From 8f6aee0df5b728ec4842a4a2b8f902be126f51ee Mon Sep 17 00:00:00 2001
From: David Vacca <dvacca@fb.com>
Date: Tue, 14 Dec 2021 19:31:24 -0800
Subject: [PATCH] Create experiment to increase size of TextMeasureCache and
 enable in RNPanel apps

Summary:
Fabric uses a cache where it stores the result of the text measurement in C++ (to avoid unnecessary text measurement that are very costly). This cache has a "max size" of 256 and this size is not enough to store all the texts we have in the screen

In my tests, the amount of texts being measured are ~290 and after scrolling many times they increase to 611.

This diff increases the size of the TextMeasure to 1024 for users in the experiment. As a result this improves performance of HoverEvents by +5x times (see test plan)

changelog: [internal] internal

Reviewed By: JoshuaGross

Differential Revision: D33112788

fbshipit-source-id: e15feecf0f54da62b252892d37a64fb4ead29e22
---
 .../main/java/com/facebook/react/fabric/jni/Binding.cpp   | 5 +++++
 .../react/renderer/textlayoutmanager/TextLayoutManager.h  | 8 ++++++--
 ReactCommon/react/utils/SimpleThreadSafeCache.h           | 1 +
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.cpp b/ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.cpp
index 6fe77f17931..d9f1cb088bc 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.cpp
+++ b/ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.cpp
@@ -599,6 +599,11 @@ void Binding::installFabricUIManager(
   dispatchPreallocationInBackground_ = reactNativeConfig_->getBool(
       "react_native_new_architecture:dispatch_preallocation_in_bg");
 
+  contextContainer->insert(
+      "EnableLargeTextMeasureCache",
+      reactNativeConfig_->getBool(
+          "react_fabric:enable_large_text_measure_cache_android"));
+
   auto toolbox = SchedulerToolbox{};
   toolbox.contextContainer = contextContainer;
   toolbox.componentRegistryFactory = componentsRegistry->buildRegistryFunction;
diff --git a/ReactCommon/react/renderer/textlayoutmanager/platform/android/react/renderer/textlayoutmanager/TextLayoutManager.h b/ReactCommon/react/renderer/textlayoutmanager/platform/android/react/renderer/textlayoutmanager/TextLayoutManager.h
index 19ae11b2a7d..c83b81a3359 100644
--- a/ReactCommon/react/renderer/textlayoutmanager/platform/android/react/renderer/textlayoutmanager/TextLayoutManager.h
+++ b/ReactCommon/react/renderer/textlayoutmanager/platform/android/react/renderer/textlayoutmanager/TextLayoutManager.h
@@ -27,7 +27,11 @@ using SharedTextLayoutManager = std::shared_ptr<const TextLayoutManager>;
 class TextLayoutManager {
  public:
   TextLayoutManager(const ContextContainer::Shared &contextContainer)
-      : contextContainer_(contextContainer) {
+      : contextContainer_(contextContainer),
+        measureCache_{
+            contextContainer->at<bool>("EnableLargeTextMeasureCache")
+                ? 1024
+                : kSimpleThreadSafeCacheSizeCap} {
     static auto value =
         contextContainer->at<bool>("MapBufferSerializationEnabled");
     mapBufferSerializationEnabled_ = value;
@@ -85,7 +89,7 @@ class TextLayoutManager {
   void *self_;
   ContextContainer::Shared contextContainer_;
   bool mapBufferSerializationEnabled_;
-  TextMeasureCache measureCache_{};
+  TextMeasureCache measureCache_;
 };
 
 } // namespace react
diff --git a/ReactCommon/react/utils/SimpleThreadSafeCache.h b/ReactCommon/react/utils/SimpleThreadSafeCache.h
index b500535bb7f..56b038931d1 100644
--- a/ReactCommon/react/utils/SimpleThreadSafeCache.h
+++ b/ReactCommon/react/utils/SimpleThreadSafeCache.h
@@ -22,6 +22,7 @@ template <typename KeyT, typename ValueT, int maxSize>
 class SimpleThreadSafeCache {
  public:
   SimpleThreadSafeCache() : map_{maxSize} {}
+  SimpleThreadSafeCache(unsigned long size) : map_{size} {}
 
   /*
    * Returns a value from the map with a given key.