widgets: mainly implement k3d object ref locking; also, add ipywidgets state help function

- this k3d locking is needed to workaround k3d implementing their own
  internal custom references, and just assuming everything is created in
  exactly the order it is in jupyterlab. With RTC the order can be more
  random, so we manually enforce it.

Author: williamstein

src/packages/frontend/jupyter/widgets/manager.ts

@@ -24,6 +24,9 @@ import React from "react";
 import ReactDOM from "react-dom/client";
 import type { JupyterActions } from "@cocalc/frontend/jupyter/browser-actions";
 import { FileContext } from "@cocalc/frontend/lib/file-context";
+import { delay } from "awaiting";
+
+const K3D_DELAY_MS = 25;
 
 type DeserializedModelState = { [key: string]: any };
 
@@ -39,6 +42,7 @@ export class WidgetManager {
   private last_changed: { [model_id: string]: { [key: string]: any } } = {};
   private state_lock: Set<string> = new Set();
   private watching: Set<string> = new Set();
+  public k3dObjectIds = new Set<number>();
 
   constructor({
     ipywidgets_state,
@@ -147,12 +151,19 @@ VBox([s1, s2])
     changed: SerializedModelState,
     merge: boolean,
   ): Promise<void> => {
-    const model: base.DOMWidgetModel | undefined =
-      await this.manager.get_model(model_id);
+    const model = await this.manager.get_model(model_id);
     log("updateModel", { model_id, merge, changed });
-    if (model == null) {
-      return;
+    if (model.module == "k3d") {
+      // k3d invents its own ad hoc inter-model reference scheme, so we have
+      // to deal with that.
+      if (changed.object_ids != null) {
+        while (!isSubset(changed.object_ids, this.k3dObjectIds)) {
+          log("k3d -- waiting for object_ids", changed.object_ids);
+          await delay(K3D_DELAY_MS);
+        }
+      }
     }
+
     //log(`setting state of model "${model_id}" to `, change);
     if (changed.last_changed != null) {
       this.last_changed[model_id] = changed;
@@ -598,6 +609,7 @@ VBox([s1, s2])
 
 class Environment implements WidgetEnvironment {
   private manager: WidgetManager;
+
   constructor(manager) {
     this.manager = manager;
   }
@@ -626,12 +638,17 @@ class Environment implements WidgetEnvironment {
     if (state == null) {
       throw Error("bug");
     }
+
     if (state._model_module == "k3d" && state.type != null) {
       while (!state?.type || !state?.id) {
         log(
-          "getSerializedModelState",
+          "getSerializedModelState -- k3d case",
           model_id,
-          "k3d: waiting for state.type to be defined",
+          "k3d: waiting for state.type and state.id to be defined",
+          {
+            type: state?.type,
+            id: state?.id,
+          },
         );
 
         await once(this.manager.ipywidgets_state, "change");
@@ -660,6 +677,19 @@ class Environment implements WidgetEnvironment {
 
     log("getSerializedModelState", { model_id, state });
     setTimeout(() => this.manager.watchModel(model_id), 1);
+
+    if (state._model_module == "k3d") {
+      if (state.object_ids != null) {
+        while (!isSubset(state.object_ids, this.manager.k3dObjectIds)) {
+          log("k3d -- waiting for object_ids", state.object_ids);
+          await delay(K3D_DELAY_MS);
+        }
+      }
+      if (state.id != null) {
+        this.manager.k3dObjectIds.add(state.id);
+      }
+    }
+
     return {
       modelName: state._model_name,
       modelModule: state._model_module,
@@ -751,3 +781,12 @@ const IPY_MODEL = "IPY_MODEL_";
 function isModelReference(value): boolean {
   return typeof value == "string" && value.startsWith(IPY_MODEL);
 }
+
+function isSubset(X, Y) {
+  for (const a of X) {
+    if (!Y.has(a)) {
+      return false;
+    }
+  }
+  return true;
+}

src/packages/sync/editor/generic/ipywidgets-state.ts

@@ -524,6 +524,14 @@ scat.x, scat.y = np.random.rand(2, 50)
     await this.table.save();
   };
 
+  values = () => {
+    const x = this.table.get();
+    if (x == null) {
+      return [];
+    }
+    return Object.values(x.toJS()).filter((obj) => obj.data);
+  };
+
   // Clean up all data in the table about models that are not
   // referenced (directly or indirectly) in any cell in the notebook.
   // There is also a comm:close event/message somewhere, which