Move YGCloneChildrenIfNeeded as a method on YGNode

Reviewed By: emilsjolander

Differential Revision: D6611155

fbshipit-source-id: 463723a363e0fbd2c7686f65226eca73236bd07e

Author: priteshrnandgaonkar

ReactCommon/yoga/yoga/YGNode.cpp

@@ -155,6 +155,10 @@ void YGNode::replaceChild(YGNodeRef child, uint32_t index) {
   children_[index] = child;
 }
 
+void YGNode::replaceChild(YGNodeRef oldChild, YGNodeRef newChild) {
+  std::replace(children_.begin(), children_.end(), oldChild, newChild);
+}
+
 void YGNode::insertChild(YGNodeRef child, uint32_t index) {
   children_.insert(children_.begin() + index, child);
 }
@@ -375,21 +379,33 @@ YGNode::~YGNode() {
   // deallocate here
 }
 
-const YGNode& YGNode::defaultValue() {
-  static const YGNode n = {nullptr,
-                           nullptr,
-                           true,
-                           YGNodeTypeDefault,
-                           nullptr,
-                           nullptr,
-                           gYGNodeStyleDefaults,
-                           gYGNodeLayoutDefaults,
-                           0,
-                           nullptr,
-                           YGVector(),
-                           nullptr,
-                           nullptr,
-                           false,
-                           {{YGValueUndefined, YGValueUndefined}}};
-  return n;
+void YGNode::cloneChildrenIfNeeded() {
+  // YGNodeRemoveChild in yoga.cpp has a forked variant of this algorithm
+  // optimized for deletions.
+
+  const uint32_t childCount = children_.size();
+  if (childCount == 0) {
+    // This is an empty set. Nothing to clone.
+    return;
+  }
+
+  const YGNodeRef firstChild = children_.front();
+  if (firstChild->getParent() == this) {
+    // If the first child has this node as its parent, we assume that it is
+    // already unique. We can do this because if we have it has a child, that
+    // means that its parent was at some point cloned which made that subtree
+    // immutable. We also assume that all its sibling are cloned as well.
+    return;
+  }
+
+  const YGNodeClonedFunc cloneNodeCallback = config_->cloneNodeCallback;
+  for (uint32_t i = 0; i < childCount; ++i) {
+    const YGNodeRef oldChild = children_[i];
+    const YGNodeRef newChild = YGNodeClone(oldChild);
+    replaceChild(newChild, i);
+    newChild->setParent(this);
+    if (cloneNodeCallback) {
+      cloneNodeCallback(oldChild, newChild, this, i);
+    }
+  }
 }

ReactCommon/yoga/yoga/YGNode.h

@@ -106,6 +106,8 @@ struct YGNode {
   YGValue resolveFlexBasisPtr() const;
   void resolveDimension();
   void clearChildren();
+  /// Replaces the occurrences of oldChild with newChild
+  void replaceChild(YGNodeRef oldChild, YGNodeRef newChild);
   void replaceChild(YGNodeRef child, uint32_t index);
   void insertChild(YGNodeRef child, uint32_t index);
   /// Removes the first occurrence of child
@@ -117,6 +119,6 @@ struct YGNode {
   void setLayoutPadding(float padding, int index);
   void setLayoutPosition(float position, int index);
 
-  // Static methods
-  static const YGNode& defaultValue();
+  // Other methods
+  void cloneChildrenIfNeeded();
 };

ReactCommon/yoga/yoga/Yoga.cpp

@@ -348,36 +348,6 @@ static void YGNodeMarkDirtyInternal(const YGNodeRef node) {
   }
 }
 
-static void YGCloneChildrenIfNeeded(const YGNodeRef parent) {
-  // YGNodeRemoveChild has a forked variant of this algorithm optimized for deletions.
-  const uint32_t childCount = YGNodeGetChildCount(parent);
-  if (childCount == 0) {
-    // This is an empty set. Nothing to clone.
-    return;
-  }
-
-  const YGNodeRef firstChild = YGNodeGetChild(parent, 0);
-  if (firstChild->getParent() == parent) {
-    // If the first child has this node as its parent, we assume that it is already unique.
-    // We can do this because if we have it has a child, that means that its parent was at some
-    // point cloned which made that subtree immutable.
-    // We also assume that all its sibling are cloned as well.
-    return;
-  }
-
-  const YGNodeClonedFunc cloneNodeCallback =
-      parent->getConfig()->cloneNodeCallback;
-  for (uint32_t i = 0; i < childCount; i++) {
-    const YGNodeRef oldChild = parent->getChild(i);
-    const YGNodeRef newChild = YGNodeClone(oldChild);
-    parent->replaceChild(newChild, i);
-    newChild->setParent(parent);
-    if (cloneNodeCallback) {
-      cloneNodeCallback(oldChild, newChild, parent, i);
-    }
-  }
-}
-
 void YGNodeInsertChild(const YGNodeRef node, const YGNodeRef child, const uint32_t index) {
   YGAssertWithNode(
       node,
@@ -388,14 +358,15 @@ void YGNodeInsertChild(const YGNodeRef node, const YGNodeRef child, const uint32
       node->getMeasure() == nullptr,
       "Cannot add child: Nodes with measure functions cannot have children.");
 
-  YGCloneChildrenIfNeeded(node);
+  node->cloneChildrenIfNeeded();
   node->insertChild(child, index);
   child->setParent(node);
   YGNodeMarkDirtyInternal(node);
 }
 
 void YGNodeRemoveChild(const YGNodeRef parent, const YGNodeRef excludedChild) {
-  // This algorithm is a forked variant from YGCloneChildrenIfNeeded that excludes a child.
+  // This algorithm is a forked variant from cloneChildrenIfNeeded in YGNode
+  // that excludes a child.
   const uint32_t childCount = YGNodeGetChildCount(parent);
 
   if (childCount == 0) {
@@ -1805,7 +1776,7 @@ static bool YGNodeFixedSizeSetMeasuredDimensions(const YGNodeRef node,
 static void YGZeroOutLayoutRecursivly(const YGNodeRef node) {
   memset(&(node->getLayout()), 0, sizeof(YGLayout));
   node->setHasNewLayout(true);
-  YGCloneChildrenIfNeeded(node);
+  node->cloneChildrenIfNeeded();
   const uint32_t childCount = YGNodeGetChildCount(node);
   for (uint32_t i = 0; i < childCount; i++) {
     const YGNodeRef child = node->getChild(i);
@@ -1993,8 +1964,7 @@ static void YGNodelayoutImpl(const YGNodeRef node,
   }
 
   // At this point we know we're going to perform work. Ensure that each child has a mutable copy.
-  YGCloneChildrenIfNeeded(node);
-
+  node->cloneChildrenIfNeeded();
   // Reset layout flags, as they could have changed.
   node->setLayoutHadOverflow(false);