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use std::{collections::HashMap, fmt::Debug, hash::Hash};
#[cfg(feature = "parallel")]
use hecs::World;
use crate::{
DerefTuple, Executor, Fetch, QueryBundle, ResourceTuple, SystemClosure, SystemContext,
WrappedResources,
};
#[cfg(feature = "parallel")]
use crate::{ArchetypeSet, ComponentTypeSet, ResourceSet, TypeSet};
#[derive(Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
pub struct SystemId(usize);
pub struct System<'closure, Resources>
where
Resources: ResourceTuple + 'closure,
{
pub closure: Box<SystemClosure<'closure, Resources::Cells>>,
pub dependencies: Vec<SystemId>,
#[cfg(feature = "parallel")]
pub resource_set: ResourceSet,
#[cfg(feature = "parallel")]
pub component_type_set: ComponentTypeSet,
#[cfg(feature = "parallel")]
pub archetype_writer: Box<dyn Fn(&World, &mut ArchetypeSet) + Send>,
}
/// A factory for [`Executor`](struct.Executor.html) (and the only way of creating one).
pub struct ExecutorBuilder<'closures, Resources, Handle = DummyHandle>
where
Resources: ResourceTuple,
{
pub(crate) systems: HashMap<SystemId, System<'closures, Resources>>,
pub(crate) handles: HashMap<Handle, SystemId>,
#[cfg(feature = "parallel")]
pub(crate) all_component_types: TypeSet,
}
impl<'closures, Resources, Handle> ExecutorBuilder<'closures, Resources, Handle>
where
Resources: ResourceTuple,
Handle: Eq + Hash,
{
fn box_system<'a, Closure, ResourceRefs, Queries, Markers>(
mut closure: Closure,
) -> System<'closures, Resources>
where
Resources::Cells: 'a,
Closure: FnMut(SystemContext<'a>, ResourceRefs, Queries) + Send + Sync + 'closures,
ResourceRefs: Fetch<'a, WrappedResources<'a, Resources::Cells>, Markers> + 'a,
Queries: QueryBundle,
{
let closure = Box::new(
move |context: SystemContext<'a>, resources: &'a WrappedResources<Resources::Cells>| {
let mut fetched = ResourceRefs::fetch(resources);
closure(context, unsafe { fetched.deref() }, Queries::markers());
ResourceRefs::release(resources, fetched);
},
);
let closure = unsafe {
std::mem::transmute::<
Box<dyn FnMut(_, &'a _) + Send + Sync + 'closures>,
Box<
dyn FnMut(SystemContext, &WrappedResources<Resources::Cells>)
+ Send
+ Sync
+ 'closures,
>,
>(closure)
};
#[cfg(feature = "parallel")]
{
let mut resource_set = ResourceSet::with_capacity(Resources::LENGTH);
ResourceRefs::set_resource_bits(&mut resource_set);
let mut component_type_set =
ComponentTypeSet::with_capacity(Queries::COMPONENT_TYPE_SET_LENGTH);
Queries::insert_component_types(&mut component_type_set);
let archetype_writer = Box::new(|world: &World, archetype_set: &mut ArchetypeSet| {
Queries::set_archetype_bits(world, archetype_set)
});
System {
closure,
dependencies: vec![],
resource_set,
component_type_set,
archetype_writer,
}
}
#[cfg(not(feature = "parallel"))]
System {
closure,
dependencies: vec![],
}
}
/// Creates a new system from a closure or a function, and inserts it into the builder.
///
/// The system-to-be must return nothing and have these 3 arguments:
/// - [`SystemContext`](struct.SystemContext.html),
/// - any tuple (up to 16) or a single one of "resources": references or mutable references
/// to `Send + Sync` values not contained in a [`hecs::World`](../hecs/struct.World.html)
/// that the system will be accessing,
/// - any tuple (up to 16) or a single one of [`QueryMarker`](struct.QueryMarker.html) that
/// represent the queries the system will be making.
///
/// Additionally, closures may mutably borrow from their environment for the lifetime
/// of the executor, but must be `Send + Sync`.
