Fabric: ShadowNodeFamily, the first steps

Summary:
ShadowNodeFamily is a new concept that allows us to implement an efficient way to solve the problem of finding a path to some ancestor node (practically reimplement ShadowNode::constructAncestorPath() in some efficient way).

This diff is the first one in the series. It introduces a new class and moves some data into it.

Reviewed By: JoshuaGross

Differential Revision: D14416947

fbshipit-source-id: c93865a8929a2128498e34d3589487696aac6283

ReactCommon/fabric/core/shadownode/ShadowNode.cpp

@@ -23,20 +23,25 @@ SharedShadowNodeSharedList ShadowNode::emptySharedShadowNodeSharedList() {
   return emptySharedShadowNodeSharedList;
 }
 
+bool ShadowNode::sameFamily(const ShadowNode &first, const ShadowNode &second) {
+  return first.family_ == second.family_;
+}
+
 #pragma mark - Constructors
 
 ShadowNode::ShadowNode(
     const ShadowNodeFragment &fragment,
     const ComponentDescriptor &componentDescriptor)
-    : tag_(fragment.tag),
-      rootTag_(fragment.rootTag),
-      props_(fragment.props),
-      eventEmitter_(fragment.eventEmitter),
+    : props_(fragment.props),
       children_(
           fragment.children ? fragment.children
                             : emptySharedShadowNodeSharedList()),
       state_(fragment.state),
-      componentDescriptor_(componentDescriptor),
+      family_(std::make_shared<ShadowNodeFamily const>(
+          fragment.tag,
+          fragment.rootTag,
+          fragment.eventEmitter,
+          componentDescriptor)),
       childrenAreShared_(true),
       revision_(1) {
   assert(props_);
@@ -46,10 +51,7 @@ ShadowNode::ShadowNode(
 ShadowNode::ShadowNode(
     const ShadowNode &sourceShadowNode,
     const ShadowNodeFragment &fragment)
-    : tag_(sourceShadowNode.tag_),
-      rootTag_(sourceShadowNode.rootTag_),
-      props_(fragment.props ? fragment.props : sourceShadowNode.props_),
-      eventEmitter_(fragment.eventEmitter),
+    : props_(fragment.props ? fragment.props : sourceShadowNode.props_),
       children_(
           fragment.children ? fragment.children : sourceShadowNode.children_),
       localData_(
@@ -58,7 +60,7 @@ ShadowNode::ShadowNode(
       state_(
           fragment.state ? fragment.state
                          : sourceShadowNode.getCommitedState()),
-      componentDescriptor_(sourceShadowNode.componentDescriptor_),
+      family_(sourceShadowNode.family_),
       childrenAreShared_(true),
       revision_(sourceShadowNode.revision_ + 1) {
   // `tag`, `surfaceId`, and `eventEmitter` cannot be changed with cloning.
@@ -72,7 +74,7 @@ ShadowNode::ShadowNode(
 }
 
 UnsharedShadowNode ShadowNode::clone(const ShadowNodeFragment &fragment) const {
-  return componentDescriptor_.cloneShadowNode(*this, fragment);
+  return family_->componentDescriptor_.cloneShadowNode(*this, fragment);
 }
 
 #pragma mark - Getters
@@ -81,24 +83,24 @@ const SharedShadowNodeList &ShadowNode::getChildren() const {
   return *children_;
 }
 
-SharedProps ShadowNode::getProps() const {
+const SharedProps &ShadowNode::getProps() const {
   return props_;
 }
 
-SharedEventEmitter ShadowNode::getEventEmitter() const {
-  return eventEmitter_;
+const SharedEventEmitter &ShadowNode::getEventEmitter() const {
+  return family_->eventEmitter_;
 }
 
 Tag ShadowNode::getTag() const {
-  return tag_;
+  return family_->tag_;
 }
 
-Tag ShadowNode::getRootTag() const {
-  return rootTag_;
+SurfaceId ShadowNode::getSurfaceId() const {
+  return family_->surfaceId_;
 }
 
 const ComponentDescriptor &ShadowNode::getComponentDescriptor() const {
-  return componentDescriptor_;
+  return family_->componentDescriptor_;
 }
 
 const State::Shared &ShadowNode::getState() const {
@@ -175,7 +177,7 @@ void ShadowNode::cloneChildrenIfShared() {
 }
 
 void ShadowNode::setMounted(bool mounted) const {
-  eventEmitter_->setEnabled(mounted);
+  family_->eventEmitter_->setEnabled(mounted);
   if (mounted && state_) {
     state_->commit(*this);
   }
@@ -229,7 +231,7 @@ SharedDebugStringConvertibleList ShadowNode::getDebugChildren() const {
 SharedDebugStringConvertibleList ShadowNode::getDebugProps() const {
   return props_->getDebugProps() +
       SharedDebugStringConvertibleList{
-          debugStringConvertibleItem("tag", folly::to<std::string>(tag_))};
+          debugStringConvertibleItem("tag", folly::to<std::string>(getTag()))};
 }
 #endif
 

