Support smol as async runtime backend

Author: HigherOrderLogic

Cargo.lock

@@ -49,7 +49,7 @@ masonry_imaging = { version = "0.4.0", path = "masonry_imaging", default-feature
 masonry_testing = { version = "0.4.0", path = "masonry_testing", default-features = false }
 masonry_winit = { version = "0.4.0", path = "masonry_winit", default-features = false }
 xilem_core = { version = "0.4.0", path = "xilem_core" }
-xilem_masonry = { version = "0.4.0", path = "xilem_masonry" }
+xilem_masonry = { version = "0.4.0", path = "xilem_masonry", default-features = false }
 xilem = { version = "0.4.0", path = "xilem", default-features = false }
 tree_arena = { version = "0.2.0", path = "tree_arena" }
 include_doc_path = { version = "0.1.0", path = "include_doc_path", package = "linebender_include_doc_path" }
@@ -85,7 +85,6 @@ bitflags = "2.11.0"
 accesskit = "0.24.0"
 accesskit_winit = { version = "0.32.2", default-features = false, features = [
     "accesskit_unix",
-    "tokio",
     "rwh_06",
 ] }
 accesskit_consumer = "0.35.0"
@@ -96,6 +95,8 @@ reqwest = { version = "0.12.28", default-features = false, features = [
     "rustls-tls",
 ] }
 divan = "0.1.21"
+tokio = { version = "1.53.1", features = ["rt", "rt-multi-thread", "time", "sync"] }
+smol = "2.0.2"
 
 [workspace.lints]
 # unsafe code is not allowed in Xilem or Masonry

Cargo.toml

@@ -10,18 +10,19 @@ license.workspace = true
 repository.workspace = true
 
 [package.metadata.docs.rs]
-all-features = true
 # There are no platform specific docs.
 default-target = "x86_64-unknown-linux-gnu"
 targets = []
 # rustdoc-scrape-examples tracking issue https://github.com/rust-lang/rust/issues/88791
 cargo-args = ["-Zunstable-options", "-Zrustdoc-scrape-examples"]
 
 [features]
-default = ["imaging_vello"]
+default = ["imaging_vello", "accesskit-tokio"]
 imaging_vello = ["masonry_imaging/imaging_vello"]
 imaging_vello_hybrid = ["masonry_imaging/imaging_vello_hybrid"]
 imaging_skia = ["masonry_imaging/imaging_skia"]
+accesskit-tokio = ["accesskit_winit/tokio"]
+accesskit-async-io = ["accesskit_winit/async-io"]
 # Enables tracing using tracy if the default Masonry tracing is used.
 # https://github.com/wolfpld/tracy can be connected to when this feature is enabled.
 tracy = [

masonry_winit/Cargo.toml

@@ -15,7 +15,6 @@ exclude = [
 ]
 
 [package.metadata.docs.rs]
-all-features = true
 # There are no platform specific docs.
 default-target = "x86_64-unknown-linux-gnu"
 targets = []
@@ -32,7 +31,9 @@ debuggable = true
 name = "android.permission.INTERNET"
 
 [features]
-default = ["masonry/default", "masonry_winit/default"]
+default = ["masonry/default", "masonry_winit/default", "tokio-rt"]
+tokio-rt = ["dep:tokio", "xilem_masonry/tokio-rt", "masonry_winit/accesskit-tokio"]
+smol-rt = ["dep:smol", "xilem_masonry/smol-rt", "masonry_winit/accesskit-async-io"]
 
 [dependencies]
 xilem_core.workspace = true
@@ -41,7 +42,8 @@ masonry.workspace = true
 masonry_winit.workspace = true
 winit.workspace = true
 tracing.workspace = true
-tokio = { version = "1.50.0", features = ["rt", "rt-multi-thread", "time", "sync"] }
+tokio = { workspace = true, optional = true }
+smol = { workspace = true, optional = true }
 
 [dev-dependencies]
 # Used for `variable_clock`
@@ -69,18 +71,21 @@ name = "mason"
 # This actually enables scraping for all examples, not just this one.
 # However it is possible to set doc-scrape-examples to false for other specific examples.
 doc-scrape-examples = true
+required-features = ["tokio-rt"]
 
 [[example]]
 name = "calc"
 
 [[example]]
 name = "stopwatch"
+required-features = ["tokio-rt"]
 
 [[example]]
 name = "to_do_mvc"
 
 [[example]]
 name = "variable_clock"
+required-features = ["tokio-rt"]
 
 [[example]]
 name = "emoji_picker"
@@ -93,6 +98,11 @@ doc-scrape-examples = false
 
 [[example]]
 name = "http_cats"
+required-features = ["tokio-rt"]
+
+[[example]]
+name = "virtual_cats"
+required-features = ["tokio-rt"]
 
 # Also add to ANDROID_TARGETS in .github/ci.yml if adding a new Android example
 # and update the list in xilem/examples/android/README.md.
@@ -102,6 +112,7 @@ name = "mason_android"
 path = "examples/android/mason_android.rs"
 # cdylib is required for cargo-apk
 crate-type = ["cdylib"]
+required-features = ["tokio-rt"]
 
 [[example]]
 name = "calc_android"
@@ -114,6 +125,7 @@ name = "stopwatch_android"
 path = "examples/android/stopwatch_android.rs"
 # cdylib is required for cargo-apk
 crate-type = ["cdylib"]
+required-features = ["tokio-rt"]
 
 [[example]]
 name = "to_do_mvc_android"
@@ -126,6 +138,7 @@ name = "variable_clock_android"
 path = "examples/android/variable_clock_android.rs"
 # cdylib is required for cargo-apk
 crate-type = ["cdylib"]
+required-features = ["tokio-rt"]
 