///
/// All resources the system requires must correspond to a type in the executor's
/// signature; e.g., if any number of systems require a `&f32` or a `&mut f32`,
/// executor's generic parameter must contain `f32`.
///
/// # Example
/// ```rust
/// # use yaks::{QueryMarker, SystemContext, Executor};
/// # let world = hecs::World::new();
/// # struct A;
/// # struct B;
/// # struct C;
/// fn system_0(
/// context: SystemContext,
/// res_a: &A,
/// (query_0, query_1): (
/// QueryMarker<(&B, &mut C)>,
/// QueryMarker<hecs::Without<B, &C>>
/// ),
/// ) {
/// // This system may read resource of type `A`, and may prepare & execute queries
/// // of `(&B, &mut C)` and `hecs::Without<B, &C>`.
/// }
///
/// fn system_1(
/// context: SystemContext,
/// (res_a, res_b): (&mut A, &B),
/// query_0: QueryMarker<(&mut B, &mut C)>,
/// ) {
/// // This system may read or write resource of type `A`, may read resource of type `B`,
/// // and may prepare & execute queries of `(&mut B, &mut C)`.
/// }
///
/// let mut increment = 0;
/// // All together, systems require resources of types `A`, `B`, and `C`.
/// let mut executor = Executor::<(A, B, C)>::builder()
/// .system(system_0)
/// .system(system_1)
/// .system(|context, res_c: &C, _queries: ()| {
/// // This system may read resource of type `C` and will not perform any queries.
/// increment += 1; // `increment` will be borrowed by the executor.
/// })
/// .build();
/// let (mut a, mut b, mut c) = (A, B, C);
/// executor.run(&world, (&mut a, &mut b, &mut c));
/// executor.run(&world, (&mut a, &mut b, &mut c));
/// executor.run(&world, (&mut a, &mut b, &mut c));
/// drop(executor); // This releases the borrow of `increment`.
/// assert_eq!(increment, 3);
/// ```
pub fn system<'a, Closure, ResourceRefs, Queries, Markers>(mut self, closure: Closure) -> Self
where
Resources::Cells: 'a,
Closure: FnMut(SystemContext<'a>, ResourceRefs, Queries) + Send + Sync + 'closures,
ResourceRefs: Fetch<'a, WrappedResources<'a, Resources::Cells>, Markers> + 'a,
Queries: QueryBundle,
{
let id = SystemId(self.systems.len());
let system = Self::box_system::<'a, Closure, ResourceRefs, Queries, Markers>(closure);
#[cfg(feature = "parallel")]
{
self.all_component_types
.extend(&system.component_type_set.immutable);
self.all_component_types
.extend(&system.component_type_set.mutable);
}
self.systems.insert(id, system);
self
}
/// Creates a new system from a closure or a function, and inserts it into
/// the builder with given handle; see [`::system()`](#method.system).
///
/// Handles allow defining relative order of execution between systems,
/// and using them is optional. They can be of any type that is `Sized + Eq + Hash + Debug`
/// and do not persist after [`::build()`](struct.ExecutorBuilder.html#method.build) - the
/// resulting executor relies on lightweight opaque IDs;
/// see [`SystemContext::id()`](struct.SystemContext.html#method.id).
///
/// Handles must be unique, and systems with dependencies must be inserted
/// into the builder after said dependencies.
/// If the default `parallel` feature is disabled the systems will be executed in insertion
/// order, which these rules guarantee to be a valid order.
///
/// Since specifying a dependency between systems forbids them to run concurrently, this
/// functionality should be used only when necessary. In fact, for executors where systems
/// form a single chain of execution it is more performant to call them as functions,
/// in a sequence, inside a single [`rayon::scope()`](../rayon/fn.scope.html) or
/// [`rayon::ThreadPool::install()`](../rayon/struct.ThreadPool.html#method.install) block.
///
/// # Examples
/// These two executors are identical.
