1 files changed, 329 insertions, 0 deletions

diff --git a/crates/hir_def/src/adt.rs b/crates/hir_def/src/adt.rs
new file mode 100644
index 000000000..d69ff2fc7
--- /dev/null
+++ b/crates/hir_def/src/adt.rs
@@ -0,0 +1,329 @@
+//! Defines hir-level representation of structs, enums and unions
+
+use std::sync::Arc;
+
+use arena::{map::ArenaMap, Arena};
+use either::Either;
+use hir_expand::{
+    name::{AsName, Name},
+    InFile,
+};
+use syntax::ast::{self, NameOwner, VisibilityOwner};
+use tt::{Delimiter, DelimiterKind, Leaf, Subtree, TokenTree};
+
+use crate::{
+    body::{CfgExpander, LowerCtx},
+    db::DefDatabase,
+    item_tree::{AttrOwner, Field, Fields, ItemTree, ModItem},
+    src::HasChildSource,
+    src::HasSource,
+    trace::Trace,
+    type_ref::TypeRef,
+    visibility::RawVisibility,
+    EnumId, HasModule, LocalEnumVariantId, LocalFieldId, Lookup, ModuleId, StructId, UnionId,
+    VariantId,
+};
+use cfg::CfgOptions;
+
+/// Note that we use `StructData` for unions as well!
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct StructData {
+    pub name: Name,
+    pub variant_data: Arc<VariantData>,
+    pub repr: Option<ReprKind>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct EnumData {
+    pub name: Name,
+    pub variants: Arena<EnumVariantData>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct EnumVariantData {
+    pub name: Name,
+    pub variant_data: Arc<VariantData>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum VariantData {
+    Record(Arena<FieldData>),
+    Tuple(Arena<FieldData>),
+    Unit,
+}
+
+/// A single field of an enum variant or struct
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct FieldData {
+    pub name: Name,
+    pub type_ref: TypeRef,
+    pub visibility: RawVisibility,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum ReprKind {
+    Packed,
+    Other,
+}
+
+fn repr_from_value(item_tree: &ItemTree, of: AttrOwner) -> Option<ReprKind> {
+    item_tree.attrs(of).by_key("repr").tt_values().find_map(parse_repr_tt)
+}
+
+fn parse_repr_tt(tt: &Subtree) -> Option<ReprKind> {
+    match tt.delimiter {
+        Some(Delimiter { kind: DelimiterKind::Parenthesis, .. }) => {}
+        _ => return None,
+    }
+
+    let mut it = tt.token_trees.iter();
+    match it.next()? {
+        TokenTree::Leaf(Leaf::Ident(ident)) if ident.text == "packed" => Some(ReprKind::Packed),
+        _ => Some(ReprKind::Other),
+    }
+}
+
+impl StructData {
+    pub(crate) fn struct_data_query(db: &dyn DefDatabase, id: StructId) -> Arc<StructData> {
+        let loc = id.lookup(db);
+        let item_tree = db.item_tree(loc.id.file_id);
+        let repr = repr_from_value(&item_tree, ModItem::from(loc.id.value).into());
+        let cfg_options = db.crate_graph()[loc.container.module(db).krate].cfg_options.clone();
+
+        let strukt = &item_tree[loc.id.value];
+        let variant_data = lower_fields(&item_tree, &cfg_options, &strukt.fields);
+        Arc::new(StructData {
+            name: strukt.name.clone(),
+            variant_data: Arc::new(variant_data),
+            repr,
+        })
+    }
+    pub(crate) fn union_data_query(db: &dyn DefDatabase, id: UnionId) -> Arc<StructData> {
+        let loc = id.lookup(db);
+        let item_tree = db.item_tree(loc.id.file_id);
+        let repr = repr_from_value(&item_tree, ModItem::from(loc.id.value).into());
+        let cfg_options = db.crate_graph()[loc.container.module(db).krate].cfg_options.clone();
+
+        let union = &item_tree[loc.id.value];
+        let variant_data = lower_fields(&item_tree, &cfg_options, &union.fields);
+
+        Arc::new(StructData {
+            name: union.name.clone(),
+            variant_data: Arc::new(variant_data),
+            repr,
+        })
+    }
+}
+
+impl EnumData {
+    pub(crate) fn enum_data_query(db: &dyn DefDatabase, e: EnumId) -> Arc<EnumData> {
