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50 lines
1.5 KiB
50 lines
1.5 KiB
use tokio::sync::broadcast;
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/// Listens for the server shutdown signal.
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///
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/// Shutdown is signalled using a `broadcast::Receiver`. Only a single value is
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/// ever sent. Once a value has been sent via the broadcast channel, the server
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/// should shutdown.
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///
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/// The `Shutdown` struct listens for the signal and tracks that the signal has
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/// been received. Callers may query for whether the shutdown signal has been
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/// received or not.
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#[derive(Debug)]
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pub(crate) struct Shutdown {
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/// `true` if the shutdown signal has been received
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shutdown: bool,
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/// The receive half of the channel used to listen for shutdown.
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notify: broadcast::Receiver<()>,
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}
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impl Shutdown {
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/// Create a new `Shutdown` backed by the given `broadcast::Receiver`.
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pub(crate) fn new(notify: broadcast::Receiver<()>) -> Shutdown {
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Shutdown {
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shutdown: false,
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notify,
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}
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}
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/// Returns `true` if the shutdown signal has been received.
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pub(crate) fn is_shutdown(&self) -> bool {
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self.shutdown
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}
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/// Receive the shutdown notice, waiting if necessary.
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pub(crate) async fn recv(&mut self) {
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// If the shutdown signal has already been received, then return
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// immediately.
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if self.shutdown {
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return;
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}
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// Cannot receive a "lag error" as only one value is ever sent.
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let _ = self.notify.recv().await;
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// Remember that the signal has been received.
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self.shutdown = true;
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}
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}
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