add simple suspense methods

packages/core/src/create.rs

@@ -5,10 +5,9 @@ use crate::mutations::Mutation::*;
 use crate::nodes::VNode;
 use crate::nodes::{DynamicNode, TemplateNode};
 use crate::virtual_dom::VirtualDom;
-use crate::{AttributeValue, ElementId, RenderReturn, ScopeId, SuspenseContext, Template};
+use crate::{AttributeValue, ElementId, RenderReturn, ScopeId, Template};
 use std::cell::Cell;
 use std::iter::Peekable;
-use std::rc::Rc;
 use TemplateNode::*;
 
 #[cfg(debug_assertions)]
@@ -445,7 +444,7 @@ impl<'b> VirtualDom {
         match node {
             Text(text) => self.create_dynamic_text(template, text, idx),
             Placeholder(place) => self.create_placeholder(place, template, idx),
-            Component(component) => self.create_component_node(template, component, idx),
+            Component(component) => self.create_component_node(template, component),
             Fragment(frag) => frag.iter().map(|child| self.create(child)).sum(),
         }
     }
@@ -502,7 +501,6 @@ impl<'b> VirtualDom {
         &mut self,
         template: &'b VNode<'b>,
         component: &'b VComponent<'b>,
-        idx: usize,
     ) -> usize {
         use RenderReturn::*;
 
@@ -512,7 +510,8 @@ impl<'b> VirtualDom {
         component.scope.set(Some(scope));
 
         match unsafe { self.run_scope(scope).extend_lifetime_ref() } {
-            Ready(t) => self.mount_component(scope, template, t, idx),
+            // Create the component's root element
+            Ready(t) => self.create_scope(scope, t),
             Aborted(t) => self.mount_aborted(template, t),
         }
     }
@@ -529,60 +528,6 @@ impl<'b> VirtualDom {
             .unwrap_or_else(|| component.scope.get().unwrap())
     }
 
-    fn mount_component(
-        &mut self,
-        scope: ScopeId,
-        parent: &'b VNode<'b>,
-        new: &'b VNode<'b>,
-        idx: usize,
-    ) -> usize {
-        // Keep track of how many mutations are in the buffer in case we need to split them out if a suspense boundary
-        // is encountered
-        let mutations_to_this_point = self.mutations.edits.len();
-
-        // Create the component's root element
-        let created = self.create_scope(scope, new);
-
-        // If there are no suspense leaves below us, then just don't bother checking anything suspense related
-        if self.collected_leaves.is_empty() {
-            return created;
-        }
-
-        // If running the scope has collected some leaves and *this* component is a boundary, then handle the suspense
-        let boundary = match self.scopes[scope].has_context::<Rc<SuspenseContext>>() {
-            Some(boundary) => boundary,
-            _ => return created,
-        };
-
-        // Since this is a boundary, use its placeholder within the template as the placeholder for the suspense tree
-        let new_id = self.next_element(new, parent.template.get().node_paths[idx]);
-
-        // Now connect everything to the boundary
-        self.scopes[scope].placeholder.set(Some(new_id));
-
-        // This involves breaking off the mutations to this point, and then creating a new placeholder for the boundary
-        // Note that we break off dynamic mutations only - since static mutations aren't rendered immediately
-        let split_off = unsafe {
-            std::mem::transmute::<Vec<Mutation>, Vec<Mutation>>(
-                self.mutations.edits.split_off(mutations_to_this_point),
-            )
-        };
-        boundary.mutations.borrow_mut().edits.extend(split_off);
-        boundary.created_on_stack.set(created);
-        boundary
-            .waiting_on
-            .borrow_mut()
-            .extend(self.collected_leaves.drain(..));
-
-        // Now assign the placeholder in the DOM
-        self.mutations.push(AssignId {
-            id: new_id,
-            path: &parent.template.get().node_paths[idx][1..],
-        });
-
-        0
-    }
-
     fn mount_aborted(&mut self, parent: &'b VNode<'b>, placeholder: &VPlaceholder) -> usize {
         let id = self.next_element(parent, &[]);
         self.mutations.push(Mutation::CreatePlaceholder { id });

packages/core/src/diff.rs

@@ -124,9 +124,8 @@ impl<'b> VirtualDom {
             .dynamic_nodes
             .iter()
             .zip(right_template.dynamic_nodes.iter())
-            .enumerate()
-            .for_each(|(idx, (left_node, right_node))| {
-                self.diff_dynamic_node(left_node, right_node, right_template, idx);
+            .for_each(|(left_node, right_node)| {
+                self.diff_dynamic_node(left_node, right_node, right_template);
             });
 
