Lazily instantiate native modules

Summary: Instead of sending a list of modules over to JS on startup (and actually blocking script execution) instead provide a proxy object that constructs each of these lazily.

Reviewed By: lexs

Differential Revision: D3936979

fbshipit-source-id: 71bde822f01eb17a29f56c5e60e95e98e207d74d

Libraries/BatchedBridge/BatchedBridgedModules/NativeModules.js

@@ -58,6 +58,9 @@ function genModule(config: ?ModuleConfig, moduleID: number): ?{name: string, mod
   return { name: moduleName, module };
 }
 
+// export this method as a global so we can call it from native
+global.__fbGenNativeModule = genModule;
+
 function loadModule(name: string, moduleID: number): ?Object {
   invariant(global.nativeRequireModuleConfig,
     'Can\'t lazily create module without nativeRequireModuleConfig');
@@ -115,27 +118,31 @@ function createErrorFromErrorData(errorData: {message: string}): Error {
   return Object.assign(error, extraErrorInfo);
 }
 
-const bridgeConfig = global.__fbBatchedBridgeConfig;
-invariant(bridgeConfig, '__fbBatchedBridgeConfig is not set, cannot invoke native modules');
-
-const NativeModules : {[moduleName: string]: Object} = {};
-(bridgeConfig.remoteModuleConfig || []).forEach((config: ModuleConfig, moduleID: number) => {
-  // Initially this config will only contain the module name when running in JSC. The actual
-  // configuration of the module will be lazily loaded.
-  const info = genModule(config, moduleID);
-  if (!info) {
-    return;
-  }
-
-  if (info.module) {
-    NativeModules[info.name] = info.module;
-  }
-  // If there's no module config, define a lazy getter
-  else {
-    defineLazyObjectProperty(NativeModules, info.name, {
-      get: () => loadModule(info.name, moduleID)
-    });
-  }
-});
+let NativeModules : {[moduleName: string]: Object} = {};
+if (global.nativeModuleProxy) {
+  NativeModules = global.nativeModuleProxy;
+} else {
+  const bridgeConfig = global.__fbBatchedBridgeConfig;
+  invariant(bridgeConfig, '__fbBatchedBridgeConfig is not set, cannot invoke native modules');
+
+  (bridgeConfig.remoteModuleConfig || []).forEach((config: ModuleConfig, moduleID: number) => {
+    // Initially this config will only contain the module name when running in JSC. The actual
+    // configuration of the module will be lazily loaded.
+    const info = genModule(config, moduleID);
+    if (!info) {
+      return;
+    }
+
+    if (info.module) {
+      NativeModules[info.name] = info.module;
+    }
+    // If there's no module config, define a lazy getter
+    else {
+      defineLazyObjectProperty(NativeModules, info.name, {
+        get: () => loadModule(info.name, moduleID)
+      });
+    }
+  });
+}
 
 module.exports = NativeModules;

ReactAndroid/src/main/jni/xreact/jni/ProxyExecutor.cpp

@@ -42,12 +42,13 @@ ProxyExecutor::ProxyExecutor(jni::global_ref<jobject>&& executorInstance,
     , m_delegate(delegate) {
 
   folly::dynamic nativeModuleConfig = folly::dynamic::array;
-  auto moduleRegistry = delegate->getModuleRegistry();
 
   {
     SystraceSection s("collectNativeModuleDescriptions");
+    auto moduleRegistry = delegate->getModuleRegistry();
     for (const auto& name : moduleRegistry->moduleNames()) {
-      nativeModuleConfig.push_back(moduleRegistry->getConfig(name));
+      auto config = moduleRegistry->getConfig(name);
+      nativeModuleConfig.push_back(config ? config->config : nullptr);
     }
   }
 

ReactCommon/cxxreact/Android.mk

@@ -13,6 +13,7 @@ LOCAL_SRC_FILES := \
   JSCLegacyProfiler.cpp \
   JSCLegacyTracing.cpp \
   JSCMemory.cpp \
+  JSCNativeModules.cpp \
   JSCPerfStats.cpp \
   JSCTracing.cpp \
   JSCWebWorker.cpp \

