From fca43a651f57f51dd0499ba03a75b1ffc9a6195a Mon Sep 17 00:00:00 2001
From: rcancro <@pinterest.com>
Date: Fri, 28 Aug 2015 20:41:40 -0700
Subject: [PATCH] Make layoutOptions readonly

---
 AsyncDisplayKit/Layout/ASLayoutOptions.h      |  9 +++-
 AsyncDisplayKit/Layout/ASLayoutOptions.m      | 44 +++++++++++--------
 .../Layout/ASLayoutOptionsPrivate.mm          |  7 +--
 AsyncDisplayKit/Layout/ASLayoutSpec.mm        |  5 +--
 AsyncDisplayKit/Layout/ASLayoutablePrivate.h  |  2 +-
 5 files changed, 38 insertions(+), 29 deletions(-)

diff --git a/AsyncDisplayKit/Layout/ASLayoutOptions.h b/AsyncDisplayKit/Layout/ASLayoutOptions.h
index 3df0f7c673..937f6c7640 100644
--- a/AsyncDisplayKit/Layout/ASLayoutOptions.h
+++ b/AsyncDisplayKit/Layout/ASLayoutOptions.h
@@ -24,6 +24,14 @@
 - (instancetype)initWithLayoutable:(id<ASLayoutable>)layoutable;
 - (void)setValuesFromLayoutable:(id<ASLayoutable>)layoutable;
 
+#pragma mark - Subclasses should implement these!
++ (NSSet *)keyPathsForValuesAffectingChangeMonitor;
+- (void)setupDefaults;
+- (instancetype)copyWithZone:(NSZone *)zone;
+- (void)copyIntoOptions:(ASLayoutOptions *)layoutOptions;
+
+#pragma mark - Mutability checks
+
 @property (nonatomic, assign) BOOL isMutable;
 
 #if DEBUG
@@ -49,6 +57,5 @@
 @property (nonatomic, readwrite) ASRelativeSizeRange sizeRange;
 @property (nonatomic, readwrite) CGPoint layoutPosition;
 
-- (void)setupDefaults;
 
 @end
diff --git a/AsyncDisplayKit/Layout/ASLayoutOptions.m b/AsyncDisplayKit/Layout/ASLayoutOptions.m
index e0ebf622f5..9d8d9c6a0e 100644
--- a/AsyncDisplayKit/Layout/ASLayoutOptions.m
+++ b/AsyncDisplayKit/Layout/ASLayoutOptions.m
@@ -13,7 +13,6 @@
 #import <AsyncDisplayKit/ASAssert.h>
 #import <AsyncDisplayKit/ASTextNode.h>
 #import "ASInternalHelpers.h"
-#import <objc/runtime.h>
 
 @implementation ASLayoutOptions
 
@@ -35,6 +34,10 @@ static Class gDefaultLayoutOptionsClass = nil;
   return gDefaultLayoutOptionsClass;
 }
 
+- (instancetype)init
+{
+  return [self initWithLayoutable:nil];
+}
 
 - (instancetype)initWithLayoutable:(id<ASLayoutable>)layoutable;
 {
@@ -42,30 +45,31 @@ static Class gDefaultLayoutOptionsClass = nil;
   if (self) {
     [self setupDefaults];
     [self setValuesFromLayoutable:layoutable];
+    _isMutable = YES;
 #if DEBUG
-    [self addObserver:self forKeyPath:@"changeMonitor"
-                     options:NSKeyValueObservingOptionNew
-                     context:nil];
+    [self addObserver:self
+           forKeyPath:@"changeMonitor"
+              options:NSKeyValueObservingOptionNew
+              context:nil];
 #endif
   }
   return self;
 }
 
+- (void)dealloc
+{
+#if DEBUG
+  [self removeObserver:self forKeyPath:@"changeMonitor"];
+#endif
+}
+
 #if DEBUG
 + (NSSet *)keyPathsForValuesAffectingChangeMonitor
 {
   NSMutableSet *keys = [NSMutableSet set];
-  unsigned int count;
-  
-  objc_property_t *properties = class_copyPropertyList([self class], &count);
-  for (size_t i = 0; i < count; ++i) {
-    NSString *property = [NSString stringWithCString:property_getName(properties[i]) encoding:NSASCIIStringEncoding];
-    
-    if ([property isEqualToString: @"observableSelf"] == NO) {
-      [keys addObject: property];
-    }
-  }
-  free(properties);
+  [keys addObjectsFromArray:@[@"spacingBefore", @"spacingAfter", @"flexGrow", @"flexShrink", @"flexBasis", @"alignSelf"]];
+  [keys addObjectsFromArray:@[@"ascender", @"descender"]];
+  [keys addObjectsFromArray:@[@"sizeRange", @"layoutPosition"]];
   
