debug-server-next
Version:
Dev server for hippy-core.
52 lines (51 loc) • 2.25 kB
JavaScript
// Copyright 2021 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import * as Coordinator from '../render_coordinator/render_coordinator.js';
const coordinator = Coordinator.RenderCoordinator.RenderCoordinator.instance();
const pendingRenders = new WeakSet();
const activeRenders = new WeakSet();
const subsequentRender = new WeakMap();
const wrappedCallbacks = new WeakMap();
export async function scheduleRender(component, callback) {
// If scheduleRender is called when there is already a render scheduled for this
// component, store the callback against the renderer for after the current
// call has finished.
if (activeRenders.has(component)) {
subsequentRender.set(component, callback);
return;
}
// If this render was already scheduled but hasn't started yet, just return.
if (pendingRenders.has(component)) {
return;
}
pendingRenders.add(component);
// Create a wrapper around the callback so that we know that it has moved from
// pending to active. When it has completed we remove it from the active renderers.
let wrappedCallback = wrappedCallbacks.get(callback);
if (!wrappedCallback) {
wrappedCallback = async () => {
pendingRenders.delete(component);
activeRenders.add(component);
await callback.call(component);
activeRenders.delete(component);
};
// Store it for next time so we aren't creating wrappers unnecessarily.
wrappedCallbacks.set(callback, wrappedCallback);
}
// Track that there is render rendering, wait for it to finish, and stop tracking.
await coordinator.write(wrappedCallback);
// If during the render there was another schedule render call, get
// the callback and schedule it to happen now.
if (subsequentRender.has(component)) {
const newCallback = subsequentRender.get(component);
subsequentRender.delete(component);
if (!newCallback) {
return;
}
scheduleRender(component, newCallback);
}
}
export function isScheduledRender(component) {
return activeRenders.has(component);
}