+        let loc = e.lookup(db);
+        let item_tree = db.item_tree(loc.id.file_id);
+        let cfg_options = db.crate_graph()[loc.container.module(db).krate].cfg_options.clone();
+
+        let enum_ = &item_tree[loc.id.value];
+        let mut variants = Arena::new();
+        for var_id in enum_.variants.clone() {
+            if item_tree.attrs(var_id.into()).is_cfg_enabled(&cfg_options) {
+                let var = &item_tree[var_id];
+                let var_data = lower_fields(&item_tree, &cfg_options, &var.fields);
+
+                variants.alloc(EnumVariantData {
+                    name: var.name.clone(),
+                    variant_data: Arc::new(var_data),
+                });
+            }
+        }
+
+        Arc::new(EnumData { name: enum_.name.clone(), variants })
+    }
+
+    pub fn variant(&self, name: &Name) -> Option<LocalEnumVariantId> {
+        let (id, _) = self.variants.iter().find(|(_id, data)| &data.name == name)?;
+        Some(id)
+    }
+}
+
+impl HasChildSource for EnumId {
+    type ChildId = LocalEnumVariantId;
+    type Value = ast::Variant;
+    fn child_source(&self, db: &dyn DefDatabase) -> InFile<ArenaMap<Self::ChildId, Self::Value>> {
+        let src = self.lookup(db).source(db);
+        let mut trace = Trace::new_for_map();
+        lower_enum(db, &mut trace, &src, self.lookup(db).container.module(db));
+        src.with_value(trace.into_map())
+    }
+}
+
+fn lower_enum(
+    db: &dyn DefDatabase,
+    trace: &mut Trace<EnumVariantData, ast::Variant>,
+    ast: &InFile<ast::Enum>,
+    module_id: ModuleId,
+) {
+    let expander = CfgExpander::new(db, ast.file_id, module_id.krate);
+    let variants = ast
+        .value
+        .variant_list()
+        .into_iter()
+        .flat_map(|it| it.variants())
+        .filter(|var| expander.is_cfg_enabled(var));
+    for var in variants {
+        trace.alloc(
+            || var.clone(),
+            || EnumVariantData {
+                name: var.name().map_or_else(Name::missing, |it| it.as_name()),
+                variant_data: Arc::new(VariantData::new(db, ast.with_value(var.kind()), module_id)),
+            },
+        );
+    }
+}
+
+impl VariantData {
+    fn new(db: &dyn DefDatabase, flavor: InFile<ast::StructKind>, module_id: ModuleId) -> Self {
+        let mut expander = CfgExpander::new(db, flavor.file_id, module_id.krate);
+        let mut trace = Trace::new_for_arena();
+        match lower_struct(db, &mut expander, &mut trace, &flavor) {
+            StructKind::Tuple => VariantData::Tuple(trace.into_arena()),
+            StructKind::Record => VariantData::Record(trace.into_arena()),
+            StructKind::Unit => VariantData::Unit,
+        }
+    }
+
+    pub fn fields(&self) -> &Arena<FieldData> {
+        const EMPTY: &Arena<FieldData> = &Arena::new();
+        match &self {
+            VariantData::Record(fields) | VariantData::Tuple(fields) => fields,
+            _ => EMPTY,
+        }
+    }
+
+    pub fn field(&self, name: &Name) -> Option<LocalFieldId> {
+        self.fields().iter().find_map(|(id, data)| if &data.name == name { Some(id) } else { None })
+    }
+
+    pub fn kind(&self) -> StructKind {
+        match self {
+            VariantData::Record(_) => StructKind::Record,
+            VariantData::Tuple(_) => StructKind::Tuple,
+            VariantData::Unit => StructKind::Unit,
+        }
+    }
+}
+
+impl HasChildSource for VariantId {
+    type ChildId = LocalFieldId;
+    type Value = Either<ast::TupleField, ast::RecordField>;
+
+    fn child_source(&self, db: &dyn DefDatabase) -> InFile<ArenaMap<Self::ChildId, Self::Value>> {
+        let (src, module_id) = match self {
+            VariantId::EnumVariantId(it) => {
+                // I don't really like the fact that we call into parent source
+                // here, this might add to more queries then necessary.
