Hook up request animation frame plumbing to decouple execution

frontend/wasm/Cargo.toml

@@ -23,15 +23,23 @@ editor = { path = "../../editor", package = "graphite-editor" }
 document-legacy = { path = "../../document-legacy", package = "graphite-document-legacy" }
 graph-craft = { path = "../../node-graph/graph-craft" }
 log = "0.4"
-graphene-core = { path = "../../node-graph/gcore", features = ["async", "std", "alloc"] }
+graphene-core = { path = "../../node-graph/gcore", features = [
+	"async",
+	"std",
+	"alloc",
+] }
 serde = { version = "1.0", features = ["derive"] }
 wasm-bindgen = { version = "0.2.84" }
 serde-wasm-bindgen = "0.4.1"
 js-sys = "0.3.55"
 wasm-bindgen-futures = "0.4.33"
-ron = {version = "0.8", optional = true}
+ron = { version = "0.8", optional = true }
 bezier-rs = { path = "../../libraries/bezier-rs" }
 
+[dependencies.web-sys]
+version = "0.3.4"
+features = ['Window']
+
 [dev-dependencies]
 wasm-bindgen-test = "0.3.22"
 

frontend/wasm/src/editor_api.rs

@@ -18,6 +18,7 @@ use graphene_core::raster::color::Color;
 
 use serde::Serialize;
 use serde_wasm_bindgen::{self, from_value};
+use std::cell::RefCell;
 use std::sync::atomic::Ordering;
 use wasm_bindgen::prelude::*;
 
@@ -53,6 +54,50 @@ pub struct JsEditorHandle {
 	frontend_message_handler_callback: js_sys::Function,
 }
 
+fn window() -> web_sys::Window {
+	web_sys::window().expect("no global `window` exists")
+}
+
+fn request_animation_frame(f: &Closure<dyn FnMut()>) {
+	window().request_animation_frame(f.as_ref().unchecked_ref()).expect("should register `requestAnimationFrame` OK");
+}
+
+// Sends a message to the dispatcher in the Editor Backend
+fn poll_node_graph_evaluation() {
+	// Process no further messages after a crash to avoid spamming the console
+	if EDITOR_HAS_CRASHED.load(Ordering::SeqCst) {
+		return;
+	}
+	editor::node_graph_executor::run_node_graph();
+
+	// Get the editor instances, dispatch the message, and store the `FrontendMessage` queue response
+	EDITOR_INSTANCES.with(|instances| {
+		JS_EDITOR_HANDLES.with(|handles| {
+			// Mutably borrow the editors, and if successful, we can access them in the closure
+			instances.try_borrow_mut().map(|mut editors| {
+				// Get the editor instance for this editor ID, then dispatch the message to the backend, and return its response `FrontendMessage` queue
+				for (id, editor) in editors.iter_mut() {
+					let handles = handles.borrow_mut();
+					let handle = handles.get(id).unwrap();
+					let mut messages = VecDeque::new();
+					editor.poll_node_graph_evaluation(&mut messages);
+					// Send each `FrontendMessage` to the JavaScript frontend
+
+					let mut responses = Vec::new();
+					for message in messages.into_iter() {
+						responses.extend(editor.handle_message(message));
+					}
+
+					for response in responses.into_iter() {
+						handle.send_frontend_message_to_js(response);
+					}
+					// If the editor cannot be borrowed then it has encountered a panic - we should just ignore new dispatches
+				}
+			})
+		})
+	});
+}
+
 #[wasm_bindgen]
 #[allow(clippy::too_many_arguments)]
 impl JsEditorHandle {
@@ -165,6 +210,18 @@ impl JsEditorHandle {
 
 		self.dispatch(GlobalsMessage::SetPlatform { platform });
 		self.dispatch(Message::Init);
+
+		let f = std::rc::Rc::new(RefCell::new(None));
+		let g = f.clone();
+
+		*g.borrow_mut() = Some(Closure::new(move || {
+			poll_node_graph_evaluation();
+
+			// Schedule ourself for another requestAnimationFrame callback.
+			request_animation_frame(f.borrow().as_ref().unwrap());
+		}));
+
+		request_animation_frame(g.borrow().as_ref().unwrap());
 	}
 
 	#[wasm_bindgen(js_name = tauriResponse)]