Add basics of pointer event interception

Summary:
Changelog: [Internal] - Add basics of pointer event interception

This diff adds the scaffolding for intercepting Pointer Events (without actually doing anything with them yet). Most notably introduces the logic of determining which events are of the PointerEvent type and downcasting to the type so the interceptor can properly work with the typed properties.

Originally my plan was to leverage `dynamic_cast` but sandcastle's signals let me know that there exists internal apps (particularly VR ones) which don't have RTTI enabled — so to avoid that usage I introduced an additional abstract method on EventPayload which lets subclasses identify themselves cheaply and then subsequently leverage `static_cast`.

Differential Revision: https://internalfb.com/D47443773

fbshipit-source-id: deb804a229db7c57f0d36cd6b34fbf39bd550859

packages/react-native/ReactCommon/react/renderer/components/view/PointerEvent.cpp

@@ -44,6 +44,10 @@ jsi::Value PointerEvent::asJSIValue(jsi::Runtime &runtime) const {
   return object;
 }
 
+EventPayloadType PointerEvent::getType() const {
+  return EventPayloadType::PointerEvent;
+}
+
 #if RN_DEBUG_STRING_CONVERTIBLE
 
 std::string getDebugName(PointerEvent const & /*pointerEvent*/) {

packages/react-native/ReactCommon/react/renderer/components/view/PointerEvent.h

@@ -115,6 +115,7 @@ struct PointerEvent : public EventPayload {
    * EventPayload implementations
    */
   jsi::Value asJSIValue(jsi::Runtime &runtime) const override;
+  EventPayloadType getType() const override;
 };
 
 #if RN_DEBUG_STRING_CONVERTIBLE

packages/react-native/ReactCommon/react/renderer/core/EventPayload.h

@@ -9,6 +9,8 @@
 
 #include <jsi/jsi.h>
 
+#include <react/renderer/core/EventPayloadType.h>
+
 namespace facebook::react {
 
 /**
@@ -24,6 +26,13 @@ struct EventPayload {
   EventPayload &operator=(EventPayload &&) = default;
 
   virtual jsi::Value asJSIValue(jsi::Runtime &runtime) const = 0;
+
+  /**
+   * Reports the type of the event payload for efficient downcasting.
+   * When adding a new EventPayload be sure to add a new type of it
+   * in `EventPayloadType` and return it from its overriden `getType()` method.
+   */
+  virtual EventPayloadType getType() const = 0;
 };
 
 using SharedEventPayload = std::shared_ptr<const EventPayload>;

packages/react-native/ReactCommon/react/renderer/core/EventPayloadType.h

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+namespace facebook::react {
+
+enum class EventPayloadType { ValueFactory, PointerEvent };
+
+}

packages/react-native/ReactCommon/react/renderer/core/ValueFactoryEventPayload.cpp

@@ -16,4 +16,8 @@ jsi::Value ValueFactoryEventPayload::asJSIValue(jsi::Runtime &runtime) const {
   return valueFactory_(runtime);
 }
 
+EventPayloadType ValueFactoryEventPayload::getType() const {
+  return EventPayloadType::ValueFactory;
+}
+
 } // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/core/ValueFactoryEventPayload.h

@@ -16,6 +16,7 @@ class ValueFactoryEventPayload : public EventPayload {
  public:
   explicit ValueFactoryEventPayload(ValueFactory factory);
   jsi::Value asJSIValue(jsi::Runtime &runtime) const override;
+  EventPayloadType getType() const override;
 
  private:
   ValueFactory valueFactory_;

packages/react-native/ReactCommon/react/renderer/uimanager/PointerEventsProcessor.cpp

