hir_def/
dyn_map.rs

1//! This module defines a `DynMap` -- a container for heterogeneous maps.
2//!
3//! This means that `DynMap` stores a bunch of hash maps inside, and those maps
4//! can be of different types.
5//!
6//! It is used like this:
7//!
8//! ```ignore
9//! # use hir_def::dyn_map::DynMap;
10//! # use hir_def::dyn_map::Key;
11//! // keys define submaps of a `DynMap`
12//! const STRING_TO_U32: Key<String, u32> = Key::new();
13//! const U32_TO_VEC: Key<u32, Vec<bool>> = Key::new();
14//!
15//! // Note: concrete type, no type params!
16//! let mut map = DynMap::new();
17//!
18//! // To access a specific map, index the `DynMap` by `Key`:
19//! map[STRING_TO_U32].insert("hello".to_string(), 92);
20//! let value = map[U32_TO_VEC].get(92);
21//! assert!(value.is_none());
22//! ```
23//!
24//! This is a work of fiction. Any similarities to Kotlin's `BindingContext` are
25//! a coincidence.
26
27pub mod keys {
28    use std::marker::PhantomData;
29
30    use hir_expand::{MacroCallId, attrs::AttrId};
31    use rustc_hash::FxHashMap;
32    use syntax::{AstNode, AstPtr, ast};
33
34    use crate::{
35        BlockId, ConstId, EnumId, EnumVariantId, ExternBlockId, ExternCrateId, FieldId, FunctionId,
36        ImplId, LifetimeParamId, Macro2Id, MacroRulesId, ProcMacroId, StaticId, StructId, TraitId,
37        TypeAliasId, TypeOrConstParamId, UnionId, UseId,
38        dyn_map::{DynMap, Policy},
39    };
40
41    pub type Key<K, V> = crate::dyn_map::Key<AstPtr<K>, V, AstPtrPolicy<K, V>>;
42
43    pub const BLOCK: Key<ast::BlockExpr, BlockId> = Key::new();
44    pub const FUNCTION: Key<ast::Fn, FunctionId> = Key::new();
45    pub const CONST: Key<ast::Const, ConstId> = Key::new();
46    pub const STATIC: Key<ast::Static, StaticId> = Key::new();
47    pub const TYPE_ALIAS: Key<ast::TypeAlias, TypeAliasId> = Key::new();
48    pub const IMPL: Key<ast::Impl, ImplId> = Key::new();
49    pub const EXTERN_BLOCK: Key<ast::ExternBlock, ExternBlockId> = Key::new();
50    pub const TRAIT: Key<ast::Trait, TraitId> = Key::new();
51    pub const STRUCT: Key<ast::Struct, StructId> = Key::new();
52    pub const UNION: Key<ast::Union, UnionId> = Key::new();
53    pub const ENUM: Key<ast::Enum, EnumId> = Key::new();
54    pub const EXTERN_CRATE: Key<ast::ExternCrate, ExternCrateId> = Key::new();
55    pub const USE: Key<ast::Use, UseId> = Key::new();
56
57    pub const ENUM_VARIANT: Key<ast::Variant, EnumVariantId> = Key::new();
58    pub const TUPLE_FIELD: Key<ast::TupleField, FieldId> = Key::new();
59    pub const RECORD_FIELD: Key<ast::RecordField, FieldId> = Key::new();
60    pub const TYPE_PARAM: Key<ast::TypeParam, TypeOrConstParamId> = Key::new();
61    pub const CONST_PARAM: Key<ast::ConstParam, TypeOrConstParamId> = Key::new();
62    pub const LIFETIME_PARAM: Key<ast::LifetimeParam, LifetimeParamId> = Key::new();
63
64    pub const MACRO_RULES: Key<ast::MacroRules, MacroRulesId> = Key::new();
65    pub const MACRO2: Key<ast::MacroDef, Macro2Id> = Key::new();
66    pub const PROC_MACRO: Key<ast::Fn, ProcMacroId> = Key::new();
67    pub const MACRO_CALL: Key<ast::MacroCall, MacroCallId> = Key::new();
68    pub const ATTR_MACRO_CALL: Key<ast::Item, MacroCallId> = Key::new();
69    pub const DERIVE_MACRO_CALL: Key<
70        ast::Attr,
71        (
72            AttrId,
73            /* derive() */ MacroCallId,
74            /* actual derive macros */ Box<[Option<MacroCallId>]>,
75        ),
76    > = Key::new();
77
78    /// XXX: AST Nodes and SyntaxNodes have identity equality semantics: nodes are
79    /// equal if they point to exactly the same object.
