trecs/world/
query.rs

1use std::marker::PhantomData;
2
3#[cfg(feature = "system")]
4use crate::system::SystemParm;
5use crate::{
6    iter::{EIter, Iter},
7    tools::{WorldFetch, WorldFilter},
8    world::World,
9};
10
11#[allow(unused_imports)]
12use crate::bundle::Components;
13/// [FnSystem]的参数之一
14///
15/// 用来操作从world中选定的部分[Components]
16///
17/// 有可能会出现别名冲突导致[FnSystem]第一次运行时painc
18///
19/// [FnSystem]: system::fnsys::FnSystem
20#[derive(Clone)]
21pub struct Query<'a, F: WorldFetch, Q: WorldFilter = ()> {
22    world: &'a World,
23    _p: PhantomData<(F, Q)>,
24}
25
26impl<'a, F: WorldFetch, Q: WorldFilter> Query<'a, F, Q> {
27    pub fn new(world: &mut World) -> Query<'_, F, Q> {
28        Query {
29            world,
30            _p: PhantomData,
31        }
32    }
33
34    pub fn into_eiter(self) -> EIter<'a, F> {
35        unsafe {
36            #[allow(mutable_transmutes)]
37            EIter::new::<Q>(std::mem::transmute(self.world))
38        }
39    }
40}
41
42impl<'a, F: WorldFetch + 'a, Q: WorldFilter> IntoIterator for Query<'a, F, Q> {
43    type Item = F::Item<'a>;
44
45    type IntoIter = Iter<'a, F>;
46
47    fn into_iter(self) -> Self::IntoIter {
48        unsafe {
49            #[allow(mutable_transmutes)]
50            Iter::new::<Q>(std::mem::transmute(self.world))
51        }
52    }
53}
54
55#[cfg(feature = "system")]
56impl<F: WorldFetch, Q: WorldFilter> SystemParm for Query<'_, F, Q> {
57    unsafe fn build(world: &World) -> Self {
58        #[allow(mutable_transmutes)]
59        let world: &mut World = std::mem::transmute(world);
60        Query::<'_, F, Q>::new(world)
61    }
62
63    fn init(state: &mut crate::system::state::SystemState) {
64        F::alias_conflict(&mut state.alias_map);
65    }
66}
trecs/world/query.rs

trecs/world/
query.rs