   return keys;
 }
@@ -89,7 +93,12 @@ static Class gDefaultLayoutOptionsClass = nil;
 - (id)copyWithZone:(NSZone *)zone
 {
   ASLayoutOptions *copy = [[[self class] alloc] init];
+  [self copyIntoOptions:copy];
+  return copy;
+}
 
+- (void)copyIntoOptions:(ASLayoutOptions *)copy
+{
   copy.flexBasis = self.flexBasis;
   copy.spacingAfter = self.spacingAfter;
   copy.spacingBefore = self.spacingBefore;
@@ -98,13 +107,12 @@ static Class gDefaultLayoutOptionsClass = nil;
   
   copy.ascender = self.ascender;
   copy.descender = self.descender;
-
+  
   copy.sizeRange = self.sizeRange;
   copy.layoutPosition = self.layoutPosition;
-
-  return copy;
 }
 
+
 #pragma mark - Defaults
 - (void)setupDefaults
 {
diff --git a/AsyncDisplayKit/Layout/ASLayoutOptionsPrivate.mm b/AsyncDisplayKit/Layout/ASLayoutOptionsPrivate.mm
index f04c010936..39d129ba11 100644
--- a/AsyncDisplayKit/Layout/ASLayoutOptionsPrivate.mm
+++ b/AsyncDisplayKit/Layout/ASLayoutOptionsPrivate.mm
@@ -17,17 +17,12 @@
 {\
 dispatch_once(&_layoutOptionsInitializeToken, ^{\
 if (_layoutOptions == nil) {\
-_layoutOptions = [[[ASLayoutOptions defaultLayoutOptionsClass] alloc] init];\
+_layoutOptions = [[[ASLayoutOptions defaultLayoutOptionsClass] alloc] initWithLayoutable:self];\
 }\
 });\
 return _layoutOptions;\
 }\
 \
-- (void)setLayoutOptions:(ASLayoutOptions *)layoutOptions\
-{\
-  _layoutOptions = layoutOptions;\
-}\
-\
 - (CGFloat)spacingBefore\
 {\
 return self.layoutOptions.spacingBefore;\
diff --git a/AsyncDisplayKit/Layout/ASLayoutSpec.mm b/AsyncDisplayKit/Layout/ASLayoutSpec.mm
index 904c30cc69..6c506b655c 100644
--- a/AsyncDisplayKit/Layout/ASLayoutSpec.mm
+++ b/AsyncDisplayKit/Layout/ASLayoutSpec.mm
@@ -66,9 +66,8 @@ static NSString * const kDefaultChildrenKey = @"kDefaultChildrenKey";
   
   id<ASLayoutable> finalLayoutable = [child finalLayoutableWithParent:self];
   if (finalLayoutable) {
-    ASLayoutOptions *finalLayoutOptions = [layoutOptions copy];
-    finalLayoutOptions.isMutable = NO;
-    finalLayoutable.layoutOptions = finalLayoutOptions;
+    [layoutOptions copyIntoOptions:finalLayoutable.layoutOptions];
+    finalLayoutable.layoutOptions.isMutable = NO;
     return finalLayoutable;
   }
   return child;
diff --git a/AsyncDisplayKit/Layout/ASLayoutablePrivate.h b/AsyncDisplayKit/Layout/ASLayoutablePrivate.h
index c7ab3b7ad3..2d317fc7ca 100644
--- a/AsyncDisplayKit/Layout/ASLayoutablePrivate.h
+++ b/AsyncDisplayKit/Layout/ASLayoutablePrivate.h
@@ -15,5 +15,5 @@
 
 @protocol ASLayoutablePrivate <NSObject>
 - (ASLayoutSpec *)finalLayoutableWithParent:(ASLayoutSpec *)parentSpec;
-@property (nonatomic, strong) ASLayoutOptions *layoutOptions;
+@property (nonatomic, strong, readonly) ASLayoutOptions *layoutOptions;
 @end