Added deferred module loading feature

Reviewed By: javache

Differential Revision: D2717687

fb-gh-sync-id: 4c03c721c794a2e7ac67a0b20474129fde7f0a0d

Libraries/BatchedBridge/BatchedBridgedModules/NativeModules.js

@@ -11,10 +11,78 @@
  */
 'use strict';
 
-var NativeModules = require('BatchedBridge').RemoteModules;
+const BatchedBridge = require('BatchedBridge');
+const RemoteModules = BatchedBridge.RemoteModules;
 
-var nativeModulePrefixNormalizer = require('nativeModulePrefixNormalizer');
+function normalizePrefix(moduleName: string): string {
+  return moduleName.replace(/^(RCT|RK)/, '');
+}
 
-nativeModulePrefixNormalizer(NativeModules);
+/**
+ * Dirty hack to support old (RK) and new (RCT) native module name conventions.
+ */
+Object.keys(RemoteModules).forEach((moduleName) => {
+  const strippedName = normalizePrefix(moduleName);
+  if (RemoteModules['RCT' + strippedName] && RemoteModules['RK' + strippedName]) {
+    throw new Error(
+      'Module cannot be registered as both RCT and RK: ' + moduleName
+    );
+  }
+  if (strippedName !== moduleName) {
+    RemoteModules[strippedName] = RemoteModules[moduleName];
+    delete RemoteModules[moduleName];
+  }
+});
+
+/**
+ * Define lazy getters for each module.
+ * These will return the module if already loaded, or load it if not.
+ */
+const NativeModules = {};
+Object.keys(RemoteModules).forEach((moduleName) => {
+  Object.defineProperty(NativeModules, moduleName, {
+    enumerable: true, 
+    get: () => {
+      let module = RemoteModules[moduleName];
+      if (module && module.moduleID) {
+        const json = global.nativeRequireModuleConfig(moduleName);
+        const config = json && JSON.parse(json);
+        module = config && BatchedBridge.processModuleConfig(config, module.moduleID);
+        RemoteModules[moduleName] = module;
+      }
+      return module;
+    },
+  });
+});
+
+/**
+ * Copies the ViewManager constants into UIManager. This is only
+ * needed for iOS, which puts the constants in the ViewManager
+ * namespace instead of UIManager, unlike Android.
+ *
+ * We'll eventually move this logic to UIManager.js, once all
+ * the call sites accessing NativeModules.UIManager directly have
+ * been removed #9344445
+ */
+const UIManager = NativeModules.UIManager;
+UIManager && Object.keys(UIManager).forEach(viewName => {
+  const viewConfig = UIManager[viewName];
+  const constants = {};
+  if (viewConfig.Manager) {
+    Object.defineProperty(viewConfig, 'Constants', {
+      enumerable: true, 
+      get: () => {
+        const viewManager = NativeModules[normalizePrefix(viewConfig.Manager)];
+        viewManager && Object.keys(viewManager).forEach(key => {
+          const value = viewManager[key];
+          if (typeof value !== 'function') {
+            constants[key] = value;
+          }
+        });
+        return constants;
+      },
+    });
+  }
+});
 
 module.exports = NativeModules;

Libraries/Utilities/MessageQueue.js

@@ -66,8 +66,6 @@ class MessageQueue {
       this._genModulesConfig(localModules),this._moduleTable, this._methodTable
     );
 
-    this._copyNativeComponentConstants(this.RemoteModules);
-
     this._debugInfo = {};
     this._remoteModuleTable = {};
     this._remoteMethodTable = {};
@@ -105,6 +103,12 @@ class MessageQueue {
     return queue[0].length ? queue : null;
   }
 
+  processModuleConfig(config, moduleID) {
+    const module = this._genModule(config, moduleID);
+    this._genLookup(config, moduleID, this._remoteModuleTable, this._remoteMethodTable)
+    return module;
+  }
+
   /**
    * "Private" methods
    */
@@ -200,30 +204,6 @@ class MessageQueue {
    * Private helper methods
    */
 
