1 files changed, 70 insertions, 0 deletions
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/keys.rs b/src/tools/rust-analyzer/crates/hir-def/src/keys.rs
new file mode 100644
index 000000000..c5cb9a2af
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/hir-def/src/keys.rs
@@ -0,0 +1,70 @@
+//! keys to be used with `DynMap`
+
+use std::marker::PhantomData;
+
+use hir_expand::MacroCallId;
+use rustc_hash::FxHashMap;
+use syntax::{ast, AstNode, AstPtr};
+
+use crate::{
+    attr::AttrId,
+    dyn_map::{DynMap, Policy},
+    ConstId, EnumId, EnumVariantId, FieldId, FunctionId, ImplId, LifetimeParamId, Macro2Id,
+    MacroRulesId, ProcMacroId, StaticId, StructId, TraitId, TypeAliasId, TypeOrConstParamId,
+    UnionId,
+};
+
+pub type Key<K, V> = crate::dyn_map::Key<K, V, AstPtrPolicy<K, V>>;
+
+pub const FUNCTION: Key<ast::Fn, FunctionId> = Key::new();
+pub const CONST: Key<ast::Const, ConstId> = Key::new();
+pub const STATIC: Key<ast::Static, StaticId> = Key::new();
+pub const TYPE_ALIAS: Key<ast::TypeAlias, TypeAliasId> = Key::new();
+pub const IMPL: Key<ast::Impl, ImplId> = Key::new();
+pub const TRAIT: Key<ast::Trait, TraitId> = Key::new();
+pub const STRUCT: Key<ast::Struct, StructId> = Key::new();
+pub const UNION: Key<ast::Union, UnionId> = Key::new();
+pub const ENUM: Key<ast::Enum, EnumId> = Key::new();
+
+pub const VARIANT: Key<ast::Variant, EnumVariantId> = Key::new();
+pub const TUPLE_FIELD: Key<ast::TupleField, FieldId> = Key::new();
+pub const RECORD_FIELD: Key<ast::RecordField, FieldId> = Key::new();
+pub const TYPE_PARAM: Key<ast::TypeParam, TypeOrConstParamId> = Key::new();
+pub const CONST_PARAM: Key<ast::ConstParam, TypeOrConstParamId> = Key::new();
+pub const LIFETIME_PARAM: Key<ast::LifetimeParam, LifetimeParamId> = Key::new();
+
+pub const MACRO_RULES: Key<ast::MacroRules, MacroRulesId> = Key::new();
+pub const MACRO2: Key<ast::MacroDef, Macro2Id> = Key::new();
+pub const PROC_MACRO: Key<ast::Fn, ProcMacroId> = Key::new();
+pub const ATTR_MACRO_CALL: Key<ast::Item, MacroCallId> = Key::new();
+pub const DERIVE_MACRO_CALL: Key<ast::Attr, (AttrId, MacroCallId, Box<[Option<MacroCallId>]>)> =
+    Key::new();
+
+/// XXX: AST Nodes and SyntaxNodes have identity equality semantics: nodes are
+/// equal if they point to exactly the same object.
+///
+/// In general, we do not guarantee that we have exactly one instance of a
+/// syntax tree for each file. We probably should add such guarantee, but, for
+/// the time being, we will use identity-less AstPtr comparison.
+pub struct AstPtrPolicy<AST, ID> {
+    _phantom: PhantomData<(AST, ID)>,
+}
+
+impl<AST: AstNode + 'static, ID: 'static> Policy for AstPtrPolicy<AST, ID> {
+    type K = AST;
+    type V = ID;
+    fn insert(map: &mut DynMap, key: AST, value: ID) {
+        let key = AstPtr::new(&key);
+        map.map
+            .entry::<FxHashMap<AstPtr<AST>, ID>>()
+            .or_insert_with(Default::default)
+            .insert(key, value);
+    }
+    fn get<'a>(map: &'a DynMap, key: &AST) -> Option<&'a ID> {
+        let key = AstPtr::new(key);
+        map.map.get::<FxHashMap<AstPtr<AST>, ID>>()?.get(&key)
+    }
+    fn is_empty(map: &DynMap) -> bool {
+        map.map.get::<FxHashMap<AstPtr<AST>, ID>>().map_or(true, |it| it.is_empty())
+    }
+}