From 545b084cc829dd3af10a84c3c27400201ea86be6 Mon Sep 17 00:00:00 2001
From: Luna Wei <luwe@fb.com>
Date: Fri, 14 Jun 2019 07:36:03 -0700
Subject: [PATCH] Back out "[RN] Layout Animation fix for normalized indices"

Summary:
Original commit changeset: 43e57dffa807

[Errors are growing and very ominious](https://our.intern.facebook.com/intern/logview/details/facebook_android_crashes/6acac038d7dd9d8ca95d1b9bccc4dfaa/?trace_key=39c72364f916998602bd55f091b04682)
I don't have a good idea what's going on.
This will re-introduce this bug: T44343673

Next steps:
* Would be great to try and get a repro to fix.
* Refactor this logic out to its own class and write actual tests.

Reviewed By: mdvacca

Differential Revision: D15822555

fbshipit-source-id: 0a2ec3d5c73420ca56aad93a4323a34cff1cc9c7
---
 .../uimanager/NativeViewHierarchyManager.java | 54 ++++---------------
 1 file changed, 10 insertions(+), 44 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/uimanager/NativeViewHierarchyManager.java b/ReactAndroid/src/main/java/com/facebook/react/uimanager/NativeViewHierarchyManager.java
index 070d30de2eb..f54998b3cc1 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/uimanager/NativeViewHierarchyManager.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/uimanager/NativeViewHierarchyManager.java
@@ -338,52 +338,17 @@ public class NativeViewHierarchyManager {
   }
 
   /**
-   * Given an index, normalize against pending view deletion indices in the native view hierarchy
-   * @param index the index in the view operation under the assumption all view operations are synchronous
-   * @param pendingIndicesToDelete sparse array of view tags at normalized indices
+   * Given an index to action on under synchronous deletes, return an updated index factoring in
+   * asynchronous deletes (where the async delete operations have not yet been performed)
    */
-  private int normalizeIndex(int index, SparseIntArray pendingIndicesToDelete) {
-    int normalizedIndex = -1;
-    while (index >= 0) {
-      normalizedIndex += 1;
-      if (pendingIndicesToDelete.get(normalizedIndex, -1) == -1) { // assuming we never have negative tag
-        index--;
-      }
+  private int normalizeIndex(int index, SparseIntArray pendingIndices) {
+    int normalizedIndex = index;
+    for (int i = 0; i <= index; i++) {
+      normalizedIndex += pendingIndices.get(i);
     }
     return normalizedIndex;
   }
 
-  /**
-   * Add view tag to pendingIndicesToDelete. Views in pendingIndicesToDelete are marked for deletion but have not been deleted yet
-   * @param index the index in the view to be deleted as provided by the view operation
-   * @param tag the view tag
-   * @param pendingIndicesToDelete sparse array of normalizedIndices to view tags marked for deletion
-   */
-  private void addPendingIndex(int index, int tag, SparseIntArray pendingIndicesToDelete) {
-    int normalizedIndex = normalizeIndex(index, pendingIndicesToDelete);
-    if (pendingIndicesToDelete.get(normalizedIndex) > 0) {
-      throw new IllegalViewOperationException("Invalid!!");
-    }
-    pendingIndicesToDelete.put(normalizedIndex, tag);
-  }
-
-  /**
-   * When delete is completed, remove view from pendingIndicesToDelete
-   * @param tag tag of the view to be removed
-   * @param pendingIndicesToDelete sparse array of normalizedIndices to view tags marked for deletion
-   */
-  private void removePendingIndex(int tag, SparseIntArray pendingIndicesToDelete) {
-    // indexAt refers to index within pendingIndicesToDelete sparse array, not the normalized index
-    int indexAt = pendingIndicesToDelete.indexOfValue(tag);
-    pendingIndicesToDelete.removeAt(indexAt);
-    for (indexAt = indexAt + 1; indexAt < pendingIndicesToDelete.size(); indexAt ++) {
-      int nextTag = pendingIndicesToDelete.valueAt(indexAt);
-      int nextKey = pendingIndicesToDelete.keyAt(indexAt);
-      pendingIndicesToDelete.removeAt(indexAt);
-      pendingIndicesToDelete.put(nextKey - 1, nextTag);
-    }
-  }
-
   /**
    * Given React tag, return sparse array of direct child indices that are pending deletion (due to
    * async view deletion)
@@ -506,8 +471,8 @@ public class NativeViewHierarchyManager {
 
         if (mLayoutAnimationEnabled &&
           mLayoutAnimator.shouldAnimateLayout(viewToDestroy)) {
-
-          addPendingIndex(indexToDelete, tagToDelete, pendingIndicesToDelete);
+          int updatedCount = pendingIndicesToDelete.get(indexToDelete, 0) + 1;
+          pendingIndicesToDelete.put(indexToDelete, updatedCount);
           mLayoutAnimator.deleteView(
             viewToDestroy,
             new LayoutAnimationListener() {
@@ -516,7 +481,8 @@ public class NativeViewHierarchyManager {
                 viewManager.removeView(viewToManage, viewToDestroy);
                 dropView(viewToDestroy);
 
-                removePendingIndex(viewToDestroy.getId(), pendingIndicesToDelete);
+                int count = pendingIndicesToDelete.get(indexToDelete, 0);
+                pendingIndicesToDelete.put(indexToDelete, Math.max(0, count - 1));
               }
             });
         } else {