[Bridge] Scope the module loading and initialization to a single bridge

React/Base/RCTBridge.m

@@ -16,6 +16,7 @@
 #import <mach-o/dyld.h>
 #import <mach-o/getsect.h>
 
+#import "RCTBridgeModuleLoader.h"
 #import "RCTContextExecutor.h"
 #import "RCTConvert.h"
 #import "RCTEventDispatcher.h"
@@ -41,14 +42,6 @@ typedef NS_ENUM(NSUInteger, RCTBridgeFields) {
 
 NSString *const RCTReloadBridge = @"RCTReloadBridge";
 
-/**
- * This function returns the module name for a given class.
- */
-static NSString *RCTModuleNameForClass(Class cls)
-{
-  return [cls respondsToSelector:@selector(moduleName)] ? [cls moduleName] : NSStringFromClass(cls);
-}
-
 /**
  * This function scans all classes available at runtime and returns an array
  * of all JSMethods registered.
@@ -72,38 +65,6 @@ typedef NS_ENUM(NSUInteger, RCTBridgeFields) {
   return JSMethods;
 }
 
-/**
- * This function scans all classes available at runtime and returns an array
- * of all classes that implement the RTCBridgeModule protocol.
- */
-static NSArray *RCTModuleNamesByID;
-static NSArray *RCTBridgeModuleClassesByModuleID(void)
-{
-  static NSArray *modules;
-  static dispatch_once_t onceToken;
-  dispatch_once(&onceToken, ^{
-    modules = [NSMutableArray array];
-    RCTModuleNamesByID = [NSMutableArray array];
-
-    RCTEnumerateClasses(^(__unsafe_unretained Class cls) {
-      if ([cls conformsToProtocol:@protocol(RCTBridgeModule)]) {
-
-        // Add module
-        [(NSMutableArray *)modules addObject:cls];
-
-        // Add module name
-        NSString *moduleName = RCTModuleNameForClass(cls);
-        [(NSMutableArray *)RCTModuleNamesByID addObject:moduleName];
-      }
-    });
-
-    modules = [modules copy];
-    RCTModuleNamesByID = [RCTModuleNamesByID copy];
-  });
-
-  return modules;
-}
-
 @interface RCTBridge ()
 
 - (void)_invokeAndProcessModule:(NSString *)module
@@ -302,7 +263,7 @@ - (NSString *)description
  * generates an array of arrays of RCTModuleMethod objects, keyed
  * by module index.
  */
-static RCTSparseArray *RCTExportedMethodsByModuleID(void)
+static RCTSparseArray *RCTExportedMethodsByModuleID(RCTBridgeModuleLoader *moduleLoader)
 {
   static RCTSparseArray *methodsByModuleID;
   static dispatch_once_t onceToken;
@@ -328,7 +289,7 @@ - (NSString *)description
       return;
     }
 
-    NSArray *classes = RCTBridgeModuleClassesByModuleID();
+    NSArray *classes = moduleLoader.moduleClassesByModuleID;
     NSMutableDictionary *methodsByModuleClassName = [NSMutableDictionary dictionaryWithCapacity:[classes count]];
 
     for (RCTExportValue addr = section->offset;
@@ -384,16 +345,16 @@ - (NSString *)description
  * },
  * etc...
  */
-static NSDictionary *RCTRemoteModulesConfig(NSDictionary *modulesByName)
+static NSDictionary *RCTRemoteModulesConfig(RCTBridgeModuleLoader *moduleLoader, NSDictionary *modulesByName)
 {
   static NSMutableDictionary *remoteModuleConfigByClassName;
   static dispatch_once_t onceToken;
   dispatch_once(&onceToken, ^{
-
     remoteModuleConfigByClassName = [[NSMutableDictionary alloc] init];
-    [RCTBridgeModuleClassesByModuleID() enumerateObjectsUsingBlock:^(Class moduleClass, NSUInteger moduleID, BOOL *stop) {
 
-      NSArray *methods = RCTExportedMethodsByModuleID()[moduleID];
+    RCTSparseArray *exportedMethodsByModuleID = RCTExportedMethodsByModuleID(moduleLoader);
+    [moduleLoader.moduleClassesByModuleID enumerateObjectsUsingBlock:^(Class moduleClass, NSUInteger moduleID, BOOL *stop) {
+      NSArray *methods = exportedMethodsByModuleID[moduleID];
       NSMutableDictionary *methodsByName = [NSMutableDictionary dictionaryWithCapacity:methods.count];
       [methods enumerateObjectsUsingBlock:^(RCTModuleMethod *method, NSUInteger methodID, BOOL *_stop) {
         methodsByName[method.JSMethodName] = @{
@@ -503,6 +464,7 @@ - (NSString *)description
 