/// ```rust
/// # use yaks::{QueryMarker, SystemContext, Executor};
/// # let world = hecs::World::new();
/// # fn system_0(_: SystemContext, _: (), _: ()) {}
/// # fn system_1(_: SystemContext, _: (), _: ()) {}
/// # fn system_2(_: SystemContext, _: (), _: ()) {}
/// # fn system_3(_: SystemContext, _: (), _: ()) {}
/// # fn system_4(_: SystemContext, _: (), _: ()) {}
/// let _ = Executor::<()>::builder()
/// .system_with_handle(system_0, 0)
/// .system_with_handle(system_1, 1)
/// .system_with_handle_and_deps(system_2, 2, vec![0, 1])
/// .system_with_deps(system_3, vec![2])
/// .system_with_deps(system_4, vec![0])
/// .build();
/// let _ = Executor::<()>::builder()
/// .system_with_handle(system_0, "system_0")
/// .system_with_handle(system_1, "system_1")
/// .system_with_handle_and_deps(system_2, "system_2", vec!["system_1", "system_0"])
/// .system_with_deps(system_3, vec!["system_2"])
/// .system_with_deps(system_4, vec!["system_0"])
/// .build();
/// ```
/// The order of execution (with the default `parallel` feature enabled) is:
/// - systems 0 ***and*** 1,
/// - system 4 as soon as 0 is finished ***and*** system 2 as soon as both 0 and 1 is finished,
/// - system 3 as soon as 2 is finished.
///
/// This executor will behave identically to the two above if the default `parallel`
/// feature is enabled; otherwise, the execution order will be different, but
/// that doesn't matter as long as the given dependencies truthfully reflect any
/// relationships the systems may have.
/// ```rust
/// # use yaks::{QueryMarker, SystemContext, Executor};
/// # let world = hecs::World::new();
/// # fn system_0(_: SystemContext, _: (), _: ()) {}
/// # fn system_1(_: SystemContext, _: (), _: ()) {}
/// # fn system_2(_: SystemContext, _: (), _: ()) {}
/// # fn system_3(_: SystemContext, _: (), _: ()) {}
/// # fn system_4(_: SystemContext, _: (), _: ()) {}
/// let _ = Executor::<()>::builder()
/// .system_with_handle(system_1, 1)
/// .system_with_handle(system_0, 0)
/// .system_with_deps(system_4, vec![0])
/// .system_with_handle_and_deps(system_2, 2, vec![0, 1])
/// .system_with_deps(system_3, vec![2])
/// .build();
/// ```
///
/// # Panics
/// This function will panic if:
/// - a system with given handle is already present in the builder.
pub fn system_with_handle<'a, Closure, ResourceRefs, Queries, Markers, NewHandle>(
mut self,
closure: Closure,
handle: NewHandle,
) -> ExecutorBuilder<'closures, Resources, NewHandle>
where
Resources::Cells: 'a,
Closure: FnMut(SystemContext<'a>, ResourceRefs, Queries) + Send + Sync + 'closures,
ResourceRefs: Fetch<'a, WrappedResources<'a, Resources::Cells>, Markers> + 'a,
Queries: QueryBundle,
NewHandle: HandleConversion<Handle> + Debug,
{
let mut handles = NewHandle::convert_hash_map(self.handles);
if handles.contains_key(&handle) {
panic!("system {:?} already exists", handle);
}
let id = SystemId(self.systems.len());
let system = Self::box_system::<'a, Closure, ResourceRefs, Queries, Markers>(closure);
#[cfg(feature = "parallel")]
{
self.all_component_types
.extend(&system.component_type_set.immutable);
self.all_component_types
.extend(&system.component_type_set.mutable);
}
self.systems.insert(id, system);
handles.insert(handle, id);
ExecutorBuilder {
systems: self.systems,
handles,
#[cfg(feature = "parallel")]
all_component_types: self.all_component_types,
}
}
/// Creates a new system from a closure or a function, and inserts it into
/// the builder with given dependencies; see [`::system()`](#method.system).
///
/// Given system will start running only after all systems in given list of dependencies
/// have finished running.
///
/// This function cannot be used unless the builder already has
/// at least one system with a handle;
/// see [`::system_with_handle()`](#method.system_with_handle).
