diff options
Diffstat (limited to 'tokio/src/stream/mod.rs')
-rw-r--r-- | tokio/src/stream/mod.rs | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/tokio/src/stream/mod.rs b/tokio/src/stream/mod.rs index a99dfca3..94ed6bd1 100644 --- a/tokio/src/stream/mod.rs +++ b/tokio/src/stream/mod.rs @@ -7,6 +7,9 @@ mod all; use all::AllFuture; +mod any; +use any::AnyFuture; + mod filter; use filter::Filter; @@ -322,6 +325,59 @@ pub trait StreamExt: Stream { { AllFuture::new(self, f) } + + /// Tests if any element of the stream matches a predicate. + /// + /// `any()` takes a closure that returns `true` or `false`. It applies + /// this closure to each element of the stream, and if any of them return + /// `true`, then so does `any()`. If they all return `false`, it + /// returns `false`. + /// + /// `any()` is short-circuiting; in other words, it will stop processing + /// as soon as it finds a `true`, given that no matter what else happens, + /// the result will also be `true`. + /// + /// An empty stream returns `false`. + /// + /// Basic usage: + /// + /// ``` + /// # #[tokio::main] + /// # async fn main() { + /// use tokio::stream::{self, StreamExt}; + /// + /// let a = [1, 2, 3]; + /// + /// assert!(stream::iter(&a).any(|&x| x > 0).await); + /// + /// assert!(!stream::iter(&a).any(|&x| x > 5).await); + /// # } + /// ``` + /// + /// Stopping at the first `true`: + /// + /// ``` + /// # #[tokio::main] + /// # async fn main() { + /// use tokio::stream::{self, StreamExt}; + /// + /// let a = [1, 2, 3]; + /// + /// let mut iter = stream::iter(&a); + /// + /// assert!(iter.any(|&x| x != 2).await); + /// + /// // we can still use `iter`, as there are more elements. + /// assert_eq!(iter.next().await, Some(&2)); + /// # } + /// ``` + fn any<F>(&mut self, f: F) -> AnyFuture<'_, Self, F> + where + Self: Unpin, + F: FnMut(Self::Item) -> bool, + { + AnyFuture::new(self, f) + } } impl<St: ?Sized> StreamExt for St where St: Stream {} |