Send warning when bloks tree not prepared

Summary: Give the user something actionable when tree is not ready due to flipper connected check failing

Reviewed By: lblasa

Differential Revision: D49455254

fbshipit-source-id: 8869cacde5b65260f4615f5ba2ba34f967d7d27f

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

@@ -27,6 +27,7 @@ class DescriptorRegister {
     fun withDefaults(): DescriptorRegister {
       val mapping = DescriptorRegister()
       mapping.register(Any::class.java, ObjectDescriptor)
+      mapping.register(WarningMessage::class.java, WarningMessageDescriptor)
       mapping.register(ApplicationRef::class.java, ApplicationRefDescriptor)
       mapping.register(Activity::class.java, ActivityDescriptor)
       mapping.register(Window::class.java, WindowDescriptor)

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

@@ -0,0 +1,37 @@
+/*
+ * 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.descriptors
+
+import com.facebook.flipper.plugins.uidebugger.model.Bounds
+import com.facebook.flipper.plugins.uidebugger.model.InspectableObject
+import com.facebook.flipper.plugins.uidebugger.model.MetadataId
+import com.facebook.flipper.plugins.uidebugger.util.Immediate
+import com.facebook.flipper.plugins.uidebugger.util.MaybeDeferred
+import com.facebook.flipper.plugins.uidebugger.util.objectIdentity
+
+data class WarningMessage(val message: String, val parentBounds: Bounds)
+
+object WarningMessageDescriptor : NodeDescriptor<WarningMessage> {
+  override fun getId(node: WarningMessage): Id = node.message.objectIdentity()
+
+  override fun getBounds(node: WarningMessage): Bounds = node.parentBounds.copy(x = 0, y = 0)
+
+  override fun getName(node: WarningMessage): String = node.message
+
+  override fun getQualifiedName(node: WarningMessage): String = ""
+
+  override fun getChildren(node: WarningMessage): List<Any> = listOf()
+
+  override fun getActiveChild(node: WarningMessage): Any? = null
+
+  override fun getAttributes(
+      node: WarningMessage
+  ): MaybeDeferred<Map<MetadataId, InspectableObject>> = Immediate(mapOf())
+
+  override fun getTags(node: WarningMessage): Set<String> = setOf("Warning")
+}

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

@@ -16,6 +16,8 @@ data class Bounds(val x: Int, val y: Int, val width: Int, val height: Int) {
     fun fromRect(rect: Rect): Bounds {
       return Bounds(rect.left, rect.top, rect.width(), rect.height())
     }
+
+    fun zero() = Bounds(0, 0, 0, 0)
   }
 }