144 lines
3.5 KiB
Rust
144 lines
3.5 KiB
Rust
//! Proc Macro Expander stub
|
|
|
|
use crate::{db::AstDatabase, LazyMacroId};
|
|
use base_db::{CrateId, ProcMacroId};
|
|
use tt::buffer::{Cursor, TokenBuffer};
|
|
|
|
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
|
|
pub struct ProcMacroExpander {
|
|
krate: CrateId,
|
|
proc_macro_id: ProcMacroId,
|
|
}
|
|
|
|
macro_rules! err {
|
|
($fmt:literal, $($tt:tt),*) => {
|
|
mbe::ExpandError::ProcMacroError(tt::ExpansionError::Unknown(format!($fmt, $($tt),*)))
|
|
};
|
|
($fmt:literal) => {
|
|
mbe::ExpandError::ProcMacroError(tt::ExpansionError::Unknown($fmt.to_string()))
|
|
}
|
|
}
|
|
|
|
impl ProcMacroExpander {
|
|
pub fn new(krate: CrateId, proc_macro_id: ProcMacroId) -> ProcMacroExpander {
|
|
ProcMacroExpander { krate, proc_macro_id }
|
|
}
|
|
|
|
pub fn expand(
|
|
self,
|
|
db: &dyn AstDatabase,
|
|
_id: LazyMacroId,
|
|
tt: &tt::Subtree,
|
|
) -> Result<tt::Subtree, mbe::ExpandError> {
|
|
let krate_graph = db.crate_graph();
|
|
let proc_macro = krate_graph[self.krate]
|
|
.proc_macro
|
|
.get(self.proc_macro_id.0 as usize)
|
|
.clone()
|
|
.ok_or_else(|| err!("No derive macro found."))?;
|
|
|
|
let tt = remove_derive_attrs(tt)
|
|
.ok_or_else(|| err!("Fail to remove derive for custom derive"))?;
|
|
|
|
proc_macro.expander.expand(&tt, None).map_err(mbe::ExpandError::from)
|
|
}
|
|
}
|
|
|
|
fn eat_punct(cursor: &mut Cursor, c: char) -> bool {
|
|
if let Some(tt::TokenTree::Leaf(tt::Leaf::Punct(punct))) = cursor.token_tree() {
|
|
if punct.char == c {
|
|
*cursor = cursor.bump();
|
|
return true;
|
|
}
|
|
}
|
|
false
|
|
}
|
|
|
|
fn eat_subtree(cursor: &mut Cursor, kind: tt::DelimiterKind) -> bool {
|
|
if let Some(tt::TokenTree::Subtree(subtree)) = cursor.token_tree() {
|
|
if Some(kind) == subtree.delimiter_kind() {
|
|
*cursor = cursor.bump_subtree();
|
|
return true;
|
|
}
|
|
}
|
|
false
|
|
}
|
|
|
|
fn eat_ident(cursor: &mut Cursor, t: &str) -> bool {
|
|
if let Some(tt::TokenTree::Leaf(tt::Leaf::Ident(ident))) = cursor.token_tree() {
|
|
if t == ident.text.as_str() {
|
|
*cursor = cursor.bump();
|
|
return true;
|
|
}
|
|
}
|
|
false
|
|
}
|
|
|
|
fn remove_derive_attrs(tt: &tt::Subtree) -> Option<tt::Subtree> {
|
|
let buffer = TokenBuffer::new(&tt.token_trees);
|
|
let mut p = buffer.begin();
|
|
let mut result = tt::Subtree::default();
|
|
|
|
while !p.eof() {
|
|
let curr = p;
|
|
|
|
if eat_punct(&mut p, '#') {
|
|
eat_punct(&mut p, '!');
|
|
let parent = p;
|
|
if eat_subtree(&mut p, tt::DelimiterKind::Bracket) {
|
|
if eat_ident(&mut p, "derive") {
|
|
p = parent.bump();
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
|
|
result.token_trees.push(curr.token_tree()?.clone());
|
|
p = curr.bump();
|
|
}
|
|
|
|
Some(result)
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
use test_utils::assert_eq_text;
|
|
|
|
#[test]
|
|
fn test_remove_derive_attrs() {
|
|
let tt = mbe::parse_to_token_tree(
|
|
r#"
|
|
#[allow(unused)]
|
|
#[derive(Copy)]
|
|
#[derive(Hello)]
|
|
struct A {
|
|
bar: u32
|
|
}
|
|
"#,
|
|
)
|
|
.unwrap()
|
|
.0;
|
|
let result = format!("{:#?}", remove_derive_attrs(&tt).unwrap());
|
|
|
|
assert_eq_text!(
|
|
&result,
|
|
r#"
|
|
SUBTREE $
|
|
PUNCH # [alone] 0
|
|
SUBTREE [] 1
|
|
IDENT allow 2
|
|
SUBTREE () 3
|
|
IDENT unused 4
|
|
IDENT struct 15
|
|
IDENT A 16
|
|
SUBTREE {} 17
|
|
IDENT bar 18
|
|
PUNCH : [alone] 19
|
|
IDENT u32 20
|
|
"#
|
|
.trim()
|
|
);
|
|
}
|
|
}
|