 @implementation RCTBridge
 {
+  RCTBridgeModuleLoader *_moduleLoader;
   RCTSparseArray *_modulesByID;
   NSDictionary *_modulesByName;
   id<RCTJavaScriptExecutor> _javaScriptExecutor;
@@ -523,6 +485,7 @@ - (instancetype)initWithBundlePath:(NSString *)bundlePath
     _bundlePath = bundlePath;
     _moduleProvider = block;
     _launchOptions = launchOptions;
+    _moduleLoader = [RCTBridgeModuleLoader sharedLoader];
     [self setUp];
     [self bindKeys];
   }
@@ -541,35 +504,27 @@ - (void)setUp
   _eventDispatcher = [[RCTEventDispatcher alloc] initWithBridge:self];
   _shadowQueue = dispatch_queue_create("com.facebook.ReactKit.ShadowQueue", DISPATCH_QUEUE_SERIAL);
 
-  // Register passed-in module instances
-  NSMutableDictionary *preregisteredModules = [[NSMutableDictionary alloc] init];
-  for (id<RCTBridgeModule> module in _moduleProvider ? _moduleProvider() : nil) {
-    preregisteredModules[RCTModuleNameForClass([module class])] = module;
-  }
-
-  // Instantiate modules
   _modulesByID = [[RCTSparseArray alloc] init];
-  NSMutableDictionary *modulesByName = [preregisteredModules mutableCopy];
-  [RCTBridgeModuleClassesByModuleID() enumerateObjectsUsingBlock:^(Class moduleClass, NSUInteger moduleID, BOOL *stop) {
-    NSString *moduleName = RCTModuleNamesByID[moduleID];
-    // Check if module instance has already been registered for this name
-    if ((_modulesByID[moduleID] = modulesByName[moduleName])) {
-      // Preregistered instances takes precedence, no questions asked
-      if (!preregisteredModules[moduleName]) {
-        // It's OK to have a name collision as long as the second instance is nil
-        RCTAssert([[moduleClass alloc] init] == nil,
-                  @"Attempted to register RCTBridgeModule class %@ for the name '%@', \
-                  but name was already registered by class %@", moduleClass,
-                  moduleName, [modulesByName[moduleName] class]);
-      }
-    } else {
-      // Module name hasn't been used before, so go ahead and instantiate
+  NSMutableDictionary *modulesByName = [NSMutableDictionary dictionary];
+  if (_moduleProvider) {
+    // Register passed-in module instances
+    for (id<RCTBridgeModule> module in _moduleProvider()) {
+      NSUInteger moduleID = [_moduleLoader addModuleClass:[module class]];
+      NSString *moduleName = [_moduleLoader moduleNameForModuleID:moduleID];
+      _modulesByID[moduleID] = module;
+      modulesByName[moduleName] = module;
+    }
+  } else {
+    // Automatically load and instantiate all modules (note: this can take several hundred milliseconds)
+    [_moduleLoader loadAllModuleClasses];
+    [_moduleLoader.moduleClassesByModuleID enumerateObjectsUsingBlock:^(Class moduleClass, NSUInteger moduleID, BOOL *stop) {
+      NSString *moduleName = [_moduleLoader moduleNameForModuleID:moduleID];
       id<RCTBridgeModule> module = [[moduleClass alloc] init];
       if (module) {
         _modulesByID[moduleID] = modulesByName[moduleName] = module;
       }
-    }
-  }];
+    }];
+  }
 
   // Store modules
   _modulesByName = [modulesByName copy];
@@ -583,9 +538,9 @@ - (void)setUp
 
   // Inject module data into JS context
   NSString *configJSON = RCTJSONStringify(@{
-                                            @"remoteModuleConfig": RCTRemoteModulesConfig(_modulesByName),
-                                            @"localModulesConfig": RCTLocalModulesConfig()
-                                            }, NULL);
+    @"remoteModuleConfig": RCTRemoteModulesConfig([RCTBridgeModuleLoader sharedLoader], _modulesByName),
+    @"localModulesConfig": RCTLocalModulesConfig()
+  }, NULL);
   dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
   [_javaScriptExecutor injectJSONText:configJSON asGlobalObjectNamed:@"__fbBatchedBridgeConfig" callback:^(id err) {
     dispatch_semaphore_signal(semaphore);

React/Base/RCTBridgeModuleConfiguration.h

@@ -0,0 +1,20 @@
+/**
+ * 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.
+ */
+
+@import Foundation;
+
+@class RCTBridgeModuleLoader;
+
+@interface RCTBridgeModuleConfiguration : NSObject
+
+- (instancetype)initFromModuleLoader:(RCTBridgeModuleLoader *)moduleLoader;
+
+
+
+@end

