Expose dirtied func in Javascript bindings (#842)

Summary:
Yoga currently has the concept of a 'dirtied func', which is called when a Node becomes dirty, which can be useful to trigger a repaint. This PR exposes that functionality in the Javascript bindings.
Pull Request resolved: https://github.com/facebook/yoga/pull/842

Reviewed By: SidharthGuglani

Differential Revision: D13847093

Pulled By: davidaurelio

fbshipit-source-id: 41913abd6eedc46ee7d66929140e08a084f23972

javascript/sources/Node.cc

@@ -23,6 +23,13 @@ static YGSize globalMeasureFunc(YGNodeRef nodeRef, float width, YGMeasureMode wi
     return ygSize;
 }
 
+static void globalDirtiedFunc(YGNodeRef nodeRef)
+{
+    Node const & node = *reinterpret_cast<Node const *>(YGNodeGetContext(nodeRef));
+
+    node.callDirtiedFunc();
+}
+
 /* static */ Node * Node::createDefault(void)
 {
     return new Node(nullptr);
@@ -46,6 +53,7 @@ static YGSize globalMeasureFunc(YGNodeRef nodeRef, float width, YGMeasureMode wi
 Node::Node(Config * config)
 : m_node(config != nullptr ? YGNodeNewWithConfig(config->m_config) : YGNodeNew())
 , m_measureFunc(nullptr)
+, m_dirtiedFunc(nullptr)
 {
     YGNodeSetContext(m_node, reinterpret_cast<void *>(this));
 }
@@ -58,6 +66,7 @@ Node::~Node(void)
 void Node::reset(void)
 {
     m_measureFunc.reset(nullptr);
+    m_dirtiedFunc.reset(nullptr);
 
     YGNodeReset(m_node);
 }
@@ -429,6 +438,24 @@ Size Node::callMeasureFunc(double width, int widthMode, double height, int heigh
     return m_measureFunc->call<Size>(width, widthMode, height, heightMode);
 }
 
+void Node::setDirtiedFunc(nbind::cbFunction & dirtiedFunc)
+{
+    m_dirtiedFunc.reset(new nbind::cbFunction(dirtiedFunc));
+
+    YGNodeSetDirtiedFunc(m_node, &globalDirtiedFunc);
+}
+
+void Node::unsetDirtiedFunc(void) {
+    m_dirtiedFunc.reset(nullptr);
+
+    YGNodeSetDirtiedFunc(m_node, nullptr);
+}
+
+void Node::callDirtiedFunc(void) const
+{
+    m_dirtiedFunc->call<void>();
+}
+
 void Node::markDirty(void)
 {
     YGNodeMarkDirty(m_node);

javascript/sources/Node.hh

@@ -161,6 +161,15 @@ class Node {
 
     Size callMeasureFunc(double width, int widthMode, double height, int heightMode) const;
 
+ public: // Dirtied func mutators
+
+   void setDirtiedFunc(nbind::cbFunction & dirtiedFunc);
+   void unsetDirtiedFunc(void);
+
+ public: // Dirtied func inspectors
+
+    void callDirtiedFunc(void) const;
+
  public: // Dirtiness accessors
 
     void markDirty(void);
@@ -194,5 +203,5 @@ class Node {
     YGNodeRef m_node;
 
     std::unique_ptr<nbind::cbFunction> m_measureFunc;
-
+    std::unique_ptr<nbind::cbFunction> m_dirtiedFunc;
 };

javascript/sources/nbind.cc

@@ -155,6 +155,9 @@ NBIND_CLASS(Node)
     method(setMeasureFunc);
     method(unsetMeasureFunc);
 
+    method(setDirtiedFunc);
+    method(unsetDirtiedFunc);
+
     method(markDirty);
     method(isDirty);