From 3a624ed0e974b58258f770a1b34201f3a478f3b9 Mon Sep 17 00:00:00 2001
From: Adlai Holler <adlai@icloud.com>
Date: Mon, 12 Mar 2018 10:42:24 -0700
Subject: [PATCH] Fix Text Node Thread Sanitizer Warning (#830)

* Fix thread sanitizer warning in ASTextNodeRendererKey

* Update changelog

* Comment on missing class check
---
 CHANGELOG.md         |  1 +
 Source/ASTextNode.mm | 14 ++++++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 466623147..8889c2696 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -33,6 +33,7 @@
 - Pass scrollViewWillEndDragging delegation through in ASIGListAdapterDataSource for IGListKit integration. [#796](https://github.com/TextureGroup/Texture/pull/796)
 - Fix UIResponder handling with view backing ASDisplayNode. [Michael Schneider](https://github.com/maicki) [#789] (https://github.com/TextureGroup/Texture/pull/789/)
 - Optimized thread-local storage by replacing pthread_specific with C11 thread-local variables. [Adlai Holler](https://github.com/Adlai-Holler) [#811] (https://github.com/TextureGroup/Texture/pull/811/)
+- Fixed a thread-sanitizer warning in ASTextNode. [Adlai Holler](https://github.com/Adlai-Holler) [#830] (https://github.com/TextureGroup/Texture/pull/830/)
 
 ## 2.6
 - [Xcode 9] Updated to require Xcode 9 (to fix warnings) [Garrett Moon](https://github.com/garrettmoon)
diff --git a/Source/ASTextNode.mm b/Source/ASTextNode.mm
index 768223070..0b6421e7a 100644
--- a/Source/ASTextNode.mm
+++ b/Source/ASTextNode.mm
@@ -63,10 +63,13 @@ @interface ASTextNodeRendererKey : NSObject
 @property (assign, nonatomic) CGSize constrainedSize;
 @end
 
-@implementation ASTextNodeRendererKey
+@implementation ASTextNodeRendererKey {
+  std::mutex _m;
+}
 
 - (NSUInteger)hash
 {
+  std::lock_guard<std::mutex> _l(_m);
 #pragma clang diagnostic push
 #pragma clang diagnostic warning "-Wpadded"
   struct {
@@ -86,7 +89,14 @@ - (BOOL)isEqual:(ASTextNodeRendererKey *)object
     return YES;
   }
   
-  return _attributes == object.attributes && CGSizeEqualToSize(_constrainedSize, object.constrainedSize);
+  // NOTE: Skip the class check for this specialized, internal Key object.
+
+  // Lock both objects, avoiding deadlock.
+  std::lock(_m, object->_m);
+  std::lock_guard<std::mutex> lk1(_m, std::adopt_lock);
+  std::lock_guard<std::mutex> lk2(object->_m, std::adopt_lock);
+  
+  return _attributes == object->_attributes && CGSizeEqualToSize(_constrainedSize, object->_constrainedSize);
 }
 
 @end