-  /**
-   * Copies the ViewManager constants into UIManager. This is only
-   * needed for iOS, which puts the constants in the ViewManager
-   * namespace instead of UIManager, unlike Android.
-   */
-  _copyNativeComponentConstants(remoteModules) {
-    let UIManager = remoteModules.RCTUIManager;
-    UIManager && Object.keys(UIManager).forEach(viewName => {
-      let viewConfig = UIManager[viewName];
-      if (viewConfig.Manager) {
-        const viewManager = remoteModules[viewConfig.Manager];
-        viewManager && Object.keys(viewManager).forEach(key => {
-          const value = viewManager[key];
-          if (typeof value !== 'function') {
-            if (!viewConfig.Constants) {
-              viewConfig.Constants = {};
-            }
-            viewConfig.Constants[key] = value;
-          }
-        });
-      }
-    });
-  }
-
   /**
    * Converts the old, object-based module structure to the new
    * array-based structure. TODO (t8823865) Removed this
@@ -269,55 +249,62 @@ class MessageQueue {
   }
 
   _genLookupTables(modulesConfig, moduleTable, methodTable) {
-    modulesConfig.forEach((module, moduleID) => {
-      if (!module) {
-        return;
-      }
-
-      let moduleName, methods;
-      if (moduleHasConstants(module)) {
-        [moduleName, , methods] = module;
-      } else {
-        [moduleName, methods] = module;
-      }
-
-      moduleTable[moduleID] = moduleName;
-      methodTable[moduleID] = Object.assign({}, methods);
+    modulesConfig.forEach((config, moduleID) => {
+      this._genLookup(config, moduleID, moduleTable, methodTable);
     });
   }
+  
+  _genLookup(config, moduleID, moduleTable, methodTable) {
+    if (!config) {
+      return;
+    }
+
+    let moduleName, methods;
+    if (moduleHasConstants(config)) {
+      [moduleName, , methods] = config;
+    } else {
+      [moduleName, methods] = config;
+    }
+
+    moduleTable[moduleID] = moduleName;
+    methodTable[moduleID] = Object.assign({}, methods);
+  }
 
   _genModules(remoteModules) {
-    remoteModules.forEach((module, moduleID) => {
-      if (!module) {
-        return;
-      }
-
-      let moduleName, constants, methods, asyncMethods;
-      if (moduleHasConstants(module)) {
-        [moduleName, constants, methods, asyncMethods] = module;
-      } else {
-        [moduleName, methods, asyncMethods] = module;
-      }
-
-      const moduleConfig = {moduleID, constants, methods, asyncMethods};
-      this.RemoteModules[moduleName] = this._genModule({}, moduleConfig);
+    remoteModules.forEach((config, moduleID) => {
+      this._genModule(config, moduleID);
     });
   }
 
-  _genModule(module, moduleConfig) {
-    const {moduleID, constants, methods = [], asyncMethods = []} = moduleConfig;
+  _genModule(config, moduleID) {
+    if (!config) {
+      return;
+    }
 
-    methods.forEach((methodName, methodID) => {
+    let moduleName, constants, methods, asyncMethods;
+    if (moduleHasConstants(config)) {
+      [moduleName, constants, methods, asyncMethods] = config;
+    } else {
+      [moduleName, methods, asyncMethods] = config;
+    }
+
+    let module = {};
+    methods && methods.forEach((methodName, methodID) => {
       const methodType =
-        arrayContains(asyncMethods, methodID) ?
+        asyncMethods && arrayContains(asyncMethods, methodID) ?
           MethodTypes.remoteAsync : MethodTypes.remote;
       module[methodName] = this._genMethod(moduleID, methodID, methodType);
     });
     Object.assign(module, constants);
-
+    
+    if (!constants && !methods && !asyncMethods) {
+      module.moduleID = moduleID;
+    }
+    
+    this.RemoteModules[moduleName] = module;
     return module;
   }
-
+  
   _genMethod(module, method, type) {
     let fn = null;
     let self = this;

Libraries/Utilities/nativeModulePrefixNormalizer.js

@@ -1,32 +0,0 @@
-/**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
- *
- * @providesModule nativeModulePrefixNormalizer
- * @flow
- */
-'use strict';
-
-// Dirty hack to support old (RK) and new (RCT) native module name conventions
-function nativeModulePrefixNormalizer(
-  modules: {[key: string]: any}
-): void {
-  Object.keys(modules).forEach((moduleName) => {
-    var strippedName = moduleName.replace(/^(RCT|RK)/, '');
-    if (modules['RCT' + strippedName] && modules['RK' + strippedName]) {
-      throw new Error(
-        'Module cannot be registered as both RCT and RK: ' + moduleName
-      );
-    }
-    if (strippedName !== moduleName) {
-      modules[strippedName] = modules[moduleName];
-      delete modules[moduleName];
-    }
-  });
-}
-
-module.exports = nativeModulePrefixNormalizer;