Merge pull request #234 from hecrj/improvement/subscription-send-requirement

Improve compatibility of `iced_futures`

futures/src/command.rs

@@ -1,11 +1,102 @@
-#[cfg(not(target_arch = "wasm32"))]
+use crate::BoxFuture;
-mod native;
+use futures::future::{Future, FutureExt};
 
-#[cfg(not(target_arch = "wasm32"))]
+/// A collection of async operations.
-pub use native::Command;
+///
+/// You should be able to turn a future easily into a [`Command`], either by
+/// using the `From` trait or [`Command::perform`].
+///
+/// [`Command`]: struct.Command.html
+pub struct Command<T> {
+    futures: Vec<BoxFuture<T>>,
+}
 
-#[cfg(target_arch = "wasm32")]
+impl<T> Command<T> {
-mod web;
+    /// Creates an empty [`Command`].
+    ///
+    /// In other words, a [`Command`] that does nothing.
+    ///
+    /// [`Command`]: struct.Command.html
+    pub fn none() -> Self {
+        Self {
+            futures: Vec::new(),
+        }
+    }
 
-#[cfg(target_arch = "wasm32")]
+    /// Creates a [`Command`] that performs the action of the given future.
-pub use web::Command;
+    ///
+    /// [`Command`]: struct.Command.html
+    pub fn perform<A>(
+        future: impl Future<Output = T> + 'static + Send,
+        f: impl Fn(T) -> A + 'static + Send,
+    ) -> Command<A> {
+        Command {
+            futures: vec![Box::pin(future.map(f))],
+        }
+    }
+
+    /// Applies a transformation to the result of a [`Command`].
+    ///
+    /// [`Command`]: struct.Command.html
+    pub fn map<A>(
+        mut self,
+        f: impl Fn(T) -> A + 'static + Send + Sync,
+    ) -> Command<A>
+    where
+        T: 'static,
+    {
+        let f = std::sync::Arc::new(f);
+
+        Command {
+            futures: self
+                .futures
+                .drain(..)
+                .map(|future| {
+                    let f = f.clone();
+
+                    Box::pin(future.map(move |result| f(result)))
+                        as BoxFuture<A>
+                })
+                .collect(),
+        }
+    }
+
+    /// Creates a [`Command`] that performs the actions of all the given
+    /// commands.
+    ///
+    /// Once this command is run, all the commands will be executed at once.
+    ///
+    /// [`Command`]: struct.Command.html
+    pub fn batch(commands: impl IntoIterator<Item = Command<T>>) -> Self {
+        Self {
+            futures: commands
+                .into_iter()
+                .flat_map(|command| command.futures)
+                .collect(),
+        }
+    }
+
+    /// Converts a [`Command`] into its underlying list of futures.
+    ///
+    /// [`Command`]: struct.Command.html
+    pub fn futures(self) -> Vec<BoxFuture<T>> {
+        self.futures
+    }
+}
+
+impl<T, A> From<A> for Command<T>
+where
+    A: Future<Output = T> + 'static + Send,
+{
+    fn from(future: A) -> Self {
+        Self {
+            futures: vec![future.boxed()],
+        }
+    }
+}
+
+impl<T> std::fmt::Debug for Command<T> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("Command").finish()
+    }
+}

futures/src/command/native.rs

@@ -1,100 +0,0 @@
-use futures::future::{BoxFuture, Future, FutureExt};
-
-/// A collection of async operations.
-///
-/// You should be able to turn a future easily into a [`Command`], either by
-/// using the `From` trait or [`Command::perform`].
-///
-/// [`Command`]: struct.Command.html
-pub struct Command<T> {
-    futures: Vec<BoxFuture<'static, T>>,
-}
-
-impl<T> Command<T> {
-    /// Creates an empty [`Command`].
-    ///
-    /// In other words, a [`Command`] that does nothing.
-    ///
-    /// [`Command`]: struct.Command.html
-    pub fn none() -> Self {
-        Self {
-            futures: Vec::new(),
-        }
-    }
-
-    /// Creates a [`Command`] that performs the action of the given future.
-    ///
-    /// [`Command`]: struct.Command.html
-    pub fn perform<A>(
-        future: impl Future<Output = T> + 'static + Send,
-        f: impl Fn(T) -> A + 'static + Send,
-    ) -> Command<A> {
-        Command {
-            futures: vec![future.map(f).boxed()],
-        }
-    }
-
-    /// Applies a transformation to the result of a [`Command`].
-    ///
-    /// [`Command`]: struct.Command.html
-    pub fn map<A>(
-        mut self,
-        f: impl Fn(T) -> A + 'static + Send + Sync,
-    ) -> Command<A>
-    where
-        T: 'static,
-    {
-        let f = std::sync::Arc::new(f);
-
-        Command {
-            futures: self
-                .futures
-                .drain(..)
-                .map(|future| {
-                    let f = f.clone();
-
-                    future.map(move |result| f(result)).boxed()
-                })
-                .collect(),
-        }
-    }
-
-    /// Creates a [`Command`] that performs the actions of all the given
-    /// commands.
-    ///
-    /// Once this command is run, all the commands will be executed at once.
-    ///
-    /// [`Command`]: struct.Command.html
-    pub fn batch(commands: impl IntoIterator<Item = Command<T>>) -> Self {
-        Self {
-            futures: commands
-                .into_iter()
-                .flat_map(|command| command.futures)
-                .collect(),
-        }
-    }
-
-    /// Converts a [`Command`] into its underlying list of futures.
-    ///
-    /// [`Command`]: struct.Command.html
-    pub fn futures(self) -> Vec<BoxFuture<'static, T>> {
-        self.futures
-    }
-}
-
-impl<T, A> From<A> for Command<T>
-where
-    A: Future<Output = T> + 'static + Send,
-{
-    fn from(future: A) -> Self {
-        Self {
-            futures: vec![future.boxed()],
-        }
-    }
-}
-
-impl<T> std::fmt::Debug for Command<T> {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.debug_struct("Command").finish()
-    }
-}

