-//! Bookkeeping to make sure only one long-running operation is executed.
+//! Bookkeeping to make sure only one long-running operation is being executed
+//! at a time.
-pub(crate) struct OpQueue<D> {
- op_scheduled: Option<D>,
+pub(crate) struct OpQueue<Args, Output> {
+ op_requested: Option<Args>,
op_in_progress: bool,
+ last_op_result: Output,
}
-impl<D> Default for OpQueue<D> {
+impl<Args, Output: Default> Default for OpQueue<Args, Output> {
fn default() -> Self {
- Self { op_scheduled: None, op_in_progress: false }
+ Self { op_requested: None, op_in_progress: false, last_op_result: Default::default() }
}
}
-impl<D> OpQueue<D> {
- pub(crate) fn request_op(&mut self, data: D) {
- self.op_scheduled = Some(data);
+impl<Args, Output> OpQueue<Args, Output> {
+ pub(crate) fn request_op(&mut self, data: Args) {
+ self.op_requested = Some(data);
}
- pub(crate) fn should_start_op(&mut self) -> Option<D> {
+ pub(crate) fn should_start_op(&mut self) -> Option<Args> {
if self.op_in_progress {
return None;
}
- self.op_in_progress = self.op_scheduled.is_some();
- self.op_scheduled.take()
+ self.op_in_progress = self.op_requested.is_some();
+ self.op_requested.take()
}
- pub(crate) fn op_completed(&mut self) {
+ pub(crate) fn op_completed(&mut self, result: Output) {
assert!(self.op_in_progress);
self.op_in_progress = false;
+ self.last_op_result = result;
+ }
+
+ #[allow(unused)]
+ pub(crate) fn last_op_result(&self) -> &Output {
+ &self.last_op_result
+ }
+ pub(crate) fn op_in_progress(&self) -> bool {
+ self.op_in_progress
+ }
+ pub(crate) fn op_requested(&self) -> bool {
+ self.op_requested.is_some()
}
}