Introduce "Sealing" of ReactShadowNodes

Summary: This diff introduces the concept of "Seal" ReactShadowNodes. This new field will be used to guarantee immutability of commited ReactShodow Nodes.

Reviewed By: fkgozali

Differential Revision: D8552709

fbshipit-source-id: dfd95730f10341af0dd762f8a8aa186563cf33e9

ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java

@@ -10,7 +10,6 @@ package com.facebook.react.fabric;
 import static android.view.View.MeasureSpec.AT_MOST;
 import static android.view.View.MeasureSpec.EXACTLY;
 import static android.view.View.MeasureSpec.UNSPECIFIED;
-import static com.facebook.react.uimanager.common.UIManagerType.DEFAULT;
 import static com.facebook.react.uimanager.common.UIManagerType.FABRIC;
 
 import android.os.SystemClock;
@@ -22,7 +21,6 @@ import com.facebook.infer.annotation.Assertions;
 import com.facebook.proguard.annotations.DoNotStrip;
 import com.facebook.react.bridge.JavaScriptContextHolder;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.ReadableNativeMap;
@@ -41,13 +39,11 @@ import com.facebook.react.uimanager.ReactShadowNode;
 import com.facebook.react.uimanager.ReactShadowNodeImpl;
 import com.facebook.react.uimanager.ReactStylesDiffMap;
 import com.facebook.react.uimanager.ThemedReactContext;
-import com.facebook.react.uimanager.UIManagerHelper;
 import com.facebook.react.uimanager.UIViewOperationQueue;
 import com.facebook.react.uimanager.ViewManager;
 import com.facebook.react.uimanager.ViewManagerRegistry;
 import com.facebook.react.uimanager.common.MeasureSpecProvider;
 import com.facebook.react.uimanager.common.SizeMonitoringFrameLayout;
-import com.facebook.react.uimanager.common.ViewUtil;
 import com.facebook.react.uimanager.events.EventDispatcher;
 import com.facebook.systrace.Systrace;
 import com.facebook.systrace.SystraceMessage;
@@ -295,10 +291,10 @@ public class FabricUIManager implements UIManager, JSHandler {
       "FabricUIManager.appendChild")
       .flush();
     try {
-      // If the child to append is shared with another tree (child.getParent() != null),
+      // If the child to append was already committed (child.isSealed()),
       // then we add a mutation of it. In the future this will be performed by FabricJS / Fiber.
       //TODO: T27926878 avoid cloning shared child
-      if (child.getParent() != null) {
+      if (child.isSealed()) {
         child = child.mutableCopy(child.getInstanceHandle());
       }
       parent.addChildAt(child, parent.getChildCount());
@@ -474,6 +470,7 @@ public class FabricUIManager implements UIManager, JSHandler {
     // and we do not need to hold references to the previous tree anymore
     node.setOriginalReactShadowNode(null);
     node.markUpdateSeen();
+    node.markAsSealed();
   }
 
   @Override

ReactAndroid/src/main/java/com/facebook/react/uimanager/ReactShadowNode.java

@@ -377,4 +377,16 @@ public interface ReactShadowNode<T extends ReactShadowNode> {
   long getInstanceHandle();
 
   void setInstanceHandle(long instanceHandle);
+
+  /**
+   * Mark this {@link ReactShadowNode} as sealed. This means that the node was already committed
+   * and it should not be updated anymore.
+   */
+  void markAsSealed();
+
+  /**
+   * @return a {@link boolean} that represents if the {@link ReactShadowNode} is sealed.
+   */
+  boolean isSealed();
+
 }

ReactAndroid/src/main/java/com/facebook/react/uimanager/ReactShadowNodeImpl.java

@@ -128,6 +128,7 @@ public class ReactShadowNodeImpl implements ReactShadowNode<ReactShadowNodeImpl>
 
   private @Nullable ReactStylesDiffMap mNewProps;
   private long mInstanceHandle;
+  private boolean mIsSealed = false;
 
   public ReactShadowNodeImpl() {
     mDefaultPadding = new Spacing(0);
@@ -164,6 +165,7 @@ public class ReactShadowNodeImpl implements ReactShadowNode<ReactShadowNodeImpl>
     mNewProps = null;
     mParent = null;
     mOriginalReactShadowNode = original;
+    mIsSealed = false;
   }
 
   private void replaceChild(ReactShadowNodeImpl newNode, int childIndex) {
@@ -1147,4 +1149,14 @@ public class ReactShadowNodeImpl implements ReactShadowNode<ReactShadowNodeImpl>
   public void setInstanceHandle(long instanceHandle) {
     mInstanceHandle = instanceHandle;
   }
+
+  @Override
+  public void markAsSealed() {
+    mIsSealed = true;
+  }
+
+  @Override
+  public boolean isSealed() {
+    return mIsSealed;
+  }
 }

ReactAndroid/src/test/java/com/facebook/react/fabric/FabricUIManagerTest.java

@@ -233,6 +233,24 @@ public class FabricUIManagerTest {
     mFabricUIManager.completeRoot(rootTag, children);
   }
 
+  @Test
+  public void testSealReactShadowNode() {
+    ReactRootView rootView =
+      new ReactRootView(RuntimeEnvironment.application.getApplicationContext());
+    int rootTag = mFabricUIManager.addRootView(rootView);
+    String viewClass = ReactViewManager.REACT_CLASS;
+
+    ReactShadowNode container = mFabricUIManager.createNode(6, viewClass, rootTag, null, randomInstanceHandle());
+    List<ReactShadowNode> childSet = mFabricUIManager.createChildSet(rootTag);
+    mFabricUIManager.appendChildToSet(childSet, container);
+
+    assertThat(container.isSealed()).isFalse();
+
+    mFabricUIManager.completeRoot(rootTag, childSet);
+
+    assertThat(container.isSealed()).isTrue();
+  }
+
   /**
    * Tests that cloned text nodes will not share measure functions
    */