Flatten layout during traversal

Summary: Move from a nested structure to a flatten one for data exchange, this will allow us to only send sections of the UI in the future

Reviewed By: lblasa

Differential Revision: D38982138

fbshipit-source-id: d578a07a6d2d7e117fbd741bd6e33062223ce10d

android/src/main/java/com/facebook/flipper/plugins/uidebugger/UIDebuggerFlipperPlugin.kt

@@ -8,12 +8,14 @@
 package com.facebook.flipper.plugins.uidebugger
 
 import android.app.Application
+import android.util.Log
 import com.facebook.flipper.core.FlipperConnection
 import com.facebook.flipper.core.FlipperPlugin
-import com.facebook.flipper.plugins.uidebugger.common.Node
 import com.facebook.flipper.plugins.uidebugger.core.ApplicationInspector
 import com.facebook.flipper.plugins.uidebugger.core.ApplicationRef
 import com.facebook.flipper.plugins.uidebugger.core.Context
+import com.facebook.flipper.plugins.uidebugger.model.InitEvent
+import com.facebook.flipper.plugins.uidebugger.model.NativeScanEvent
 import kotlinx.serialization.json.Json
 
 val LogTag = "FlipperUIDebugger"
@@ -32,17 +34,22 @@ class UIDebuggerFlipperPlugin(val application: Application) : FlipperPlugin {
     this.connection = connection
     // temp solution, get from descriptor
     val inspector = ApplicationInspector(context)
-    val root: Node = inspector.inspect()!!
-    val initEvent = InitEvent(System.identityHashCode(application).toString())
 
+    val rootDescriptor =
+        inspector.descriptorRegister.descriptorForClassUnsafe(context.applicationRef.javaClass)
     connection.send(
         InitEvent.name,
         Json.encodeToString(
-            InitEvent.serializer(), InitEvent(System.identityHashCode(application).toString())))
+            InitEvent.serializer(), InitEvent(rootDescriptor.getId(context.applicationRef))))
 
+    try {
+      val nodes = inspector.traversal.traverse()
       connection.send(
           NativeScanEvent.name,
-        Json.encodeToString(NativeScanEvent.serializer(), NativeScanEvent(root)))
+          Json.encodeToString(NativeScanEvent.serializer(), NativeScanEvent(nodes)))
+    } catch (e: java.lang.Exception) {
+      Log.e(LogTag, e.message.toString(), e)
+    }
   }
 
   @Throws(Exception::class)

android/src/main/java/com/facebook/flipper/plugins/uidebugger/common/Node.kt

@@ -1,16 +0,0 @@
-/*
- * 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.
- */
-
-package com.facebook.flipper.plugins.uidebugger.common
-
-@kotlinx.serialization.Serializable
-class Node() {
-  var id: String? = null
-  var name: String? = null
-  var attributes: Map<String, InspectableObject> = mapOf()
-  var children: List<Node>? = null
-}

android/src/main/java/com/facebook/flipper/plugins/uidebugger/core/ApplicationInspector.kt

@@ -9,16 +9,11 @@ package com.facebook.flipper.plugins.uidebugger.core
 
 import android.view.View
 import android.view.ViewTreeObserver
-import com.facebook.flipper.plugins.uidebugger.common.Node
 import com.facebook.flipper.plugins.uidebugger.descriptors.DescriptorRegister
 
 class ApplicationInspector(val context: Context) {
   val descriptorRegister = DescriptorRegister.withDefaults()
-  val traversal = LayoutTraversal(descriptorRegister)
+  val traversal = LayoutTraversal(descriptorRegister, context.applicationRef)
-
-  fun inspect(): Node? {
-    return traversal.inspect(context.application)
-  }
 
   fun attachListeners(view: View) {
     // An OnGlobalLayoutListener watches the entire hierarchy for layout changes
@@ -49,7 +44,6 @@ class ApplicationInspector(val context: Context) {
           }
 
           override fun onRootViewRemoved(view: View) {}
-
           override fun onRootViewsChanged(views: java.util.List<View>) {}
         })
 

android/src/main/java/com/facebook/flipper/plugins/uidebugger/core/Context.kt

@@ -7,4 +7,4 @@
 
 package com.facebook.flipper.plugins.uidebugger.core
 
-class Context(val application: ApplicationRef) {}
+class Context(val applicationRef: ApplicationRef) {}

android/src/main/java/com/facebook/flipper/plugins/uidebugger/core/LayoutTraversal.kt

