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use crate::db::AstDatabase;
use base_db::{CrateId, ProcMacroExpansionError, ProcMacroId};
use mbe::ExpandResult;
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
pub struct ProcMacroExpander {
krate: CrateId,
proc_macro_id: Option<ProcMacroId>,
}
impl ProcMacroExpander {
pub fn new(krate: CrateId, proc_macro_id: ProcMacroId) -> Self {
Self { krate, proc_macro_id: Some(proc_macro_id) }
}
pub fn dummy(krate: CrateId) -> Self {
Self { krate, proc_macro_id: None }
}
pub fn is_dummy(&self) -> bool {
self.proc_macro_id.is_none()
}
pub fn expand(
self,
db: &dyn AstDatabase,
calling_crate: CrateId,
tt: &tt::Subtree,
attr_arg: Option<&tt::Subtree>,
) -> ExpandResult<tt::Subtree> {
match self.proc_macro_id {
Some(id) => {
let krate_graph = db.crate_graph();
let proc_macro = match krate_graph[self.krate].proc_macro.get(id.0 as usize) {
Some(proc_macro) => proc_macro,
None => return ExpandResult::str_err("No derive macro found.".to_string()),
};
let env = &krate_graph[calling_crate].env;
proc_macro
.expander
.expand(tt, attr_arg, env)
.map_err(|err| match err {
ProcMacroExpansionError::Panic(text) => mbe::ExpandError::Other(text),
ProcMacroExpansionError::System(text) => mbe::ExpandError::Other(text),
})
.into()
}
None => ExpandResult::only_err(mbe::ExpandError::UnresolvedProcMacro),
}
}
}