         // Make sure the roots get transferred over while we're here
@@ -145,13 +144,12 @@ impl<'b> VirtualDom {
         left_node: &'b DynamicNode<'b>,
         right_node: &'b DynamicNode<'b>,
         node: &'b VNode<'b>,
-        idx: usize,
     ) {
         match (left_node, right_node) {
             (Text(left), Text(right)) => self.diff_vtext(left, right, node),
             (Fragment(left), Fragment(right)) => self.diff_non_empty_fragment(left, right),
             (Placeholder(left), Placeholder(right)) => right.id.set(left.id.get()),
-            (Component(left), Component(right)) => self.diff_vcomponent(left, right, node, idx),
+            (Component(left), Component(right)) => self.diff_vcomponent(left, right, node),
             (Placeholder(left), Fragment(right)) => self.replace_placeholder(left, *right),
             (Fragment(left), Placeholder(right)) => self.node_to_placeholder(left, right),
             _ => todo!("This is an usual custom case for dynamic nodes. We don't know how to handle it yet."),
@@ -175,7 +173,6 @@ impl<'b> VirtualDom {
         left: &'b VComponent<'b>,
         right: &'b VComponent<'b>,
         right_template: &'b VNode<'b>,
-        idx: usize,
     ) {
         if std::ptr::eq(left, right) {
             return;
@@ -183,7 +180,7 @@ impl<'b> VirtualDom {
 
         // Replace components that have different render fns
         if left.render_fn != right.render_fn {
-            return self.replace_vcomponent(right_template, right, idx, left);
+            return self.replace_vcomponent(right_template, right, left);
         }
 
         // Make sure the new vcomponent has the right scopeid associated to it
@@ -220,10 +217,9 @@ impl<'b> VirtualDom {
         &mut self,
         right_template: &'b VNode<'b>,
         right: &'b VComponent<'b>,
-        idx: usize,
         left: &'b VComponent<'b>,
     ) {
-        let m = self.create_component_node(right_template, right, idx);
+        let m = self.create_component_node(right_template, right);
 
         let pre_edits = self.mutations.edits.len();
 
@@ -282,8 +278,7 @@ impl<'b> VirtualDom {
             None => self.replace(left, [right]),
             Some(components) => components
                 .into_iter()
-                .enumerate()
-                .for_each(|(idx, (l, r))| self.diff_vcomponent(l, r, right, idx)),
+                .for_each(|(l, r)| self.diff_vcomponent(l, r, right)),
         }
     }
 

packages/core/src/lib.rs

@@ -72,7 +72,7 @@ pub(crate) mod innerlude {
 pub use crate::innerlude::{
     fc_to_builder, AnyValue, Attribute, AttributeValue, BorrowedAttributeValue, CapturedError,
     Component, DynamicNode, Element, ElementId, Event, Fragment, IntoDynNode, LazyNodes, Mutation,
-    Mutations, Properties, RenderReturn, Scope, ScopeId, ScopeState, Scoped, SuspenseContext,
+    Mutations, Properties, RenderReturn, Scope, ScopeId, ScopeState, Scoped,
     TaskId, Template, TemplateAttribute, TemplateNode, VComponent, VNode, VPlaceholder, VText,
     VirtualDom,
 };

packages/core/src/scheduler/mod.rs

@@ -1,11 +1,9 @@
 use crate::ScopeId;
 use slab::Slab;
 
-mod suspense;
 mod task;
 mod wait;
 
-pub use suspense::*;
 pub use task::*;
 
 /// The type of message that can be sent to the scheduler.

packages/core/src/scheduler/suspense.rs

@@ -11,17 +11,10 @@ use std::{
     collections::HashSet,
 };
 
