1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
use std::any::Any;
use std::convert::Infallible;
use std::fmt::Debug;
use std::ptr::addr_of_mut;
use seq_macro::seq;
use crate::component::Component;
use crate::system::util::check_params_are_compatible;
use crate::tuple::{FilterElement as TupleFilterElement, With as TupleWith};
use crate::ComponentStorage;
pub mod stateful;
mod util;
pub trait System<Impl>: 'static
{
type Input;
#[must_use]
fn initialize(self, input: Self::Input) -> Self;
fn run(&mut self, component_storage: &mut ComponentStorage);
fn into_type_erased(self) -> TypeErased;
fn get_local_component_mut<LocalComponent: Component>(
&mut self,
) -> Option<&mut LocalComponent>;
fn set_local_component<LocalComponent: Component>(
&mut self,
local_component: LocalComponent,
);
}
macro_rules! impl_system {
($c: tt) => {
seq!(I in 0..=$c {
impl<'world, Func, #(TParam~I,)*> System<fn(#(TParam~I,)*)>
for Func
where
Func: Fn(#(TParam~I,)*) + Copy + 'static,
#(TParam~I: Param<'world, Flags = NoInitParamFlag>,)*
{
type Input = Infallible;
fn initialize(self, _input: Self::Input) -> Self
{
self
}
fn run(&mut self, component_storage: &mut ComponentStorage)
{
#(
check_params_are_compatible!(I, TParam~I, $c);
)*
let func = *self;
func(#({
// SAFETY: All parameters are compatible so this is fine
let this = unsafe {
&mut *addr_of_mut!(*self)
};
// SAFETY: All parameters are compatible so this is fine
let component_storage = unsafe {
&mut *addr_of_mut!(*component_storage)
};
TParam~I::new(this, component_storage)
},)*);
}
fn into_type_erased(self) -> TypeErased
{
TypeErased {
data: Box::new(self),
func: Box::new(|data, component_storage| {
let me = data.downcast_mut::<Func>().unwrap();
me.run(component_storage);
}),
}
}
fn get_local_component_mut<LocalComponent: Component>(
&mut self,
) -> Option<&mut LocalComponent>
{
panic!("System does not have any local components");
}
fn set_local_component<LocalComponent: Component>(
&mut self,
_local_component: LocalComponent,
) {
panic!("System does not have any local components");
}
}
});
};
}
seq!(C in 0..=4 {
impl_system!(C);
});
pub trait Into<Impl>
{
type System;
fn into_system(self) -> Self::System;
}
pub struct TypeErased
{
data: Box<dyn Any>,
func: Box<TypeErasedFunc>,
}
impl TypeErased
{
pub fn run(&mut self, component_storage: &mut ComponentStorage)
{
(self.func)(self.data.as_mut(), component_storage);
}
}
impl Debug for TypeErased
{
fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
{
formatter.debug_struct("TypeErased").finish_non_exhaustive()
}
}
/// Function in [`TypeErased`] used to run the system.
type TypeErasedFunc = dyn Fn(&mut dyn Any, &mut ComponentStorage);
/// A parameter to a [`System`].
///
/// # Safety
/// The `is_compatible` function is used for safety so it must be implemented properly.
pub unsafe trait Param<'world>
{
type Input;
type Flags;
fn initialize<SystemImpl>(system: &mut impl System<SystemImpl>, input: Self::Input);
fn new<SystemImpl>(
system: &'world mut impl System<SystemImpl>,
component_storage: &'world mut ComponentStorage,
) -> Self;
fn is_compatible<Other: Param<'world>>() -> bool;
fn get_comparable() -> Box<dyn Any>;
}
pub struct NoInitParamFlag {}
/// A type which can be used as input to a [`System`].
pub trait Input: 'static {}
impl<InputT: Input, Tup> TupleFilterElement<Tup> for InputT
where
Tup: TupleWith<Self>,
{
type Tuple = Tup::With;
}
|
