facet_core/impls_std/
hashmap.rs

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