futures/src/command/web.rs

@@ -1,101 +0,0 @@
-use futures::future::{Future, FutureExt};
-use std::pin::Pin;
-
-/// A collection of async operations.
-///
-/// You should be able to turn a future easily into a [`Command`], either by
-/// using the `From` trait or [`Command::perform`].
-///
-/// [`Command`]: struct.Command.html
-pub struct Command<T> {
-    futures: Vec<Pin<Box<dyn Future<Output = T> + 'static>>>,
-}
-
-impl<T> Command<T> {
-    /// Creates an empty [`Command`].
-    ///
-    /// In other words, a [`Command`] that does nothing.
-    ///
-    /// [`Command`]: struct.Command.html
-    pub fn none() -> Self {
-        Self {
-            futures: Vec::new(),
-        }
-    }
-
-    /// Creates a [`Command`] that performs the action of the given future.
-    ///
-    /// [`Command`]: struct.Command.html
-    pub fn perform<A>(
-        future: impl Future<Output = T> + 'static,
-        f: impl Fn(T) -> A + 'static,
-    ) -> Command<A> {
-        Command {
-            futures: vec![future.map(f).boxed_local()],
-        }
-    }
-
-    /// Applies a transformation to the result of a [`Command`].
-    ///
-    /// [`Command`]: struct.Command.html
-    pub fn map<A>(
-        mut self,
-        f: impl Fn(T) -> A + 'static + Send + Sync + Unpin,
-    ) -> Command<A>
-    where
-        T: 'static,
-    {
-        let f = std::sync::Arc::new(f);
-
-        Command {
-            futures: self
-                .futures
-                .drain(..)
-                .map(|future| {
-                    let f = f.clone();
-
-                    future.map(move |result| f(result)).boxed_local()
-                })
-                .collect(),
-        }
-    }
-
-    /// Creates a [`Command`] that performs the actions of all the given
-    /// commands.
-    ///
-    /// Once this command is run, all the commands will be executed at once.
-    ///
-    /// [`Command`]: struct.Command.html
-    pub fn batch(commands: impl IntoIterator<Item = Command<T>>) -> Self {
-        Self {
-            futures: commands
-                .into_iter()
-                .flat_map(|command| command.futures)
-                .collect(),
-        }
-    }
-
-    /// Converts a [`Command`] into its underlying list of futures.
-    ///
-    /// [`Command`]: struct.Command.html
-    pub fn futures(self) -> Vec<Pin<Box<dyn Future<Output = T> + 'static>>> {
-        self.futures
-    }
-}
-
-impl<T, A> From<A> for Command<T>
-where
-    A: Future<Output = T> + 'static,
-{
-    fn from(future: A) -> Self {
-        Self {
-            futures: vec![future.boxed_local()],
-        }
-    }
-}
-
-impl<T> std::fmt::Debug for Command<T> {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.debug_struct("Command").finish()
-    }
-}