-/// An ID representing an ongoing suspended component
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
-pub(crate) struct SuspenseId(pub usize);
-
 /// A boundary in the VirtualDom that captures all suspended components below it
 pub struct SuspenseContext {
     pub(crate) id: ScopeId,
-    pub(crate) waiting_on: RefCell<HashSet<SuspenseId>>,
-    pub(crate) mutations: RefCell<Mutations<'static>>,
-    pub(crate) placeholder: Cell<Option<ElementId>>,
-    pub(crate) created_on_stack: Cell<usize>,
+    pub(crate) waiting_on: RefCell<HashSet<ScopeId>>,
 }
 
 impl SuspenseContext {
@@ -30,9 +23,10 @@ impl SuspenseContext {
         Self {
             id,
             waiting_on: Default::default(),
-            mutations: RefCell::new(Mutations::default()),
-            placeholder: Cell::new(None),
-            created_on_stack: Cell::new(0),
         }
     }
+
+    pub fn mark_suspend(&self, id: ScopeId) {
+        self.waiting_on.borrow_mut().insert(id);
+    }
 }

packages/core/src/scheduler/wait.rs

@@ -1,5 +1,5 @@
-use crate::{innerlude::SuspenseContext, ScopeId, TaskId, VirtualDom};
-use std::{rc::Rc, task::Context};
+use crate::{TaskId, VirtualDom};
+use std::task::Context;
 
 impl VirtualDom {
     /// Handle notifications by tasks inside the scheduler
@@ -27,10 +27,4 @@ impl VirtualDom {
             tasks.try_remove(id.0);
         }
     }
-
-    pub(crate) fn acquire_suspense_boundary(&self, id: ScopeId) -> Rc<SuspenseContext> {
-        self.scopes[id]
-            .consume_context::<Rc<SuspenseContext>>()
-            .unwrap()
-    }
 }

packages/core/src/scope_arena.rs

@@ -25,10 +25,10 @@ impl VirtualDom {
             name,
             props: Some(props),
             tasks: self.scheduler.clone(),
-            placeholder: Default::default(),
             node_arena_1: BumpFrame::new(0),
             node_arena_2: BumpFrame::new(0),
             spawned_tasks: Default::default(),
+            suspended: Default::default(),
             render_cnt: Default::default(),
             hooks: Default::default(),
             hook_idx: Default::default(),
@@ -54,6 +54,7 @@ impl VirtualDom {
             self.scopes[scope_id].previous_frame().bump_mut().reset();
 
             let scope = &self.scopes[scope_id];
+            scope.suspended.set(false);
 
             scope.hook_idx.set(0);
 
@@ -82,6 +83,10 @@ impl VirtualDom {
             id: scope.id,
         });
 
+        if scope.suspended.get() {
+            self.suspended_scopes.insert(scope.id);
+        }
+
         // rebind the lifetime now that its stored internally
         unsafe { allocated.extend_lifetime_ref() }
     }

packages/core/src/scopes.rs

@@ -1,7 +1,6 @@
 use crate::{
     any_props::AnyProps,
     any_props::VProps,
-    arena::ElementId,
     bump_frame::BumpFrame,
     innerlude::{DynamicNode, EventHandler, VComponent, VText},
     innerlude::{ErrorBoundary, Scheduler, SchedulerMsg},
@@ -169,6 +168,7 @@ pub struct ScopeState {
     pub(crate) id: ScopeId,
 
     pub(crate) height: u32,
+    pub(crate) suspended: Cell<bool>,
 
     pub(crate) hooks: RefCell<Vec<Box<UnsafeCell<dyn Any>>>>,
     pub(crate) hook_idx: Cell<usize>,
@@ -182,7 +182,6 @@ pub struct ScopeState {
     pub(crate) attributes_to_drop: RefCell<Vec<*const Attribute<'static>>>,
 
     pub(crate) props: Option<Box<dyn AnyProps<'static>>>,
-    pub(crate) placeholder: Cell<Option<ElementId>>,
 }
 
 impl<'src> ScopeState {
@@ -655,6 +654,12 @@ impl<'src> ScopeState {
         None
     }
 