ReactCommon/cxxreact/BUCK

@@ -116,6 +116,7 @@ CXXREACT_PUBLIC_HEADERS = [
   'Instance.h',
   'JSCExecutor.h',
   'JSCHelpers.h',
+  'JSCNativeModules.h',
   'JSCWebWorker.h',
   'JSModulesUnbundle.h',
   'MessageQueueThread.h',

ReactCommon/cxxreact/JSCExecutor.cpp

@@ -20,6 +20,7 @@
 #include "Platform.h"
 #include "SystraceSection.h"
 #include "Value.h"
+#include "JSCNativeModules.h"
 #include "JSCSamplingProfiler.h"
 #include "JSModulesUnbundle.h"
 #include "ModuleRegistry.h"
@@ -79,6 +80,28 @@ inline JSObjectCallAsFunctionCallback exceptionWrapMethod() {
   return &funcWrapper::call;
 }
 
+template<JSValueRef (JSCExecutor::*method)(JSObjectRef object, JSStringRef propertyName)>
+inline JSObjectGetPropertyCallback exceptionWrapMethod() {
+  struct funcWrapper {
+    static JSValueRef call(
+         JSContextRef ctx,
+         JSObjectRef object,
+         JSStringRef propertyName,
+         JSValueRef *exception) {
+      try {
+        auto globalObj = JSContextGetGlobalObject(ctx);
+        auto executor = static_cast<JSCExecutor*>(JSObjectGetPrivate(globalObj));
+        return (executor->*method)(object, propertyName);
+      } catch (...) {
+        *exception = translatePendingCppExceptionToJSError(ctx, object);
+        return JSValueMakeUndefined(ctx);
+      }
+    }
+  };
+
+  return &funcWrapper::call;
+}
+
 }
 
 #if DEBUG
@@ -109,28 +132,15 @@ JSCExecutor::JSCExecutor(std::shared_ptr<ExecutorDelegate> delegate,
     m_delegate(delegate),
     m_deviceCacheDir(cacheDir),
     m_messageQueueThread(messageQueueThread),
+    m_nativeModules(delegate->getModuleRegistry()),
     m_jscConfig(jscConfig) {
   initOnJSVMThread();
 
-  SystraceSection s("setBatchedBridgeConfig");
-
-  folly::dynamic nativeModuleConfig = folly::dynamic::array();
-
   {
-    SystraceSection s("collectNativeModuleNames");
-    for (auto& name : delegate->getModuleRegistry()->moduleNames()) {
-      nativeModuleConfig.push_back(folly::dynamic::array(std::move(name)));
-    }
+    SystraceSection s("nativeModuleProxy object");
+    installGlobalProxy(m_context, "nativeModuleProxy",
+                       exceptionWrapMethod<&JSCExecutor::getNativeModule>());
   }
-
-  folly::dynamic config =
-    folly::dynamic::object
-      ("remoteModuleConfig", std::move(nativeModuleConfig));
-
-  SystraceSection t("setGlobalVariable");
-  setGlobalVariable(
-    "__fbBatchedBridgeConfig",
-    folly::make_unique<JSBigStdString>(folly::toJson(config)));
 }
 
 JSCExecutor::JSCExecutor(
@@ -146,6 +156,7 @@ JSCExecutor::JSCExecutor(
     m_owner(owner),
     m_deviceCacheDir(owner->m_deviceCacheDir),
     m_messageQueueThread(messageQueueThread),
+    m_nativeModules(delegate->getModuleRegistry()),
     m_jscConfig(jscConfig) {
   // We post initOnJSVMThread here so that the owner doesn't have to wait for
   // initialization on its own thread
@@ -211,7 +222,6 @@ void JSCExecutor::initOnJSVMThread() throw(JSException) {
   // Add a pointer to ourselves so we can retrieve it later in our hooks
   JSObjectSetPrivate(JSContextGetGlobalObject(m_context), this);
 
