From 70bb6444aad37727def0108242f6a1370a45322a Mon Sep 17 00:00:00 2001
From: Pieter De Baets <pieterdb@meta.com>
Date: Tue, 29 Nov 2022 08:29:05 -0800
Subject: [PATCH] Remove iOS TurboModuleManager experiment with shared mutex

Summary: Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D41551085

fbshipit-source-id: f4d1d8126529d5f384ada941f6fb140abcfd9716
---
 React/Base/RCTBridge.h                        |  4 ---
 React/Base/RCTBridge.m                        | 11 -------
 .../platform/ios/RCTTurboModuleManager.mm     | 33 ++-----------------
 3 files changed, 2 insertions(+), 46 deletions(-)

diff --git a/React/Base/RCTBridge.h b/React/Base/RCTBridge.h
index 1373eaae2fa942..7733e387635d16 100644
--- a/React/Base/RCTBridge.h
+++ b/React/Base/RCTBridge.h
@@ -52,10 +52,6 @@ RCT_EXTERN void RCTEnableTurboModule(BOOL enabled);
 RCT_EXTERN BOOL RCTTurboModuleEagerInitEnabled(void);
 RCT_EXTERN void RCTEnableTurboModuleEagerInit(BOOL enabled);
 
-// Turn on TurboModule shared mutex initialization
-RCT_EXTERN BOOL RCTTurboModuleSharedMutexInitEnabled(void);
-RCT_EXTERN void RCTEnableTurboModuleSharedMutexInit(BOOL enabled);
-
 // Turn off TurboModule delegate locking
 RCT_EXTERN BOOL RCTTurboModuleManagerDelegateLockingDisabled(void);
 RCT_EXTERN void RCTDisableTurboModuleManagerDelegateLocking(BOOL enabled);
diff --git a/React/Base/RCTBridge.m b/React/Base/RCTBridge.m
index 531f42edaca330..135bdc263c2fff 100644
--- a/React/Base/RCTBridge.m
+++ b/React/Base/RCTBridge.m
@@ -108,17 +108,6 @@ void RCTEnableTurboModuleEagerInit(BOOL enabled)
   turboModuleEagerInitEnabled = enabled;
 }
 
-static BOOL turboModuleSharedMutexInitEnabled = NO;
-BOOL RCTTurboModuleSharedMutexInitEnabled(void)
-{
-  return turboModuleSharedMutexInitEnabled;
-}
-
-void RCTEnableTurboModuleSharedMutexInit(BOOL enabled)
-{
-  turboModuleSharedMutexInitEnabled = enabled;
-}
-
 // Turn off TurboModule delegate locking
 static BOOL turboModuleManagerDelegateLockingDisabled = YES;
 BOOL RCTTurboModuleManagerDelegateLockingDisabled(void)
diff --git a/ReactCommon/react/nativemodule/core/platform/ios/RCTTurboModuleManager.mm b/ReactCommon/react/nativemodule/core/platform/ios/RCTTurboModuleManager.mm
index 90c18409dfe3c4..5b2881bc305e3c 100644
--- a/ReactCommon/react/nativemodule/core/platform/ios/RCTTurboModuleManager.mm
+++ b/ReactCommon/react/nativemodule/core/platform/ios/RCTTurboModuleManager.mm
@@ -11,7 +11,6 @@
 #import <cassert>
 #import <condition_variable>
 #import <mutex>
-#import <shared_mutex>
 
 #import <objc/runtime.h>
 
@@ -173,7 +172,6 @@ @implementation RCTTurboModuleManager {
   std::mutex _turboModuleManagerDelegateMutex;
 
   // Enforce synchronous access to _invalidating and _turboModuleHolders
-  std::shared_timed_mutex _turboModuleHoldersSharedMutex;
   std::mutex _turboModuleHoldersMutex;
   std::atomic<bool> _invalidating;
 }
@@ -317,23 +315,6 @@ - (void)notifyAboutTurboModuleSetup:(const char *)name
 
 - (TurboModuleHolder *)_getOrCreateTurboModuleHolder:(const char *)moduleName
 {
-  if (RCTTurboModuleSharedMutexInitEnabled()) {
-    {
-      std::shared_lock<std::shared_timed_mutex> guard(_turboModuleHoldersSharedMutex);
-      if (_invalidating) {
-        return nullptr;
-      }
-
-      auto it = _turboModuleHolders.find(moduleName);
-      if (it != _turboModuleHolders.end()) {
-        return &it->second;
-      }
-    }
-
-    std::unique_lock<std::shared_timed_mutex> guard(_turboModuleHoldersSharedMutex);
-    return &_turboModuleHolders[moduleName];
-  }
-
   std::lock_guard<std::mutex> guard(_turboModuleHoldersMutex);
   if (_invalidating) {
     return nullptr;
@@ -785,11 +766,6 @@ - (id)moduleForName:(const char *)moduleName warnOnLookupFailure:(BOOL)warnOnLoo
 
 - (BOOL)moduleIsInitialized:(const char *)moduleName
 {
-  if (RCTTurboModuleSharedMutexInitEnabled()) {
-    std::shared_lock<std::shared_timed_mutex> guard(_turboModuleHoldersSharedMutex);
-    return _turboModuleHolders.find(moduleName) != _turboModuleHolders.end();
-  }
-
   std::unique_lock<std::mutex> guard(_turboModuleHoldersMutex);
   return _turboModuleHolders.find(moduleName) != _turboModuleHolders.end();
 }
@@ -843,13 +819,8 @@ - (void)invalidate
 - (void)_enterInvalidatingState
 {
   // This should halt all insertions into _turboModuleHolders
-  if (RCTTurboModuleSharedMutexInitEnabled()) {
-    std::unique_lock<std::shared_timed_mutex> guard(_turboModuleHoldersSharedMutex);
-    _invalidating = true;
-  } else {
-    std::lock_guard<std::mutex> guard(_turboModuleHoldersMutex);
-    _invalidating = true;
-  }
+  std::lock_guard<std::mutex> guard(_turboModuleHoldersMutex);
+  _invalidating = true;
 }
 
 - (void)_invalidateModules