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|
//! Macro input conditioning.
use syntax::{
ast::{self, make, AttrsOwner},
AstNode, SyntaxNode,
};
use crate::{
db::AstDatabase,
name::{name, AsName},
MacroCallId, MacroCallKind, MacroCallLoc,
};
pub(crate) fn process_macro_input(
db: &dyn AstDatabase,
node: SyntaxNode,
id: MacroCallId,
) -> SyntaxNode {
let loc: MacroCallLoc = db.lookup_intern_macro(id);
match loc.kind {
MacroCallKind::FnLike { .. } => node,
MacroCallKind::Derive { derive_attr_index, .. } => {
let item = match ast::Item::cast(node.clone()) {
Some(item) => item,
None => return node,
};
remove_derives_up_to(item, derive_attr_index as usize).syntax().clone()
}
MacroCallKind::Attr { invoc_attr_index, .. } => {
let item = match ast::Item::cast(node.clone()) {
Some(item) => item,
None => return node,
};
remove_attr_invoc(item, invoc_attr_index as usize).syntax().clone()
}
}
}
/// Removes `#[derive]` attributes from `item`, up to `attr_index`.
fn remove_derives_up_to(item: ast::Item, attr_index: usize) -> ast::Item {
let item = item.clone_for_update();
for attr in item.attrs().take(attr_index + 1) {
if let Some(name) =
attr.path().and_then(|path| path.as_single_segment()).and_then(|seg| seg.name_ref())
{
if name.as_name() == name![derive] {
attr.syntax().detach();
}
}
}
item
}
/// Removes the attribute invoking an attribute macro from `item`.
fn remove_attr_invoc(item: ast::Item, attr_index: usize) -> ast::Item {
let item = item.clone_for_update();
let attr = item
.attrs()
.nth(attr_index)
.unwrap_or_else(|| panic!("cannot find attribute #{}", attr_index));
let syntax_index = attr.syntax().index();
let ws = make::tokens::whitespace(&" ".repeat(u32::from(attr.syntax().text().len()) as usize));
item.syntax().splice_children(syntax_index..syntax_index + 1, vec![ws.into()]);
item
}
#[cfg(test)]
mod tests {
use base_db::fixture::WithFixture;
use base_db::SourceDatabase;
use expect_test::{expect, Expect};
use crate::test_db::TestDB;
use super::*;
fn test_remove_derives_up_to(attr: usize, ra_fixture: &str, expect: Expect) {
let (db, file_id) = TestDB::with_single_file(ra_fixture);
let parsed = db.parse(file_id);
let mut items: Vec<_> =
parsed.syntax_node().descendants().filter_map(ast::Item::cast).collect();
assert_eq!(items.len(), 1);
let item = remove_derives_up_to(items.pop().unwrap(), attr);
expect.assert_eq(&item.to_string());
}
#[test]
fn remove_derive() {
test_remove_derives_up_to(
2,
r#"
#[allow(unused)]
#[derive(Copy)]
#[derive(Hello)]
#[derive(Clone)]
struct A {
bar: u32
}
"#,
expect![[r#"
#[allow(unused)]
#[derive(Clone)]
struct A {
bar: u32
}"#]],
);
}
}
|
