45 lines
1.3 KiB
Rust
45 lines
1.3 KiB
Rust
//! Bookkeeping to make sure only one long-running operation is being executed
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//! at a time.
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pub(crate) type Cause = String;
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pub(crate) struct OpQueue<Args = (), Output = ()> {
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op_requested: Option<(Cause, Args)>,
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op_in_progress: bool,
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last_op_result: Output,
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}
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impl<Args, Output: Default> Default for OpQueue<Args, Output> {
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fn default() -> Self {
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Self { op_requested: None, op_in_progress: false, last_op_result: Default::default() }
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}
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}
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impl<Args, Output> OpQueue<Args, Output> {
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pub(crate) fn request_op(&mut self, reason: Cause, args: Args) {
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self.op_requested = Some((reason, args));
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}
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pub(crate) fn should_start_op(&mut self) -> Option<(Cause, Args)> {
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if self.op_in_progress {
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return None;
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}
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self.op_in_progress = self.op_requested.is_some();
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self.op_requested.take()
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}
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pub(crate) fn op_completed(&mut self, result: Output) {
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assert!(self.op_in_progress);
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self.op_in_progress = false;
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self.last_op_result = result;
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}
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pub(crate) fn last_op_result(&self) -> &Output {
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&self.last_op_result
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}
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pub(crate) fn op_in_progress(&self) -> bool {
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self.op_in_progress
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}
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pub(crate) fn op_requested(&self) -> bool {
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self.op_requested.is_some()
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}
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}
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