+                let src = it.parent.child_source(db);
+                (src.map(|map| map[it.local_id].kind()), it.parent.lookup(db).container.module(db))
+            }
+            VariantId::StructId(it) => {
+                (it.lookup(db).source(db).map(|it| it.kind()), it.lookup(db).container.module(db))
+            }
+            VariantId::UnionId(it) => (
+                it.lookup(db).source(db).map(|it| {
+                    it.record_field_list()
+                        .map(ast::StructKind::Record)
+                        .unwrap_or(ast::StructKind::Unit)
+                }),
+                it.lookup(db).container.module(db),
+            ),
+        };
+        let mut expander = CfgExpander::new(db, src.file_id, module_id.krate);
+        let mut trace = Trace::new_for_map();
+        lower_struct(db, &mut expander, &mut trace, &src);
+        src.with_value(trace.into_map())
+    }
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum StructKind {
+    Tuple,
+    Record,
+    Unit,
+}
+
+fn lower_struct(
+    db: &dyn DefDatabase,
+    expander: &mut CfgExpander,
+    trace: &mut Trace<FieldData, Either<ast::TupleField, ast::RecordField>>,
+    ast: &InFile<ast::StructKind>,
+) -> StructKind {
+    let ctx = LowerCtx::new(db, ast.file_id);
+
+    match &ast.value {
+        ast::StructKind::Tuple(fl) => {
+            for (i, fd) in fl.fields().enumerate() {
+                if !expander.is_cfg_enabled(&fd) {
+                    continue;
+                }
+
+                trace.alloc(
+                    || Either::Left(fd.clone()),
+                    || FieldData {
+                        name: Name::new_tuple_field(i),
+                        type_ref: TypeRef::from_ast_opt(&ctx, fd.ty()),
+                        visibility: RawVisibility::from_ast(db, ast.with_value(fd.visibility())),
+                    },
+                );
+            }
+            StructKind::Tuple
+        }
+        ast::StructKind::Record(fl) => {
+            for fd in fl.fields() {
+                if !expander.is_cfg_enabled(&fd) {
+                    continue;
+                }
+
+                trace.alloc(
+                    || Either::Right(fd.clone()),
+                    || FieldData {
+                        name: fd.name().map(|n| n.as_name()).unwrap_or_else(Name::missing),
+                        type_ref: TypeRef::from_ast_opt(&ctx, fd.ty()),
+                        visibility: RawVisibility::from_ast(db, ast.with_value(fd.visibility())),
+                    },
+                );
+            }
+            StructKind::Record
+        }
+        ast::StructKind::Unit => StructKind::Unit,
+    }
+}
+
+fn lower_fields(item_tree: &ItemTree, cfg_options: &CfgOptions, fields: &Fields) -> VariantData {
+    match fields {
+        Fields::Record(flds) => {
+            let mut arena = Arena::new();
+            for field_id in flds.clone() {
+                if item_tree.attrs(field_id.into()).is_cfg_enabled(cfg_options) {
+                    arena.alloc(lower_field(item_tree, &item_tree[field_id]));
+                }
+            }
+            VariantData::Record(arena)
+        }
+        Fields::Tuple(flds) => {
+            let mut arena = Arena::new();
+            for field_id in flds.clone() {
+                if item_tree.attrs(field_id.into()).is_cfg_enabled(cfg_options) {
+                    arena.alloc(lower_field(item_tree, &item_tree[field_id]));
+                }
+            }
+            VariantData::Tuple(arena)
+        }
+        Fields::Unit => VariantData::Unit,
+    }
+}
+
+fn lower_field(item_tree: &ItemTree, field: &Field) -> FieldData {
+    FieldData {
+        name: field.name.clone(),
+        type_ref: field.type_ref.clone(),
+        visibility: item_tree[field.visibility].clone(),
+    }
+}