 [[example]]
 name = "emoji_picker_android"
@@ -139,6 +152,7 @@ name = "http_cats_android"
 path = "examples/android/http_cats_android.rs"
 # cdylib is required for cargo-apk
 crate-type = ["cdylib"]
+required-features = ["tokio-rt"]
 
 [[example]]
 name = "canvas"

xilem/Cargo.toml

@@ -8,8 +8,11 @@ use masonry::core::DefaultProperties;
 use masonry::peniko::{Blob, Color};
 use masonry::theme::{BACKGROUND_COLOR, default_property_set};
 use masonry_winit::app::{EventLoopBuilder, MasonryState, MasonryUserEvent, NewWindow, WindowId};
-use tokio::runtime::Runtime as TokioRuntime;
 use winit::error::EventLoopError;
+use xilem_masonry::runtime::Executor;
+
+#[cfg(feature = "tokio-rt")]
+use tokio::runtime::Runtime as TokioRuntime;
 
 use crate::core::map_state;
 use crate::window_options::WindowCallbacks;
@@ -22,7 +25,7 @@ use crate::{MasonryDriver, WidgetView, WindowOptions, WindowView};
 pub struct Xilem<State, Logic> {
     state: State,
     logic: Logic,
-    runtime: Arc<TokioRuntime>,
+    runtime: Arc<Executor>,
     default_properties: Option<DefaultProperties>,
     default_base_color: Color,
     // Font data to include in loading.
@@ -62,21 +65,34 @@ impl<State>
     where
         View: WidgetView<State>,
     {
-        Self::new_simple_with_tokio(
-            state,
-            logic,
-            window_options,
-            Arc::new(TokioRuntime::new().unwrap()),
-        )
+        Self::new_simple_with_executor(state, logic, window_options, Executor::new().into())
     }
 
     /// Same as [`Self::new_simple`] but allows passing an existing tokio runtime.
+    #[deprecated(
+        since = "0.4.0",
+        note = "use `Xilem::new_simple_with_executor` with `xilem_masonry::runtime::Executor` instead"
+    )]
+    #[cfg(feature = "tokio-rt")]
     pub fn new_simple_with_tokio<View>(
         state: State,
-        mut logic: impl FnMut(&mut State) -> View + 'static,
+        logic: impl FnMut(&mut State) -> View + 'static,
         window_options: WindowOptions<State>,
         tokio_rt: Arc<TokioRuntime>,
     ) -> Self
+    where
+        View: WidgetView<State>,
+    {
+        Self::new_simple_with_executor(state, logic, window_options, Arc::new(tokio_rt.into()))
+    }
+
+    /// Same as [`Self::new_simple`] but allows passing an existing runtime executor.
+    pub fn new_simple_with_executor<View>(
+        state: State,
+        mut logic: impl FnMut(&mut State) -> View + 'static,
+        window_options: WindowOptions<State>,
+        runtime: Arc<Executor>,
+    ) -> Self
     where
         View: WidgetView<State>,
     {
@@ -112,7 +128,7 @@ impl<State>
                     }),
                 )
             }),
-            tokio_rt,
+            runtime,
         )
     }
 }
@@ -138,10 +154,10 @@ where
     where
         State: AppState,
     {
-        Self::new_inner(state, logic, Arc::new(TokioRuntime::new().unwrap()))
+        Self::new_inner(state, logic, Arc::new(Executor::new()))
     }
 
-    fn new_inner(state: State, logic: Logic, runtime: Arc<TokioRuntime>) -> Self {
+    fn new_inner(state: State, logic: Logic, runtime: Arc<Executor>) -> Self {
         Self {
             state,
             logic,

xilem/src/app.rs

@@ -17,17 +17,18 @@ use crate::core::{
 };
 use crate::window_view::{WindowView, WindowViewState};
 use crate::{AppState, Color, ViewCtx};
+use xilem_masonry::runtime::Executor;
 
 /// The composition root of Xilem's Masonry backend.
 ///
 /// Owns the root state, the root view (kind of), the window state, the event loop proxy,
-/// the tokio runtime, etc.
+/// the async runtime executor, etc.
 pub struct MasonryDriver<State: 'static, Logic> {
     state: State,
     logic: Logic,
     windows: HashMap<WindowId, Window<State>>,
     proxy: Arc<MasonryProxy>,
-    runtime: Arc<tokio::runtime::Runtime>,
+    runtime: Arc<Executor>,
     default_base_color: Color,
     // Fonts which will be registered on startup.
     fonts: Vec<Blob<u8>>,
@@ -53,7 +54,7 @@ where
         // TODO: narrow down MasonryUserEvent in event_sink once masonry_winit supports custom event types
         // (we only ever use it to send MasonryUserEvent::Action with ASYNC_MARKER_WIDGET)
         event_sink: impl Fn(MasonryUserEvent) -> Result<(), MasonryUserEvent> + Send + Sync + 'static,
-        runtime: Arc<tokio::runtime::Runtime>,
+        runtime: Arc<Executor>,
         default_base_color: Color,
         fonts: Vec<Blob<u8>>,
         start_callback: Option<Box<dyn FnOnce(&mut MasonryState<'_>)>>,

xilem/src/driver.rs

@@ -153,6 +153,9 @@ pub use masonry;
 pub use masonry::dpi;
 pub use masonry::palette;
 pub use masonry::{kurbo, peniko};
+#[cfg(feature = "smol-rt")]
+pub use smol;
+#[cfg(feature = "tokio-rt")]
 pub use tokio;
 pub use winit;
 pub use xilem_core as core;