Revert "[ASLayoutSpec] Use childrenMap directly to prevent creating an NSArray within ASDK Part 2 (#2021)"

This reverts commit d5a7c19522.

AsyncDisplayKit/Layout/ASLayoutSpec.mm

@@ -8,7 +8,7 @@
 //  of patent rights can be found in the PATENTS file in the same directory.
 //
 
-#import "ASLayoutSpec+Private.h"
+#import "ASLayoutSpec.h"
 
 #import "ASAssert.h"
 #import "ASEnvironmentInternal.h"
@@ -17,13 +17,16 @@
 #import "ASThread.h"
 #import "ASTraitCollection.h"
 
+#import <objc/runtime.h>
+#import <map>
 #import <vector>
 
+typedef std::map<unsigned long, id<ASLayoutable>, std::less<unsigned long>> ASChildMap;
+
 @interface ASLayoutSpec() {
   ASEnvironmentState _environmentState;
   ASDN::RecursiveMutex __instanceLock__;
-  ASChildrenMap _childrenMap;
-  unsigned long _mutations;
+  ASChildMap _children;
 }
 @end
 
@@ -32,7 +35,6 @@
 // these dynamic properties all defined in ASLayoutOptionsPrivate.m
 @dynamic spacingAfter, spacingBefore, flexGrow, flexShrink, flexBasis,
          alignSelf, ascender, descender, sizeRange, layoutPosition, layoutableType;
-@synthesize parent = _parent;
 @synthesize isFinalLayoutable = _isFinalLayoutable;
 
 - (instancetype)init
@@ -42,7 +44,6 @@
   }
   _isMutable = YES;
   _environmentState = ASEnvironmentStateMakeDefault();
-  _mutations = 0;
   return self;
 }
 
@@ -104,8 +105,6 @@
   return child;
 }
 
-#pragma mark - Parent
-
 - (void)setParent:(id<ASLayoutable>)parent
 {
   // FIXME: Locking should be evaluated here.  _parent is not widely used yet, though.
@@ -116,16 +115,18 @@
   }
 }
 
-- (id<ASLayoutable>)parent
-{
-  return _parent;
-}
-
-#pragma mark - Children
-
 - (void)setChild:(id<ASLayoutable>)child
 {
-  [self setChild:child forIndex:0];
+  ASDisplayNodeAssert(self.isMutable, @"Cannot set properties when layout spec is not mutable");
+  if (child) {
+    id<ASLayoutable> finalLayoutable = [self layoutableToAddFromLayoutable:child];
+    if (finalLayoutable) {
+      _children[0] = finalLayoutable;
+      [self propagateUpLayoutable:finalLayoutable];
+    }
+  } else {
+    _children.erase(0);
+  }
 }
 
 - (void)setChild:(id<ASLayoutable>)child forIndex:(NSUInteger)index
@@ -133,16 +134,11 @@
   ASDisplayNodeAssert(self.isMutable, @"Cannot set properties when layout spec is not mutable");
   if (child) {
     id<ASLayoutable> finalLayoutable = [self layoutableToAddFromLayoutable:child];
-    if (finalLayoutable) {
-      _childrenMap[index] = finalLayoutable;
-      [self propagateUpLayoutable:finalLayoutable];
-    }
+    _children[index] = finalLayoutable;
   } else {
-    _childrenMap.erase(index);
+    _children.erase(index);
   }
-  _mutations++;
-  
-  // TODO: Should we propagate up the layoutable as it could happen that multiple children will propagated up their
+  // TODO: Should we propagate up the layoutable at it could happen that multiple children will propagated up their
   //       layout options and one child will overwrite values from another child
   // [self propagateUpLayoutable:finalLayoutable];
 }
@@ -151,73 +147,37 @@
 {
   ASDisplayNodeAssert(self.isMutable, @"Cannot set properties when layout spec is not mutable");
   
-  _childrenMap.clear();
+  _children.clear();
   NSUInteger i = 0;
   for (id<ASLayoutable> child in children) {
-    _childrenMap[i] = [self layoutableToAddFromLayoutable:child];
+    _children[i] = [self layoutableToAddFromLayoutable:child];
     i += 1;
-    
-    _mutations++;
   }
 }
 
 - (id<ASLayoutable>)childForIndex:(NSUInteger)index
 {
-  if (index < _childrenMap.size()) {
-    return _childrenMap[index];
+  if (index < _children.size()) {
+    return _children[index];
   }
   return nil;
 }
 
 - (id<ASLayoutable>)child
 {
-  return _childrenMap[0];
+  return _children[0];
 }
 
 - (NSArray *)children
 {
-  // If used inside ASDK, the childrenMap property should be preferred over the children array to prevent
-  // unecessary boxing
   std::vector<ASLayout *> children;
-  for (auto const &entry : _childrenMap) {
-    children.push_back(entry.second);
+  for (ASChildMap::iterator it = _children.begin(); it != _children.end(); ++it ) {
+    children.push_back(it->second);
   }
-
+  
   return [NSArray arrayWithObjects:&children[0] count:children.size()];
 }
 
-#pragma mark - NSFastEnumeration
-
-- (NSUInteger)countByEnumeratingWithState:(NSFastEnumerationState *)state
-                                  objects:(id __unsafe_unretained [])stackbuf
-                                    count:(NSUInteger)stackbufLength
-{
-  NSUInteger count = 0;
-  unsigned long countOfItemsAlreadyEnumerated = state->state;
-  
-  if (countOfItemsAlreadyEnumerated == 0) {
-    state->mutationsPtr = &_mutations;
-  }
-
-  if (countOfItemsAlreadyEnumerated < _childrenMap.size()) {
-    state->itemsPtr = stackbuf;
-        
-    while((countOfItemsAlreadyEnumerated < _childrenMap.size()) && (count < stackbufLength)) {
-      // Hold on for the object while enumerating
-      __autoreleasing id child = _childrenMap[countOfItemsAlreadyEnumerated];
-      stackbuf[count] = child;
-      countOfItemsAlreadyEnumerated++;
-      count++;
-    }
-  } else {
-    count = 0;
-  }
-  
-  state->state = countOfItemsAlreadyEnumerated;
-
-  return count;
-}
-
 #pragma mark - ASEnvironment
 
 - (ASEnvironmentState)environmentState
@@ -273,15 +233,6 @@ ASEnvironmentLayoutExtensibilityForwarding
 
 @end
 
-@implementation ASLayoutSpec (Private)
-
-- (ASChildrenMap)childrenMap
-{
-  return _childrenMap;
-}
-
-@end
-
 @implementation ASLayoutSpec (Debugging)
 
 #pragma mark - ASLayoutableAsciiArtProtocol