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|
use std::any::{Any, TypeId};
use std::collections::HashMap;
use std::panic::{RefUnwindSafe, UnwindSafe};
use seq_macro::seq;
use crate::component::Component;
use crate::lock::Lock;
use crate::system::{
ComponentRefMut,
Into as IntoSystem,
Param,
ParamWithInputFilter,
System,
TypeErased,
};
use crate::tuple::{
Reduce as TupleReduce,
Tuple,
WithAllElemLtStatic as TupleWithAllElemLtStatic,
};
use crate::uid::Uid;
use crate::World;
/// A stateful system.
pub struct Stateful<Func>
{
func: Func,
local_components: HashMap<Uid, Lock<Box<dyn Component>>>,
}
macro_rules! impl_system {
($c: tt) => {
seq!(I in 0..$c {
impl<'world, Func, #(TParam~I,)*> System<'world, fn(&'world (), #(TParam~I,)*)>
for Stateful<Func>
where
Func: Fn(#(TParam~I,)*) + Copy + RefUnwindSafe + UnwindSafe + 'static,
#(TParam~I: Param<'world>,)*
#(TParam~I::Input: 'static,)*
(#(TParam~I::Input,)*): TupleReduce<
ParamWithInputFilter,
Out: Tuple<InOptions: TupleWithAllElemLtStatic>
>,
{
type Input =
<(#(TParam~I::Input,)*) as TupleReduce<ParamWithInputFilter>>::Out;
fn initialize(mut self, input: Self::Input) -> Self
{
let mut option_input = input.into_in_options();
let mut index = 0;
#(
if TypeId::of::<TParam~I::Input>() !=
TypeId::of::<()>()
{
let input = option_input
.get_mut::<Option<TParam~I::Input>>(index)
.expect("Input element index out of range")
.take()
.expect("Input element is already taken");
TParam~I::initialize(
&mut self,
input
);
#[allow(unused_assignments)]
{
index += 1;
}
}
)*
self
}
fn run<'this>(&'this self, world: &'world World)
where
'this: 'world
{
let func = self.func;
func(#({
TParam~I::new(self, &world)
},)*);
}
fn into_type_erased(self) -> TypeErased
{
TypeErased {
data: Box::new(self),
run: Box::new(|data, world| {
// SAFETY: The caller of TypeErased::run ensures the lifetime
// is correct
let data = unsafe { &*std::ptr::from_ref::<dyn Any>(data) };
let me = data.downcast_ref::<Self>().unwrap();
// SAFETY: The caller of TypeErased::run ensures the lifetime
// is correct
let world = unsafe { &*std::ptr::from_ref(world) };
me.run(world);
}),
}
}
fn get_local_component_mut<LocalComponent: Component>(
&self,
) -> Option<ComponentRefMut<LocalComponent>>
{
let local_component = self.local_components
.get(&LocalComponent::id())?
.write_nonblock()
.expect("Failed to aquire read-write local component lock");
Some(ComponentRefMut::new(local_component))
}
fn set_local_component<LocalComponent: Component>(
&mut self,
local_component: LocalComponent,
)
{
self.local_components
.insert(
LocalComponent::id(),
Lock::new(Box::new(local_component))
);
}
}
impl<Func, #(TParam~I,)*> IntoSystem<fn(#(TParam~I,)*)>
for Func
where
Func: Fn(#(TParam~I,)*) + Copy + 'static,
{
type System = Stateful<Func>;
fn into_system(self) -> Self::System
{
Self::System {
func: self,
local_components: HashMap::new(),
}
}
}
});
};
}
seq!(C in 1..16 {
impl_system!(C);
});
|