80    ///
81    /// In general, we do not guarantee that we have exactly one instance of a
82    /// syntax tree for each file. We probably should add such guarantee, but, for
83    /// the time being, we will use identity-less AstPtr comparison.
84    pub struct AstPtrPolicy<AST, ID> {
85        _phantom: PhantomData<(AST, ID)>,
86    }
87
88    impl<AST: AstNode + 'static, ID: 'static> Policy for AstPtrPolicy<AST, ID> {
89        type K = AstPtr<AST>;
90        type V = ID;
91        fn insert(map: &mut DynMap, key: AstPtr<AST>, value: ID) {
92            map.map
93                .entry::<FxHashMap<AstPtr<AST>, ID>>()
94                .or_insert_with(Default::default)
95                .insert(key, value);
96        }
97        fn get<'a>(map: &'a DynMap, key: &AstPtr<AST>) -> Option<&'a ID> {
98            map.map.get::<FxHashMap<AstPtr<AST>, ID>>()?.get(key)
99        }
100        fn is_empty(map: &DynMap) -> bool {
101            map.map.get::<FxHashMap<AstPtr<AST>, ID>>().is_none_or(|it| it.is_empty())
102        }
103    }
104}
105
106use std::{
107    hash::Hash,
108    marker::PhantomData,
109    ops::{Index, IndexMut},
110};
111
112use rustc_hash::FxHashMap;
113use stdx::anymap::Map;
114
115pub struct Key<K, V, P = (K, V)> {
116    _phantom: PhantomData<(K, V, P)>,
117}
118
119impl<K, V, P> Key<K, V, P> {
120    #[allow(
121        clippy::new_without_default,
122        reason = "this a const fn, so it can't be default yet. See <https://github.com/rust-lang/rust/issues/63065>"
123    )]
124    pub(crate) const fn new() -> Key<K, V, P> {
125        Key { _phantom: PhantomData }
126    }
127}
128
129impl<K, V, P> Copy for Key<K, V, P> {}
130
131impl<K, V, P> Clone for Key<K, V, P> {
132    fn clone(&self) -> Key<K, V, P> {
133        *self
134    }
135}
136
137pub trait Policy {
138    type K;
139    type V;
140
141    fn insert(map: &mut DynMap, key: Self::K, value: Self::V);
142    fn get<'a>(map: &'a DynMap, key: &Self::K) -> Option<&'a Self::V>;
143    fn is_empty(map: &DynMap) -> bool;
144}
145
146impl<K: Hash + Eq + 'static, V: 'static> Policy for (K, V) {
147    type K = K;
148    type V = V;
149    fn insert(map: &mut DynMap, key: K, value: V) {
150        map.map.entry::<FxHashMap<K, V>>().or_insert_with(Default::default).insert(key, value);
151    }
152    fn get<'a>(map: &'a DynMap, key: &K) -> Option<&'a V> {
153        map.map.get::<FxHashMap<K, V>>()?.get(key)
154    }
155    fn is_empty(map: &DynMap) -> bool {
156        map.map.get::<FxHashMap<K, V>>().is_none_or(|it| it.is_empty())
157    }
158}
159
160#[derive(Default)]
161pub struct DynMap {
162    pub(crate) map: Map,
163}
164
165#[repr(transparent)]
166pub struct KeyMap<KEY> {
167    map: DynMap,
168    _phantom: PhantomData<KEY>,
169}
170
171impl<P: Policy> KeyMap<Key<P::K, P::V, P>> {
172    pub fn insert(&mut self, key: P::K, value: P::V) {
173        P::insert(&mut self.map, key, value)
174    }
175    pub fn get(&self, key: &P::K) -> Option<&P::V> {
176        P::get(&self.map, key)
177    }
178
179    pub fn is_empty(&self) -> bool {
180        P::is_empty(&self.map)
181    }
182}
183
184impl<P: Policy> Index<Key<P::K, P::V, P>> for DynMap {
185    type Output = KeyMap<Key<P::K, P::V, P>>;
186    fn index(&self, _key: Key<P::K, P::V, P>) -> &Self::Output {
187        // Safe due to `#[repr(transparent)]`.
188        unsafe { std::mem::transmute::<&DynMap, &KeyMap<Key<P::K, P::V, P>>>(self) }
189    }
190}
191
192impl<P: Policy> IndexMut<Key<P::K, P::V, P>> for DynMap {
193    fn index_mut(&mut self, _key: Key<P::K, P::V, P>) -> &mut Self::Output {
194        // Safe due to `#[repr(transparent)]`.
195        unsafe { std::mem::transmute::<&mut DynMap, &mut KeyMap<Key<P::K, P::V, P>>>(self) }
196    }
197}
hir_def/dyn_map.rs

hir_def/
dyn_map.rs
