Implement View for Arc<dyn AnyView>, and add super bounds of `Vie…

…w` to `AnyView`
linebender · Jan 25, 2024 · 12dc722 · 12dc722
1 parent f2216c2
commit 12dc722
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Showing 7 changed files with 62 additions and 24 deletions.
diff --git a/crates/xilem_core/src/any_view.rs b/crates/xilem_core/src/any_view.rs
@@ -9,13 +9,12 @@ macro_rules! generate_anyview_trait {
         $viewmarker:ty,
         $cx:ty,
         $changeflags:ty,
-        $anywidget:ident,
-        $boxedview:ident;
+        $anywidget:ident;
         $(($($super_bounds:tt)*))?
         $(,($($state_bounds:tt)*))?
     ) => {
         /// A trait enabling type erasure of views.
-        pub trait $anyview<T, A = ()> {
+        pub trait $anyview<T, A = ()>: $($( $super_bounds )*)? {
             fn as_any(&self) -> &dyn std::any::Any;
 
             fn dyn_build(
@@ -105,11 +104,9 @@ macro_rules! generate_anyview_trait {
             }
         }
 
-        pub type $boxedview<T, A = ()> = Box<dyn $anyview<T, A> + $($( $super_bounds )*)? >;
+        impl<T, A> $viewmarker for Box<dyn $anyview<T, A>> {}
 
-        impl<T, A> $viewmarker for $boxedview<T, A> {}
-
-        impl<T, A> $viewtrait<T, A> for $boxedview<T, A> {
+        impl<T, A> $viewtrait<T, A> for Box<dyn $anyview<T, A>> {
             type State = Box<dyn std::any::Any + $($( $state_bounds )*)? >;
 
             type Element = Box<dyn $anywidget>;

diff --git a/crates/xilem_core/src/view/rc.rs b/crates/xilem_core/src/view/rc.rs
@@ -3,10 +3,10 @@
 
 #[macro_export]
 macro_rules! generate_rc_view {
-    ($($rc_ty:ident)::*, $viewtrait:ident, $viewmarker:ty, $cx:ty, $changeflags:ty; $($ss:tt)*) => {
+    ($($rc_ty:ident)::*, $viewtrait:ident, $viewmarker:ty, $cx:ty, $changeflags:ty, $anyview:ident, $anywidget:ident; $($state_bounds:tt)*) => {
         impl<V> $viewmarker for $($rc_ty)::*<V> {}
 
-        impl<T, A, V: $viewtrait<T, A> $( $ss )*> $viewtrait<T, A> for $($rc_ty)::*<V> {
+        impl<T, A, V: $viewtrait<T, A>> $viewtrait<T, A> for $($rc_ty)::*<V> {
             type State = V::State;
 
             type Element = V::Element;
@@ -40,5 +40,47 @@ macro_rules! generate_rc_view {
                 V::message(self, id_path, state, message, app_state)
             }
         }
+
+        impl<T, A> $viewmarker for $($rc_ty)::*<dyn $anyview<T, A>> {}
+        impl<T, A> $viewtrait<T, A> for $($rc_ty)::*<dyn $anyview<T, A>> {
+            type State = Box<dyn std::any::Any + $( $state_bounds )*>;
+
+            type Element = Box<dyn $anywidget>;
+
+            fn build(&self, cx: &mut $cx) -> ($crate::Id, Self::State, Self::Element) {
+                use std::ops::Deref;
+                self.deref().dyn_build(cx)
+            }
+
+            fn rebuild(
+                &self,
+                cx: &mut $cx,
+                prev: &Self,
+                id: &mut $crate::Id,
+                state: &mut Self::State,
+                element: &mut Self::Element,
+            ) -> $changeflags {
+                if !$($rc_ty)::*::ptr_eq(self, prev) {
+                    use std::ops::Deref;
+                    self.deref()
+                        .dyn_rebuild(cx, prev.deref(), id, state, element)
+                } else {
+                    ChangeFlags::empty()
+                }
+
+            }
+
+            fn message(
+                &self,
+                id_path: &[$crate::Id],
+                state: &mut Self::State,
+                message: Box<dyn std::any::Any>,
+                app_state: &mut T,
+            ) -> $crate::MessageResult<A> {
+                use std::ops::{Deref, DerefMut};
+                self.deref()
+                    .dyn_message(id_path, state.deref_mut(), message, app_state)
+            }
+        }
     };
 }
diff --git a/crates/xilem_web/src/lib.rs b/crates/xilem_web/src/lib.rs
@@ -36,8 +36,8 @@ pub use one_of::{
 pub use optional_action::{Action, OptionalAction};
 pub use pointer::{Pointer, PointerDetails, PointerMsg};
 pub use view::{
-    memoize, static_view, Adapt, AdaptState, AdaptThunk, AnyView, BoxedView, Memoize, MemoizeState,
-    Pod, View, ViewMarker, ViewSequence,
+    memoize, static_view, Adapt, AdaptState, AdaptThunk, AnyView, Memoize, MemoizeState, Pod, View,
+    ViewMarker, ViewSequence,
 };
 pub use view_ext::ViewExt;
 

