rust/crates/hir-def/src/lower.rs

52 lines
1.6 KiB
Rust

//! Context for lowering paths.
use std::cell::OnceCell;
use hir_expand::{
ast_id_map::{AstIdMap, AstIdNode},
span_map::{SpanMap, SpanMapRef},
AstId, HirFileId, InFile,
};
use syntax::ast;
use triomphe::Arc;
use crate::{db::DefDatabase, path::Path};
pub struct LowerCtx<'a> {
pub db: &'a dyn DefDatabase,
span_map: SpanMap,
// FIXME: This optimization is probably pointless, ast id map should pretty much always exist anyways.
ast_id_map: Option<(HirFileId, OnceCell<Arc<AstIdMap>>)>,
}
impl<'a> LowerCtx<'a> {
pub fn new(db: &'a dyn DefDatabase, span_map: SpanMap, file_id: HirFileId) -> Self {
LowerCtx { db, span_map, ast_id_map: Some((file_id, OnceCell::new())) }
}
pub fn with_file_id(db: &'a dyn DefDatabase, file_id: HirFileId) -> Self {
LowerCtx {
db,
span_map: db.span_map(file_id),
ast_id_map: Some((file_id, OnceCell::new())),
}
}
pub fn with_span_map(db: &'a dyn DefDatabase, span_map: SpanMap) -> Self {
LowerCtx { db, span_map, ast_id_map: None }
}
pub(crate) fn span_map(&self) -> SpanMapRef<'_> {
self.span_map.as_ref()
}
pub(crate) fn lower_path(&self, ast: ast::Path) -> Option<Path> {
Path::from_src(self, ast)
}
pub(crate) fn ast_id<N: AstIdNode>(&self, item: &N) -> Option<AstId<N>> {
let &(file_id, ref ast_id_map) = self.ast_id_map.as_ref()?;
let ast_id_map = ast_id_map.get_or_init(|| self.db.ast_id_map(file_id));
Some(InFile::new(file_id, ast_id_map.ast_id(item)))
}
}