Prevent unnecessary rendering.

yewstack · Nov 11, 2022 · c31c47b · c31c47b
1 parent e9b60b3
commit c31c47b
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Showing 4 changed files with 31 additions and 19 deletions.
diff --git a/packages/yew/src/app_handle.rs b/packages/yew/src/app_handle.rs
@@ -14,7 +14,7 @@ use crate::scheduler;
 #[derive(Debug)]
 pub struct AppHandle<COMP: Component> {
     /// `Scope` holder
-    pub(crate) scope: Scope,
+    scope: Scope,
     _marker: PhantomData<COMP>,
     destroyed: bool,
 }
@@ -43,18 +43,16 @@ where
         };
         let hosting_root = BSubtree::create_root(&host);
 
-        {
-            let scope = app.scope.clone();
-            scheduler::push(move || {
-                scope.mount(
-                    intrinsic,
-                    hosting_root,
-                    host,
-                    NodeRef::default(),
-                    NodeRef::default(),
-                );
-            });
-        }
+        let scope = app.scope.clone();
+        scheduler::push(move || {
+            scope.mount(
+                intrinsic,
+                hosting_root,
+                host,
+                NodeRef::default(),
+                NodeRef::default(),
+            );
+        });
 
         app
     }

diff --git a/packages/yew/src/dom_bundle/mod.rs b/packages/yew/src/dom_bundle/mod.rs
@@ -48,7 +48,6 @@ pub(crate) struct Bundle(BNode);
 
 impl Bundle {
     /// Creates a new bundle.
-
     pub const fn new() -> Self {
         Self(BNode::List(BList::new()))
     }

diff --git a/packages/yew/src/html/component/lifecycle.rs b/packages/yew/src/html/component/lifecycle.rs
@@ -8,7 +8,7 @@ use super::scope::Scope;
 use crate::dom_bundle::{DomSlot, Realized};
 use crate::html::{Html, Intrinsical, NodeRef, RenderError};
 use crate::suspense::{resume_suspension, suspend_suspension, DispatchSuspension, Suspension};
-use crate::{scheduler, Callback, ContextProvider, HookContext};
+use crate::{Callback, ContextProvider, HookContext};
 
 pub(crate) struct ComponentState {
     pub(super) ctx: HookContext,
@@ -64,7 +64,14 @@ impl ComponentState {
         }
     }
 
-    pub fn run_render(scope: &Scope) {
+    pub fn run_render(scope: &Scope, step: usize) {
+        let current_step = scope.render_step_cell().get();
+        // The desired change has been applied.
+        if current_step > step {
+            return;
+        }
+
+        scope.render_step_cell().set(current_step + 1);
         if let Some(state) = scope.state_cell().borrow_mut().as_mut() {
             state.render(scope);
         }
@@ -166,8 +173,7 @@ impl ComponentState {
             {
                 let scope = scope.clone();
                 suspension.listen(Callback::from(move |_| {
-                    let scope = scope.clone();
-                    scheduler::push(move || ComponentState::run_render(&scope));
+                    scope.schedule_render();
                 }));
             }
 

diff --git a/packages/yew/src/html/component/scope.rs b/packages/yew/src/html/component/scope.rs
@@ -1,6 +1,7 @@
 //! Component scope module
 
 use std::any::TypeId;
+use std::cell::Cell;
 #[cfg(feature = "csr")]
 use std::cell::RefCell;
 use std::rc::Rc;
@@ -21,6 +22,7 @@ struct ScopeInner {
     #[cfg(feature = "csr")]
     pub(crate) state: RefCell<Option<ComponentState>>,
 
+    render_step: Cell<usize>,
     parent: Option<Scope>,
 }
 
@@ -41,14 +43,19 @@ impl Scope {
         self.inner.id
     }
 
+    pub(crate) fn render_step_cell(&self) -> &Cell<usize> {
+        &self.inner.render_step
+    }
+
     /// Schedules a render.
     pub(crate) fn schedule_render(&self) {
         #[cfg(feature = "csr")]
         {
             use crate::scheduler;
 
             let scope = self.clone();
-            scheduler::push(move || ComponentState::run_render(&scope));
+            let step = self.inner.render_step.get();
+            scheduler::push(move || ComponentState::run_render(&scope, step));
         }
     }
 
@@ -166,6 +173,7 @@ mod feat_csr_ssr {
                     state: RefCell::new(None),
                     parent,
 
+                    render_step: Cell::new(0),
                     id: COMP_ID_COUNTER.fetch_add(1, Ordering::SeqCst),
                 }),
             }
@@ -191,6 +199,7 @@ mod feat_csr {
                     type_id: TypeId::of::<()>(),
                     state: RefCell::default(),
                     parent: None,
+                    render_step: Cell::new(0),
                 }),
             }
         }