Async Loading outdir and proc-macro

crates/rust-analyzer/src/op_queue.rs

@@ -1,22 +1,26 @@
 //! Bookkeeping to make sure only one long-running operation is executed.
 
-#[derive(Default)]
-pub(crate) struct OpQueue {
-    op_scheduled: bool,
+pub(crate) struct OpQueue<D> {
+    op_scheduled: Option<D>,
     op_in_progress: bool,
 }
 
-impl OpQueue {
-    pub(crate) fn request_op(&mut self) {
-        self.op_scheduled = true;
+impl<D> Default for OpQueue<D> {
+    fn default() -> Self {
+        Self { op_scheduled: None, op_in_progress: false }
     }
-    pub(crate) fn should_start_op(&mut self) -> bool {
-        if !self.op_in_progress && self.op_scheduled {
-            self.op_in_progress = true;
-            self.op_scheduled = false;
-            return true;
+}
+
+impl<D> OpQueue<D> {
+    pub(crate) fn request_op(&mut self, data: D) {
+        self.op_scheduled = Some(data);
+    }
+    pub(crate) fn should_start_op(&mut self) -> Option<D> {
+        if self.op_in_progress {
+            return None;
         }
-        false
+        self.op_in_progress = self.op_scheduled.is_some();
+        self.op_scheduled.take()
     }
     pub(crate) fn op_completed(&mut self) {
         assert!(self.op_in_progress);