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Add API for mapping Attr back to its syntax node

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This commit is contained in:
Jonas Schievink 2020-12-19 15:15:02 +01:00
parent bd270cbc02
commit 218e88ab55
1 changed files with 55 additions and 23 deletions
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78
crates/hir_def/src/attr.rs
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@ -75,32 +75,31 @@ impl RawAttrs {
pub(crate) const EMPTY: Self = Self { entries: None };
pub(crate) fn new(owner: &dyn AttrsOwner, hygiene: &Hygiene) -> Self {
let (inner_attrs, inner_docs) = inner_attributes(owner.syntax())
.map_or((None, None), |(attrs, docs)| ((Some(attrs), Some(docs))));
let outer_attrs = owner.attrs().filter(|attr| attr.excl_token().is_none());
let attrs = outer_attrs
.chain(inner_attrs.into_iter().flatten())
.map(|attr| (attr.syntax().text_range().start(), Attr::from_src(attr, hygiene)));
let outer_docs =
ast::CommentIter::from_syntax_node(owner.syntax()).filter(ast::Comment::is_outer);
let docs = outer_docs.chain(inner_docs.into_iter().flatten()).map(|docs_text| {
(
docs_text.syntax().text_range().start(),
docs_text.doc_comment().map(|doc| Attr {
input: Some(AttrInput::Literal(SmolStr::new(doc))),
path: ModPath::from(hir_expand::name!(doc)),
}),
)
});
// sort here by syntax node offset because the source can have doc attributes and doc strings be interleaved
let attrs: Vec<_> = docs.chain(attrs).sorted_by_key(|&(offset, _)| offset).collect();
let attrs: Vec<_> = collect_attrs(owner).collect();
let entries = if attrs.is_empty() {
// Avoid heap allocation
None
} else {
Some(attrs.into_iter().flat_map(|(_, attr)| attr).collect())
Some(
attrs
.into_iter()
.enumerate()
.flat_map(|(i, attr)| match attr {
Either::Left(attr) => Attr::from_src(attr, hygiene).map(|attr| (i, attr)),
Either::Right(comment) => comment.doc_comment().map(|doc| {
(
i,
Attr {
index: 0,
input: Some(AttrInput::Literal(SmolStr::new(doc))),
path: ModPath::from(hir_expand::name!(doc)),
},
)
}),
})
.map(|(i, attr)| Attr { index: i as u32, ..attr })
.collect(),
)
};
Self { entries }
}
@ -316,6 +315,7 @@ fn inner_attributes(
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Attr {
index: u32,
pub(crate) path: ModPath,
pub(crate) input: Option<AttrInput>,
}
@ -342,7 +342,19 @@ impl Attr {
} else {
None
};
Some(Attr { path, input })
Some(Attr { index: 0, path, input })
}
/// Maps this lowered `Attr` back to its original syntax node.
///
/// `owner` must be the original owner of the attribute.
///
/// Note that the returned syntax node might be a `#[cfg_attr]`, or a doc comment, instead of
/// the attribute represented by `Attr`.
pub fn to_src(&self, owner: &dyn AttrsOwner) -> Either<ast::Attr, ast::Comment> {
collect_attrs(owner).nth(self.index as usize).unwrap_or_else(|| {
panic!("cannot find `Attr` at index {} in {}", self.index, owner.syntax())
})
}
/// Parses this attribute as a `#[derive]`, returns an iterator that yields all contained paths
@ -432,3 +444,23 @@ fn attrs_from_item_tree<N: ItemTreeNode>(id: ItemTreeId<N>, db: &dyn DefDatabase
let mod_item = N::id_to_mod_item(id.value);
tree.raw_attrs(mod_item.into()).clone()
}
fn collect_attrs(owner: &dyn AttrsOwner) -> impl Iterator<Item = Either<ast::Attr, ast::Comment>> {
let (inner_attrs, inner_docs) = inner_attributes(owner.syntax())
.map_or((None, None), |(attrs, docs)| ((Some(attrs), Some(docs))));
let outer_attrs = owner.attrs().filter(|attr| attr.excl_token().is_none());
let attrs = outer_attrs
.chain(inner_attrs.into_iter().flatten())
.map(|attr| (attr.syntax().text_range().start(), Either::Left(attr)));
let outer_docs =
ast::CommentIter::from_syntax_node(owner.syntax()).filter(ast::Comment::is_outer);
let docs = outer_docs
.chain(inner_docs.into_iter().flatten())
.map(|docs_text| (docs_text.syntax().text_range().start(), Either::Right(docs_text)));
// sort here by syntax node offset because the source can have doc attributes and doc strings be interleaved
let attrs: Vec<_> = docs.chain(attrs).sorted_by_key(|&(offset, _)| offset).collect();
attrs.into_iter().map(|(_, attr)| attr)
}