@@ -7,63 +7,57 @@
 
 package com.facebook.flipper.plugins.uidebugger.core
 
+import android.util.Log
+import com.facebook.flipper.plugins.uidebugger.LogTag
 import com.facebook.flipper.plugins.uidebugger.common.InspectableObject
-import com.facebook.flipper.plugins.uidebugger.common.Node
 import com.facebook.flipper.plugins.uidebugger.descriptors.Descriptor
 import com.facebook.flipper.plugins.uidebugger.descriptors.DescriptorRegister
+import com.facebook.flipper.plugins.uidebugger.model.Node
 
-class LayoutTraversal(private val descriptorRegister: DescriptorRegister) {
+class LayoutTraversal(
-  class IntermediateNode(val node: Node) {
+    private val descriptorRegister: DescriptorRegister,
-    var children: List<Any>? = null
+    val root: ApplicationRef
-  }
+) {
 
   internal inline fun Descriptor<*>.asAny(): Descriptor<Any> = this as Descriptor<Any>
 
-  private fun describe(obj: Any): IntermediateNode {
+  /** Traverses the native android hierarchy */
-    var intermediate = IntermediateNode(Node())
+  fun traverse(): List<Node> {
 
-    val descriptor = descriptorRegister.descriptorForClass(obj::class.java)
+    val result = mutableListOf<Node>()
-    descriptor?.let { descriptor ->
+    val stack = mutableListOf<Any>()
-      val anyDescriptor = descriptor.asAny()
+    stack.add(this.root)
 
-      intermediate.node.id = anyDescriptor.getId(obj)
+    while (stack.isNotEmpty()) {
-      intermediate.node.name = anyDescriptor.getName(obj)
 
-      val attributes = mutableMapOf<String, InspectableObject>()
+      val node = stack.removeLast()
-      anyDescriptor.getData(obj, attributes)
+
-      intermediate.node.attributes = attributes
+      try {
+
+        val descriptor = descriptorRegister.descriptorForClassUnsafe(node::class.java).asAny()
 
         val children = mutableListOf<Any>()
-      anyDescriptor.getChildren(obj, children)
+        descriptor.getChildren(node, children)
-      intermediate.children = children
+
+        val childrenIds = mutableListOf<String>()
+        for (child in children) {
+          // it might make sense one day to remove id from the descriptor since its always the
+          // hash code
+          val childDescriptor =
+              descriptorRegister.descriptorForClassUnsafe(child::class.java).asAny()
+          childrenIds.add(childDescriptor.getId(child))
+          stack.add(child)
         }
 
-    return intermediate
+        val attributes = mutableMapOf<String, InspectableObject>()
-  }
+        descriptor.getData(node, attributes)
 
-  private fun traverse(entry: Any): Node? {
+        result.add(Node(descriptor.getId(node), descriptor.getName(node), attributes, childrenIds))
-    val root = describe(entry)
+      } catch (exception: Exception) {
-    root?.let { intermediate ->
+        Log.e(LogTag, "Error while processing node ${node.javaClass.name} ${node} ", exception)
-      val queue = mutableListOf<IntermediateNode>()
-      queue.add(intermediate)
-
-      while (queue.isNotEmpty()) {
-        val intermediateNode = queue.removeFirst()
-
-        val children = mutableListOf<Node>()
-        intermediateNode.children?.forEach {
-          val intermediateChild = describe(it)
-          children.add(intermediateChild.node)
-          queue.add(intermediateChild)
-        }
-        intermediateNode.node.children = children
       }
     }
 
