Merge pull request #2496 from iced-rs/abortable-tasks

Abortable `Task`

runtime/src/task.rs

@@ -55,24 +55,6 @@ impl<T> Task<T> {
         Self::stream(stream.map(f))
     }
 
-    /// Creates a new [`Task`] that runs the given [`Future`] and produces
-    /// its output.
-    pub fn future(future: impl Future<Output = T> + MaybeSend + 'static) -> Self
-    where
-        T: 'static,
-    {
-        Self::stream(stream::once(future))
-    }
-
-    /// Creates a new [`Task`] that runs the given [`Stream`] and produces
-    /// each of its items.
-    pub fn stream(stream: impl Stream<Item = T> + MaybeSend + 'static) -> Self
-    where
-        T: 'static,
-    {
-        Self(Some(boxed_stream(stream.map(Action::Output))))
-    }
-
     /// Combines the given tasks and produces a single [`Task`] that will run all of them
     /// in parallel.
     pub fn batch(tasks: impl IntoIterator<Item = Self>) -> Self
@@ -176,6 +158,61 @@ impl<T> Task<T> {
             ))),
         }
     }
+
+    /// Creates a new [`Task`] that can be aborted with the returned [`Handle`].
+    pub fn abortable(self) -> (Self, Handle)
+    where
+        T: 'static,
+    {
+        match self.0 {
+            Some(stream) => {
+                let (stream, handle) = stream::abortable(stream);
+
+                (Self(Some(boxed_stream(stream))), Handle(Some(handle)))
+            }
+            None => (Self(None), Handle(None)),
+        }
+    }
+
+    /// Creates a new [`Task`] that runs the given [`Future`] and produces
+    /// its output.
+    pub fn future(future: impl Future<Output = T> + MaybeSend + 'static) -> Self
+    where
+        T: 'static,
+    {
+        Self::stream(stream::once(future))
+    }
+
+    /// Creates a new [`Task`] that runs the given [`Stream`] and produces
+    /// each of its items.
+    pub fn stream(stream: impl Stream<Item = T> + MaybeSend + 'static) -> Self
+    where
+        T: 'static,
+    {
+        Self(Some(boxed_stream(stream.map(Action::Output))))
+    }
+}
+
+/// A handle to a [`Task`] that can be used for aborting it.
+#[derive(Debug, Clone)]
+pub struct Handle(Option<stream::AbortHandle>);
+
+impl Handle {
+    /// Aborts the [`Task`] of this [`Handle`].
+    pub fn abort(&self) {
+        if let Some(handle) = &self.0 {
+            handle.abort();
+        }
+    }
+
+    /// Returns `true` if the [`Task`] of this [`Handle`] has been aborted.
+    pub fn is_aborted(&self) -> bool {
+        if let Some(handle) = &self.0 {
+            handle.is_aborted()
+        } else {
+            true
+        }
+    }
 }
 
 impl<T> Task<Option<T>> {

src/lib.rs

@@ -202,9 +202,14 @@ pub use crate::core::{
     Length, Padding, Pixels, Point, Radians, Rectangle, Rotation, Shadow, Size,
     Theme, Transformation, Vector,
 };
-pub use crate::runtime::{exit, Task};
+pub use crate::runtime::exit;
 pub use iced_futures::Subscription;
 
+pub mod task {
+    //! Create runtime tasks.
+    pub use crate::runtime::task::{Handle, Task};
+}
+
 pub mod clipboard {
     //! Access the clipboard.
     pub use crate::runtime::clipboard::{
@@ -309,6 +314,7 @@ pub use executor::Executor;
 pub use font::Font;
 pub use renderer::Renderer;
 pub use settings::Settings;
+pub use task::Task;
 
 #[doc(inline)]
 pub use application::application;