SilverBullet pivot to become an offline-first PWA (#403)

plugos/worker_runtime.ts

@@ -0,0 +1,114 @@
+// This is the runtime imported from the compiled plug worker code
+
+import type { ControllerMessage, WorkerMessage } from "./protocol.ts";
+import type { Manifest } from "../common/manifest.ts";
+
+declare global {
+  function syscall(name: string, ...args: any[]): Promise<any>;
+}
+
+if (typeof Deno === "undefined") {
+  // @ts-ignore: Deno hack
+  self.Deno = {
+    args: [],
+    // @ts-ignore: Deno hack
+    build: {
+      arch: "x86_64",
+    },
+    env: {
+      // @ts-ignore: Deno hack
+      get() {
+      },
+    },
+  };
+}
+
+const pendingRequests = new Map<
+  number,
+  {
+    resolve: (result: unknown) => void;
+    reject: (e: any) => void;
+  }
+>();
+
+let syscallReqId = 0;
+
+function workerPostMessage(msg: ControllerMessage) {
+  self.postMessage(msg);
+}
+
+self.syscall = async (name: string, ...args: any[]) => {
+  return await new Promise((resolve, reject) => {
+    syscallReqId++;
+    pendingRequests.set(syscallReqId, { resolve, reject });
+    workerPostMessage({
+      type: "sys",
+      id: syscallReqId,
+      name,
+      args,
+    });
+  });
+};
+
+export function setupMessageListener(
+  // deno-lint-ignore ban-types
+  functionMapping: Record<string, Function>,
+  manifest: Manifest,
+) {
+  self.addEventListener("message", (event: { data: WorkerMessage }) => {
+    (async () => {
+      const data = event.data;
+      switch (data.type) {
+        case "inv":
+          {
+            const fn = functionMapping[data.name!];
+            if (!fn) {
+              throw new Error(`Function not loaded: ${data.name}`);
+            }
+            try {
+              const result = await Promise.resolve(fn(...(data.args || [])));
+              workerPostMessage({
+                type: "invr",
+                id: data.id,
+                result: result,
+              } as ControllerMessage);
+            } catch (e: any) {
+              console.error(e);
+              workerPostMessage({
+                type: "invr",
+                id: data.id!,
+                error: e.message,
+              });
+            }
+          }
+
+          break;
+        case "sysr":
+          {
+            const syscallId = data.id;
+            const lookup = pendingRequests.get(syscallId);
+            if (!lookup) {
+              throw Error("Invalid request id");
+            }
+            pendingRequests.delete(syscallId);
+            if (data.error) {
+              lookup.reject(new Error(data.error));
+            } else {
+              lookup.resolve(data.result);
+            }
+          }
+
+          break;
+      }
+    })().catch(console.error);
+  });
+  // Signal initialization with manifest
+  workerPostMessage({
+    type: "manifest",
+    manifest,
+  });
+}
+
+// Monkey patch fetch()
+import { monkeyPatchFetch } from "../plug-api/plugos-syscall/fetch.ts";
+monkeyPatchFetch();