Fabric: Introducing ComponentDescriptor::Flavor

Summary:
Currently, the same ComponentDescriptor class cannot be registered as a responder for components with different names. However, we have marginal cases where we really need it. The examples are `UnimplementedView` or possible universal interop with the classic RN or any other UI framework.

This change adds a special optional argument to ComponentDescript constructor that allows implementing this functionality.

Reviewed By: fkgozali

Differential Revision: D17211915

fbshipit-source-id: 18f59e09fe06b875a8e8975b7b2ab423489238bb

ReactCommon/fabric/components/image/ImageComponentDescriptor.h

@@ -23,8 +23,9 @@ class ImageComponentDescriptor final
  public:
   ImageComponentDescriptor(
       EventDispatcher::Weak eventDispatcher,
-      ContextContainer::Shared const &contextContainer)
-      : ConcreteComponentDescriptor(eventDispatcher),
+      ContextContainer::Shared const &contextContainer,
+      ComponentDescriptor::Flavor const &flavor = {})
+      : ConcreteComponentDescriptor(eventDispatcher, contextContainer, flavor),
         imageManager_(std::make_shared<ImageManager>(contextContainer)){};
 
   void adopt(UnsharedShadowNode shadowNode) const override {

ReactCommon/fabric/components/slider/SliderComponentDescriptor.h

@@ -22,8 +22,9 @@ class SliderComponentDescriptor final
  public:
   SliderComponentDescriptor(
       EventDispatcher::Weak eventDispatcher,
-      ContextContainer::Shared const &contextContainer)
-      : ConcreteComponentDescriptor(eventDispatcher),
+      ContextContainer::Shared const &contextContainer,
+      ComponentDescriptor::Flavor const &flavor = {})
+      : ConcreteComponentDescriptor(eventDispatcher, contextContainer, flavor),
         imageManager_(std::make_shared<ImageManager>(contextContainer)),
         measurementsManager_(
             SliderMeasurementsManager::shouldMeasureSlider()

ReactCommon/fabric/components/text/paragraph/ParagraphComponentDescriptor.h

@@ -27,8 +27,12 @@ class ParagraphComponentDescriptor final
  public:
   ParagraphComponentDescriptor(
       EventDispatcher::Weak eventDispatcher,
-      ContextContainer::Shared const &contextContainer)
-      : ConcreteComponentDescriptor<ParagraphShadowNode>(eventDispatcher) {
+      ContextContainer::Shared const &contextContainer,
+      ComponentDescriptor::Flavor const &flavor = {})
+      : ConcreteComponentDescriptor<ParagraphShadowNode>(
+            eventDispatcher,
+            contextContainer,
+            flavor) {
     // Every single `ParagraphShadowNode` will have a reference to
     // a shared `TextLayoutManager`.
     textLayoutManager_ = std::make_shared<TextLayoutManager>(contextContainer);

ReactCommon/fabric/core/componentdescriptor/ComponentDescriptor.cpp

@@ -12,8 +12,11 @@ namespace react {
 
 ComponentDescriptor::ComponentDescriptor(
     EventDispatcher::Weak const &eventDispatcher,
-    ContextContainer::Shared const &contextContainer)
-    : eventDispatcher_(eventDispatcher), contextContainer_(contextContainer) {}
+    ContextContainer::Shared const &contextContainer,
+    ComponentDescriptor::Flavor const &flavor)
+    : eventDispatcher_(eventDispatcher),
+      contextContainer_(contextContainer),
+      flavor_(flavor) {}
 
 ContextContainer::Shared const &ComponentDescriptor::getContextContainer()
     const {

ReactCommon/fabric/core/componentdescriptor/ComponentDescriptor.h

@@ -33,9 +33,21 @@ class ComponentDescriptor {
   using Shared = std::shared_ptr<ComponentDescriptor const>;
   using Unique = std::unique_ptr<ComponentDescriptor const>;
 
+  /*
+   * `Flavor` is a special concept designed to allow registering instances of
+   * the exact same `ComponentDescriptor` class with different `ComponentName`
+   * and `ComponentHandle` (the particular custom implementation might use
+   * stored `flavor` to return different values from those virtual methods).
+   * Since it's a very niche requirement (e.g. we plan to use it for
+   * an interoperability layer with Paper), we are thinking about removing this
+   * feature completely after it's no longer needed.
+   */
+  using Flavor = std::shared_ptr<void const>;
+
   ComponentDescriptor(
       EventDispatcher::Weak const &eventDispatcher,
-      ContextContainer::Shared const &contextContainer);
+      ContextContainer::Shared const &contextContainer,
+      ComponentDescriptor::Flavor const &flavor);
 
   virtual ~ComponentDescriptor() = default;
 
