feat(daemon): Thread cancellation context into worklets

packages/daemon/src/daemon.js

@@ -53,6 +53,14 @@ const makeInspector = (type, number, record) =>
     list: () => Object.keys(record),
   });
 
+const makeFarContext = context =>
+  Far('Context', {
+    cancel: context.cancel,
+    whenCancelled: () => context.cancelled,
+    whenDisposed: () => context.disposed,
+    addDisposalHook: context.onCancel,
+  });
+
 /**
  * @param {import('./types.js').DaemonicPowers} powers
  * @param {Promise<number>} webletPortP
@@ -289,7 +297,11 @@ const makeEndoBootstrap = async (
       // eslint-disable-next-line no-use-before-define
       provideValueForFormulaIdentifier(guestFormulaIdentifier)
     );
-    const external = E(workerDaemonFacet).makeUnconfined(specifier, guestP);
+    const external = E(workerDaemonFacet).makeUnconfined(
+      specifier,
+      guestP,
+      makeFarContext(context),
+    );
     return { external, internal: undefined };
   };
 
@@ -332,7 +344,11 @@ const makeEndoBootstrap = async (
       // eslint-disable-next-line no-use-before-define
       provideValueForFormulaIdentifier(guestFormulaIdentifier)
     );
-    const external = E(workerDaemonFacet).makeBundle(readableBundleP, guestP);
+    const external = E(workerDaemonFacet).makeBundle(
+      readableBundleP,
+      guestP,
+      makeFarContext(context),
+    );
     return { external, internal: undefined };
   };
 

packages/daemon/src/worker.js

@@ -65,22 +65,24 @@ export const makeWorkerFacet = ({ cancel }) => {
 
     /**
      * @param {string} specifier
-     * @param {unknown} powersP
+     * @param {Promise<unknown>} powersP
+     * @param {Promise<unknown>} contextP
      */
-    makeUnconfined: async (specifier, powersP) => {
+    makeUnconfined: async (specifier, powersP, contextP) => {
       // Windows absolute path includes drive letter which is confused for
       // protocol specifier. So, we reformat the specifier to include the
       // file protocol.
       const specifierUrl = normalizeFilePath(specifier);
       const namespace = await import(specifierUrl);
-      return namespace.make(powersP);
+      return namespace.make(powersP, contextP);
     },
 
     /**
      * @param {import('@endo/eventual-send').ERef<import('./types.js').EndoReadable>} readableP
-     * @param {unknown} powersP
+     * @param {Promise<unknown>} powersP
+     * @param {Promise<unknown>} contextP
      */
-    makeBundle: async (readableP, powersP) => {
+    makeBundle: async (readableP, powersP, contextP) => {
       const bundleText = await E(readableP).text();
       const bundle = JSON.parse(bundleText);
 
@@ -90,7 +92,7 @@ export const makeWorkerFacet = ({ cancel }) => {
       const namespace = await importBundle(bundle, {
         endowments,
       });
-      return namespace.make(powersP);
+      return namespace.make(powersP, contextP);
     },
   });
 };