React/Base/RCTBridgeModuleConfiguration.m

@@ -0,0 +1,14 @@
+/**
+ * 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.
+ */
+
+#import "RCTBridgeModuleConfiguration.h"
+
+@implementation RCTBridgeModuleConfiguration
+
+@end

React/Base/RCTBridgeModuleLoader.h

@@ -0,0 +1,24 @@
+/**
+ * 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.
+ */
+
+@import Foundation;
+
+@interface RCTBridgeModuleLoader : NSObject
+
+@property (nonatomic, strong, readonly) NSArray *moduleClassesByModuleID;
+
++ (instancetype)sharedLoader;
+
+- (NSUInteger)addModuleClass:(Class)moduleClass;
+- (void)loadAllModuleClasses;
+
+- (NSUInteger)moduleIDForModuleName:(NSString *)moduleName;
+- (NSString *)moduleNameForModuleID:(NSUInteger)moduleID;
+
+@end

React/Base/RCTBridgeModuleLoader.m

@@ -0,0 +1,80 @@
+/**
+ * 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.
+ */
+
+#import "RCTBridgeModuleLoader.h"
+
+#import "RCTBridgeModule.h"
+#import "RCTUtils.h"
+
+@implementation RCTBridgeModuleLoader {
+  NSMutableArray *_moduleNamesByID;
+  NSMutableArray *_moduleClassesByID;
+  NSMutableDictionary *_moduleIDsByName;
+}
+
++ (instancetype)sharedLoader
+{
+  static RCTBridgeModuleLoader *instance;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    instance = [[RCTBridgeModuleLoader alloc] init];
+  });
+  return instance;
+}
+
+- (instancetype)init
+{
+  if (self = [super init]) {
+    _moduleNamesByID = [NSMutableArray array];
+    _moduleClassesByID = [NSMutableArray array];
+    _moduleIDsByName = [NSMutableDictionary dictionary];
+  }
+  return self;
+}
+
+- (NSArray *)moduleClassesByModuleID
+{
+  return _moduleClassesByID;
+}
+
+- (NSUInteger)addModuleClass:(Class)moduleClass
+{
+  NSString *moduleName = RCTModuleNameForClass(moduleClass);
+  NSNumber *moduleIDNumber = _moduleIDsByName[moduleName];
+  if (moduleIDNumber) {
+    return moduleIDNumber.unsignedIntegerValue;
+  }
+
+  NSUInteger moduleID = _moduleNamesByID.count;
+  _moduleIDsByName[moduleName] = @(moduleID);
+  [_moduleNamesByID addObject:moduleName];
+  [_moduleClassesByID addObject:moduleClass];
+  return moduleID;
+}
+
+- (void)loadAllModuleClasses
+{
+  RCTEnumerateClasses(^(__unsafe_unretained Class cls) {
+    if ([cls conformsToProtocol:@protocol(RCTBridgeModule)]) {
+      [self addModuleClass:cls];
+    }
+  });
+}
+
+- (NSUInteger)moduleIDForModuleName:(NSString *)moduleName
+{
+  return ((NSNumber *)_moduleIDsByName[moduleName]).unsignedIntegerValue;
+}
+
+- (NSString *)moduleNameForModuleID:(NSUInteger)moduleID
+{
+  return _moduleNamesByID[moduleID];
+}
+
+@end

React/Base/RCTUtils.h

@@ -45,6 +45,9 @@ void RCTSwapInstanceMethods(Class cls, SEL original, SEL replacement);
 BOOL RCTClassOverridesClassMethod(Class cls, SEL selector);
 BOOL RCTClassOverridesInstanceMethod(Class cls, SEL selector);
 
+// Returns the canonical JS module name for the given bridge module class
+NSString *RCTModuleNameForClass(Class cls);
+
 // Enumerate all classes that conform to NSObject protocol
 void RCTEnumerateClasses(void (^block)(Class cls));
 

React/Base/RCTUtils.m

@@ -16,6 +16,7 @@
 
 #import <CommonCrypto/CommonCrypto.h>
 
+#import "RCTBridgeModule.h"
 #import "RCTLog.h"
 
 NSString *RCTJSONStringify(id jsonObject, NSError **error)
@@ -183,6 +184,11 @@ BOOL RCTClassOverridesInstanceMethod(Class cls, SEL selector)
   return NO;
 }
 
+NSString *RCTModuleNameForClass(Class cls)
+{
+  return [cls respondsToSelector:@selector(moduleName)] ? [cls moduleName] : NSStringFromClass(cls);
+}
+
 void RCTEnumerateClasses(void (^block)(Class cls))
 {
   static Class *classes;