From d30c35787c4ea026325aaca03213a07f878514ca Mon Sep 17 00:00:00 2001
From: Adlai Holler <adlai@icloud.com>
Date: Wed, 17 May 2017 18:08:50 -0700
Subject: [PATCH] Fix Alignment of Hashed Structs (#287)

* Fix alignment of ASImageNodeContentsKey struct to fix hashing

* Change the change log by logging a change

* Add the world's stupidest explicit cast

* Actually its simpler
---
 CHANGELOG.md                          | 2 +-
 Source/ASImageNode.mm                 | 5 ++++-
 Source/ASTextNode.mm                  | 3 +++
 Source/Private/ASHashing.h            | 5 +++++
 Source/TextKit/ASTextKitAttributes.mm | 3 +++
 5 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ce58586f62..9d28b712a7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,4 +24,4 @@
 - [Layout] Extract layout implementation code into it's own subcategories [Michael Schneider] (https://github.com/maicki)[#272](https://github.com/TextureGroup/Texture/pull/272)
 - [Fix] Fix a potential crash when cell nodes that need layout are deleted during the same runloop.  [Adlai Holler](https://github.com/Adlai-Holler) [#279](https://github.com/TextureGroup/Texture/pull/279)
 - [Batch fetching] Add ASBatchFetchingDelegate that takes scroll velocity and remaining time into account [Huy Nguyen](https://github.com/nguyenhuy) [#281](https://github.com/TextureGroup/Texture/pull/281)
-
+- [Fix] Fix a major regression in our image node contents caching. [Adlai Holler](https://github.com/Adlai-Holler) [#287](https://github.com/TextureGroup/Texture/pull/287)
diff --git a/Source/ASImageNode.mm b/Source/ASImageNode.mm
index 94e1440fbe..d36509d566 100644
--- a/Source/ASImageNode.mm
+++ b/Source/ASImageNode.mm
@@ -113,15 +113,18 @@ typedef void (^ASImageNodeDrawParametersBlock)(ASWeakMapEntry *entry);
 
 - (NSUInteger)hash
 {
+#pragma clang diagnostic push
+#pragma clang diagnostic warning "-Wpadded"
   struct {
     NSUInteger imageHash;
     CGSize backingSize;
     CGRect imageDrawRect;
-    BOOL isOpaque;
+    NSInteger isOpaque;
     NSUInteger backgroundColorHash;
     void *willDisplayNodeContentWithRenderingContext;
     void *didDisplayNodeContentWithRenderingContext;
     void *imageModificationBlock;
+#pragma clang diagnostic pop
   } data = {
     _image.hash,
     _backingSize,
diff --git a/Source/ASTextNode.mm b/Source/ASTextNode.mm
index d1334b21bb..5102ad6a0d 100644
--- a/Source/ASTextNode.mm
+++ b/Source/ASTextNode.mm
@@ -64,9 +64,12 @@ static NSString *ASTextNodeTruncationTokenAttributeName = @"ASTextNodeTruncation
 
 - (NSUInteger)hash
 {
+#pragma clang diagnostic push
+#pragma clang diagnostic warning "-Wpadded"
   struct {
     size_t attributesHash;
     CGSize constrainedSize;
+#pragma clang diagnostic pop
   } data = {
     _attributes.hash(),
     _constrainedSize
diff --git a/Source/Private/ASHashing.h b/Source/Private/ASHashing.h
index c658a42d36..0fc8d72ff8 100644
--- a/Source/Private/ASHashing.h
+++ b/Source/Private/ASHashing.h
@@ -34,6 +34,11 @@ ASDISPLAYNODE_EXTERN_C_BEGIN
  *    _bounds.size
  *  };
  *  return ASHashBytes(&data, sizeof(data));
+ *
+ * @warning: If a struct has padding, any fields that are intiailized in {} 
+ *   will have garbage data for their padding, which will break this hash! Either
+ *   use `pragma clang diagnostic warning "-Wpadded"` around your struct definition
+ *   or manually initialize the fields of your struct (`myStruct.x = 7;` etc).
  */
 NSUInteger ASHashBytes(void *bytes, size_t length);
 
diff --git a/Source/TextKit/ASTextKitAttributes.mm b/Source/TextKit/ASTextKitAttributes.mm
index 3e6dc80823..abe55c81d7 100755
--- a/Source/TextKit/ASTextKitAttributes.mm
+++ b/Source/TextKit/ASTextKitAttributes.mm
@@ -24,6 +24,8 @@ NSString *const ASTextKitEntityAttributeName = @"ck_entity";
 
 size_t ASTextKitAttributes::hash() const
 {
+#pragma clang diagnostic push
+#pragma clang diagnostic warning "-Wpadded"
   struct {
     NSUInteger attrStringHash;
     NSUInteger truncationStringHash;
@@ -35,6 +37,7 @@ size_t ASTextKitAttributes::hash() const
     NSUInteger shadowColorHash;
     CGFloat shadowOpacity;
     CGFloat shadowRadius;
+#pragma clang diagnostic pop
   } data = {
     [attributedString hash],
     [truncationAttributedString hash],