
|
|
let out = self.func.run(input, params);
|
|
self.system_meta.last_run = change_tick;
|
|
out
|
|
}
|
|
|
|
#[inline]
|
|
fn apply_deferred(&mut self, world: &mut World) {
|
|
let param_state = &mut self.state.as_mut().expect(Self::ERROR_UNINITIALIZED).param;
|
|
F::Param::apply(param_state, &self.system_meta, world);
|
|
}
|
|
|
|
#[inline]
|
|
fn queue_deferred(&mut self, world: DeferredWorld) {
|
|
let param_state = &mut self.state.as_mut().expect(Self::ERROR_UNINITIALIZED).param;
|
|
F::Param::queue(param_state, &self.system_meta, world);
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn validate_param_unsafe(
|
|
&mut self,
|
|
world: UnsafeWorldCell,
|
|
) -> Result<(), SystemParamValidationError> {
|
|
let param_state = &self.state.as_ref().expect(Self::ERROR_UNINITIALIZED).param;
|
|
// SAFETY:
|
|
// - The caller has invoked `update_archetype_component_access`, which will panic
|
|
// if the world does not match.
|
|
// - All world accesses used by `F::Param` have been registered, so the caller
|
|
// will ensure that there are no data access conflicts.
|
|
unsafe { F::Param::validate_param(param_state, &self.system_meta, world) }
|
|
}
|
|
|
|
#[inline]
|
|
fn initialize(&mut self, world: &mut World) {
|
|
if let Some(state) = &self.state {
|
|
assert_eq!(
|
|
state.world_id,
|
|
world.id(),
|
|
"System built with a different world than the one it was added to.",
|
|
);
|
|
} else {
|
|
self.state = Some(FunctionSystemState {
|
|
param: F::Param::init_state(world, &mut self.system_meta),
|
|
world_id: world.id(),
|
|
});
|
|
}
|
|
self.system_meta.last_run = world.change_tick().relative_to(Tick::MAX);
|
|
}
|
|
|
|
fn update_archetype_component_access(&mut self, world: UnsafeWorldCell) {
|
|
let state = self.state.as_mut().expect(Self::ERROR_UNINITIALIZED);
|
|
assert_eq!(state.world_id, world.id(), "Encountered a mismatched World. A System cannot be used with Worlds other than the one it was initialized with.");
|
|
|
|
let archetypes = world.archetypes();
|
|
let old_generation =
|
|
core::mem::replace(&mut self.archetype_generation, archetypes.generation());
|
|
|
|
for archetype in &archetypes[old_generation..] {
|
|
// SAFETY: The assertion above ensures that the param_state was initialized from `world`.
|
|
unsafe { F::Param::new_archetype(&mut state.param, archetype, &mut self.system_meta) };
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn check_change_tick(&mut self, change_tick: Tick) {
|
|
check_system_change_tick(
|
|
&mut self.system_meta.last_run,
|
|
change_tick,
|
|
self.system_meta.name.as_ref(),
|
|
);
|
|
}
|
|
|
|
fn default_system_sets(&self) -> Vec<InternedSystemSet> {
|
|
let set = crate::schedule::SystemTypeSet::<Self>::new();
|
|
vec![set.intern()]
|
|
}
|
|
|
|
fn get_last_run(&self) -> Tick {
|
|
self.system_meta.last_run
|
|
}
|
|
|
|
fn set_last_run(&mut self, last_run: Tick) {
|
|
self.system_meta.last_run = last_run;
|
|
}
|
|
}
|
|
|
|
/// SAFETY: `F`'s param is [`ReadOnlySystemParam`], so this system will only read from the world.
|
|
unsafe impl<Marker, F> ReadOnlySystem for FunctionSystem<Marker, F>
|
|
where
|
|
Marker: 'static,
|
|
F: SystemParamFunction<Marker>,
|
|
F::Param: ReadOnlySystemParam,
|
|
{
|
|
}
|
|
|
|
/// A trait implemented for all functions that can be used as [`System`]s.
|
|
///
|
|
/// This trait can be useful for making your own systems which accept other systems,
|
|
/// sometimes called higher order systems.
