Fabric: ValueFactory and EventEmitter::dispatchEvent based on that

Summary:
Now the event delive pipeline supports `JSI::Value`-based payload. Instead of passing `folly::dynamic`, now we are passing `std::function<jsi::Value(jsi::Runtime &runtime)>` as factory that can build a `JSI::Value` with given `jsi::Runtime` and any captured data.
The old (now legacy) way of calling `EventEmitter::dispatchEvent(..., const folly::dynamic &payload, ...)` is also supported.

Reviewed By: sahrens

Differential Revision: D13123043

fbshipit-source-id: d65348bb215013042abb2fcfe5083a8c697333d0

ReactCommon/fabric/events/BUCK

@@ -56,6 +56,7 @@ rn_xplat_cxx_library(
         "xplat//folly:memory",
         "xplat//folly:molly",
         "xplat//jsi:jsi",
+        "xplat//jsi:JSIDynamic",
         "xplat//third-party/glog:glog",
         react_native_xplat_target("fabric/debug:debug"),
     ],

ReactCommon/fabric/events/EventEmitter.cpp

@@ -8,6 +8,8 @@
 #include "EventEmitter.h"
 
 #include <folly/dynamic.h>
+#include <jsi/JSIDynamic.h>
+#include <jsi/jsi.h>
 #include <react/debug/SystraceSection.h>
 
 #include "RawEvent.h"
@@ -34,6 +36,12 @@ std::recursive_mutex &EventEmitter::DispatchMutex() {
   return mutex;
 }
 
+ValueFactory EventEmitter::defaultPayloadFactory() {
+  static auto payloadFactory =
+      ValueFactory{[](jsi::Runtime &runtime) { return jsi::Object(runtime); }};
+  return payloadFactory;
+}
+
 EventEmitter::EventEmitter(
     SharedEventTarget eventTarget,
     Tag tag,
@@ -46,6 +54,18 @@ void EventEmitter::dispatchEvent(
     const std::string &type,
     const folly::dynamic &payload,
     const EventPriority &priority) const {
+  dispatchEvent(
+      type,
+      [payload](jsi::Runtime &runtime) {
+        return valueFromDynamic(runtime, payload);
+      },
+      priority);
+}
+
+void EventEmitter::dispatchEvent(
+    const std::string &type,
+    const ValueFactory &payloadFactory,
+    const EventPriority &priority) const {
   SystraceSection s("EventEmitter::dispatchEvent");
 
   auto eventDispatcher = eventDispatcher_.lock();
@@ -54,7 +74,8 @@ void EventEmitter::dispatchEvent(
   }
 
   eventDispatcher->dispatchEvent(
-      RawEvent(normalizeEventType(type), payload, eventTarget_), priority);
+      RawEvent(normalizeEventType(type), payloadFactory, eventTarget_),
+      priority);
 }
 
 void EventEmitter::enable() const {

ReactCommon/fabric/events/EventEmitter.h

@@ -45,6 +45,8 @@ class EventEmitter {
  public:
   static std::recursive_mutex &DispatchMutex();
 
+  static ValueFactory defaultPayloadFactory();
+
   EventEmitter(
       SharedEventTarget eventTarget,
       Tag tag,
@@ -76,7 +78,13 @@ class EventEmitter {
    */
   void dispatchEvent(
       const std::string &type,
-      const folly::dynamic &payload = folly::dynamic::object(),
+      const ValueFactory &payloadFactory =
+          EventEmitter::defaultPayloadFactory(),
+      const EventPriority &priority = EventPriority::AsynchronousBatched) const;
+
+  void dispatchEvent(
+      const std::string &type,
+      const folly::dynamic &payload,
       const EventPriority &priority = EventPriority::AsynchronousBatched) const;
 
  private:

ReactCommon/fabric/events/EventQueue.cpp

@@ -44,7 +44,10 @@ void EventQueue::onBeat(jsi::Runtime &runtime) const {
 
     for (const auto &event : queue) {
       eventPipe_(
-          runtime, event.eventTarget.lock().get(), event.type, event.payload);
+          runtime,
+          event.eventTarget.lock().get(),
+          event.type,
+          event.payloadFactory);
     }
   }
 }

