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@ -38,6 +38,11 @@ impl fmt::Display for InitWaitError
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}
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}
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/// Provides a method of waiting on and setting a single initialisation.
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///
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/// In general, it should only be set once, as multiple sets do nothing but hog `Arc`s.
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/// Dropping the `Initialiser` after waiting or setting should generally be done immediately.
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/// Choose the `into_wait()` and `set()` varients over the non-consuming ones.
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#[derive(Clone, Debug)]
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pub struct Initialiser
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{
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@ -47,6 +52,7 @@ pub struct Initialiser
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impl Initialiser
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{
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/// Create a new, unset initialiser
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pub fn new() -> Self
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{
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let (tx, rx) = watch::channel(false);
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@ -56,6 +62,7 @@ impl Initialiser
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}
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}
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/// Create a pre-set initialiser. Calls to `wait()` will immediately resolve.
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pub fn new_set() -> Self
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{
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let (tx, rx) = watch::channel(true);
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@ -64,7 +71,8 @@ impl Initialiser
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rx,
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}
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}
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/// Consume into a future that completes when init is set.
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pub fn into_wait(self) -> impl Future<Output=Result<(), InitWaitError>> + 'static
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{
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let mut rx = self.rx;
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@ -80,6 +88,10 @@ impl Initialiser
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}
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}
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/// Clone into a future that completes when init is set.
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///
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/// This method does not clone any `Arc`s and is prefered to `self.clone().into_wait()`.
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/// Use this when the `Initialiser` you want to wait on is behind a shared reference.
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pub fn clone_into_wait(&self) -> impl Future<Output=Result<(), InitWaitError>> + 'static
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{
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let mut rx = self.rx.clone();
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@ -94,7 +106,8 @@ impl Initialiser
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}
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}
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}
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/// Completes when init is set
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pub async fn wait(&mut self) -> Result<(), InitWaitError>
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{
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if !*self.rx.borrow() {
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@ -107,11 +120,13 @@ impl Initialiser
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}
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}
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/// Is init set?
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pub fn is_set(&self) -> bool
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{
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*self.rx.borrow()
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}
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/// Consume and set init if it's not already set
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pub fn set(self) -> Result<(), InitError>
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{
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if !*self.rx.borrow() {
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@ -120,6 +135,20 @@ impl Initialiser
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Ok(())
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}
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}
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/// Set init without consuming.
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///
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/// # Note
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/// It is prefered to use `set()`, as this method may make `Arc`s hang around longer than they need to.
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/// Calling this multiple times is useless.
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pub fn set_in_place(&self) -> Result<(), InitError>
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{
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if !*self.rx.borrow() {
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self.tx.broadcast(true).map_err(|_| InitError)
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} else {
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Ok(())
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}
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}
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}
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impl Future for Initialiser
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