2 files changed, 27 insertions, 30 deletions
diff --git a/js/dispatch.ts b/js/dispatch.ts
index cd11c93f6..babea5739 100644
--- a/js/dispatch.ts
+++ b/js/dispatch.ts
@@ -10,6 +10,11 @@ import {
   handleAsyncMsgFromRustMinimal
 } from "./dispatch_minimal";
 
+// TODO(ry) Currently we only use three values for opId: OP_READ, OP_WRITE,
+// FLATBUFFER_OP_ID. Later on use opId for actual individual ops, not just
+// classes of ops.
+const FLATBUFFER_OP_ID = 44;
+
 const promiseTable = new Map<number, util.Resolvable<msg.Base>>();
 
 interface FlatbufferRecord {
@@ -26,11 +31,11 @@ function flatbufferRecordFromBuf(buf: Uint8Array): FlatbufferRecord {
   };
 }
 
-export function handleAsyncMsgFromRust(ui8: Uint8Array): void {
+export function handleAsyncMsgFromRust(opId: number, ui8: Uint8Array): void {
   const buf32 = new Int32Array(ui8.buffer, ui8.byteOffset, ui8.byteLength / 4);
-  const recordMin = recordFromBufMinimal(buf32);
-  if (recordMin) {
+  if (opId !== FLATBUFFER_OP_ID) {
     // Fast and new
+    const recordMin = recordFromBufMinimal(opId, buf32);
     handleAsyncMsgFromRustMinimal(ui8, recordMin);
   } else {
     // Legacy
@@ -83,6 +88,7 @@ function sendInternal(
   const control = builder.asUint8Array();
 
   const response = core.dispatch(
+    FLATBUFFER_OP_ID, // TODO(ry) Use actual opId later.
     control,
     zeroCopy ? ui8FromArrayBufferView(zeroCopy) : undefined
   );
diff --git a/js/dispatch_minimal.ts b/js/dispatch_minimal.ts
index 17d328110..df0a290b2 100644
--- a/js/dispatch_minimal.ts
+++ b/js/dispatch_minimal.ts
@@ -3,7 +3,6 @@
 import * as util from "./util";
 import { core } from "./core";
 
-const DISPATCH_MINIMAL_TOKEN = 0xcafe;
 const promiseTableMin = new Map<number, util.Resolvable<number>>();
 let _nextPromiseId = 0;
 
@@ -13,31 +12,27 @@ export function nextPromiseId(): number {
 
 export interface RecordMinimal {
   promiseId: number;
-  opId: number;
+  opId: number; // Maybe better called dispatchId
   arg: number;
   result: number;
 }
 
-/** Determines if a message has the "minimal" serialization format. If false, it
- * is flatbuffer encoded.
- */
-export function hasMinimalToken(i32: Int32Array): boolean {
-  return i32[0] == DISPATCH_MINIMAL_TOKEN;
-}
-
-export function recordFromBufMinimal(buf32: Int32Array): null | RecordMinimal {
-  if (hasMinimalToken(buf32)) {
-    return {
-      promiseId: buf32[1],
-      opId: buf32[2],
-      arg: buf32[3],
-      result: buf32[4]
-    };
+export function recordFromBufMinimal(
+  opId: number,
+  buf32: Int32Array
+): RecordMinimal {
+  if (buf32.length != 3) {
+    throw Error("Bad message");
   }
-  return null;
+  return {
+    promiseId: buf32[0],
+    opId,
+    arg: buf32[1],
+    result: buf32[2]
+  };
 }
 
-const scratch32 = new Int32Array(5);
+const scratch32 = new Int32Array(3);
 const scratchBytes = new Uint8Array(
   scratch32.buffer,
   scratch32.byteOffset,
@@ -63,15 +58,11 @@ export function sendAsyncMinimal(
   zeroCopy: Uint8Array
 ): Promise<number> {
   const promiseId = nextPromiseId(); // AKA cmdId
-
-  scratch32[0] = DISPATCH_MINIMAL_TOKEN;
-  scratch32[1] = promiseId;
-  scratch32[2] = opId;
-  scratch32[3] = arg;
-
+  scratch32[0] = promiseId;
+  scratch32[1] = arg;
+  scratch32[2] = 0; // result
   const promise = util.createResolvable<number>();
   promiseTableMin.set(promiseId, promise);
-
-  core.dispatch(scratchBytes, zeroCopy);
+  core.dispatch(opId, scratchBytes, zeroCopy);
   return promise;
 }