TM iOS: Introduce OSS-compatible RCTCoreModulesClassProvider()

Summary: To look up TurboModule Class based on its name, this new function `RCTCoreModulesClassProvider()` can be used to find a TurboModule impl in the app. For now this is manually maintained and sync'ed with FB internal version. Only modules that live under React/CoreModules/ should be handled here.

Reviewed By: PeteTheHeat

Differential Revision: D16100291

fbshipit-source-id: 6b7556dec1fa83d1e081c7e8c0fe295187934274

Author: fkgozali

RNTester/RNTester/RNTesterTurboModuleProvider.mm

@@ -10,8 +10,7 @@
 
 #import "RNTesterTurboModuleProvider.h"
 
-#import <React/RCTPlatform.h>
-
+#import <React/CoreModulesPlugins.h>
 #import <jsireact/SampleTurboCxxModule.h>
 #import <jsireact/RCTSampleTurboModule.h>
 
@@ -21,10 +20,7 @@
 namespace react {
 
 Class RNTesterTurboModuleClassProvider(const char *name) {
-  if (strcmp(name, "PlatformConstants") == 0) {
-    return RCTPlatform.class;
-  }
-  return nil;
+  return RCTCoreModulesClassProvider(name);
 }
 
 std::shared_ptr<TurboModule> RNTesterTurboModuleProvider(const std::string &name, std::shared_ptr<JSCallInvoker> jsInvoker) {

React/CoreModules/CoreModulesPlugins.h

@@ -12,7 +12,7 @@
 
 #else
 
-//OSS-compatibility layer: manually define these for github.
+// OSS-compatibility layer: manually define these for github.
 
 #import <Foundation/Foundation.h>
 
@@ -23,6 +23,9 @@
 extern "C" {
 #endif
 
+// RCTTurboModuleManagerDelegate should call this to resolve module classes.
+Class RCTCoreModulesClassProvider(const char *name);
+
 // NOTE: Sync these with FB internal version.
 
 Class RCTPlatformCls(void);

React/CoreModules/CoreModulesPlugins.mm

@@ -0,0 +1,32 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#ifndef RN_DISABLE_OSS_PLUGIN_HEADER
+
+// OSS-compatibility layer: manually define these for github.
+// TODO: This should be codegen'ed
+
+#import "CoreModulesPlugins.h"
+
+#import <string>
+#import <unordered_map>
+
+static std::unordered_map<std::string, Class (*)(void)> sCoreModuleClassMap = {
+  // NOTE: Sync these with FB internal plugin definitions.
+  {"PlatformConstants", RCTPlatformCls},
+};
+
+Class RCTCoreModulesClassProvider(const char *name) {
+  auto p = sCoreModuleClassMap.find(name);
+  if (p != sCoreModuleClassMap.end()) {
+    auto classFunc = p->second;
+    return classFunc();
+  }
+  return nil;
+}
+
+#endif // RN_DISABLE_OSS_PLUGIN_HEADER