add --enable-experimental-byob-streams flag to turn the feature on

Author: Jake Champion

c-dependencies/js-compute-runtime/js-compute-runtime.cpp

@@ -115,12 +115,14 @@ bool init_js() {
   if (!js::UseInternalJobQueues(cx) || !JS::InitSelfHostedCode(cx))
     return false;
 
+  bool ENABLE_EXPERIMENTAL_BYOB_STREAMS = std::string(std::getenv("ENABLE_EXPERIMENTAL_BYOB_STREAMS")) == "1";
+
   // TODO: check if we should set a different creation zone.
   JS::RealmOptions options;
   options.creationOptions()
       .setStreamsEnabled(true)
-      .setReadableByteStreamsEnabled(true)
-      .setBYOBStreamReadersEnabled(true)
+      .setReadableByteStreamsEnabled(ENABLE_EXPERIMENTAL_BYOB_STREAMS)
+      .setBYOBStreamReadersEnabled(ENABLE_EXPERIMENTAL_BYOB_STREAMS)
       .setReadableStreamPipeToEnabled(true)
       .setWritableStreamsEnabled(true)
       .setWeakRefsEnabled(JS::WeakRefSpecifier::EnabledWithoutCleanupSome);

c-dependencies/spidermonkey

@@ -9,4 +9,4 @@ name = "byob"
 service_id = ""
 
 [scripts]
-  build = "node ../../../../js-compute-runtime-cli.js"
+  build = "node ../../../../js-compute-runtime-cli.js --enable-experimental-byob-streams"

integration-tests/js-compute/fixtures/byob/fastly.toml.in

@@ -5,7 +5,7 @@ import { printVersion } from "./src/printVersion.js";
 import { printHelp } from "./src/printHelp.js";
 import { addSdkMetadataField } from "./src/addSdkMetadataField.js";
 
-const {wasmEngine, input, component, output, version, help} = await parseInputs(process.argv.slice(2))
+const {enableExperimentalByobStreams, wasmEngine, input, component, output, version, help} = await parseInputs(process.argv.slice(2))
 
 if (version) {
   await printVersion();
@@ -19,7 +19,7 @@ if (version) {
   // it could be that the user is using an older version of js-compute-runtime
   // and a newer version does support the platform they are using.
   const {compileApplicationToWasm} = await import('./src/compileApplicationToWasm.js')
-  await compileApplicationToWasm(input, output, wasmEngine);
+  await compileApplicationToWasm(input, output, wasmEngine, enableExperimentalByobStreams);
   if (component) {
     const {compileComponent} = await import('./src/component.js');
     await compileComponent(output);

js-compute-runtime-cli.js

@@ -8,7 +8,7 @@ import { precompile } from "./precompile.js";
 import { bundle } from "./bundle.js";
 import { containsSyntaxErrors } from "./containsSyntaxErrors.js";
 
-export async function compileApplicationToWasm(input, output, wasmEngine) {
+export async function compileApplicationToWasm(input, output, wasmEngine, enableExperimentalByobStreams = false) {
   try {
     if (!(await isFile(input))) {
       console.error(
@@ -85,6 +85,7 @@ export async function compileApplicationToWasm(input, output, wasmEngine) {
     let wizerProcess = spawnSync(
       wizer,
       [
+        "--inherit-env=true",
         "--allow-wasi",
         `--dir=.`,
         `--wasm-bulk-memory=true`,
@@ -97,6 +98,9 @@ export async function compileApplicationToWasm(input, output, wasmEngine) {
         input: application,
         shell: true,
         encoding: "utf-8",
+        env: {
+          ENABLE_EXPERIMENTAL_BYOB_STREAMS: enableExperimentalByobStreams ? 1 : 0
+        }
       }
     );
     process.exitCode = wizerProcess.status;

src/compileApplicationToWasm.js

@@ -7,6 +7,7 @@ export async function parseInputs(cliInputs) {
   const __dirname = dirname(fileURLToPath(import.meta.url));
 
   let component = false;
+  let enableExperimentalByobStreams = false;
   let customEngineSet = false;
   let wasmEngine = join(__dirname, "../js-compute-runtime.wasm");
   let customInputSet = false;
@@ -20,6 +21,10 @@ export async function parseInputs(cliInputs) {
       case "--": {
         break loop;
       }
+      case "--enable-experimental-byob-streams": {
+        enableExperimentalByobStreams = true;
+        break;
+      }
       case "-V":
       case "--version": {
         return { version: true };
@@ -88,5 +93,5 @@ export async function parseInputs(cliInputs) {
       }
     }
   }
-  return { wasmEngine, component, input, output };
+  return { wasmEngine, component, input, output, enableExperimentalByobStreams };
 }