diff --git a/crates/xilem_web/src/view.rs b/crates/xilem_web/src/view.rs
@@ -86,12 +86,12 @@ impl Pod {
 
 xilem_core::generate_view_trait! {View, DomNode, Cx, ChangeFlags;}
 xilem_core::generate_viewsequence_trait! {ViewSequence, View, ViewMarker, DomNode, Cx, ChangeFlags, Pod;}
-xilem_core::generate_anyview_trait! {AnyView, View, ViewMarker, Cx, ChangeFlags, AnyNode, BoxedView;}
+xilem_core::generate_anyview_trait! {AnyView, View, ViewMarker, Cx, ChangeFlags, AnyNode;}
 xilem_core::generate_memoize_view! {Memoize, MemoizeState, View, ViewMarker, Cx, ChangeFlags, static_view, memoize;}
 xilem_core::generate_adapt_view! {View, Cx, ChangeFlags;}
 xilem_core::generate_adapt_state_view! {View, Cx, ChangeFlags;}
-xilem_core::generate_rc_view! {std::rc::Rc, View, ViewMarker, Cx, ChangeFlags; }
-xilem_core::generate_rc_view! {std::sync::Arc, View, ViewMarker, Cx, ChangeFlags; + Sync}
+xilem_core::generate_rc_view! {std::rc::Rc, View, ViewMarker, Cx, ChangeFlags, AnyView, AnyNode;}
+xilem_core::generate_rc_view! {std::sync::Arc, View, ViewMarker, Cx, ChangeFlags, AnyView, AnyNode;}
 
 // strings -> text nodes
 

diff --git a/examples/memoization.rs b/examples/memoization.rs
@@ -1,5 +1,5 @@
 use std::sync::Arc;
-use xilem::view::{button, memoize, v_stack, BoxedView};
+use xilem::view::{button, memoize, v_stack, AnyView};
 use xilem::{view::View, App, AppLauncher};
 
 // There are currently two ways to do memoization
@@ -39,19 +39,18 @@ fn app_logic(state: &mut AppState) -> impl View<AppState> {
 
 struct AppState {
     count: i32,
-    // TODO Maybe support `impl View for Arc<dyn AnyView>` to avoid double indirection
-    count_view: Option<Arc<BoxedView<AppState>>>,
+    count_view: Option<Arc<dyn AnyView<AppState>>>,
 }
 
 impl AppState {
-    fn make_increase_button(&self) -> Arc<BoxedView<AppState>> {
-        Arc::new(Box::new(button(
+    fn make_increase_button(&self) -> Arc<dyn AnyView<AppState>> {
+        Arc::new(button(
             format!("current count is {}", self.count),
             |state: &mut AppState| {
                 state.count += 1;
                 state.count_view = None;
             },
-        )))
+        ))
     }
 }
 

diff --git a/src/view/mod.rs b/src/view/mod.rs
@@ -32,8 +32,8 @@ pub use linear_layout::{h_stack, v_stack, LinearLayout};
 pub use list::{list, List};
 pub use switch::switch;
 pub use view::{
-    memoize, static_view, Adapt, AdaptState, AnyView, BoxedView, Cx, Memoize, MemoizeState, View,
-    ViewMarker, ViewSequence,
+    memoize, static_view, Adapt, AdaptState, AnyView, Cx, Memoize, MemoizeState, View, ViewMarker,
+    ViewSequence,
 };
 
 #[cfg(feature = "taffy")]

diff --git a/src/view/view.rs b/src/view/view.rs
@@ -25,11 +25,11 @@ use crate::widget::{AnyWidget, ChangeFlags, Pod, Widget};
 
 xilem_core::generate_view_trait! {View, Widget, Cx, ChangeFlags; (Send + Sync), (Send)}
 xilem_core::generate_viewsequence_trait! {ViewSequence, View, ViewMarker, Widget, Cx, ChangeFlags, Pod; (Send + Sync), (Send)}
-xilem_core::generate_anyview_trait! {AnyView, View, ViewMarker, Cx, ChangeFlags, AnyWidget, BoxedView; (Send + Sync), (Send)}
+xilem_core::generate_anyview_trait! {AnyView, View, ViewMarker, Cx, ChangeFlags, AnyWidget; (Send + Sync), (Send)}
 xilem_core::generate_memoize_view! {Memoize, MemoizeState, View, ViewMarker, Cx, ChangeFlags, static_view, memoize; + Send + Sync}
 xilem_core::generate_adapt_view! {View, Cx, ChangeFlags; + Send + Sync}
 xilem_core::generate_adapt_state_view! {View, Cx, ChangeFlags; + Send + Sync}
-xilem_core::generate_rc_view! {std::sync::Arc, View, ViewMarker, Cx, ChangeFlags; + Sync + Sync}
+xilem_core::generate_rc_view! {std::sync::Arc, View, ViewMarker, Cx, ChangeFlags, AnyView, AnyWidget; Send}
 
 #[derive(Clone)]
 pub struct Cx {