|
|
///
|
|
/// This should be used in combination with [`ParamSet`] when calling other systems
|
|
/// within your system.
|
|
/// Using [`ParamSet`] in this case avoids [`SystemParam`] collisions.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// To create something like [`PipeSystem`], but in entirely safe code.
|
|
///
|
|
/// ```
|
|
/// use std::num::ParseIntError;
|
|
///
|
|
/// use bevy_ecs::prelude::*;
|
|
/// use bevy_ecs::system::StaticSystemInput;
|
|
///
|
|
/// /// Pipe creates a new system which calls `a`, then calls `b` with the output of `a`
|
|
/// pub fn pipe<A, B, AMarker, BMarker>(
|
|
/// mut a: A,
|
|
/// mut b: B,
|
|
/// ) -> impl FnMut(StaticSystemInput<A::In>, ParamSet<(A::Param, B::Param)>) -> B::Out
|
|
/// where
|
|
/// // We need A and B to be systems, add those bounds
|
|
/// A: SystemParamFunction<AMarker>,
|
|
/// B: SystemParamFunction<BMarker>,
|
|
/// for<'a> B::In: SystemInput<Inner<'a> = A::Out>,
|
|
/// {
|
|
/// // The type of `params` is inferred based on the return of this function above
|
|
/// move |StaticSystemInput(a_in), mut params| {
|
|
/// let shared = a.run(a_in, params.p0());
|
|
/// b.run(shared, params.p1())
|
|
/// }
|
|
/// }
|
|
///
|
|
/// // Usage example for `pipe`:
|
|
/// fn main() {
|
|
/// let mut world = World::default();
|
|
/// world.insert_resource(Message("42".to_string()));
|
|
///
|
|
/// // pipe the `parse_message_system`'s output into the `filter_system`s input
|
|
/// let mut piped_system = IntoSystem::into_system(pipe(parse_message, filter));
|
|
/// piped_system.initialize(&mut world);
|
|
/// assert_eq!(piped_system.run((), &mut world), Some(42));
|
|
/// }
|
|
///
|
|
/// #[derive(Resource)]
|
|
/// struct Message(String);
|
|
///
|
|
/// fn parse_message(message: Res<Message>) -> Result<usize, ParseIntError> {
|
|
/// message.0.parse::<usize>()
|
|
/// }
|
|
///
|
|
/// fn filter(In(result): In<Result<usize, ParseIntError>>) -> Option<usize> {
|
|
/// result.ok().filter(|&n| n < 100)
|
|
/// }
|
|
/// ```
|
|
/// [`PipeSystem`]: crate::system::PipeSystem
|
|
/// [`ParamSet`]: crate::system::ParamSet
|
|
#[diagnostic::on_unimplemented(
|
|
message = "`{Self}` is not a valid system",
|
|
label = "invalid system"
|
|
)]
|
|
pub trait SystemParamFunction<Marker>: Send + Sync + 'static {
|
|
/// The input type of this system. See [`System::In`].
|
|
type In: SystemInput;
|
|
/// The return type of this system. See [`System::Out`].
|
|
type Out;
|
|
|
|
/// The [`SystemParam`]/s used by this system to access the [`World`].
|
|
type Param: SystemParam;
|
|
|
|
/// Executes this system once. See [`System::run`] or [`System::run_unsafe`].
|
|
fn run(
|
|
&mut self,
|
|
input: <Self::In as SystemInput>::Inner<'_>,
|
|
param_value: SystemParamItem<Self::Param>,
|
|
) -> Self::Out;
|
|
}
|
|
|
|
/// A marker type used to distinguish function systems with and without input.
|
|
#[doc(hidden)]
|
|
pub struct HasSystemInput;
|
|
|
|
macro_rules! impl_system_function {
|
|
($($param: ident),*) => {
|
|
#[expect(
|
|
clippy::allow_attributes,
|
|
reason = "This is within a macro, and as such, the below lints may not always apply."
|
|
)]
|
|
#[allow(
|
|
non_snake_case,
|
|
reason = "Certain variable names are provided by the caller, not by us."