ReactCommon/fabric/core/shadownode/ShadowNode.h

@@ -17,6 +17,7 @@
 #include <react/core/Props.h>
 #include <react/core/ReactPrimitives.h>
 #include <react/core/Sealable.h>
+#include <react/core/ShadowNodeFamily.h>
 #include <react/core/State.h>
 #include <react/debug/DebugStringConvertible.h>
 
@@ -47,6 +48,12 @@ class ShadowNode : public virtual Sealable,
 
   static SharedShadowNodeSharedList emptySharedShadowNodeSharedList();
 
+  /*
+   * Returns `true` if nodes belong to the same family (they were cloned one
+   * from each other or from the same source node).
+   */
+  static bool sameFamily(const ShadowNode &first, const ShadowNode &second);
+
 #pragma mark - Constructors
 
   /*
@@ -77,11 +84,11 @@ class ShadowNode : public virtual Sealable,
   virtual ComponentHandle getComponentHandle() const = 0;
   virtual ComponentName getComponentName() const = 0;
 
-  const SharedShadowNodeList &getChildren() const;
-  SharedProps getProps() const;
-  SharedEventEmitter getEventEmitter() const;
+  SharedProps const &getProps() const;
+  SharedShadowNodeList const &getChildren() const;
+  SharedEventEmitter const &getEventEmitter() const;
   Tag getTag() const;
-  Tag getRootTag() const;
+  SurfaceId getSurfaceId() const;
 
   /*
    * Returns a concrete `ComponentDescriptor` that manages nodes of this type.
@@ -155,10 +162,7 @@ class ShadowNode : public virtual Sealable,
 #endif
 
  protected:
-  Tag tag_;
-  Tag rootTag_;
   SharedProps props_;
-  SharedEventEmitter eventEmitter_;
   SharedShadowNodeSharedList children_;
   SharedLocalData localData_;
   State::Shared state_;
@@ -171,10 +175,9 @@ class ShadowNode : public virtual Sealable,
   void cloneChildrenIfShared();
 
   /*
-   * A reference to a concrete `ComponentDescriptor` that manages nodes of this
-   * type.
+   * Pointer to a family object that this shadow node belongs to.
    */
-  const ComponentDescriptor &componentDescriptor_;
+  ShadowNodeFamily::Shared family_;
 
   /*
    * Indicates that `children` list is shared between nodes and need

ReactCommon/fabric/core/shadownode/ShadowNodeFamily.cpp

@@ -0,0 +1,24 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "ShadowNodeFamily.h"
+
+namespace facebook {
+namespace react {
+
+ShadowNodeFamily::ShadowNodeFamily(
+    Tag tag,
+    SurfaceId surfaceId,
+    SharedEventEmitter const &eventEmitter,
+    ComponentDescriptor const &componentDescriptor)
+    : tag_(tag),
+      surfaceId_(surfaceId),
+      eventEmitter_(eventEmitter),
+      componentDescriptor_(componentDescriptor) {}
+
+} // namespace react
+} // namespace facebook

ReactCommon/fabric/core/shadownode/ShadowNodeFamily.h

@@ -0,0 +1,61 @@
+/**
+ * Copyright (c) Facebook, Inc. and its 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 <memory>
+
+#include <react/core/EventEmitter.h>
+#include <react/core/ReactPrimitives.h>
+
+namespace facebook {
+namespace react {
+
+class ComponentDescriptor;
+
+/*
+ * Represents all things that shadow nodes from the same family have in common.
+ * To be used inside `ShadowNode` class *only*.
+ */
+class ShadowNodeFamily {
+ public:
+  using Shared = std::shared_ptr<ShadowNodeFamily const>;
+  using Weak = std::weak_ptr<ShadowNodeFamily const>;
+
+  ShadowNodeFamily(
+      Tag tag,
+      SurfaceId surfaceId,
+      SharedEventEmitter const &eventEmitter,
+      ComponentDescriptor const &componentDescriptor);
+
+ private:
+  friend ShadowNode;
+
+  /*
+   * Deprecated.
+   */
+  Tag const tag_;
+
+  /*
+   * Identifier of a running Surface instance.
+   */
+  SurfaceId const surfaceId_;
+
+  /*
+   * `EventEmitter` associated with all nodes of the family.
+   */
+  SharedEventEmitter const eventEmitter_;
+
+  /*
+   * Reference to a concrete `ComponentDescriptor` that manages nodes of this
+   * type.
+   */
+  ComponentDescriptor const &componentDescriptor_;
+};
+
+} // namespace react
+} // namespace facebook

ReactCommon/fabric/core/tests/ComponentDescriptorTest.cpp

@@ -34,7 +34,7 @@ TEST(ComponentDescriptorTest, createShadowNode) {
       node->getComponentName().c_str(), TestShadowNode::Name().c_str());
   ASSERT_STREQ(node->getComponentName().c_str(), "Test");
   ASSERT_EQ(node->getTag(), 9);
-  ASSERT_EQ(node->getRootTag(), 1);
+  ASSERT_EQ(node->getSurfaceId(), 1);
   ASSERT_STREQ(node->getProps()->nativeId.c_str(), "abc");
 }
 