+    /// Mark this component as suspended and then return None
+    pub fn suspend(&self) -> Option<()> {
+        self.suspended.set(true);
+        None
+    }
+
     /// Store a value between renders. The foundational hook for all other hooks.
     ///
     /// Accepts an `initializer` closure, which is run on the first use of the hook (typically the initial render). The return value of this closure is stored for the lifetime of the component, and a mutable reference to it is provided on every render as the return value of `use_hook`.

packages/core/src/virtual_dom.rs

@@ -9,14 +9,13 @@ use crate::{
     mutations::Mutation,
     nodes::RenderReturn,
     nodes::{Template, TemplateId},
-    scheduler::SuspenseId,
     scopes::{ScopeId, ScopeState},
-    AttributeValue, Element, Event, Scope, SuspenseContext,
+    AttributeValue, Element, Event, Scope,
 };
 use futures_util::{pin_mut, StreamExt};
-use rustc_hash::FxHashMap;
+use rustc_hash::{FxHashMap, FxHashSet};
 use slab::Slab;
-use std::{any::Any, borrow::BorrowMut, cell::Cell, collections::BTreeSet, future::Future, rc::Rc};
+use std::{any::Any, cell::Cell, collections::BTreeSet, future::Future, rc::Rc};
 
 /// A virtual node system that progresses user events and diffs UI trees.
 ///
@@ -186,11 +185,9 @@ pub struct VirtualDom {
 
     // While diffing we need some sort of way of breaking off a stream of suspended mutations.
     pub(crate) scope_stack: Vec<ScopeId>,
-    pub(crate) collected_leaves: Vec<SuspenseId>,
 
-    // Whenever a suspense tree is finished, we push its boundary onto this stack.
-    // When "render_with_deadline" is called, we pop the stack and return the mutations
-    pub(crate) finished_fibers: Vec<ScopeId>,
+    // Currently suspended scopes
+    pub(crate) suspended_scopes: FxHashSet<ScopeId>,
 
     pub(crate) rx: futures_channel::mpsc::UnboundedReceiver<SchedulerMsg>,
 
@@ -262,8 +259,7 @@ impl VirtualDom {
             elements: Default::default(),
             scope_stack: Vec::new(),
             dirty_scopes: BTreeSet::new(),
-            collected_leaves: Vec::new(),
-            finished_fibers: Vec::new(),
+            suspended_scopes: FxHashSet::default(),
             mutations: Mutations::default(),
         };
 
@@ -272,12 +268,6 @@ impl VirtualDom {
             "app",
         );
 
-        // The root component is always a suspense boundary for any async children
-        // This could be unexpected, so we might rethink this behavior later
-        //
-        // We *could* just panic if the suspense boundary is not found
-        root.provide_context(Rc::new(SuspenseContext::new(ScopeId(0))));
-
         // Unlike react, we provide a default error boundary that just renders the error as a string
         root.provide_context(Rc::new(ErrorBoundary::new(ScopeId(0))));
 
@@ -319,26 +309,6 @@ impl VirtualDom {
         }
     }
 
-    /// Determine whether or not a scope is currently in a suspended state
-    ///
-    /// This does not mean the scope is waiting on its own futures, just that the tree that the scope exists in is
-    /// currently suspended.
-    pub fn is_scope_suspended(&self, id: ScopeId) -> bool {
-        !self.scopes[id]
-            .consume_context::<Rc<SuspenseContext>>()
-            .unwrap()
-            .waiting_on
-            .borrow()
-            .is_empty()
-    }
-
-    /// Determine if the tree is at all suspended. Used by SSR and other outside mechanisms to determine if the tree is
-    /// ready to be rendered.
-    pub fn has_suspended_work(&self) -> bool {
-        todo!()
-        // !self.scheduler.leaves.borrow().is_empty()
-    }
-
     /// Call a listener inside the VirtualDom with data from outside the VirtualDom.
     ///
     /// This method will identify the appropriate element. The data must match up with the listener delcared. Note that
@@ -495,7 +465,7 @@ impl VirtualDom {
                         Ok(None) => return,
                         Err(_) => {
                             // If we have any dirty scopes, or finished fiber trees then we should exit
-                            if !self.dirty_scopes.is_empty() || !self.finished_fibers.is_empty() {
+                            if !self.dirty_scopes.is_empty() || !self.suspended_scopes.is_empty() {
                                 return;
                             }
 
