bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-expand/src/span_map.rs')
-rw-r--r--crates/hir-expand/src/span_map.rs125
1 files changed, 125 insertions, 0 deletions
diff --git a/crates/hir-expand/src/span_map.rs b/crates/hir-expand/src/span_map.rs
new file mode 100644
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+++ b/crates/hir-expand/src/span_map.rs
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+//! Spanmaps allow turning absolute ranges into relative ranges for incrementality purposes as well
+//! as associating spans with text ranges in a particular file.
+
+// FIXME: Consider moving this into the span crate
+
+use base_db::FileId;
+use span::{ErasedFileAstId, Span, SpanAnchor, SyntaxContextId, ROOT_ERASED_FILE_AST_ID};
+use syntax::{ast::HasModuleItem, AstNode, TextRange, TextSize};
+use triomphe::Arc;
+
+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 mbe::SpanMapper<Span> for RealSpanMap {
+ 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 {
+ 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),
+ }
+ }
+}
+
+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),
+ }
+ }
+}
+
+#[derive(PartialEq, Eq, Hash, Debug)]
+pub struct RealSpanMap {
+ file_id: FileId,
+ /// Invariant: Sorted vec over TextSize
+ // FIXME: SortedVec<(TextSize, ErasedFileAstId)>?
+ pairs: Box<[(TextSize, ErasedFileAstId)]>,
+ end: TextSize,
+}
+
+impl RealSpanMap {
+ /// Creates a real file span map that returns absolute ranges (relative ranges to the root ast id).
+ pub fn absolute(file_id: FileId) -> Self {
+ RealSpanMap {
+ file_id,
+ pairs: Box::from([(TextSize::new(0), ROOT_ERASED_FILE_AST_ID)]),
+ end: TextSize::new(!0),
+ }
+ }
+
+ pub fn from_file(db: &dyn ExpandDatabase, file_id: FileId) -> Self {
+ let mut pairs = vec![(TextSize::new(0), ROOT_ERASED_FILE_AST_ID)];
+ let ast_id_map = db.ast_id_map(file_id.into());
+ let tree = db.parse(file_id).tree();
+ pairs
+ .extend(tree.items().map(|item| {
+ (item.syntax().text_range().start(), ast_id_map.ast_id(&item).erase())
+ }));
+ RealSpanMap {
+ file_id,
+ pairs: pairs.into_boxed_slice(),
+ end: tree.syntax().text_range().end(),
+ }
+ }
+
+ pub fn span_for_range(&self, range: TextRange) -> Span {
+ assert!(
+ range.end() <= self.end,
+ "range {range:?} goes beyond the end of the file {:?}",
+ self.end
+ );
+ let start = range.start();
+ let idx = self
+ .pairs
+ .binary_search_by(|&(it, _)| it.cmp(&start).then(std::cmp::Ordering::Less))
+ .unwrap_err();
+ let (offset, ast_id) = self.pairs[idx - 1];
+ Span {
+ range: range - offset,
+ anchor: SpanAnchor { file_id: self.file_id, ast_id },
+ ctx: SyntaxContextId::ROOT,
+ }
+ }
+}