WebWorkers: Allow web worker owner to inject globals into worker, supply modified __fbBatchedBridgeConfig

Summary: Now that web workers are just JSCExecutors, we can move forward with adding native module support. The means we need to supply the worker with a correct __fbBatchedBridgeConfig global so it can appropriately set up its JS MessageQueue. Unfortunately, native modules can't support multiple JS execution contexts out-of-the-box, so we need to whitelist those modules that actually can be referenced from a webworker. In order to do that, we add the supportsWebWorkers call in NativeModule and the SupportsWebWorkers annotation for JS modules. These add metadata to __fbBatchedBridgeConfig which allows us to create a new config with only those modules that support web workers.

Reviewed By: lexs

Differential Revision: D2927091

fb-gh-sync-id: 9b47331253b277940b552e7d899198b5f0a3ed8c
shipit-source-id: 9b47331253b277940b552e7d899198b5f0a3ed8c

ReactAndroid/src/main/java/com/facebook/react/bridge/BaseJavaModule.java

@@ -341,4 +341,9 @@ public abstract class BaseJavaModule implements NativeModule {
   public void onCatalystInstanceDestroy() {
     // do nothing
   }
+
+  @Override
+  public boolean supportsWebWorkers() {
+    return false;
+  }
 }

ReactAndroid/src/main/java/com/facebook/react/bridge/JavaScriptModulesConfig.java

@@ -52,6 +52,9 @@ public class JavaScriptModulesConfig {
       jg.writeEndObject();
     }
     jg.writeEndObject();
+    if (registration.getModuleInterface().isAnnotationPresent(SupportsWebWorkers.class)) {
+      jg.writeBooleanField("supportsWebWorkers", true);
+    }
   }
 
   public static class Builder {

ReactAndroid/src/main/java/com/facebook/react/bridge/NativeModule.java

@@ -72,4 +72,9 @@ public interface NativeModule {
    * Called before {CatalystInstance#onHostDestroy}
    */
   void onCatalystInstanceDestroy();
+
+  /**
+   * Whether this native module supports calls from web workers. Ignored for now.
+   */
+  boolean supportsWebWorkers();
 }

ReactAndroid/src/main/java/com/facebook/react/bridge/NativeModuleRegistry.java

@@ -65,6 +65,7 @@ public class NativeModuleRegistry {
       for (ModuleDefinition moduleDef : mModuleTable) {
         jg.writeObjectFieldStart(moduleDef.name);
         jg.writeNumberField("moduleID", moduleDef.id);
+        jg.writeBooleanField("supportsWebWorkers", moduleDef.target.supportsWebWorkers());
         jg.writeObjectFieldStart("methods");
         for (int i = 0; i < moduleDef.methods.size(); i++) {
           MethodRegistration method = moduleDef.methods.get(i);

ReactAndroid/src/main/java/com/facebook/react/bridge/SupportsWebWorkers.java

@@ -0,0 +1,15 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+package com.facebook.react.bridge;
+
+import java.lang.annotation.Retention;
+
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+/**
+ * Annotation indicating that a JS module should be made available to web
+ * workers spawned by the main JS executor.
+ */
+@Retention(RUNTIME)
+public @interface SupportsWebWorkers {
+}

ReactAndroid/src/main/jni/react/JSCExecutor.cpp

@@ -97,7 +97,8 @@ JSCExecutor::JSCExecutor(
     Bridge *bridge,
     int workerId,
     JSCExecutor *owner,
-    const std::string& script) :
+    const std::string& script,
+    const std::unordered_map<std::string, std::string>& globalObjAsJSON) :
     m_bridge(bridge),
     m_workerId(workerId),
     m_owner(owner),
@@ -105,11 +106,15 @@ JSCExecutor::JSCExecutor(
     m_messageQueueThread(MessageQueues::getCurrentMessageQueueThread()) {
   // We post initOnJSVMThread here so that the owner doesn't have to wait for
   // initialization on its own thread
-  m_messageQueueThread->runOnQueue([this, script] () {
+  m_messageQueueThread->runOnQueue([this, script, globalObjAsJSON] () {
     initOnJSVMThread();
 
     installGlobalFunction(m_context, "postMessage", nativePostMessage);
 
+    for (auto& it : globalObjAsJSON) {
+      setGlobalVariable(it.first, it.second);
+    }
+
     // TODO(9604438): Protect against script does not exist
     std::string scriptSrc = WebWorkerUtil::loadScriptFromAssets(script);
     // TODO(9994180): Throw on error
@@ -302,14 +307,17 @@ void JSCExecutor::loadModule(uint32_t moduleId) {
 
 int JSCExecutor::addWebWorker(
     const std::string& script,
-    JSValueRef workerRef) {
+    JSValueRef workerRef,
+    JSValueRef globalObjRef) {
   static std::atomic_int nextWorkerId(1);
   int workerId = nextWorkerId++;
 
+  Object globalObj = Value(m_context, globalObjRef).asObject();
+
   auto workerMQT = WebWorkerUtil::createWebWorkerThread(workerId, m_messageQueueThread.get());
   std::unique_ptr<JSCExecutor> worker;
-  workerMQT->runOnQueueSync([this, &worker, &script, workerId] () {
-    worker.reset(new JSCExecutor(m_bridge, workerId, this, script));
+  workerMQT->runOnQueueSync([this, &worker, &script, &globalObj, workerId] () {
+    worker.reset(new JSCExecutor(m_bridge, workerId, this, script, globalObj.toJSONMap()));
   });
 
   Object workerObj = Value(m_context, workerRef).asObject();
@@ -487,7 +495,7 @@ JSValueRef JSCExecutor::nativeStartWorker(
     size_t argumentCount,
     const JSValueRef arguments[],
     JSValueRef *exception) {
-  if (argumentCount != 2) {
+  if (argumentCount != 3) {
     *exception = createErrorString(ctx, "Got wrong number of args");
     return JSValueMakeUndefined(ctx);
   }
@@ -495,6 +503,7 @@ JSValueRef JSCExecutor::nativeStartWorker(
   std::string scriptFile = Value(ctx, arguments[0]).toString().str();
 
   JSValueRef worker = arguments[1];
+  JSValueRef globalObj = arguments[2];
 
   JSCExecutor *executor;
   try {
@@ -504,7 +513,7 @@ JSValueRef JSCExecutor::nativeStartWorker(
     return JSValueMakeUndefined(ctx);
   }
 
-  int workerId = executor->addWebWorker(scriptFile, worker);
+  int workerId = executor->addWebWorker(scriptFile, worker, globalObj);
 
   return JSValueMakeNumber(ctx, workerId);
 }

ReactAndroid/src/main/jni/react/JSCExecutor.h

@@ -92,7 +92,8 @@ private:
       Bridge *bridge,
       int workerId,
       JSCExecutor *owner,
-      const std::string& script);
+      const std::string& script,
+      const std::unordered_map<std::string, std::string>& globalObjAsJSON);
 
   void initOnJSVMThread();
   void terminateOnJSVMThread();
@@ -100,7 +101,7 @@ private:
   void flushQueueImmediate(std::string queueJSON);
   void loadModule(uint32_t moduleId);
 
-  int addWebWorker(const std::string& script, JSValueRef workerRef);
+  int addWebWorker(const std::string& script, JSValueRef workerRef, JSValueRef globalObjRef);
   void postMessageToOwnedWebWorker(int worker, JSValueRef message, JSValueRef *exn);
   void postMessageToOwner(JSValueRef result);
   void receiveMessageFromOwnedWebWorker(int workerId, const std::string& message);