@@ -114,6 +126,7 @@ class ComponentDescriptor {
   EventDispatcher::Weak eventDispatcher_;
   ContextContainer::Shared contextContainer_;
   RawPropsParser rawPropsParser_{};
+  Flavor flavor_;
 };
 
 } // namespace react

ReactCommon/fabric/core/componentdescriptor/ConcreteComponentDescriptor.h

@@ -47,8 +47,9 @@ class ConcreteComponentDescriptor : public ComponentDescriptor {
 
   ConcreteComponentDescriptor(
       EventDispatcher::Weak const &eventDispatcher,
-      ContextContainer::Shared const &contextContainer = {})
-      : ComponentDescriptor(eventDispatcher, contextContainer) {
+      ContextContainer::Shared const &contextContainer = {},
+      ComponentDescriptor::Flavor const &flavor = {})
+      : ComponentDescriptor(eventDispatcher, contextContainer, flavor) {
     rawPropsParser_.prepare<ConcreteProps>();
   }
 

ReactCommon/fabric/uimanager/ComponentDescriptorProvider.h

@@ -22,6 +22,7 @@ class ComponentDescriptorParameters {
  public:
   EventDispatcher::Weak eventDispatcher;
   ContextContainer::Shared contextContainer;
+  ComponentDescriptor::Flavor flavor;
 };
 
 /*
@@ -30,36 +31,40 @@ class ComponentDescriptorParameters {
  * abstract type and ownership of the newly created object.
  */
 using ComponentDescriptorConstructor = ComponentDescriptor::Unique(
-    EventDispatcher::Weak const &eventDispatcher,
-    ContextContainer::Shared const &contextContainer);
+    ComponentDescriptorParameters const &parameters);
 
 /*
  * Represents a unified way to construct an instance of a particular stored
  * `ComponentDescriptor` class. C++ does not allow to create pointers to
  * constructors, so we have to have such data structure to manipulate a
  * collection of classes.
+ *
+ * Note: The actual values of `handle` and `name` for some components depend on
+ * `flavor`. The provider is valid if instantiated by `constructor` object with
+ * given `flavor` exposes the same values of `handle` and `name`.
  */
 class ComponentDescriptorProvider final {
  public:
   ComponentHandle handle;
   ComponentName name;
+  ComponentDescriptor::Flavor flavor;
   ComponentDescriptorConstructor *constructor;
 };
 
 /*
- * Creates a `ComponentDescriptorConstructor` for given `ComponentDescriptor`
- * class.
+ * Creates a `ComponentDescriptor` for given `ComponentDescriptorParameters`.
  */
 template <typename ComponentDescriptorT>
 ComponentDescriptor::Unique concreteComponentDescriptorConstructor(
-    EventDispatcher::Weak const &eventDispatcher,
-    ContextContainer::Shared const &contextContainer) {
+    ComponentDescriptorParameters const &parameters) {
   static_assert(
       std::is_base_of<ComponentDescriptor, ComponentDescriptorT>::value,
       "ComponentDescriptorT must be a descendant of ComponentDescriptor");
 
   return std::make_unique<ComponentDescriptorT const>(
-      eventDispatcher, contextContainer);
+      parameters.eventDispatcher,
+      parameters.contextContainer,
+      parameters.flavor);
 }
 
 /*
@@ -74,7 +79,8 @@ ComponentDescriptorProvider concreteComponentDescriptorProvider() {
 
   return {ComponentDescriptorT::ConcreteShadowNode::Handle(),
           ComponentDescriptorT::ConcreteShadowNode::Name(),
-          &concreteComponentDescriptorConstructor<ComponentDescriptorT>};
+          &concreteComponentDescriptorConstructor<ComponentDescriptorT>,
+          nullptr};
 }
 
 } // namespace react

ReactCommon/fabric/uimanager/ComponentDescriptorRegistry.cpp

@@ -20,7 +20,9 @@ void ComponentDescriptorRegistry::add(
   std::unique_lock<better::shared_mutex> lock(mutex_);
 
   auto componentDescriptor = componentDescriptorProvider.constructor(
-      parameters_.eventDispatcher, parameters_.contextContainer);
+      {parameters_.eventDispatcher,
+       parameters_.contextContainer,
+       componentDescriptorProvider.flavor});
   assert(
       componentDescriptor->getComponentHandle() ==
       componentDescriptorProvider.handle);