feat(ocap-kernel): Add makeOcapUrl endowment

Author: grypez

packages/ocap-kernel/src/endowments/factories/index.ts

@@ -1,8 +1,10 @@
+import * as makeOcapUrl from './make-ocap-url.ts';
 import * as makeRevoker from './make-revoker.ts';
 import * as scry from './scry.ts';
 import type { EndowmentDefinition } from '../types.ts';
 
 const endowmentDefinitions = {
+  makeOcapUrl,
   makeRevoker,
   scry,
 } as const satisfies Record<string, EndowmentDefinition>;

packages/ocap-kernel/src/endowments/factories/make-ocap-url.ts

@@ -0,0 +1,49 @@
+import { makePromiseKit } from '@endo/promise-kit';
+import { waitUntilQuiescent } from '@metamask/kernel-utils';
+
+import type { EndowmentContext } from '../types.ts';
+
+/**
+ * An ocap url.
+ */
+export type OcapUrl = `ocap://${string}`;
+
+/**
+ * A function that makes an ocap url for a given object.
+ */
+export type MakeOcapUrl = (object: unknown) => Promise<OcapUrl>;
+
+/**
+ * Make a function that makes an ocap url for a given object. Intended to be
+ * used as a user code endowment.
+ *
+ * @param context - The context in which the endowment is created.
+ * @returns A function that makes an ocap url for a given object.
+ */
+export function factory(context: EndowmentContext): MakeOcapUrl {
+  const { toRef } = context;
+
+  /**
+   * Make an ocap url for a given object.
+   *
+   * @param object - The object to make an ocap url for.
+   * @returns A promise that resolves with the ocap url.
+   */
+  const makeOcapUrl = async (object: unknown): Promise<OcapUrl> => {
+    const { promise, resolve } = makePromiseKit<OcapUrl>();
+    // This vpid can be sent to the kernel as the resolution target.
+    const vpid = toRef(promise);
+    const vref = toRef(object);
+    console.log('makeOcapUrl', vpid, vref);
+    // XXX this is a placeholder for the actual implementation which sends the
+    // kernel a request to resolve the promise with an ocap url for the given
+    // vref.
+    waitUntilQuiescent()
+      .catch((error) => console.error('wait until quiescent failed:', error))
+      .then(() => resolve(`ocap://${vref}`))
+      .catch((error) => console.error('resolve failed:', error));
+    return promise;
+  };
+
+  return harden(makeOcapUrl);
+}