1 files changed, 97 insertions, 0 deletions
diff --git a/cli/js/ops/dispatch_json.ts b/cli/js/ops/dispatch_json.ts
new file mode 100644
index 000000000..6fb9007df
--- /dev/null
+++ b/cli/js/ops/dispatch_json.ts
@@ -0,0 +1,97 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import * as util from "../util.ts";
+import { TextEncoder, TextDecoder } from "../web/text_encoding.ts";
+import { core } from "../core.ts";
+import { OPS_CACHE } from "../runtime.ts";
+import { ErrorKind, getErrorClass } from "../errors.ts";
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+type Ok = any;
+
+interface JsonError {
+  kind: ErrorKind;
+  message: string;
+}
+
+interface JsonResponse {
+  ok?: Ok;
+  err?: JsonError;
+  promiseId?: number; // Only present in async messages.
+}
+
+const promiseTable = new Map<number, util.Resolvable<JsonResponse>>();
+let _nextPromiseId = 1;
+
+function nextPromiseId(): number {
+  return _nextPromiseId++;
+}
+
+function decode(ui8: Uint8Array): JsonResponse {
+  const s = new TextDecoder().decode(ui8);
+  return JSON.parse(s) as JsonResponse;
+}
+
+function encode(args: object): Uint8Array {
+  const s = JSON.stringify(args);
+  return new TextEncoder().encode(s);
+}
+
+function unwrapResponse(res: JsonResponse): Ok {
+  if (res.err != null) {
+    throw new (getErrorClass(res.err.kind))(res.err.message);
+  }
+  util.assert(res.ok != null);
+  return res.ok;
+}
+
+export function asyncMsgFromRust(resUi8: Uint8Array): void {
+  const res = decode(resUi8);
+  util.assert(res.promiseId != null);
+
+  const promise = promiseTable.get(res.promiseId!);
+  util.assert(promise != null);
+  promiseTable.delete(res.promiseId!);
+  promise.resolve(res);
+}
+
+export function sendSync(
+  opName: string,
+  args: object = {},
+  zeroCopy?: Uint8Array
+): Ok {
+  const opId = OPS_CACHE[opName];
+  util.log("sendSync", opName, opId);
+  const argsUi8 = encode(args);
+  const resUi8 = core.dispatch(opId, argsUi8, zeroCopy);
+  util.assert(resUi8 != null);
+
+  const res = decode(resUi8);
+  util.assert(res.promiseId == null);
+  return unwrapResponse(res);
+}
+
+export async function sendAsync(
+  opName: string,
+  args: object = {},
+  zeroCopy?: Uint8Array
+): Promise<Ok> {
+  const opId = OPS_CACHE[opName];
+  util.log("sendAsync", opName, opId);
+  const promiseId = nextPromiseId();
+  args = Object.assign(args, { promiseId });
+  const promise = util.createResolvable<Ok>();
+
+  const argsUi8 = encode(args);
+  const buf = core.dispatch(opId, argsUi8, zeroCopy);
+  if (buf) {
+    // Sync result.
+    const res = decode(buf);
+    promise.resolve(res);
+  } else {
+    // Async result.
+    promiseTable.set(promiseId, promise);
+  }
+
+  const res = await promise;
+  return unwrapResponse(res);
+}