Avoid adding node itself as child node.

Apps can call addChild through AccessibilityNodeProvider, so it's
possible that an app adds a node itself as a child node. This will break
down the integrity of UI tree and cause failure to operation in
UIAutomator. Thus I suggest do this integrity check when adding child.

Test: as follows
    - built
    - flashed
    - booted
    - run my test script based on uiautomator

Change-Id: I8cba22a1d9d1a49365c6bce4241ef5067502fb79
Signed-off-by: qinyige <qinyige@xiaomi.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/core/java/android/view/accessibility/AccessibilityNodeInfo.java b/core/java/android/view/accessibility/AccessibilityNodeInfo.java
index 158ac6b0cdb5..28550ee61fbb 100644
--- a/core/java/android/view/accessibility/AccessibilityNodeInfo.java
+++ b/core/java/android/view/accessibility/AccessibilityNodeInfo.java
@@ -40,6 +40,7 @@ import android.text.style.AccessibilityURLSpan;
 import android.text.style.ClickableSpan;
 import android.text.style.URLSpan;
 import android.util.ArraySet;
+import android.util.Log;
 import android.util.LongArray;
 import android.util.Pools.SynchronizedPool;
 import android.view.View;
@@ -85,6 +86,8 @@ public class AccessibilityNodeInfo implements Parcelable {
 
     private static final boolean DEBUG = false;
 
+    private static final String TAG = "AccessibilityNodeInfo";
+
     /** @hide */
     public static final int UNDEFINED_CONNECTION_ID = -1;
 
@@ -990,6 +993,7 @@ public class AccessibilityNodeInfo implements Parcelable {
      * <strong>Note:</strong> Cannot be called from an
      * {@link android.accessibilityservice.AccessibilityService}.
      * This class is made immutable before being delivered to an AccessibilityService.
+     * Note that a view cannot be made its own child.
      * </p>
      *
      * @param child The child.
@@ -1037,6 +1041,7 @@ public class AccessibilityNodeInfo implements Parcelable {
      * hierarchy for accessibility purposes. This enables custom views that draw complex
      * content to report them selves as a tree of virtual views, thus conveying their
      * logical structure.
+     * Note that a view cannot be made its own child.
      * </p>
      *
      * @param root The root of the virtual subtree.
@@ -1054,6 +1059,11 @@ public class AccessibilityNodeInfo implements Parcelable {
         final int rootAccessibilityViewId =
             (root != null) ? root.getAccessibilityViewId() : UNDEFINED_ITEM_ID;
         final long childNodeId = makeNodeId(rootAccessibilityViewId, virtualDescendantId);
+        if (childNodeId == mSourceNodeId) {
+            Log.e(TAG, "Rejecting attempt to make a View its own child");
+            return;
+        }
+
         // If we're checking uniqueness and the ID already exists, abort.
         if (checked && mChildNodeIds.indexOf(childNodeId) >= 0) {
             return;