Use `Either` instead of 2 mutually exclusive `Option`s.
PiperOrigin-RevId: 477573659
diff --git a/cc_bindings_from_rs/cc_bindings_from_rs.rs b/cc_bindings_from_rs/cc_bindings_from_rs.rs
index e2c003b..080b75d 100644
--- a/cc_bindings_from_rs/cc_bindings_from_rs.rs
+++ b/cc_bindings_from_rs/cc_bindings_from_rs.rs
@@ -32,6 +32,7 @@
/// module.
mod bindings_driver {
+ use either::Either;
use rustc_interface::interface::Compiler;
use rustc_interface::Queries;
use rustc_middle::ty::TyCtxt;
@@ -63,8 +64,7 @@
R: Send,
{
args: &'a [String],
- callback: Option<F>,
- callback_result: Option<anyhow::Result<R>>,
+ callback_or_result: Either<F, anyhow::Result<R>>,
}
impl<'a, F, R> AfterAnalysisCallback<'a, F, R>
@@ -73,7 +73,7 @@
R: Send,
{
fn new(args: &'a [String], callback: F) -> Self {
- Self { args, callback: Some(callback), callback_result: None }
+ Self { args, callback_or_result: Either::Left(callback) }
}
/// Runs Rust compiler and then passes the `TyCtxt` of the
@@ -105,11 +105,7 @@
// Return either `rustc_result` or `self.callback_result`.
rustc_result.and_then(|()| {
- assert!(
- self.callback_result.is_some(),
- "The callback should have been called by now"
- );
- self.callback_result.unwrap()
+ self.callback_or_result.right_or_else(|_| panic!("The callback should have been called by now"))
})
}
}
@@ -125,12 +121,12 @@
queries: &'tcx Queries<'tcx>,
) -> rustc_driver::Compilation {
let rustc_result = enter_tcx(queries, |tcx| {
- assert!(
- self.callback_result.is_none(),
- "after_analysis should only run once (1)"
- );
- let callback = self.callback.take().expect("after_analysis should only run once (2)");
- self.callback_result = Some(callback(tcx));
+ let callback = {
+ let temporary_placeholder = Either::Right(Err(anyhow::anyhow!("unused")));
+ std::mem::replace(&mut self.callback_or_result, temporary_placeholder)
+ .left_or_else(|_| panic!("`after_analysis` should only run once"))
+ };
+ self.callback_or_result = Either::Right(callback(tcx));
});
// `expect`ing no errors in `rustc_result`, because `after_analysis` is only