|
|
)]
|
|
impl<Out, Func, $($param: SystemParam),*> SystemParamFunction<fn($($param,)*) -> Out> for Func
|
|
where
|
|
Func: Send + Sync + 'static,
|
|
for <'a> &'a mut Func:
|
|
FnMut($($param),*) -> Out +
|
|
FnMut($(SystemParamItem<$param>),*) -> Out,
|
|
Out: 'static
|
|
{
|
|
type In = ();
|
|
type Out = Out;
|
|
type Param = ($($param,)*);
|
|
#[inline]
|
|
fn run(&mut self, _input: (), param_value: SystemParamItem< ($($param,)*)>) -> Out {
|
|
// Yes, this is strange, but `rustc` fails to compile this impl
|
|
// without using this function. It fails to recognize that `func`
|
|
// is a function, potentially because of the multiple impls of `FnMut`
|
|
fn call_inner<Out, $($param,)*>(
|
|
mut f: impl FnMut($($param,)*)->Out,
|
|
$($param: $param,)*
|
|
)->Out{
|
|
f($($param,)*)
|
|
}
|
|
let ($($param,)*) = param_value;
|
|
call_inner(self, $($param),*)
|
|
}
|
|
}
|
|
|
|
#[expect(
|
|
clippy::allow_attributes,
|
|
reason = "This is within a macro, and as such, the below lints may not always apply."
|
|
)]
|
|
#[allow(
|
|
non_snake_case,
|
|
reason = "Certain variable names are provided by the caller, not by us."
|
|
)]
|
|
impl<In, Out, Func, $($param: SystemParam),*> SystemParamFunction<(HasSystemInput, fn(In, $($param,)*) -> Out)> for Func
|
|
where
|
|
Func: Send + Sync + 'static,
|
|
for <'a> &'a mut Func:
|
|
FnMut(In, $($param),*) -> Out +
|
|
FnMut(In::Param<'_>, $(SystemParamItem<$param>),*) -> Out,
|
|
In: SystemInput + 'static,
|
|
Out: 'static
|
|
{
|
|
type In = In;
|
|
type Out = Out;
|
|
type Param = ($($param,)*);
|
|
#[inline]
|
|
fn run(&mut self, input: In::Inner<'_>, param_value: SystemParamItem< ($($param,)*)>) -> Out {
|
|
fn call_inner<In: SystemInput, Out, $($param,)*>(
|
|
mut f: impl FnMut(In::Param<'_>, $($param,)*)->Out,
|
|
input: In::Inner<'_>,
|
|
$($param: $param,)*
|
|
)->Out{
|
|
f(In::wrap(input), $($param,)*)
|
|
}
|
|
let ($($param,)*) = param_value;
|
|
call_inner(self, input, $($param),*)
|
|
}
|
|
}
|
|
};
|
|
}
|
|
|
|
// Note that we rely on the highest impl to be <= the highest order of the tuple impls
|
|
// of `SystemParam` created.
|
|
all_tuples!(impl_system_function, 0, 16, F);
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
|
|
#[test]
|
|
fn into_system_type_id_consistency() {
|
|
fn test<T, In: SystemInput, Out, Marker>(function: T)
|
|
where
|
|
T: IntoSystem<In, Out, Marker> + Copy,
|
|
{
|
|
fn reference_system() {}
|
|
|
|
use core::any::TypeId;
|
|
|
|
let system = IntoSystem::into_system(function);
|
|
|
|
assert_eq!(
|
|
system.type_id(),
|
|
function.system_type_id(),
|
|
"System::type_id should be consistent with IntoSystem::system_type_id"
|
|
);
|
|
|
|
assert_eq!(
|
|
system.type_id(),
|
|
TypeId::of::<T::System>(),
|
|
"System::type_id should be consistent with TypeId::of::<T::System>()"
|
|
);
|
|
|
|
assert_ne!(
|
|
system.type_id(),
|
|
IntoSystem::into_system(reference_system).type_id(),
|
|
"Different systems should have different TypeIds"
|
|
);
|
|
}
|
|
|
|
fn function_system() {}
|
|
|
|
test(function_system);
|
|
}
|
|
}
|