rust/crates/hir-expand/src/span_map.rs
2024-01-26 19:28:39 +01:00

97 lines
3.3 KiB
Rust

//! Span maps for real files and macro expansions.
use span::{FileId, HirFileId, HirFileIdRepr, Span};
use syntax::{AstNode, TextRange};
use triomphe::Arc;
pub use span::RealSpanMap;
use crate::db::ExpandDatabase;
pub type ExpansionSpanMap = span::SpanMap<Span>;
/// Spanmap for a macro file or a real file
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum SpanMap {
/// Spanmap for a macro file
ExpansionSpanMap(Arc<ExpansionSpanMap>),
/// Spanmap for a real file
RealSpanMap(Arc<RealSpanMap>),
}
#[derive(Copy, Clone)]
pub enum SpanMapRef<'a> {
/// Spanmap for a macro file
ExpansionSpanMap(&'a ExpansionSpanMap),
/// Spanmap for a real file
RealSpanMap(&'a RealSpanMap),
}
impl mbe::SpanMapper<Span> for SpanMap {
fn span_for(&self, range: TextRange) -> Span {
self.span_for_range(range)
}
}
impl mbe::SpanMapper<Span> for SpanMapRef<'_> {
fn span_for(&self, range: TextRange) -> Span {
self.span_for_range(range)
}
}
impl SpanMap {
pub fn span_for_range(&self, range: TextRange) -> Span {
match self {
// FIXME: Is it correct for us to only take the span at the start? This feels somewhat
// wrong. The context will be right, but the range could be considered wrong. See
// https://github.com/rust-lang/rust/issues/23480, we probably want to fetch the span at
// the start and end, then merge them like rustc does in `Span::to
Self::ExpansionSpanMap(span_map) => span_map.span_at(range.start()),
Self::RealSpanMap(span_map) => span_map.span_for_range(range),
}
}
pub fn as_ref(&self) -> SpanMapRef<'_> {
match self {
Self::ExpansionSpanMap(span_map) => SpanMapRef::ExpansionSpanMap(span_map),
Self::RealSpanMap(span_map) => SpanMapRef::RealSpanMap(span_map),
}
}
#[inline]
pub(crate) fn new(db: &dyn ExpandDatabase, file_id: HirFileId) -> SpanMap {
match file_id.repr() {
HirFileIdRepr::FileId(file_id) => SpanMap::RealSpanMap(db.real_span_map(file_id)),
HirFileIdRepr::MacroFile(m) => {
SpanMap::ExpansionSpanMap(db.parse_macro_expansion(m).value.1)
}
}
}
}
impl SpanMapRef<'_> {
pub fn span_for_range(self, range: TextRange) -> Span {
match self {
Self::ExpansionSpanMap(span_map) => span_map.span_at(range.start()),
Self::RealSpanMap(span_map) => span_map.span_for_range(range),
}
}
}
pub(crate) fn real_span_map(db: &dyn ExpandDatabase, file_id: FileId) -> Arc<RealSpanMap> {
use syntax::ast::HasModuleItem;
let mut pairs = vec![(syntax::TextSize::new(0), span::ROOT_ERASED_FILE_AST_ID)];
let ast_id_map = db.ast_id_map(file_id.into());
let tree = db.parse(file_id).tree();
// FIXME: Descend into modules and other item containing items that are not annotated with attributes
// and allocate pairs for those as well. This gives us finer grained span anchors resulting in
// better incrementality
pairs.extend(
tree.items()
.map(|item| (item.syntax().text_range().start(), ast_id_map.ast_id(&item).erase())),
);
Arc::new(RealSpanMap::from_file(
file_id,
pairs.into_boxed_slice(),
tree.syntax().text_range().end(),
))
}