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
|
//! Low-level querying.
use std::iter::{repeat_n, FlatMap, RepeatN, Zip};
use crate::component::storage::archetype::{Archetype, EntityIter};
use crate::component::storage::{
ArchetypeRefIter,
ArchetypeSearchTerms,
Storage as ComponentStorage,
};
use crate::entity::Handle as EntityHandle;
use crate::lock::ReadGuard;
use crate::query::Terms;
use crate::World;
/// Low-level entity query structure.
#[derive(Debug)]
pub struct Query<'world, 'terms>
{
component_storage: ReadGuard<'world, ComponentStorage>,
terms: Terms<'terms>,
}
impl<'world, 'terms> Query<'world, 'terms>
{
/// Iterates over the entities matching this query.
#[must_use]
pub fn iter(&self) -> Iter<'_>
{
Iter {
iter: self
.component_storage
.search_archetypes(ArchetypeSearchTerms {
required_components: &self.terms.required_components,
excluded_components: &self.terms.excluded_components,
})
.flat_map(
(|archetype| {
repeat_n(archetype, archetype.entity_cnt())
.zip(archetype.entities())
}) as ComponentIterMapFn,
),
}
}
pub(crate) fn new(world: &'world World, terms: Terms<'terms>) -> Self
{
Self {
component_storage: world
.data
.component_storage
.read_nonblock()
.expect("Failed to acquire read-only component storage lock"),
terms,
}
}
}
pub struct Iter<'query>
{
iter: QueryEntityIter<'query>,
}
impl<'query> Iterator for Iter<'query>
{
type Item = EntityHandle<'query>;
fn next(&mut self) -> Option<Self::Item>
{
let (archetype, entity) = self.iter.next()?;
Some(EntityHandle::new(archetype, entity))
}
}
type ComponentIterMapFnOutput<'a> = Zip<RepeatN<&'a Archetype>, EntityIter<'a>>;
type ComponentIterMapFn = for<'a> fn(&'a Archetype) -> ComponentIterMapFnOutput<'a>;
type QueryEntityIter<'query> = FlatMap<
ArchetypeRefIter<'query, 'query>,
ComponentIterMapFnOutput<'query>,
ComponentIterMapFn,
>;
|