ReactCommon/fabric/events/RawEvent.cpp

@@ -12,10 +12,10 @@ namespace react {
 
 RawEvent::RawEvent(
     std::string type,
-    folly::dynamic payload,
+    ValueFactory payloadFactory,
     WeakEventTarget eventTarget)
     : type(std::move(type)),
-      payload(std::move(payload)),
+      payloadFactory(std::move(payloadFactory)),
       eventTarget(std::move(eventTarget)) {}
 
 } // namespace react

ReactCommon/fabric/events/RawEvent.h

@@ -9,6 +9,7 @@
 #include <memory>
 
 #include <folly/dynamic.h>
+#include <jsi/jsi.h>
 #include <react/events/primitives.h>
 
 namespace facebook {
@@ -21,11 +22,11 @@ class RawEvent {
  public:
   RawEvent(
       std::string type,
-      folly::dynamic payload,
+      ValueFactory payloadFactory,
       WeakEventTarget eventTarget);
 
   const std::string type;
-  const folly::dynamic payload;
+  const ValueFactory payloadFactory;
   const WeakEventTarget eventTarget;
 };
 

ReactCommon/fabric/events/primitives.h

@@ -47,11 +47,13 @@ struct EventTarget {};
 using SharedEventTarget = std::shared_ptr<const EventTarget>;
 using WeakEventTarget = std::weak_ptr<const EventTarget>;
 
+using ValueFactory = std::function<jsi::Value(jsi::Runtime &runtime)>;
+
 using EventPipe = std::function<void(
     jsi::Runtime &runtime,
     const EventTarget *eventTarget,
     const std::string &type,
-    const folly::dynamic &payload)>;
+    const ValueFactory &payloadFactory)>;
 
 } // namespace react
 } // namespace facebook

ReactCommon/fabric/uimanager/Scheduler.cpp

@@ -37,8 +37,8 @@ Scheduler::Scheduler(const SharedContextContainer &contextContainer)
                        jsi::Runtime &runtime,
                        const EventTarget *eventTarget,
                        const std::string &type,
-                       const folly::dynamic &payload) {
-    uiManagerBinding->dispatchEvent(runtime, eventTarget, type, payload);
+                       const ValueFactory &payloadFactory) {
+    uiManagerBinding->dispatchEvent(runtime, eventTarget, type, payloadFactory);
   };
 
   auto eventDispatcher = std::make_shared<EventDispatcher>(

ReactCommon/fabric/uimanager/UIManagerBinding.cpp

@@ -67,11 +67,11 @@ void UIManagerBinding::dispatchEvent(
     jsi::Runtime &runtime,
     const EventTarget *eventTarget,
     const std::string &type,
-    const folly::dynamic &payload) const {
+    const ValueFactory &payloadFactory) const {
   SystraceSection s("UIManagerBinding::dispatchEvent");
 
+  auto payload = payloadFactory(runtime);
   auto eventTargetValue = jsi::Value::null();
-  folly::dynamic extendedPayload;
 
   if (eventTarget) {
     auto &eventTargetWrapper =
@@ -83,10 +83,8 @@ void UIManagerBinding::dispatchEvent(
 
     // Mixing `target` into `payload`.
     assert(payload.isObject());
-    extendedPayload = folly::dynamic::object("target", eventTargetWrapper.tag);
-    extendedPayload.merge_patch(payload);
-  } else {
-    extendedPayload = payload;
+    payload.asObject(runtime).setProperty(
+        runtime, "target", eventTargetWrapper.tag);
   }
 
   auto &eventHandlerWrapper =
@@ -95,7 +93,7 @@ void UIManagerBinding::dispatchEvent(
       runtime,
       {std::move(eventTargetValue),
        jsi::String::createFromUtf8(runtime, type),
-       jsi::valueFromDynamic(runtime, extendedPayload)});
+       std::move(payload)});
 }
 
 void UIManagerBinding::invalidate() const {

ReactCommon/fabric/uimanager/UIManagerBinding.h

@@ -49,7 +49,7 @@ class UIManagerBinding : public jsi::HostObject {
       jsi::Runtime &runtime,
       const EventTarget *eventTarget,
       const std::string &type,
-      const folly::dynamic &payload) const;
+      const ValueFactory &payloadFactory) const;
 
   /*
    * Invalidates the binding and underlying UIManager.