///
/// # Panics
/// This function will panic if:
/// - given list of dependencies contains a handle that
/// doesn't correspond to any system in the builder.
pub fn system_with_deps<'a, Closure, ResourceRefs, Queries, Markers>(
mut self,
closure: Closure,
dependencies: Vec<Handle>,
) -> Self
where
Resources::Cells: 'a,
Closure: FnMut(SystemContext<'a>, ResourceRefs, Queries) + Send + Sync + 'closures,
ResourceRefs: Fetch<'a, WrappedResources<'a, Resources::Cells>, Markers> + 'a,
Queries: QueryBundle,
Handle: Eq + Hash + Debug,
{
let id = SystemId(self.systems.len());
let mut system = Self::box_system::<'a, Closure, ResourceRefs, Queries, Markers>(closure);
#[cfg(feature = "parallel")]
{
self.all_component_types
.extend(&system.component_type_set.immutable);
self.all_component_types
.extend(&system.component_type_set.mutable);
}
system
.dependencies
.extend(dependencies.iter().map(|dep_handle| {
*self.handles.get(dep_handle).unwrap_or_else(|| {
panic!(
"could not resolve dependencies of a handle-less system: no system {:?} found",
dep_handle
)
})
}));
self.systems.insert(id, system);
self
}
/// Creates a new system from a closure or a function, and inserts it into
/// the builder with given handle and dependencies; see [`::system()`](#method.system).
///
/// Given system will start running only after all systems in given list of dependencies
/// have finished running.
///
/// This function cannot be used unless the builder already has
/// at least one system with a handle;
/// see [`::system_with_handle()`](#method.system_with_handle).
///
/// # Panics
/// This function will panic if:
/// - a system with given handle is already present in the builder,
/// - given list of dependencies contains a handle that
/// doesn't correspond to any system in the builder,
/// - given handle appears in given list of dependencies.
pub fn system_with_handle_and_deps<'a, Closure, ResourceRefs, Queries, Markers>(
mut self,
closure: Closure,
handle: Handle,
dependencies: Vec<Handle>,
) -> Self
where
Resources::Cells: 'a,
Closure: FnMut(SystemContext<'a>, ResourceRefs, Queries) + Send + Sync + 'closures,
ResourceRefs: Fetch<'a, WrappedResources<'a, Resources::Cells>, Markers> + 'a,
Queries: QueryBundle,
Handle: Eq + Hash + Debug,
{
if self.handles.contains_key(&handle) {
panic!("system {:?} already exists", handle);
}
if dependencies.contains(&handle) {
panic!("system {:?} depends on itself", handle);
}
let id = SystemId(self.systems.len());
let mut system = Self::box_system::<'a, Closure, ResourceRefs, Queries, Markers>(closure);
#[cfg(feature = "parallel")]
{
self.all_component_types
.extend(&system.component_type_set.immutable);
self.all_component_types
.extend(&system.component_type_set.mutable);
}
system
.dependencies
.extend(dependencies.iter().map(|dep_handle| {
*self.handles.get(dep_handle).unwrap_or_else(|| {
panic!(
"could not resolve dependencies of system {:?}: no system {:?} found",
handle, dep_handle
)
})
}));
self.systems.insert(id, system);
self.handles.insert(handle, id);
self
}
/// Consumes the builder and returns the finalized executor.
pub fn build(self) -> Executor<'closures, Resources> {
Executor::build(self)
}
}
#[derive(PartialEq, Eq, Hash)]
pub struct DummyHandle;
pub trait HandleConversion<T>: Sized + Eq + Hash {
fn convert_hash_map(map: HashMap<T, SystemId>) -> HashMap<Self, SystemId>;
}
impl<T> HandleConversion<DummyHandle> for T
where
T: Debug + Eq + Hash,
{
fn convert_hash_map(_: HashMap<DummyHandle, SystemId>) -> HashMap<Self, SystemId> {
HashMap::new()
}
}
impl<T> HandleConversion<T> for T
where
T: Debug + Eq + Hash,
{
fn convert_hash_map(map: HashMap<T, SystemId>) -> HashMap<Self, SystemId> {
map
}
}