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "PointerEventsProcessor.h"
+
+namespace facebook::react {
+
+void PointerEventsProcessor::interceptPointerEvent(
+    jsi::Runtime &runtime,
+    EventTarget const *eventTarget,
+    std::string const &type,
+    ReactEventPriority priority,
+    PointerEvent const &event,
+    DispatchEvent const &eventDispatcher) {
+  // TODO: implement pointer capture redirection
+  eventDispatcher(runtime, eventTarget, type, priority, event);
+}
+
+} // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/uimanager/PointerEventsProcessor.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <functional>
+
+#include <jsi/jsi.h>
+#include <react/renderer/uimanager/UIManager.h>
+#include <react/renderer/uimanager/primitives.h>
+
+namespace facebook::react {
+
+using DispatchEvent = std::function<void(
+    jsi::Runtime &runtime,
+    const EventTarget *eventTarget,
+    const std::string &type,
+    ReactEventPriority priority,
+    const EventPayload &payload)>;
+
+class PointerEventsProcessor final {
+ public:
+  void interceptPointerEvent(
+      jsi::Runtime &runtime,
+      EventTarget const *eventTarget,
+      std::string const &type,
+      ReactEventPriority priority,
+      PointerEvent const &event,
+      DispatchEvent const &eventDispatcher);
+};
+
+} // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/uimanager/UIManagerBinding.cpp

@@ -10,6 +10,7 @@
 #include <glog/logging.h>
 #include <jsi/JSIDynamic.h>
 #include <react/debug/react_native_assert.h>
+#include <react/renderer/components/view/PointerEvent.h>
 #include <react/renderer/core/LayoutableShadowNode.h>
 #include <react/renderer/core/TraitCast.h>
 #include <react/renderer/debug/SystraceSection.h>
@@ -96,6 +97,32 @@ void UIManagerBinding::dispatchEvent(
     const EventPayload &eventPayload) const {
   SystraceSection s("UIManagerBinding::dispatchEvent", "type", type);
 
+  if (eventPayload.getType() == EventPayloadType::PointerEvent) {
+    auto pointerEvent = static_cast<const PointerEvent &>(eventPayload);
+    auto dispatchCallback = [this](
+                                jsi::Runtime &runtime,
+                                EventTarget const *eventTarget,
+                                std::string const &type,
+                                ReactEventPriority priority,
+                                const EventPayload &eventPayload) {
+      this->dispatchEventToJS(
+          runtime, eventTarget, type, priority, eventPayload);
+    };
+    pointerEventsProcessor_.interceptPointerEvent(
+        runtime, eventTarget, type, priority, pointerEvent, dispatchCallback);
+  } else {
+    dispatchEventToJS(runtime, eventTarget, type, priority, eventPayload);
+  }
+}
+
+void UIManagerBinding::dispatchEventToJS(
+    jsi::Runtime &runtime,
+    EventTarget const *eventTarget,
+    std::string const &type,
+    ReactEventPriority priority,
+    const EventPayload &eventPayload) const {
+  SystraceSection s("UIManagerBinding::dispatchEventToJS", "type", type);
+
   auto payload = eventPayload.asJSIValue(runtime);
 
   // If a payload is null, the factory has decided to cancel the event

packages/react-native/ReactCommon/react/renderer/uimanager/UIManagerBinding.h

@@ -10,6 +10,7 @@
 #include <folly/dynamic.h>
 #include <jsi/jsi.h>
 #include <react/renderer/core/RawValue.h>
+#include <react/renderer/uimanager/PointerEventsProcessor.h>
 #include <react/renderer/uimanager/UIManager.h>
 #include <react/renderer/uimanager/primitives.h>
 
@@ -71,8 +72,20 @@ class UIManagerBinding : public jsi::HostObject {
   UIManager &getUIManager();
 
  private:
+  /*
+   * Internal method that sends the event to JS. Should only be called from
+   * UIManagerBinding::dispatchEvent.
+   */
+  void dispatchEventToJS(
+      jsi::Runtime &runtime,
+      EventTarget const *eventTarget,
+      std::string const &type,
+      ReactEventPriority priority,
+      const EventPayload &payload) const;
+
   std::shared_ptr<UIManager> uiManager_;
   std::unique_ptr<EventHandler const> eventHandler_;
+  mutable PointerEventsProcessor pointerEventsProcessor_;
   mutable ReactEventPriority currentEventPriority_;
 };