Fix Child view to support nested updates

crates/concoct-web/src/html.rs

@@ -2,7 +2,7 @@ use super::WebContext;
 use concoct::{
     hook::{use_context, use_on_drop, use_provider, use_ref},
     view::Child,
-    View, ViewBuilder,
+    Tree, View, ViewBuilder,
 };
 use std::{borrow::Cow, cell::RefCell, rc::Rc};
 use web_sys::{
@@ -13,8 +13,8 @@ use web_sys::{
 macro_rules! make_tag_fns {
     ($($name:tt),*) => {
         $(
-            pub fn $name<C: View>(child: C) -> Html<C> {
-                Html::new(stringify!($name), child)
+            pub fn $name(child: impl View) -> Html<impl Tree> {
+                html(stringify!($name), child)
             }
         )*
     };
@@ -24,11 +24,11 @@ make_tag_fns!(
     a, abbr, address, area, article, aside, audio, b, base, bdi, bdo, blockquote, body, br, button,
     canvas, caption, cite, code, col, colgroup, data, datalist, dd, del, details, dfn, dialog, div,
     dl, dt, em, embed, fieldset, figcaption, figure, footer, form, h1, h2, h3, h4, h5, h6, head,
-    header, hr, html, i, iframe, img, input, ins, kbd, label, legend, li, link, main, map, mark,
-    meta, meter, nav, noscript, object, ol, optgroup, option, output, p, param, picture, pre,
-    progress, q, rp, rt, ruby, s, samp, script, section, select, small, source, span, strong, sub,
-    summary, sup, svg, table, tbody, td, template, textarea, tfoot, th, thead, time, title, tr,
-    track, u, ul, var, video, wbr
+    header, hr, i, iframe, img, input, ins, kbd, label, legend, li, link, main, map, mark, meta,
+    meter, nav, noscript, object, ol, optgroup, option, output, p, param, picture, pre, progress,
+    q, rp, rt, ruby, s, samp, script, section, select, small, source, span, strong, sub, summary,
+    sup, svg, table, tbody, td, template, textarea, tfoot, th, thead, time, title, tr, track, u,
+    ul, var, video, wbr
 );
 
 #[derive(Default)]
@@ -67,16 +67,16 @@ macro_rules! impl_handler_methods {
     };
 }
 
-impl<C> Html<C> {
-    pub fn new(tag: impl Into<Cow<'static, str>>, child: C) -> Self {
-        Self {
-            tag: tag.into(),
-            attrs: Vec::new(),
-            handlers: Vec::new(),
-            child: Child::new(child),
-        }
+pub fn html(tag: impl Into<Cow<'static, str>>, child: impl View) -> Html<impl Tree> {
+    Html {
+        tag: tag.into(),
+        attrs: Vec::new(),
+        handlers: Vec::new(),
+        child: concoct::view::child(child),
     }
+}
 
+impl<C> Html<C> {
     pub fn attr(
         mut self,
         name: impl Into<Cow<'static, str>>,
@@ -108,7 +108,7 @@ impl<C> Html<C> {
     );
 }
 
-impl<C: View> ViewBuilder for Html<C> {
+impl<C: Tree> ViewBuilder for Html<C> {
     fn build(&self) -> impl View {
         let data = use_ref(|| RefCell::new(Data::default()));
         let mut data_ref = data.borrow_mut();

crates/concoct/src/view/child.rs

@@ -1,34 +1,44 @@
 use crate::{Tree, View};
-use std::{cell::RefCell, rc::Rc};
+use std::{any::Any, cell::RefCell, rc::Rc};
 
-/// Child view.
+/// Create a child view.
 ///
 /// This type should be cloned and returned from a parent view to wrap its content.
-///
-/// ## Panics
-/// This view can only be used once, then it will panic.
-pub struct Child<V> {
-    cell: Rc<RefCell<Option<V>>>,
+pub fn child(view: impl View) -> Child<impl Tree> {
+    Child {
+        tree: Rc::new(RefCell::new(view.into_tree())),
+    }
 }
 
-impl<B> Child<B> {
-    pub fn new(view: B) -> Self {
-        Self {
-            cell: Rc::new(RefCell::new(Some(view))),
-        }
-    }
+pub struct Child<T> {
+    tree: Rc<RefCell<T>>,
 }
 
-impl<B> Clone for Child<B> {
+impl<T> Clone for Child<T> {
     fn clone(&self) -> Self {
         Self {
-            cell: self.cell.clone(),
+            tree: self.tree.clone(),
         }
     }
 }
 
-impl<B: View> View for Child<B> {
+impl<T: Tree> View for Child<T> {
     fn into_tree(self) -> impl Tree {
-        self.cell.take().unwrap().into_tree()
+        self
+    }
+}
+
+impl<T: Tree> Tree for Child<T> {
+    unsafe fn build(&mut self) {
+        self.tree.borrow_mut().build()
+    }
+
+    unsafe fn rebuild(&mut self, last: &mut dyn Any) {
+        let last = last.downcast_mut::<Self>().unwrap();
+        self.tree.borrow_mut().rebuild(&mut *last.tree.borrow_mut())
+    }
+
+    unsafe fn remove(&mut self) {
+        self.tree.borrow_mut().remove()
     }
 }

crates/concoct/src/view/mod.rs

@@ -4,7 +4,7 @@ use crate::{Node, Tree, ViewBuilder};
 use std::hash::Hash;
 
 mod child;
-pub use child::Child;
+pub use child::{child, Child};
 
 mod empty;
 pub use empty::Empty;