From 2e6efdefa6a995759941209b4254cdcfbd4bc6d5 Mon Sep 17 00:00:00 2001
From: Qasid Ahmad Sadiq <qasid@google.com>
Date: Thu, 6 Jun 2019 19:53:23 -0700
Subject: [PATCH] AccessibilityNodeIdManager should hold onto weak references
 of Views.

... as opposed to strong references.
In case the calls between register and unregister aren't matched, we don't want to be leaking views.
I haven't seen any real eveidence of there being leaks, just a report. But this is preventative.

Created a "WeakSparseArray", which wraps SparseArray, and passes in a kind of WeakReference that has an id.
The references become unreachable, we use the id to remove the the entry from the SparseArray.

Test: Used the device for a bit with talkback on. CTSAccessibility*
Change-Id: I8d11727428f56fc06007232ae341d1409a11991f
Fix: 134506015
---
 .../AccessibilityNodeIdManager.java           |  3 +-
 .../view/accessibility/WeakSparseArray.java   | 63 +++++++++++++++++++
 2 files changed, 64 insertions(+), 2 deletions(-)
 create mode 100644 core/java/android/view/accessibility/WeakSparseArray.java

diff --git a/core/java/android/view/accessibility/AccessibilityNodeIdManager.java b/core/java/android/view/accessibility/AccessibilityNodeIdManager.java
index 0f5e950582dd7..d78dadd294caf 100644
--- a/core/java/android/view/accessibility/AccessibilityNodeIdManager.java
+++ b/core/java/android/view/accessibility/AccessibilityNodeIdManager.java
@@ -16,12 +16,11 @@
 
 package android.view.accessibility;
 
-import android.util.SparseArray;
 import android.view.View;
 
 /** @hide */
 public final class AccessibilityNodeIdManager {
-    private SparseArray<View> mIdsToViews = new SparseArray<>();
+    private WeakSparseArray<View> mIdsToViews = new WeakSparseArray<View>();
     private static AccessibilityNodeIdManager sIdManager;
 
     /**
diff --git a/core/java/android/view/accessibility/WeakSparseArray.java b/core/java/android/view/accessibility/WeakSparseArray.java
new file mode 100644
index 0000000000000..04a4cc7f062b2
--- /dev/null
+++ b/core/java/android/view/accessibility/WeakSparseArray.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.view.accessibility;
+
+import android.util.SparseArray;
+
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.WeakReference;
+
+
+final class WeakSparseArray<E> {
+
+    private final ReferenceQueue<E> mRefQueue = new ReferenceQueue<>();
+    private final SparseArray<WeakReferenceWithId<E>> mSparseArray = new SparseArray<>();
+
+    public void append(int key, E value) {
+        removeUnreachableValues();
+        mSparseArray.append(key, new WeakReferenceWithId(value, mRefQueue, key));
+    }
+
+    public void remove(int key) {
+        removeUnreachableValues();
+        mSparseArray.remove(key);
+    }
+
+    public E get(int key) {
+        removeUnreachableValues();
+        WeakReferenceWithId<E> ref = mSparseArray.get(key);
+        return ref != null ? ref.get() : null;
+    }
+
+    private void removeUnreachableValues() {
+        for (Reference ref = mRefQueue.poll(); ref != null; ref = mRefQueue.poll()) {
+            mSparseArray.remove(((WeakReferenceWithId) ref).mId);
+        }
+    }
+
+    private static class WeakReferenceWithId<E> extends WeakReference<E> {
+
+        final int mId;
+
+        WeakReferenceWithId(E referent, ReferenceQueue<? super E> q, int id) {
+            super(referent, q);
+            mId = id;
+        }
+    }
+}
+