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Diffstat (limited to 'core/src/async_utils/condwait.rs')
-rw-r--r-- | core/src/async_utils/condwait.rs | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/core/src/async_utils/condwait.rs b/core/src/async_utils/condwait.rs new file mode 100644 index 0000000..f16a99e --- /dev/null +++ b/core/src/async_utils/condwait.rs @@ -0,0 +1,96 @@ +use smol::lock::Mutex; + +use super::CondVar; + +/// CondWait is a wrapper struct for CondVar with a Mutex boolean flag. +/// +/// # Example +/// +///``` +/// use std::sync::Arc; +/// +/// use karyons_core::async_utils::CondWait; +/// +/// async { +/// let cond_wait = Arc::new(CondWait::new()); +/// let cond_wait_cloned = cond_wait.clone(); +/// let task = smol::spawn(async move { +/// cond_wait_cloned.wait().await; +/// // ... +/// }); +/// +/// cond_wait.signal().await; +/// }; +/// +/// ``` +/// +pub struct CondWait { + /// The CondVar + condvar: CondVar, + /// Boolean flag + w: Mutex<bool>, +} + +impl CondWait { + /// Creates a new CondWait. + pub fn new() -> Self { + Self { + condvar: CondVar::new(), + w: Mutex::new(false), + } + } + + /// Waits for a signal or broadcast. + pub async fn wait(&self) { + let mut w = self.w.lock().await; + + // While the boolean flag is false, wait for a signal. + while !*w { + w = self.condvar.wait(w).await; + } + } + + /// Signal a waiting task. + pub async fn signal(&self) { + *self.w.lock().await = true; + self.condvar.signal(); + } + + /// Signal all waiting tasks. + pub async fn broadcast(&self) { + *self.w.lock().await = true; + self.condvar.broadcast(); + } + + /// Reset the boolean flag value to false. + pub async fn reset(&self) { + *self.w.lock().await = false; + } +} + +impl Default for CondWait { + fn default() -> Self { + Self::new() + } +} + +#[cfg(test)] +mod tests { + use super::*; + use std::sync::Arc; + + #[test] + fn test_cond_wait() { + smol::block_on(async { + let cond_wait = Arc::new(CondWait::new()); + let cond_wait_cloned = cond_wait.clone(); + let task = smol::spawn(async move { + cond_wait_cloned.wait().await; + true + }); + + cond_wait.signal().await; + assert!(task.await); + }); + } +} |