bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/cfg/src/cfg_attr.rs')
-rw-r--r--crates/cfg/src/cfg_attr.rs70
1 files changed, 70 insertions, 0 deletions
diff --git a/crates/cfg/src/cfg_attr.rs b/crates/cfg/src/cfg_attr.rs
new file mode 100644
index 0000000000..4eb5928b1e
--- /dev/null
+++ b/crates/cfg/src/cfg_attr.rs
@@ -0,0 +1,70 @@
+use std::{
+ fmt::{self, Debug},
+ slice::Iter as SliceIter,
+};
+
+use crate::{cfg_expr::next_cfg_expr, CfgAtom, CfgExpr};
+use tt::{Delimiter, SmolStr, Span};
+/// Represents a `#[cfg_attr(.., my_attr)]` attribute.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct CfgAttr<S> {
+ /// Expression in `cfg_attr` attribute.
+ pub cfg_expr: CfgExpr,
+ /// Inner attribute.
+ pub attr: tt::Subtree<S>,
+}
+
+impl<S: Clone + Span + Debug> CfgAttr<S> {
+ /// Parses a sub tree in the form of (cfg_expr, inner_attribute)
+ pub fn parse(tt: &tt::Subtree<S>) -> Option<CfgAttr<S>> {
+ let mut iter = tt.token_trees.iter();
+ let cfg_expr = next_cfg_expr(&mut iter).unwrap_or(CfgExpr::Invalid);
+ // FIXME: This is probably not the right way to do this
+ // Get's the span of the next token tree
+ let first_span = iter.as_slice().first().map(|tt| tt.first_span())?;
+ let attr = tt::Subtree {
+ delimiter: Delimiter::invisible_spanned(first_span),
+ token_trees: iter.cloned().collect(),
+ };
+ Some(CfgAttr { cfg_expr, attr: attr })
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use expect_test::{expect, Expect};
+ use mbe::{syntax_node_to_token_tree, DummyTestSpanMap, DUMMY};
+ use syntax::{ast, AstNode};
+
+ use crate::{CfgAttr, DnfExpr};
+
+ fn check_dnf(input: &str, expected_dnf: Expect, expected_attrs: Expect) {
+ let source_file = ast::SourceFile::parse(input).ok().unwrap();
+ let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
+ let tt = syntax_node_to_token_tree(tt.syntax(), DummyTestSpanMap, DUMMY);
+ let Some(CfgAttr { cfg_expr, attr }) = CfgAttr::parse(&tt) else {
+ assert!(false, "failed to parse cfg_attr");
+ return;
+ };
+
+ let actual = format!("#![cfg({})]", DnfExpr::new(cfg_expr));
+ expected_dnf.assert_eq(&actual);
+ let actual_attrs = format!("#![{}]", attr);
+ expected_attrs.assert_eq(&actual_attrs);
+ }
+
+ #[test]
+ fn smoke() {
+ check_dnf(
+ r#"#![cfg_attr(feature = "nightly", feature(slice_split_at_unchecked))]"#,
+ expect![[r#"#![cfg(feature = "nightly")]"#]],
+ expect![r#"#![feature (slice_split_at_unchecked)]"#],
+ );
+
+ check_dnf(
+ r#"#![cfg_attr(not(feature = "std"), no_std)]"#,
+ expect![[r#"#![cfg(not(feature = "std"))]"#]],
+ expect![r#"#![no_std]"#],
+ );
+ }
+}