nuon: Make widgets fully inmutable

Author: PolyMeilex

neothesia/src/scene/playing_scene/top_bar/widget/looper.rs

@@ -154,7 +154,7 @@ impl<MSG> Widget<MSG> for Looper<MSG> {
     }
 
     fn update(
-        &mut self,
+        &self,
         event: Event,
         layout: &Node,
         tree: &mut Tree<Self::State>,

neothesia/src/scene/playing_scene/top_bar/widget/progress_bar.rs

@@ -101,7 +101,7 @@ impl<MSG: Clone> Widget<MSG> for ProgressBar<MSG> {
     }
 
     fn update(
-        &mut self,
+        &self,
         event: Event,
         layout: &Node,
         tree: &mut Tree<Self::State>,

neothesia/src/scene/playing_scene/top_bar/widget/speed_pill.rs

@@ -75,10 +75,6 @@ impl<MSG: Clone> Widget<MSG> for SpeedPill<MSG> {
         &self.children
     }
 
-    fn children_mut(&mut self) -> &mut [Element<MSG>] {
-        &mut self.children
-    }
-
     fn layout(&self, tree: &mut Tree<Self::State>, parent: &ParentLayout, ctx: &LayoutCtx) -> Node {
         let minus = self.children[0].as_widget().layout(
             tree.children[0].remap_mut(),

nuon/src/lib.rs

@@ -103,20 +103,13 @@ pub trait WidgetAny<MSG> {
     fn state(&self) -> Box<dyn Any>;
 
     fn children(&self) -> &[Element<MSG>];
-    fn children_mut(&mut self) -> &mut [Element<MSG>];
     fn children_tree(&self) -> Vec<Tree>;
 
     fn diff(&self, tree: &mut Tree);
 
     fn layout(&self, tree: &mut Tree, avalilable: &ParentLayout, ctx: &LayoutCtx) -> Node;
     fn render(&self, renderer: &mut dyn Renderer, layout: &Node, tree: &Tree, ctx: &RenderCtx);
-    fn update(
-        &mut self,
-        event: input::Event,
-        layout: &Node,
-        tree: &mut Tree,
-        ctx: &mut UpdateCtx<MSG>,
-    );
+    fn update(&self, event: input::Event, layout: &Node, tree: &mut Tree, ctx: &mut UpdateCtx<MSG>);
 }
 
 impl<MSG, W: Widget<MSG>> WidgetAny<MSG> for W {
@@ -132,10 +125,6 @@ impl<MSG, W: Widget<MSG>> WidgetAny<MSG> for W {
         Widget::children(self)
     }
 
-    fn children_mut(&mut self) -> &mut [Element<MSG>] {
-        Widget::children_mut(self)
-    }
-
     fn children_tree(&self) -> Vec<Tree> {
         Widget::children_tree(self)
     }
@@ -153,7 +142,7 @@ impl<MSG, W: Widget<MSG>> WidgetAny<MSG> for W {
     }
 
     fn update(
-        &mut self,
+        &self,
         event: input::Event,
         layout: &Node,
         tree: &mut Tree,
@@ -174,10 +163,6 @@ pub trait Widget<MSG> {
         &[]
     }
 
-    fn children_mut(&mut self) -> &mut [Element<MSG>] {
-        &mut []
-    }
-
     fn children_tree(&self) -> Vec<Tree> {
         self.children()
             .iter()
@@ -204,7 +189,7 @@ pub trait Widget<MSG> {
     }
 
     fn update(
-        &mut self,
+        &self,
         event: input::Event,
         layout: &Node,
         tree: &mut Tree<Self::State>,
@@ -236,20 +221,20 @@ pub fn default_render<MSG, W: Widget<MSG> + ?Sized>(
 }
 
 pub fn default_update<MSG, W: Widget<MSG> + ?Sized>(
-    this: &mut W,
+    this: &W,
     event: input::Event,
     layout: &Node,
     tree: &mut Tree<W::State>,
     ctx: &mut UpdateCtx<MSG>,
 ) {
     for ((ch, layout), tree) in this
-        .children_mut()
-        .iter_mut()
+        .children()
+        .iter()
         .zip(layout.children.iter())
         .zip(tree.children.iter_mut())
         .rev()
     {
-        ch.as_widget_mut().update(event.clone(), layout, tree, ctx);
+        ch.as_widget().update(event.clone(), layout, tree, ctx);
 
         if ctx.is_event_captured() {
             return;

nuon/src/widget/button.rs

@@ -140,7 +140,7 @@ impl<MSG: Clone> Widget<MSG> for Button<MSG> {
     }
 
     fn update(
-        &mut self,
+        &self,
         event: Event,
         layout: &Node,
         tree: &mut Tree<Self::State>,

nuon/src/widget/column.rs

@@ -47,10 +47,6 @@ impl<MSG> Widget<MSG> for Column<MSG> {
         &self.children
     }
 
-    fn children_mut(&mut self) -> &mut [Element<MSG>] {
-        &mut self.children
-    }
-
     fn layout(&self, tree: &mut Tree<Self::State>, parent: &ParentLayout, ctx: &LayoutCtx) -> Node {
         column_layout(self, tree, parent, ctx, self.gap)
     }

nuon/src/widget/container.rs

@@ -65,10 +65,6 @@ impl<MSG> Widget<MSG> for Container<MSG> {
         &self.child
     }
 
-    fn children_mut(&mut self) -> &mut [Element<MSG>] {
-        &mut self.child
-    }
-
     fn layout(&self, tree: &mut Tree<Self::State>, parent: &ParentLayout, ctx: &LayoutCtx) -> Node {
         let parent = &ParentLayout {
             x: parent.x + self.x,

nuon/src/widget/row.rs

@@ -47,10 +47,6 @@ impl<MSG> Widget<MSG> for Row<MSG> {
         &self.children
     }
 
-    fn children_mut(&mut self) -> &mut [Element<MSG>] {
-        &mut self.children
-    }
-
     fn layout(&self, tree: &mut Tree<Self::State>, parent: &ParentLayout, ctx: &LayoutCtx) -> Node {
         row_layout(self, tree, parent, ctx, self.gap)
     }

nuon/src/widget/stack.rs

@@ -40,10 +40,6 @@ impl<MSG> Widget<MSG> for Stack<MSG> {
         &self.children
     }
 
-    fn children_mut(&mut self) -> &mut [Element<MSG>] {
-        &mut self.children
-    }
-
     fn layout(&self, tree: &mut Tree<Self::State>, parent: &ParentLayout, ctx: &LayoutCtx) -> Node {
         stack_layout(self, tree, parent, ctx)
     }

nuon/src/widget/trilayout.rs

@@ -54,10 +54,6 @@ impl<MSG> Widget<MSG> for TriLayout<MSG> {
         &self.children
     }
 
-    fn children_mut(&mut self) -> &mut [Element<MSG>] {
-        &mut self.children
-    }
-
     fn layout(&self, tree: &mut Tree<Self::State>, parent: &ParentLayout, ctx: &LayoutCtx) -> Node {
         let start = self.children[0].as_widget().layout(
             &mut tree.children[0],