-  installNativeHook<&JSCExecutor::nativeRequireModuleConfig>("nativeRequireModuleConfig");
   installNativeHook<&JSCExecutor::nativeFlushQueueImmediate>("nativeFlushQueueImmediate");
   installNativeHook<&JSCExecutor::nativeCallSyncHook>("nativeCallSyncHook");
 
@@ -264,6 +274,8 @@ void JSCExecutor::terminateOnJSVMThread() {
     terminateOwnedWebWorker(workerId);
   }
 
+  m_nativeModules.reset();
+
   JSGlobalContextRelease(m_context);
   m_context = nullptr;
 }
@@ -647,6 +659,14 @@ void JSCExecutor::installNativeHook(const char* name) {
   installGlobalFunction(m_context, name, exceptionWrapMethod<method>());
 }
 
+JSValueRef JSCExecutor::getNativeModule(JSObjectRef object, JSStringRef propertyName) {
+  if (JSStringIsEqualToUTF8CString(propertyName, "name")) {
+    return Value(m_context, String("NativeModules"));
+  }
+
+  return m_nativeModules.getModule(m_context, propertyName);
+}
+
 JSValueRef JSCExecutor::nativePostMessage(
     size_t argumentCount,
     const JSValueRef arguments[]) {
@@ -680,18 +700,6 @@ JSValueRef JSCExecutor::nativeRequire(
   return JSValueMakeUndefined(m_context);
 }
 
-JSValueRef JSCExecutor::nativeRequireModuleConfig(
-    size_t argumentCount,
-    const JSValueRef arguments[]) {
-  if (argumentCount != 1) {
-    throw std::invalid_argument("Got wrong number of args");
-  }
-
-  std::string moduleName = Value(m_context, arguments[0]).toString().str();
-  folly::dynamic config = m_delegate->getModuleRegistry()->getConfig(moduleName);
-  return Value::fromDynamic(m_context, config);
-}
-
 JSValueRef JSCExecutor::nativeFlushQueueImmediate(
     size_t argumentCount,
     const JSValueRef arguments[]) {

ReactCommon/cxxreact/JSCExecutor.h

@@ -15,6 +15,7 @@
 #include "ExecutorToken.h"
 #include "JSCHelpers.h"
 #include "Value.h"
+#include "JSCNativeModules.h"
 
 namespace facebook {
 namespace react {
@@ -102,6 +103,7 @@ class JSCExecutor : public JSExecutor {
   std::string m_deviceCacheDir;
   std::shared_ptr<MessageQueueThread> m_messageQueueThread;
   std::unique_ptr<JSModulesUnbundle> m_unbundle;
+  JSCNativeModules m_nativeModules;
   folly::dynamic m_jscConfig;
 
   folly::Optional<Object> m_invokeCallbackAndReturnFlushedQueueJS;
@@ -142,10 +144,8 @@ class JSCExecutor : public JSExecutor {
 
   template< JSValueRef (JSCExecutor::*method)(size_t, const JSValueRef[])>
   void installNativeHook(const char* name);
+  JSValueRef getNativeModule(JSObjectRef object, JSStringRef propertyName);
 
-  JSValueRef nativeRequireModuleConfig(
-      size_t argumentCount,
-      const JSValueRef arguments[]);
   JSValueRef nativeStartWorker(
       size_t argumentCount,
       const JSValueRef arguments[]);

ReactCommon/cxxreact/JSCHelpers.cpp

@@ -24,6 +24,25 @@ void installGlobalFunction(
   JSStringRelease(jsName);
 }
 
+void installGlobalProxy(
+    JSGlobalContextRef ctx,
+    const char* name,
+    JSObjectGetPropertyCallback callback) {
+  JSClassDefinition proxyClassDefintion = kJSClassDefinitionEmpty;
+  proxyClassDefintion.className = "_FBProxyClass";
+  proxyClassDefintion.getProperty = callback;
+  JSClassRef proxyClass = JSClassCreate(&proxyClassDefintion);
+
+  JSObjectRef proxyObj = JSObjectMake(ctx, proxyClass, nullptr);
+
+  JSObjectRef globalObject = JSContextGetGlobalObject(ctx);
+  JSStringRef jsName = JSStringCreateWithUTF8CString(name);
+  JSObjectSetProperty(ctx, globalObject, jsName, proxyObj, 0, NULL);
+
+  JSStringRelease(jsName);
+  JSClassRelease(proxyClass);
+}
+
 JSValueRef makeJSCException(
     JSContextRef ctx,
     const char* exception_text) {

