facet_core/impls_std/
hashmap.rs

1use alloc::collections::VecDeque;
2use core::hash::{BuildHasher, Hash};
3use std::collections::HashMap;
4use std::hash::RandomState;
5
6use crate::ptr::{PtrConst, PtrMut};
7
8use crate::{
9    Def, Facet, MapDef, MapIterVTable, MapVTable, MarkerTraits, ScalarAffinity, ScalarDef, Shape,
10    Type, TypeParam, UserType, VTableView, ValueVTable, value_vtable,
11};
12
13struct HashMapIterator<'mem, K> {
14    map: PtrConst<'mem>,
15    keys: VecDeque<&'mem K>,
16}
17
18unsafe impl<'a, K, V, S> Facet<'a> for HashMap<K, V, S>
19where
20    K: Facet<'a> + core::cmp::Eq + core::hash::Hash,
21    V: Facet<'a>,
22    S: Facet<'a> + Default + BuildHasher,
23{
24    const VTABLE: &'static ValueVTable = &const {
25        let mut builder = ValueVTable::builder::<Self>()
26            .marker_traits({
27                let arg_dependent_traits = MarkerTraits::SEND
28                    .union(MarkerTraits::SYNC)
29                    .union(MarkerTraits::EQ)
30                    .union(MarkerTraits::UNPIN);
31                arg_dependent_traits
32                    .intersection(V::SHAPE.vtable.marker_traits)
33                    .intersection(K::SHAPE.vtable.marker_traits)
34            })
35            .type_name(|f, opts| {
36                if let Some(opts) = opts.for_children() {
37                    write!(f, "HashMap<")?;
38                    (K::SHAPE.vtable.type_name)(f, opts)?;
39                    write!(f, ", ")?;
40                    (V::SHAPE.vtable.type_name)(f, opts)?;
41                    write!(f, ">")
42                } else {
43                    write!(f, "HashMap<⋯>")
44                }
45            });
46
47        if K::SHAPE.vtable.debug.is_some() && V::SHAPE.vtable.debug.is_some() {
48            builder = builder.debug(|value, f| {
49                let k_debug = <VTableView<K>>::of().debug().unwrap();
50                let v_debug = <VTableView<V>>::of().debug().unwrap();
51                write!(f, "{{")?;
52                for (i, (key, val)) in value.iter().enumerate() {
53                    if i > 0 {
54                        write!(f, ", ")?;
55                    }
56                    (k_debug)(key, f)?;
57                    write!(f, ": ")?;
58                    (v_debug)(val, f)?;
59                }
60                write!(f, "}}")
61            });
62        }
63
64        builder = builder.default_in_place(|target| unsafe { target.put(Self::default()) });
65
66        if V::SHAPE.vtable.clone_into.is_some() && K::SHAPE.vtable.clone_into.is_some() {
67            builder = builder.clone_into(|src, dst| unsafe {
68                let map = src;
69                let mut new_map = HashMap::with_capacity_and_hasher(map.len(), S::default());
70
71                let k_clone_into = <VTableView<K>>::of().clone_into().unwrap();
72                let v_clone_into = <VTableView<V>>::of().clone_into().unwrap();
73
74                for (k, v) in map {
75                    use crate::TypedPtrUninit;
76                    use core::mem::MaybeUninit;
77
78                    let mut new_k = MaybeUninit::<K>::uninit();
79                    let mut new_v = MaybeUninit::<V>::uninit();
80
81                    let uninit_k = TypedPtrUninit::new(new_k.as_mut_ptr());
82                    let uninit_v = TypedPtrUninit::new(new_v.as_mut_ptr());
83
84                    (k_clone_into)(k, uninit_k);
85                    (v_clone_into)(v, uninit_v);
86
87                    new_map.insert(new_k.assume_init(), new_v.assume_init());
88                }
89
90                dst.put(new_map)
91            });
92        }
93
94        if V::SHAPE.vtable.eq.is_some() {
95            builder = builder.eq(|a, b| {
96                let v_eq = <VTableView<V>>::of().eq().unwrap();
97                a.len() == b.len()
98                    && a.iter().all(|(key_a, val_a)| {
99                        b.get(key_a).is_some_and(|val_b| (v_eq)(val_a, val_b))
100                    })
101            });
102        }
103
104        if V::SHAPE.vtable.hash.is_some() {
105            builder = builder.hash(|map, hasher_this, hasher_write_fn| unsafe {
106                use crate::HasherProxy;
107                let v_hash = <VTableView<V>>::of().hash().unwrap();
108                let mut hasher = HasherProxy::new(hasher_this, hasher_write_fn);
109                map.len().hash(&mut hasher);
110                for (k, v) in map {
111                    k.hash(&mut hasher);
112                    (v_hash)(v, hasher_this, hasher_write_fn);
113                }
114            });
115        }
116
117        builder.build()
118    };
119
120    const SHAPE: &'static Shape = &const {
121        Shape::builder_for_sized::<Self>()
122            .type_params(&[
123                TypeParam {
124                    name: "K",
125                    shape: || K::SHAPE,
126                },
127                TypeParam {
128                    name: "V",
129                    shape: || V::SHAPE,
130                },
131                TypeParam {
132                    name: "S",
133                    shape: || S::SHAPE,
134                },
135            ])
136            .ty(Type::User(UserType::Opaque))
137            .def(Def::Map(
138                MapDef::builder()