futures/src/lib.rs

@@ -16,3 +16,31 @@ pub use command::Command;
 pub use executor::Executor;
 pub use runtime::Runtime;
 pub use subscription::Subscription;
+
+/// A boxed static future.
+///
+/// - On native platforms, it needs a `Send` requirement.
+/// - On the Web platform, it does not need a `Send` requirement.
+#[cfg(not(target_arch = "wasm32"))]
+pub type BoxFuture<T> = futures::future::BoxFuture<'static, T>;
+
+/// A boxed static future.
+///
+/// - On native platforms, it needs a `Send` requirement.
+/// - On the Web platform, it does not need a `Send` requirement.
+#[cfg(target_arch = "wasm32")]
+pub type BoxFuture<T> = futures::future::LocalBoxFuture<'static, T>;
+
+/// A boxed static stream.
+///
+/// - On native platforms, it needs a `Send` requirement.
+/// - On the Web platform, it does not need a `Send` requirement.
+#[cfg(not(target_arch = "wasm32"))]
+pub type BoxStream<T> = futures::stream::BoxStream<'static, T>;
+
+/// A boxed static stream.
+///
+/// - On native platforms, it needs a `Send` requirement.
+/// - On the Web platform, it does not need a `Send` requirement.
+#[cfg(target_arch = "wasm32")]
+pub type BoxStream<T> = futures::stream::LocalBoxStream<'static, T>;

futures/src/subscription.rs

@@ -3,7 +3,7 @@ mod tracker;
 
 pub use tracker::Tracker;
 
-use futures::stream::BoxStream;
+use crate::BoxStream;
 
 /// A request to listen to external events.
 ///
@@ -168,8 +168,8 @@ pub trait Recipe<Hasher: std::hash::Hasher, Event> {
     /// [`Recipe`]: trait.Recipe.html
     fn stream(
         self: Box<Self>,
-        input: BoxStream<'static, Event>,
+        input: BoxStream<Event>,
-    ) -> BoxStream<'static, Self::Output>;
+    ) -> BoxStream<Self::Output>;
 }
 
 struct Map<Hasher, Event, A, B> {
@@ -201,18 +201,16 @@ where
         self.recipe.hash(state);
     }
 
-    fn stream(
+    fn stream(self: Box<Self>, input: BoxStream<E>) -> BoxStream<Self::Output> {
-        self: Box<Self>,
-        input: BoxStream<'static, E>,
-    ) -> futures::stream::BoxStream<'static, Self::Output> {
         use futures::StreamExt;
 
         let mapper = self.mapper;
 
+        Box::pin(
             self.recipe
                 .stream(input)
-            .map(move |element| mapper(element))
+                .map(move |element| mapper(element)),
-            .boxed()
+        )
     }
 }
 
@@ -243,17 +241,15 @@ where
         self.recipe.hash(state);
     }
 
-    fn stream(
+    fn stream(self: Box<Self>, input: BoxStream<E>) -> BoxStream<Self::Output> {
-        self: Box<Self>,
-        input: BoxStream<'static, E>,
-    ) -> futures::stream::BoxStream<'static, Self::Output> {
         use futures::StreamExt;
 
         let value = self.value;
 
+        Box::pin(
             self.recipe
                 .stream(input)
-            .map(move |element| (value.clone(), element))
+                .map(move |element| (value.clone(), element)),
-            .boxed()
+        )
     }
 }

futures/src/subscription/tracker.rs

@@ -1,6 +1,6 @@
-use crate::Subscription;
+use crate::{BoxFuture, Subscription};
 
-use futures::{channel::mpsc, future::BoxFuture, sink::Sink};
+use futures::{channel::mpsc, sink::Sink};
 use std::{collections::HashMap, marker::PhantomData};
 
 /// A registry of subscription streams.
@@ -59,7 +59,7 @@ where
         &mut self,
         subscription: Subscription<Hasher, Event, Message>,
         receiver: Receiver,
-    ) -> Vec<BoxFuture<'static, ()>>
+    ) -> Vec<BoxFuture<()>>
     where
         Message: 'static + Send,
         Receiver: 'static
@@ -70,7 +70,7 @@ where
     {
         use futures::{future::FutureExt, stream::StreamExt};
 
-        let mut futures = Vec::new();
+        let mut futures: Vec<BoxFuture<()>> = Vec::new();
 
         let recipes = subscription.recipes();
         let mut alive = std::collections::HashSet::new();
@@ -115,7 +115,7 @@ where
                 },
             );
 
-            futures.push(future.boxed());
+            futures.push(Box::pin(future));
         }
 
         self.subscriptions.retain(|id, _| alive.contains(&id));

native/src/subscription/events.rs

@@ -2,7 +2,7 @@ use crate::{
     subscription::{EventStream, Recipe},
     Event, Hasher,
 };
-use iced_futures::futures::stream::BoxStream;
+use iced_futures::BoxStream;
 
 pub struct Events;
 
@@ -18,7 +18,7 @@ impl Recipe<Hasher, Event> for Events {
     fn stream(
         self: Box<Self>,
         event_stream: EventStream,
-    ) -> BoxStream<'static, Self::Output> {
+    ) -> BoxStream<Self::Output> {
         event_stream
     }
 }