Fabric: Support of updating EventHandlers on mounting layer

Summary:
Pretty trivial; new type of mount item & new method in the component protocol.
The default implementation in `UIView+ComponentViewProtocol` does nothing.

Reviewed By: fkgozali

Differential Revision: D8053355

fbshipit-source-id: a0418edf17ca75c4b94942b04acd93f3ea5d27e0

React/Fabric/Mounting/MountItems/RCTUpdateEventHandlersMountItem.h

@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <UIKit/UIKit.h>
+
+#import <React/RCTMountItemProtocol.h>
+#import <React/RCTPrimitives.h>
+#import <fabric/core/EventHandlers.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * Updates event handlers of a component view.
+ */
+@interface RCTUpdateEventHandlersMountItem : NSObject <RCTMountItemProtocol>
+
+- (instancetype)initWithTag:(ReactTag)tag
+              eventHandlers:(facebook::react::SharedEventHandlers)eventHandlers;
+
+@end
+
+NS_ASSUME_NONNULL_END

React/Fabric/Mounting/MountItems/RCTUpdateEventHandlersMountItem.mm

@@ -0,0 +1,37 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import "RCTUpdateEventHandlersMountItem.h"
+
+#import "RCTComponentViewRegistry.h"
+
+using namespace facebook::react;
+
+@implementation RCTUpdateEventHandlersMountItem {
+  ReactTag _tag;
+  SharedEventHandlers _eventHandlers;
+}
+
+- (instancetype)initWithTag:(ReactTag)tag
+              eventHandlers:(SharedEventHandlers)eventHandlers
+{
+  if (self = [super init]) {
+    _tag = tag;
+    _eventHandlers = eventHandlers;
+  }
+
+  return self;
+}
+
+- (void)executeWithRegistry:(RCTComponentViewRegistry *)registry
+{
+  UIView<RCTComponentViewProtocol> *componentView = [registry componentViewByTag:_tag];
+
+  [componentView updateEventHandlers:_eventHandlers];
+}
+
+@end

React/Fabric/Mounting/RCTComponentViewProtocol.h

@@ -7,6 +7,7 @@
 
 #import <UIKit/UIKit.h>
 
+#import <fabric/core/EventHandlers.h>
 #import <fabric/core/LocalData.h>
 #import <fabric/core/Props.h>
 #import <fabric/core/LayoutMetrics.h>
@@ -52,6 +53,12 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)updateLocalData:(facebook::react::SharedLocalData)localData
            oldLocalData:(facebook::react::SharedLocalData)oldLocalData;
 
+/*
+ * Called for updating component's event handlers set.
+ * Receiver must cache `eventHandlers` object inside and use it for emitting
+ * events when needed.
+ */
+- (void)updateEventHandlers:(facebook::react::SharedEventHandlers)eventHandlers;
 
 /*
  * Called for updating component's layout metrics.

React/Fabric/Mounting/RCTMountingManager.mm

@@ -20,6 +20,7 @@
 #import "RCTInsertMountItem.h"
 #import "RCTRemoveMountItem.h"
 #import "RCTUpdatePropsMountItem.h"
+#import "RCTUpdateEventHandlersMountItem.h"
 #import "RCTUpdateLocalDataMountItem.h"
 #import "RCTUpdateLayoutMetricsMountItem.h"
 
@@ -53,6 +54,7 @@ using namespace facebook::react;
         [mountItems addObject:mountItem];
         break;
       }
+
       case TreeMutationInstruction::Deletion: {
         NSString *componentName = [NSString stringWithCString:instruction.getOldChildNode()->getComponentName().c_str()
                                                      encoding:NSASCIIStringEncoding];
@@ -64,17 +66,15 @@ using namespace facebook::react;
       }
 
       case TreeMutationInstruction::Insertion: {
-        RCTInsertMountItem *mountItem =
-          [[RCTInsertMountItem alloc] initWithChildTag:instruction.getNewChildNode()->getTag()
-                                             parentTag:instruction.getParentNode()->getTag()
-                                                 index:instruction.getIndex()];
-        [mountItems addObject:mountItem];
-
         // Props
         [mountItems addObject:[[RCTUpdatePropsMountItem alloc] initWithTag:instruction.getNewChildNode()->getTag()
                                                                   oldProps:nullptr
                                                                   newProps:instruction.getNewChildNode()->getProps()]];
 
+        // EventHandlers
+        [mountItems addObject:[[RCTUpdateEventHandlersMountItem alloc] initWithTag:instruction.getNewChildNode()->getTag()
+                                                                     eventHandlers:instruction.getNewChildNode()->getEventHandlers()]];
+
         // LocalData
         if (instruction.getNewChildNode()->getLocalData()) {
           [mountItems addObject:[[RCTUpdateLocalDataMountItem alloc] initWithTag:instruction.getNewChildNode()->getTag()
@@ -91,6 +91,14 @@ using namespace facebook::react;
                                                                     oldLayoutMetrics:{}
                                                                     newLayoutMetrics:layoutableNewShadowNode->getLayoutMetrics()]];
         }
+
+        // Insertion
+        RCTInsertMountItem *mountItem =
+        [[RCTInsertMountItem alloc] initWithChildTag:instruction.getNewChildNode()->getTag()
+                                           parentTag:instruction.getParentNode()->getTag()
+                                               index:instruction.getIndex()];
+        [mountItems addObject:mountItem];
+
         break;
       }
 
@@ -116,6 +124,14 @@ using namespace facebook::react;
           [mountItems addObject:mountItem];
         }
 
+        // EventHandlers
+        if (oldShadowNode->getEventHandlers() != newShadowNode->getEventHandlers()) {
+          RCTUpdateEventHandlersMountItem *mountItem =
+            [[RCTUpdateEventHandlersMountItem alloc] initWithTag:instruction.getOldChildNode()->getTag()
+                                                   eventHandlers:instruction.getOldChildNode()->getEventHandlers()];
+          [mountItems addObject:mountItem];
+        }
+
         // LocalData
         if (oldShadowNode->getLocalData() != newShadowNode->getLocalData()) {
           RCTUpdateLocalDataMountItem *mountItem =

React/Fabric/Mounting/UIView+ComponentViewProtocol.h

@@ -9,6 +9,7 @@
 
 #import <React/RCTComponentViewProtocol.h>
 
+
 NS_ASSUME_NONNULL_BEGIN
 
 /**
@@ -25,6 +26,8 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)updateProps:(facebook::react::SharedProps)props
            oldProps:(facebook::react::SharedProps)oldProps;
 
+- (void)updateEventHandlers:(facebook::react::SharedEventHandlers)eventHandlers;
+
 - (void)updateLocalData:(facebook::react::SharedLocalData)localData
            oldLocalData:(facebook::react::SharedLocalData)oldLocalData;
 

React/Fabric/Mounting/UIView+ComponentViewProtocol.mm

@@ -31,6 +31,11 @@
   // Default implementation does nothing.
 }
 
+- (void)updateEventHandlers:(facebook::react::SharedEventHandlers)eventHandlers
+{
+  // Default implementation does nothing.
+}
+
 - (void)updateLocalData:(facebook::react::SharedLocalData)localData
            oldLocalData:(facebook::react::SharedLocalData)oldLocalData
 {