139                    .k(|| K::SHAPE)
140                    .v(|| V::SHAPE)
141                    .vtable(
142                        &const {
143                            MapVTable::builder()
144                                .init_in_place_with_capacity(|uninit, capacity| unsafe {
145                                    uninit
146                                        .put(Self::with_capacity_and_hasher(capacity, S::default()))
147                                })
148                                .insert(|ptr, key, value| unsafe {
149                                    let map = ptr.as_mut::<HashMap<K, V>>();
150                                    let key = key.read::<K>();
151                                    let value = value.read::<V>();
152                                    map.insert(key, value);
153                                })
154                                .len(|ptr| unsafe {
155                                    let map = ptr.get::<HashMap<K, V>>();
156                                    map.len()
157                                })
158                                .contains_key(|ptr, key| unsafe {
159                                    let map = ptr.get::<HashMap<K, V>>();
160                                    map.contains_key(key.get())
161                                })
162                                .get_value_ptr(|ptr, key| unsafe {
163                                    let map = ptr.get::<HashMap<K, V>>();
164                                    map.get(key.get()).map(|v| PtrConst::new(v))
165                                })
166                                .iter(|ptr| unsafe {
167                                    let map = ptr.get::<HashMap<K, V>>();
168                                    let keys: VecDeque<&K> = map.keys().collect();
169                                    let iter_state = Box::new(HashMapIterator { map: ptr, keys });
170                                    PtrMut::new(Box::into_raw(iter_state) as *mut u8)
171                                })
172                                .iter_vtable(
173                                    MapIterVTable::builder()
174                                        .next(|iter_ptr| unsafe {
175                                            let state = iter_ptr.as_mut::<HashMapIterator<'_, K>>();
176                                            let map = state.map.get::<HashMap<K, V>>();
177                                            while let Some(key) = state.keys.pop_front() {
178                                                if let Some(value) = map.get(key) {
179                                                    return Some((
180                                                        PtrConst::new(key as *const K),
181                                                        PtrConst::new(value as *const V),
182                                                    ));
183                                                }
184                                            }
185
186                                            None
187                                        })
188                                        .next_back(|iter_ptr| unsafe {
189                                            let state = iter_ptr.as_mut::<HashMapIterator<'_, K>>();
190                                            let map = state.map.get::<HashMap<K, V>>();
191                                            while let Some(key) = state.keys.pop_back() {
192                                                if let Some(value) = map.get(key) {
193                                                    return Some((
194                                                        PtrConst::new(key as *const K),
195                                                        PtrConst::new(value as *const V),
196                                                    ));
197                                                }
198                                            }
199
200                                            None
201                                        })
202                                        .dealloc(|iter_ptr| unsafe {
203                                            drop(Box::from_raw(
204                                                iter_ptr.as_ptr::<HashMapIterator<'_, K>>()
205                                                    as *mut HashMapIterator<'_, K>,
206                                            ));
207                                        })
208                                        .build(),
209                                )
210                                .build()
211                        },
212                    )
213                    .build(),
214            ))
215            .build()
216    };
217}
218
219unsafe impl Facet<'_> for RandomState {
220    const VTABLE: &'static ValueVTable =
221        &const { value_vtable!((), |f, _opts| write!(f, "RandomState")) };
222
223    const SHAPE: &'static Shape = &const {
224        Shape::builder_for_sized::<Self>()
225            .ty(Type::User(UserType::Opaque))
226            .def(Def::Scalar(
227                ScalarDef::builder()
228                    .affinity(ScalarAffinity::opaque().build())
229                    .build(),
230            ))
231            .build()
232    };
233}