Add Tree Configuration into UI Debugger

Summary: This diff adds a Tree Configuration into the UI Debugger for Litho components. The changes made in the code include adding a new descriptor for the ComponentTree and registering it with the DescriptorRegister. The MetadataRegister is also updated to include the Tree Configuration metadata.

Reviewed By: LukeDefeo

Differential Revision: D52206307

fbshipit-source-id: 1f2abb79d46c2361187192eb7de06795060f37a9

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

@@ -9,19 +9,37 @@ package com.facebook.flipper.plugins.uidebugger.litho.descriptors
 
 import com.facebook.flipper.plugins.uidebugger.descriptors.DescriptorRegister
 import com.facebook.flipper.plugins.uidebugger.descriptors.Id
+import com.facebook.flipper.plugins.uidebugger.descriptors.MetadataRegister
 import com.facebook.flipper.plugins.uidebugger.descriptors.NodeDescriptor
 import com.facebook.flipper.plugins.uidebugger.descriptors.OffsetChild
 import com.facebook.flipper.plugins.uidebugger.litho.LithoTag
 import com.facebook.flipper.plugins.uidebugger.model.Bounds
+import com.facebook.flipper.plugins.uidebugger.model.Inspectable
 import com.facebook.flipper.plugins.uidebugger.model.InspectableObject
+import com.facebook.flipper.plugins.uidebugger.model.InspectableValue
 import com.facebook.flipper.plugins.uidebugger.model.MetadataId
-import com.facebook.flipper.plugins.uidebugger.util.Immediate
+import com.facebook.flipper.plugins.uidebugger.util.Deferred
 import com.facebook.flipper.plugins.uidebugger.util.MaybeDeferred
 import com.facebook.litho.ComponentTree
 import com.facebook.litho.DebugComponent
+import com.facebook.litho.config.ComponentsConfiguration
+import java.lang.Exception
+import java.lang.reflect.Field
+import java.lang.reflect.Modifier
 
 class ComponentTreeDescriptor(val register: DescriptorRegister) : NodeDescriptor<ComponentTree> {
 
+  private val NAMESPACE = "ComponentTree"
+
+  private val MetadataSectionId =
+      MetadataRegister.register(MetadataRegister.TYPE_ATTRIBUTE, NAMESPACE, "Tree Metadata")
+
+  private val ConfigurationSectionId =
+      MetadataRegister.register(MetadataRegister.TYPE_ATTRIBUTE, NAMESPACE, "Tree Configuration")
+
+  private val ComponentTreeId =
+      MetadataRegister.register(MetadataRegister.TYPE_ATTRIBUTE, "treeConfiguration", "id")
+
   private val qualifiedName = ComponentTree::class.qualifiedName ?: ""
 
   override fun getId(node: ComponentTree): Id = node.id
@@ -56,8 +74,77 @@ class ComponentTreeDescriptor(val register: DescriptorRegister) : NodeDescriptor
   override fun getAttributes(
       node: ComponentTree
   ): MaybeDeferred<Map<MetadataId, InspectableObject>> {
-    return Immediate(mapOf())
+    return Deferred {
+      val attributeSections = mutableMapOf<MetadataId, InspectableObject>()
+
+      attributeSections[MetadataSectionId] =
+          InspectableObject(mapOf(ComponentTreeId to InspectableValue.Number(node.id)))
+
+      attributeSections[ConfigurationSectionId] =
+          InspectableObject(getLithoConfigurationAttributes(node))
+
+      attributeSections
+    }
+  }
+
+  private fun getLithoConfigurationAttributes(tree: ComponentTree): Map<MetadataId, Inspectable> {
+    val (configurationInstance, configurationFields) =
+        getConfigurationFieldsAndValuesUsingReflection(tree)
+
+    return configurationFields
+        .filter { !Modifier.isStatic(it.modifiers) }
+        .associate { field ->
+          val metadataId =
+              MetadataRegister.register(
+                  MetadataRegister.TYPE_ATTRIBUTE, "componentsConfiguration", field.name)
+
+          field.isAccessible = true
+
+          val inspectableValue =
+              when (val value = field.get(configurationInstance)) {
+                is Number -> InspectableValue.Number(value)
+                is Boolean -> InspectableValue.Boolean(value)
+                is String -> InspectableValue.Text(value)
+                else -> InspectableValue.Unknown(value?.toString() ?: "null")
+              }
+
+          metadataId to inspectableValue
+        }
+  }
+
+  /**
+   * This function is only being used while Litho doesn't release a new OSS version. This is needed
+   * because both the [ComponentsConfiguration] and [ComponentTree.getLithoConfiguration] have been
+   * modified since the version Flipper OSS has been associated with.
+   */
+  private fun getConfigurationFieldsAndValuesUsingReflection(
+      tree: ComponentTree
+  ): Pair<Any?, Array<Field>> {
+    try {
+      // TODO: use `getConfigurationFieldsAndValues` once Litho does a new OSS release
+      // 1. get LithoConfiguration
+      val lithoConfigurationMethod = tree.javaClass.getDeclaredMethod("getLithoConfiguration")
+      val lithoConfigurationInstance = lithoConfigurationMethod.invoke(tree)
+
+      // 2. get ComponentsConfiguration from LithoConfiguration instance
+      val configurationField =
+          lithoConfigurationInstance?.javaClass?.getDeclaredField("componentsConfig")
+      val configurationInstance = configurationField?.get(lithoConfigurationInstance)
+
+      // 3. get the fields from the configuration
+      val configurationFields = configurationInstance?.javaClass?.declaredFields ?: emptyArray()
+      return configurationInstance to configurationFields
+    } catch (exception: Exception) {
+      // Getting all exceptions since this is so britle and we don't want to crash the whole UI
+      // Debugger.
+      return null to emptyArray()
+    }
   }
 
+  // private fun getConfigurationFieldsAndValues(tree: ComponentTree): Pair<Any?, Array<Field>> {
+  //   val configuration = tree.lithoConfiguration.componentsConfig
+  //   return configuration to configuration.javaClass.declaredFields
+  // }
+
   override fun getTags(node: ComponentTree): Set<String> = setOf(LithoTag, "TreeRoot")
 }