Fix a11y cache correctness bug
If two views change, their common ancestor can send
a subtree_changed event. But the cache is dropping
events that come from views that it hasn't cached.
Now clearing the cache entirely when a node not in
the cache sends a subtree changed event, since we
don't know which nodes are descendents and which
may have changed.
I'm not thrilled with this change, since it may
degrade performance, but I want to fix the correctness
problem quickly.
Bug: 111554539
Test: atest AccessibilityCacheTest
Change-Id: Ib32d3622cddd7001663943eff71e823d21f5e500
diff --git a/core/java/android/view/accessibility/AccessibilityCache.java b/core/java/android/view/accessibility/AccessibilityCache.java
index da5a1cd..0e1e379 100644
--- a/core/java/android/view/accessibility/AccessibilityCache.java
+++ b/core/java/android/view/accessibility/AccessibilityCache.java
@@ -418,20 +418,28 @@
*
* @param nodes The nodes in the hosting window.
* @param rootNodeId The id of the root to evict.
+ *
+ * @return {@code true} if the cache was cleared
*/
- private void clearSubTreeRecursiveLocked(LongSparseArray<AccessibilityNodeInfo> nodes,
+ private boolean clearSubTreeRecursiveLocked(LongSparseArray<AccessibilityNodeInfo> nodes,
long rootNodeId) {
AccessibilityNodeInfo current = nodes.get(rootNodeId);
if (current == null) {
- return;
+ // The node isn't in the cache, but its descendents might be.
+ clear();
+ return true;
}
nodes.remove(rootNodeId);
final int childCount = current.getChildCount();
for (int i = 0; i < childCount; i++) {
final long childNodeId = current.getChildId(i);
- clearSubTreeRecursiveLocked(nodes, childNodeId);
+ if (clearSubTreeRecursiveLocked(nodes, childNodeId)) {
+ current.recycle();
+ return true;
+ }
}
current.recycle();
+ return false;
}
/**
diff --git a/core/tests/coretests/src/android/view/accessibility/AccessibilityCacheTest.java b/core/tests/coretests/src/android/view/accessibility/AccessibilityCacheTest.java
index 4de8155..993378d 100644
--- a/core/tests/coretests/src/android/view/accessibility/AccessibilityCacheTest.java
+++ b/core/tests/coretests/src/android/view/accessibility/AccessibilityCacheTest.java
@@ -300,6 +300,26 @@
}
@Test
+ public void subTreeChangeEventFromUncachedNode_clearsNodeInCache() {
+ AccessibilityNodeInfo nodeInfo = getNodeWithA11yAndWindowId(CHILD_VIEW_ID, WINDOW_ID_1);
+ long id = nodeInfo.getSourceNodeId();
+ mAccessibilityCache.add(nodeInfo);
+ nodeInfo.recycle();
+
+ AccessibilityEvent event = AccessibilityEvent
+ .obtain(AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED);
+ event.setContentChangeTypes(AccessibilityEvent.CONTENT_CHANGE_TYPE_SUBTREE);
+ event.setSource(getMockViewWithA11yAndWindowIds(PARENT_VIEW_ID, WINDOW_ID_1));
+
+ mAccessibilityCache.onAccessibilityEvent(event);
+ AccessibilityNodeInfo shouldBeNull = mAccessibilityCache.getNode(WINDOW_ID_1, id);
+ if (shouldBeNull != null) {
+ shouldBeNull.recycle();
+ }
+ assertNull(shouldBeNull);
+ }
+
+ @Test
public void scrollEvent_clearsNodeAndChild() {
AccessibilityEvent event = AccessibilityEvent
.obtain(AccessibilityEvent.TYPE_VIEW_SCROLLED);