Call handlers from context of a runtime and scope

packages/core/src/runtime.rs

@@ -87,6 +87,16 @@ impl Runtime {
         self.scope_stack.borrow().last().copied()
     }
 
+    /// Call this function with the current scope set to the given scope
+    ///
+    /// Useful in a limited number of scenarios, not public.
+    pub(crate) fn with_scope<O>(&self, id: ScopeId, f: impl FnOnce() -> O) -> O {
+        self.scope_stack.borrow_mut().push(id);
+        let o = f();
+        self.scope_stack.borrow_mut().pop();
+        o
+    }
+
     /// Get the context for any scope given its ID
     ///
     /// This is useful for inserting or removing contexts from a scope, or rendering out its root node
@@ -137,6 +147,17 @@ impl RuntimeGuard {
         push_runtime(runtime.clone());
         Self(runtime)
     }
+
+    /// Run a function with a given runtime and scope in context
+    pub fn with<O>(runtime: Rc<Runtime>, scope: Option<ScopeId>, f: impl FnOnce() -> O) -> O {
+        let guard = Self::new(runtime.clone());
+        let o = match scope {
+            Some(scope) => Runtime::with_scope(&runtime, scope, f),
+            None => f(),
+        };
+        drop(guard);
+        o
+    }
 }
 
 impl Drop for RuntimeGuard {

packages/core/src/scope_context.rs

@@ -318,11 +318,16 @@ pub fn spawn(fut: impl Future<Output = ()> + 'static) {
     with_current_scope(|cx| cx.spawn(fut));
 }
 
+/// Spawn a future on a component given its [`ScopeId`].
+pub fn spawn_at(fut: impl Future<Output = ()> + 'static, scope_id: ScopeId) -> Option<TaskId> {
+    with_runtime(|rt| rt.get_context(scope_id).unwrap().push_future(fut))
+}
+
 /// Spawn a future that Dioxus won't clean up when this component is unmounted
 ///
 /// This is good for tasks that need to be run after the component has been dropped.
 pub fn spawn_forever(fut: impl Future<Output = ()> + 'static) -> Option<TaskId> {
-    with_current_scope(|cx| cx.spawn_forever(fut))
+    spawn_at(fut, ScopeId(0))
 }
 
 /// Informs the scheduler that this task is no longer needed and should be removed.