-    return root?.node
+    return result
-  }
-
-  fun inspect(applicationRef: ApplicationRef): Node? {
-    return traverse(applicationRef)
   }
 }

android/src/main/java/com/facebook/flipper/plugins/uidebugger/descriptors/ApplicationRefDescriptor.kt

@@ -12,7 +12,7 @@ import com.facebook.flipper.plugins.uidebugger.common.InspectableObject
 import com.facebook.flipper.plugins.uidebugger.core.ApplicationRef
 import com.facebook.flipper.plugins.uidebugger.core.RootViewResolver
 
-class ApplicationDescriptor : AbstractChainedDescriptor<ApplicationRef>() {
+class ApplicationRefDescriptor : AbstractChainedDescriptor<ApplicationRef>() {
   val rootResolver = RootViewResolver()
 
   override fun onInit() {}

android/src/main/java/com/facebook/flipper/plugins/uidebugger/descriptors/DescriptorRegister.kt

@@ -13,6 +13,7 @@ import android.view.ViewGroup
 import android.view.Window
 import android.widget.Button
 import android.widget.TextView
+import com.facebook.flipper.plugins.uidebugger.common.UIDebuggerException
 import com.facebook.flipper.plugins.uidebugger.core.ApplicationRef
 
 class DescriptorRegister {
@@ -23,7 +24,7 @@ class DescriptorRegister {
     fun withDefaults(): DescriptorRegister {
       val mapping = DescriptorRegister()
       mapping.register(Any::class.java, ObjectDescriptor())
-      mapping.register(ApplicationRef::class.java, ApplicationDescriptor())
+      mapping.register(ApplicationRef::class.java, ApplicationRefDescriptor())
       mapping.register(Activity::class.java, ActivityDescriptor())
       mapping.register(Window::class.java, WindowDescriptor())
       mapping.register(ViewGroup::class.java, ViewGroupDescriptor())
@@ -57,11 +58,16 @@ class DescriptorRegister {
     register[clazz] = descriptor
   }
 
-  fun descriptorForClass(clazz: Class<*>): Descriptor<*>? {
+  fun <T> descriptorForClass(clazz: Class<T>): Descriptor<T>? {
-    var clazz = clazz
+    var clazz: Class<*> = clazz
     while (!register.containsKey(clazz)) {
       clazz = clazz.superclass
     }
-    return register[clazz]
+    return register[clazz] as Descriptor<T>
+  }
+
+  fun <T> descriptorForClassUnsafe(clazz: Class<T>): Descriptor<T> {
+    return descriptorForClass(clazz)
+        ?: throw UIDebuggerException("No descriptor found for ${clazz.name}")
   }
 }

android/src/main/java/com/facebook/flipper/plugins/uidebugger/model/Events.kt

@@ -5,21 +5,18 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-package com.facebook.flipper.plugins.uidebugger
+package com.facebook.flipper.plugins.uidebugger.model
-
-import com.facebook.flipper.plugins.uidebugger.common.Node
 
 @kotlinx.serialization.Serializable
 data class InitEvent(val rootId: String) {
   companion object {
-    val name = "init"
+    const val name = "init"
   }
 }
 
-// TODO flatten the tree into normalised list
 @kotlinx.serialization.Serializable
-data class NativeScanEvent(val root: Node) {
+data class NativeScanEvent(val nodes: List<Node>) {
   companion object {
-    val name = "nativeScan"
+    const val name = "nativeScan"
   }
 }

android/src/main/java/com/facebook/flipper/plugins/uidebugger/model/Node.kt

@@ -0,0 +1,18 @@
+/*
+ * 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.
+ */
+
+package com.facebook.flipper.plugins.uidebugger.model
+
+import com.facebook.flipper.plugins.uidebugger.common.InspectableObject
+
+@kotlinx.serialization.Serializable
+data class Node(
+    val id: String,
+    val name: String,
+    val attributes: Map<String, InspectableObject>,
+    val children: List<String>
+)

desktop/plugins/public/ui-debugger/components/main.tsx

@@ -14,43 +14,57 @@ import {Tree} from 'antd';
 import type {DataNode} from 'antd/es/tree';
 import {DownOutlined} from '@ant-design/icons';
 
