From c1b6fd8c6910a2ca1e873ec9ebb2c51d757aded5 Mon Sep 17 00:00:00 2001
From: gaaclarke <30870216+gaaclarke@users.noreply.github.com>
Date: Sun, 24 Nov 2024 12:01:34 -0800
Subject: [PATCH] Replaces Resource's shared_ptr with unique_ptr
 (flutter/engine#56778)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

A non-inconsequential amount of time is spent in ~shared_ptr for no reason in ~Resource

<img width="1057" alt="Screenshot 2024-11-23 at 3 22 11 PM" src="https://github.com/user-attachments/assets/fba73908-2e43-4908-8008-ddd78fd77831">

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
---
 engine/src/flutter/impeller/renderer/command.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/engine/src/flutter/impeller/renderer/command.h b/engine/src/flutter/impeller/renderer/command.h
index 62553269fd..a63f52f35a 100644
--- a/engine/src/flutter/impeller/renderer/command.h
+++ b/engine/src/flutter/impeller/renderer/command.h
@@ -29,7 +29,8 @@ namespace impeller {
 #endif  // IMPELLER_DEBUG
 
 template <class T>
-struct Resource {
+class Resource {
+ public:
   using ResourceType = T;
   ResourceType resource;
 
@@ -40,7 +41,7 @@ struct Resource {
 
   Resource(const ShaderMetadata& metadata, ResourceType p_resource)
       : resource(p_resource),
-        dynamic_metadata_(std::make_shared<ShaderMetadata>(metadata)) {}
+        dynamic_metadata_(std::make_unique<ShaderMetadata>(metadata)) {}
 
   const ShaderMetadata* GetMetadata() const {
     return dynamic_metadata_ ? dynamic_metadata_.get() : metadata_;
@@ -51,7 +52,7 @@ struct Resource {
   const ShaderMetadata* metadata_ = nullptr;
 
   // Dynamically generated shader metadata.
-  std::shared_ptr<const ShaderMetadata> dynamic_metadata_ = nullptr;
+  std::unique_ptr<const ShaderMetadata> dynamic_metadata_ = nullptr;
 };
 
 using BufferResource = Resource<BufferView>;