@@ -596,6 +566,19 @@ impl VirtualDom {
         }
     }
 
+    /// Render the virtual dom, waiting for all suspense to be finished
+    ///
+    /// The mutations will be thrown out, so it's best to use this method for things like SSR that have async content
+    pub async fn wait_for_suspense(&mut self) {
+        loop {
+            if self.suspended_scopes.is_empty() {
+                break;
+            }
+
+            self.wait_for_work().await;
+        }
+    }
+
     /// Render what you can given the timeline and then move on
     ///
     /// It's generally a good idea to put some sort of limit on the suspense process in case a future is having issues.
@@ -607,26 +590,6 @@ impl VirtualDom {
         self.process_events();
 
         loop {
-            // first, unload any complete suspense trees
-            for finished_fiber in self.finished_fibers.drain(..) {
-                let scope = &self.scopes[finished_fiber];
-                let context = scope.has_context::<Rc<SuspenseContext>>().unwrap();
-
-                self.mutations
-                    .templates
-                    .append(&mut context.mutations.borrow_mut().templates);
-
-                self.mutations
-                    .edits
-                    .append(&mut context.mutations.borrow_mut().edits);
-
-                // TODO: count how many nodes are on the stack?
-                self.mutations.push(Mutation::ReplaceWith {
-                    id: context.placeholder.get().unwrap(),
-                    m: 1,
-                })
-            }
-
             // Next, diff any dirty scopes
             // We choose not to poll the deadline since we complete pretty quickly anyways
             if let Some(dirty) = self.dirty_scopes.iter().next().cloned() {
@@ -637,40 +600,9 @@ impl VirtualDom {
                     continue;
                 }
 
-                // if the scope is currently suspended, then we should skip it, ignoring any tasks calling for an update
-                if self.is_scope_suspended(dirty.id) {
-                    continue;
-                }
-
-                // Save the current mutations length so we can split them into boundary
-                let mutations_to_this_point = self.mutations.edits.len();
-
                 // Run the scope and get the mutations
                 self.run_scope(dirty.id);
                 self.diff_scope(dirty.id);
-
-                // If suspended leaves are present, then we should find the boundary for this scope and attach things
-                // No placeholder necessary since this is a diff
-                if !self.collected_leaves.is_empty() {
-                    let mut boundary = self.scopes[dirty.id]
-                        .consume_context::<Rc<SuspenseContext>>()
-                        .unwrap();
-
-                    let boundary_mut = boundary.borrow_mut();
-
-                    // Attach mutations
-                    boundary_mut
-                        .mutations
-                        .borrow_mut()
-                        .edits
-                        .extend(self.mutations.edits.split_off(mutations_to_this_point));
-
-                    // Attach suspended leaves
-                    boundary
-                        .waiting_on
-                        .borrow_mut()
-                        .extend(self.collected_leaves.drain(..));
-                }
             }
 
             // If there's more work, then just continue, plenty of work to do

packages/core/tests/safety.rs

@@ -3,7 +3,6 @@
 use std::rc::Rc;
 
 use dioxus::prelude::*;
-use dioxus_core::SuspenseContext;
 
 /// Ensure no issues with not calling rebuild
 #[test]
@@ -17,8 +16,4 @@ fn root_node_isnt_null() {
 
     // The height should be 0
     assert_eq!(scope.height(), 0);
-
-    // There should be a default suspense context
-    // todo: there should also be a default error boundary
-    assert!(scope.has_context::<Rc<SuspenseContext>>().is_some());
 }

packages/core/tests/suspense.rs

@@ -1,5 +1,5 @@
 use dioxus::core::ElementId;
-use dioxus::core::{Mutation::*, SuspenseContext};
+use dioxus::core::Mutation::*;
 use dioxus::prelude::*;
 use std::future::IntoFuture;
 use std::rc::Rc;