-function treeToAntTree(uiNode: UINode): DataNode {
+// function treeToAntTree(uiNode: UINode): DataNode {
+//   return {
+//     key: uiNode.id,
+//     title: uiNode.name,
+//     children: uiNode.children ? uiNode.children.map(treeToAntTree) : [],
+//   };
+// }
+
+// function treeToMap(uiNode: UINode): Map<Id, UINode> {
+//   const result = new Map<Id, UINode>();
+//
+//   function treeToMapRec(node: UINode): void {
+//     result.set(node.id, node);
+//     for (const child of node.children) {
+//       treeToMapRec(child);
+//     }
+//   }
+//
+//   treeToMapRec(uiNode);
+//
+//   return result;
+// }
+
+function nodesToAntTree(root: Id, nodes: Map<Id, UINode>): DataNode {
+  function uiNodeToAntNode(id: Id): DataNode {
+    const node = nodes.get(id);
     return {
-    key: uiNode.id,
+      key: id,
-    title: uiNode.name,
+      title: node?.name,
-    children: uiNode.children ? uiNode.children.map(treeToAntTree) : [],
+      children: node?.children.map((id) => uiNodeToAntNode(id)),
     };
   }
 
-function treeToMap(uiNode: UINode): Map<Id, UINode> {
+  return uiNodeToAntNode(root);
-  const result = new Map<Id, UINode>();
-
-  function treeToMapRec(node: UINode): void {
-    result.set(node.id, node);
-    for (const child of node.children) {
-      treeToMapRec(child);
-    }
-  }
-
-  treeToMapRec(uiNode);
-
-  return result;
 }
 
 export function Component() {
   const instance = usePlugin(plugin);
   const rootId = useValue(instance.rootId);
-  const tree = useValue(instance.tree);
+  const nodes = useValue(instance.nodes);
 
-  if (tree) {
+  if (rootId) {
-    const nodeMap = treeToMap(tree);
+    const antTree = nodesToAntTree(rootId, nodes);
-    const antTree = treeToAntTree(tree);
+    console.log(antTree);
+    console.log(rootId);
     return (
       <Tree
         showIcon
         showLine
         onSelect={(selected) => {
-          console.log(nodeMap.get(selected[0] as string));
+          console.log(nodes.get(selected[0] as string));
         }}
         defaultExpandAll
         switcherIcon={<DownOutlined />}
@@ -59,5 +73,5 @@ export function Component() {
     );
   }
 
-  return <div>{rootId}</div>;
+  return <div>Nothing yet</div>;
 }

desktop/plugins/public/ui-debugger/index.tsx

@@ -43,26 +43,26 @@ export type UINode = {
   id: Id;
   name: string;
   attributes: Record<string, Inspectable>;
-  children: UINode[];
+  children: Id[];
 };
 
 type Events = {
   init: {rootId: string};
-
+  nativeScan: {nodes: UINode[]};
-  nativeScan: {root: UINode};
 };
 
 export function plugin(client: PluginClient<Events>) {
-  const rootId = createState<string | undefined>(undefined);
+  const rootId = createState<Id | undefined>(undefined);
 
-  const tree = createState<UINode | undefined>(undefined);
+  const nodesAtom = createState<Map<Id, UINode>>(new Map());
   client.onMessage('init', (root) => rootId.set(root.rootId));
 
-  client.onMessage('nativeScan', ({root}) => {
+  client.onMessage('nativeScan', ({nodes}) => {
-    tree.set(root as UINode);
+    nodesAtom.set(new Map(nodes.map((node) => [node.id, node])));
+    console.log(nodesAtom.get());
   });
 
-  return {rootId, tree};
+  return {rootId, nodes: nodesAtom};
 }
 
 export {Component} from './components/main';