ReactCommon/cxxreact/JSCHelpers.h

@@ -38,6 +38,11 @@ void installGlobalFunction(
     const char* name,
     JSObjectCallAsFunctionCallback callback);
 
+void installGlobalProxy(
+    JSGlobalContextRef ctx,
+    const char* name,
+    JSObjectGetPropertyCallback callback);
+
 JSValueRef makeJSCException(
     JSContextRef ctx,
     const char* exception_text);

ReactCommon/cxxreact/JSCNativeModules.cpp

@@ -0,0 +1,63 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+#include "JSCNativeModules.h"
+
+#include <string>
+
+namespace facebook {
+namespace react {
+
+JSCNativeModules::JSCNativeModules(std::shared_ptr<ModuleRegistry> moduleRegistry) :
+  m_moduleRegistry(std::move(moduleRegistry)) {}
+
+JSValueRef JSCNativeModules::getModule(JSContextRef context, JSStringRef jsName) {
+  std::string moduleName = String::ref(jsName).str();
+
+  const auto it = m_objects.find(moduleName);
+  if (it != m_objects.end()) {
+    return static_cast<JSObjectRef>(it->second);
+  }
+
+  auto module = createModule(moduleName, context);
+  if (!module.hasValue()) {
+    return JSValueMakeUndefined(context);
+  }
+
+  // Protect since we'll be holding on to this value, even though JS may not
+  module->makeProtected();
+
+  auto result = m_objects.emplace(std::move(moduleName), std::move(*module)).first;
+  return static_cast<JSObjectRef>(result->second);
+}
+
+void JSCNativeModules::reset() {
+  m_genNativeModuleJS = nullptr;
+  m_objects.clear();
+}
+
+folly::Optional<Object> JSCNativeModules::createModule(const std::string& name, JSContextRef context) {
+  if (!m_genNativeModuleJS) {
+    auto global = Object::getGlobalObject(context);
+    m_genNativeModuleJS = global.getProperty("__fbGenNativeModule").asObject();
+    m_genNativeModuleJS->makeProtected();
+
+    // Initialize the module name list, otherwise getModuleConfig won't work
+    // TODO (pieterdb): fix this in ModuleRegistry
+    m_moduleRegistry->moduleNames();
+  }
+
+  auto result = m_moduleRegistry->getConfig(name);
+  if (!result.hasValue()) {
+    return nullptr;
+  }
+
+  Value moduleInfo = m_genNativeModuleJS->callAsFunction({
+    Value::fromDynamic(context, result->config),
+    JSValueMakeNumber(context, result->index)
+  });
+  CHECK(!moduleInfo.isNull()) << "Module returned from genNativeModule is null";
+
+  return moduleInfo.asObject().getProperty("module").asObject();
+}
+
+} }

ReactCommon/cxxreact/JSCNativeModules.h

@@ -0,0 +1,35 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+#pragma once
+
+#include <folly/Optional.h>
+
+#include <memory>
+#include <string>
+
+#include "Value.h"
+#include "ModuleRegistry.h"
+
+namespace facebook {
+namespace react {
+
+/**
+ * Holds and creates JS representations of the modules in ModuleRegistry
+ */
+class JSCNativeModules {
+
+public:
+  explicit JSCNativeModules(std::shared_ptr<ModuleRegistry> moduleRegistry);
+  JSValueRef getModule(JSContextRef context, JSStringRef name);
+  void reset();
+
+private:
+  folly::Optional<Object> m_genNativeModuleJS;
+  std::shared_ptr<ModuleRegistry> m_moduleRegistry;
+  std::unordered_map<std::string, Object> m_objects;
+
+  folly::Optional<Object> createModule(const std::string& name, JSContextRef context);
+};
+
+}
+}