Fabric: Introcucing `ConcreteComponentDescriptor::adopt()`

Summary: Overriding `adopt` method allows subclasses to configure just created or cloned shadow nodes without overriding `create` and `clone` methods.

Reviewed By: mdvacca

Differential Revision: D7738581

fbshipit-source-id: bfe4e4e2d3d448591a3267b5ea7ca4e0800f5ba0

ReactCommon/fabric/core/componentdescriptor/ConcreteComponentDescriptor.h

@@ -41,7 +41,7 @@ public:
     const InstanceHandle &instanceHandle,
     const SharedProps &props
   ) const override {
-    return std::make_shared<ShadowNodeT>(
+    UnsharedShadowNode shadowNode = std::make_shared<ShadowNodeT>(
       tag,
       rootTag,
       instanceHandle,
@@ -49,14 +49,19 @@ public:
       ShadowNode::emptySharedShadowNodeSharedList(),
       getCloneFunction()
     );
+    adopt(shadowNode);
+    return shadowNode;
   }
 
   SharedShadowNode cloneShadowNode(
-    const SharedShadowNode &shadowNode,
+    const SharedShadowNode &sourceShadowNode,
     const SharedProps &props = nullptr,
     const SharedShadowNodeSharedList &children = nullptr
   ) const override {
-    return std::make_shared<ShadowNodeT>(std::static_pointer_cast<const ShadowNodeT>(shadowNode), std::static_pointer_cast<const ConcreteProps>(props), children);
+    assert(std::dynamic_pointer_cast<const ShadowNodeT>(sourceShadowNode));
+    UnsharedShadowNode shadowNode = std::make_shared<ShadowNodeT>(std::static_pointer_cast<const ShadowNodeT>(sourceShadowNode), std::static_pointer_cast<const ConcreteProps>(props), children);
+    adopt(shadowNode);
+    return shadowNode;
   }
 
   void appendChild(
@@ -75,7 +80,14 @@ public:
     return ShadowNodeT::Props(rawProps, props);
   };
 
+protected:
+
+  virtual void adopt(UnsharedShadowNode shadowNode) const {
+    // Default implementation does nothing.
+  }
+
 private:
+
   mutable ShadowNodeCloneFunction cloneFunction_;
 
   ShadowNodeCloneFunction getCloneFunction() const {

ReactCommon/fabric/core/shadownode/ConcreteShadowNode.h

@@ -36,6 +36,7 @@ public:
     }
 
     auto concreteBaseProps = std::dynamic_pointer_cast<const PropsT>(baseProps);
+    assert(concreteBaseProps);
     auto props = std::make_shared<PropsT>(*concreteBaseProps);
     props->apply(rawProps);
     return props;
@@ -79,6 +80,8 @@ public:
   }
 
   const SharedConcreteProps getProps() const {
+    assert(std::dynamic_pointer_cast<const PropsT>(props_));
+
     return std::static_pointer_cast<const PropsT>(props_);
   }
 

ReactCommon/fabric/core/shadownode/ShadowNode.h

@@ -23,6 +23,7 @@ namespace react {
 class ShadowNode;
 
 using SharedShadowNode = std::shared_ptr<const ShadowNode>;
+using UnsharedShadowNode = std::shared_ptr<ShadowNode>;
 using SharedShadowNodeList = std::vector<std::shared_ptr<const ShadowNode>>;
 using SharedShadowNodeSharedList = std::shared_ptr<const SharedShadowNodeList>;
 using SharedShadowNodeUnsharedList = std::shared_ptr<SharedShadowNodeList>;