@@ -54,7 +54,7 @@ TEST(ComponentDescriptorTest, cloneShadowNode) {
 
   ASSERT_STREQ(cloned->getComponentName().c_str(), "Test");
   ASSERT_EQ(cloned->getTag(), 9);
-  ASSERT_EQ(cloned->getRootTag(), 1);
+  ASSERT_EQ(cloned->getSurfaceId(), 1);
   ASSERT_STREQ(cloned->getProps()->nativeId.c_str(), "abc");
 }
 

ReactCommon/fabric/core/tests/ShadowNodeTest.cpp

@@ -41,7 +41,7 @@ TEST(ShadowNodeTest, handleShadowNodeCreation) {
   ASSERT_FALSE(node->getSealed());
   ASSERT_STREQ(node->getComponentName().c_str(), "Test");
   ASSERT_EQ(node->getTag(), 9);
-  ASSERT_EQ(node->getRootTag(), 1);
+  ASSERT_EQ(node->getSurfaceId(), 1);
   ASSERT_EQ(node->getEventEmitter(), nullptr);
   ASSERT_EQ(node->getChildren().size(), 0);
 
@@ -67,7 +67,7 @@ TEST(ShadowNodeTest, handleShadowNodeSimpleCloning) {
 
   ASSERT_STREQ(node->getComponentName().c_str(), "Test");
   ASSERT_EQ(node->getTag(), 9);
-  ASSERT_EQ(node->getRootTag(), 1);
+  ASSERT_EQ(node->getSurfaceId(), 1);
   ASSERT_EQ(node->getEventEmitter(), nullptr);
 }
 
@@ -154,7 +154,7 @@ TEST(ShadowNodeTest, handleCloneFunction) {
 
   // Both nodes have same content.
   ASSERT_EQ(firstNode->getTag(), firstNodeClone->getTag());
-  ASSERT_EQ(firstNode->getRootTag(), firstNodeClone->getRootTag());
+  ASSERT_EQ(firstNode->getSurfaceId(), firstNodeClone->getSurfaceId());
   ASSERT_EQ(firstNode->getProps(), firstNodeClone->getProps());
 }
 

ReactCommon/fabric/mounting/Differentiator.cpp

@@ -218,8 +218,8 @@ ShadowViewMutationList calculateShadowViewMutations(
     const ShadowNode &newRootShadowNode) {
   SystraceSection s("calculateShadowViewMutations");
 
-  // Root shadow nodes must have same tag.
-  assert(oldRootShadowNode.getTag() == newRootShadowNode.getTag());
+  // Root shadow nodes must be belong the same family.
+  assert(ShadowNode::sameFamily(oldRootShadowNode, newRootShadowNode));
 
   ShadowViewMutationList mutations;
 

ReactCommon/fabric/uimanager/Scheduler.cpp

@@ -281,7 +281,7 @@ void Scheduler::uiManagerDidCreateShadowNode(
   if (delegate_) {
     auto shadowView = ShadowView(*shadowNode);
     delegate_->schedulerDidRequestPreliminaryViewAllocation(
-        shadowNode->getRootTag(), shadowView);
+        shadowNode->getSurfaceId(), shadowView);
   }
 }
 

ReactCommon/fabric/uimanager/UIManager.cpp

@@ -98,7 +98,7 @@ void UIManager::setNativeProps(
   });
 
   shadowTreeRegistry_->visit(
-      shadowNode->getRootTag(), [&](const ShadowTree &shadowTree) {
+      shadowNode->getSurfaceId(), [&](const ShadowTree &shadowTree) {
         shadowTree.tryCommit(
             [&](const SharedRootShadowNode &oldRootShadowNode) {
               return oldRootShadowNode->clone(shadowNode, newShadowNode);
@@ -116,7 +116,7 @@ LayoutMetrics UIManager::getRelativeLayoutMetrics(
 
   if (!ancestorShadowNode) {
     shadowTreeRegistry_->visit(
-        shadowNode.getRootTag(), [&](const ShadowTree &shadowTree) {
+        shadowNode.getSurfaceId(), [&](const ShadowTree &shadowTree) {
           shadowTree.tryCommit(
               [&](const SharedRootShadowNode &oldRootShadowNode) {
                 ancestorShadowNode = oldRootShadowNode.get();
@@ -158,7 +158,7 @@ void UIManager::updateState(
   });
 
   shadowTreeRegistry_->visit(
-      shadowNode->getRootTag(), [&](const ShadowTree &shadowTree) {
+      shadowNode->getSurfaceId(), [&](const ShadowTree &shadowTree) {
         shadowTree.tryCommit(
             [&](const SharedRootShadowNode &oldRootShadowNode) {
               return oldRootShadowNode->clone(shadowNode, newShadowNode);