From f996f90cf4feac614503c0809d1a6d711be2c1aa Mon Sep 17 00:00:00 2001
From: Luke De Feo <lukedefeo@meta.com>
Date: Wed, 25 Jan 2023 04:47:11 -0800
Subject: [PATCH] Fix Interactions with TreeObserver Manager moved to main
 thread

Reviewed By: lblasa

Differential Revision: D42608384

fbshipit-source-id: 20c074eeac1372405f44edc8eb8ab41cb7dd2be9
---
 .../plugins/uidebugger/UIDebuggerFlipperPlugin.kt    | 12 +++---------
 .../uidebugger/observers/TreeObserverManager.kt      |  5 +++++
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/android/src/main/java/com/facebook/flipper/plugins/uidebugger/UIDebuggerFlipperPlugin.kt b/android/src/main/java/com/facebook/flipper/plugins/uidebugger/UIDebuggerFlipperPlugin.kt
index d5a4c3909..b5a5a1d66 100644
--- a/android/src/main/java/com/facebook/flipper/plugins/uidebugger/UIDebuggerFlipperPlugin.kt
+++ b/android/src/main/java/com/facebook/flipper/plugins/uidebugger/UIDebuggerFlipperPlugin.kt
@@ -18,9 +18,6 @@ import com.facebook.flipper.plugins.uidebugger.descriptors.MetadataRegister
 import com.facebook.flipper.plugins.uidebugger.model.InitEvent
 import com.facebook.flipper.plugins.uidebugger.model.MetadataUpdateEvent
 import com.facebook.flipper.plugins.uidebugger.observers.TreeObserverFactory
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.launch
 import kotlinx.serialization.json.Json
 
 const val LogTag = "ui-debugger"
@@ -31,7 +28,6 @@ class UIDebuggerFlipperPlugin(
     observerFactory: TreeObserverFactory?
 ) : FlipperPlugin {
 
-  val mainScope = CoroutineScope(Dispatchers.Main)
   private val context: Context =
       Context(
           ApplicationRef(application),
@@ -65,7 +61,7 @@ class UIDebuggerFlipperPlugin(
             MetadataUpdateEvent.serializer(),
             MetadataUpdateEvent(MetadataRegister.extractPendingMetadata())))
 
-    mainScope.launch { context.treeObserverManager.start() }
+    context.treeObserverManager.start()
   }
 
   @Throws(Exception::class)
@@ -75,10 +71,8 @@ class UIDebuggerFlipperPlugin(
 
     MetadataRegister.reset()
 
-    mainScope.launch {
-      context.treeObserverManager.stop()
-      context.bitmapPool.recycleAll()
-    }
+    context.treeObserverManager.stop()
+    context.bitmapPool.recycleAll()
   }
 
   override fun runInBackground(): Boolean {
diff --git a/android/src/main/java/com/facebook/flipper/plugins/uidebugger/observers/TreeObserverManager.kt b/android/src/main/java/com/facebook/flipper/plugins/uidebugger/observers/TreeObserverManager.kt
index bf8048755..2e3649ab4 100644
--- a/android/src/main/java/com/facebook/flipper/plugins/uidebugger/observers/TreeObserverManager.kt
+++ b/android/src/main/java/com/facebook/flipper/plugins/uidebugger/observers/TreeObserverManager.kt
@@ -9,6 +9,7 @@ package com.facebook.flipper.plugins.uidebugger.observers
 
 import android.annotation.SuppressLint
 import android.graphics.Bitmap
+import android.os.Looper
 import android.util.Base64
 import android.util.Base64OutputStream
 import android.util.Log
@@ -51,6 +52,7 @@ class TreeObserverManager(val context: Context) {
 
   private var job: Job? = null
   private val workerScope = CoroutineScope(Dispatchers.IO)
+  private val mainScope = CoroutineScope(Dispatchers.Main)
   private val txId = AtomicInteger()
 
   fun enqueueUpdate(update: SubtreeUpdate) {
@@ -68,6 +70,9 @@ class TreeObserverManager(val context: Context) {
   @SuppressLint("NewApi")
   fun start() {
 
+    if (Looper.myLooper() != Looper.getMainLooper()) {
+      mainScope.launch { start() }
+    }
     batchedUpdates = Channel(Channel.UNLIMITED)
     rootObserver.subscribe(context.applicationRef)