crates/rust-analyzer/src/op_queue.rs

   1 //! Bookkeeping to make sure only one long-running operation is being executed
   2 //! at a time.
   3
   4 pub(crate) type Cause = String;
   5
   6 pub(crate) struct OpQueue<Output> {
   7     op_requested: Option<Cause>,
   8     op_in_progress: bool,
   9     last_op_result: Output,
  10 }
  11
  12 impl<Output: Default> Default for OpQueue<Output> {
  13     fn default() -> Self {
  14         Self { op_requested: None, op_in_progress: false, last_op_result: Default::default() }
  15     }
  16 }
  17
  18 impl<Output> OpQueue<Output> {
  19     pub(crate) fn request_op(&mut self, reason: Cause) {
  20         self.op_requested = Some(reason);
  21     }
  22     pub(crate) fn should_start_op(&mut self) -> Option<Cause> {
  23         if self.op_in_progress {
  24             return None;
  25         }
  26         self.op_in_progress = self.op_requested.is_some();
  27         self.op_requested.take()
  28     }
  29     pub(crate) fn op_completed(&mut self, result: Output) {
  30         assert!(self.op_in_progress);
  31         self.op_in_progress = false;
  32         self.last_op_result = result;
  33     }
  34
  35     pub(crate) fn last_op_result(&self) -> &Output {
  36         &self.last_op_result
  37     }
  38     pub(crate) fn op_in_progress(&self) -> bool {
  39         self.op_in_progress
  40     }
  41     pub(crate) fn op_requested(&self) -> bool {
  42         self.op_requested.is_some()
  43     }
  44 }