/core/java/android/view/accessibility/AccessibilityNodeInfoCache.java
Java | 343 lines | 224 code | 30 blank | 89 comment | 60 complexity | 2ea7a9eba2ef7c957a79b918a22c18a0 MD5 | raw file
- /*
- * Copyright (C) 2012 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.os.Build;
- import android.util.Log;
- import android.util.LongSparseArray;
- import android.util.SparseLongArray;
- import java.util.HashSet;
- import java.util.LinkedList;
- import java.util.Queue;
- /**
- * Simple cache for AccessibilityNodeInfos. The cache is mapping an
- * accessibility id to an info. The cache allows storing of
- * <code>null</code> values. It also tracks accessibility events
- * and invalidates accordingly.
- *
- * @hide
- */
- public class AccessibilityNodeInfoCache {
- private static final String LOG_TAG = AccessibilityNodeInfoCache.class.getSimpleName();
- private static final boolean ENABLED = true;
- private static final boolean DEBUG = false;
- private static final boolean CHECK_INTEGRITY = true;
- private final Object mLock = new Object();
- private final LongSparseArray<AccessibilityNodeInfo> mCacheImpl;
- private int mWindowId;
- public AccessibilityNodeInfoCache() {
- if (ENABLED) {
- mCacheImpl = new LongSparseArray<AccessibilityNodeInfo>();
- } else {
- mCacheImpl = null;
- }
- }
- /**
- * The cache keeps track of {@link AccessibilityEvent}s and invalidates
- * cached nodes as appropriate.
- *
- * @param event An event.
- */
- public void onAccessibilityEvent(AccessibilityEvent event) {
- if (ENABLED) {
- final int eventType = event.getEventType();
- switch (eventType) {
- case AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED: {
- // New window so we clear the cache.
- mWindowId = event.getWindowId();
- clear();
- } break;
- case AccessibilityEvent.TYPE_VIEW_HOVER_ENTER:
- case AccessibilityEvent.TYPE_VIEW_HOVER_EXIT: {
- final int windowId = event.getWindowId();
- if (mWindowId != windowId) {
- // New window so we clear the cache.
- mWindowId = windowId;
- clear();
- }
- } break;
- case AccessibilityEvent.TYPE_VIEW_FOCUSED:
- case AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED:
- case AccessibilityEvent.TYPE_VIEW_SELECTED:
- case AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED:
- case AccessibilityEvent.TYPE_VIEW_TEXT_SELECTION_CHANGED: {
- // Since we prefetch the descendants of a node we
- // just remove the entire subtree since when the node
- // is fetched we will gets its descendant anyway.
- synchronized (mLock) {
- final long sourceId = event.getSourceNodeId();
- clearSubTreeLocked(sourceId);
- if (eventType == AccessibilityEvent.TYPE_VIEW_FOCUSED) {
- clearSubtreeWithOldInputFocusLocked(sourceId);
- }
- if (eventType == AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED) {
- clearSubtreeWithOldAccessibilityFocusLocked(sourceId);
- }
- }
- } break;
- case AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED:
- case AccessibilityEvent.TYPE_VIEW_SCROLLED: {
- synchronized (mLock) {
- final long accessibilityNodeId = event.getSourceNodeId();
- clearSubTreeLocked(accessibilityNodeId);
- }
- } break;
- }
- if (Build.IS_DEBUGGABLE && CHECK_INTEGRITY) {
- checkIntegrity();
- }
- }
- }
- /**
- * Gets a cached {@link AccessibilityNodeInfo} given its accessibility node id.
- *
- * @param accessibilityNodeId The info accessibility node id.
- * @return The cached {@link AccessibilityNodeInfo} or null if such not found.
- */
- public AccessibilityNodeInfo get(long accessibilityNodeId) {
- if (ENABLED) {
- synchronized(mLock) {
- AccessibilityNodeInfo info = mCacheImpl.get(accessibilityNodeId);
- if (info != null) {
- // Return a copy since the client calls to AccessibilityNodeInfo#recycle()
- // will wipe the data of the cached info.
- info = AccessibilityNodeInfo.obtain(info);
- }
- if (DEBUG) {
- Log.i(LOG_TAG, "get(" + accessibilityNodeId + ") = " + info);
- }
- return info;
- }
- } else {
- return null;
- }
- }
- /**
- * Caches an {@link AccessibilityNodeInfo} given its accessibility node id.
- *
- * @param info The {@link AccessibilityNodeInfo} to cache.
- */
- public void add(AccessibilityNodeInfo info) {
- if (ENABLED) {
- synchronized(mLock) {
- if (DEBUG) {
- Log.i(LOG_TAG, "add(" + info + ")");
- }
- final long sourceId = info.getSourceNodeId();
- AccessibilityNodeInfo oldInfo = mCacheImpl.get(sourceId);
- if (oldInfo != null) {
- // If the added node is in the cache we have to be careful if
- // the new one represents a source state where some of the
- // children have been removed to avoid having disconnected
- // subtrees in the cache.
- SparseLongArray oldChildrenIds = oldInfo.getChildNodeIds();
- SparseLongArray newChildrenIds = info.getChildNodeIds();
- final int oldChildCount = oldChildrenIds.size();
- for (int i = 0; i < oldChildCount; i++) {
- final long oldChildId = oldChildrenIds.valueAt(i);
- if (newChildrenIds.indexOfValue(oldChildId) < 0) {
- clearSubTreeLocked(oldChildId);
- }
- }
- // Also be careful if the parent has changed since the new
- // parent may be a predecessor of the old parent which will
- // make the cached tree cyclic.
- final long oldParentId = oldInfo.getParentNodeId();
- if (info.getParentNodeId() != oldParentId) {
- clearSubTreeLocked(oldParentId);
- }
- }
- // Cache a copy since the client calls to AccessibilityNodeInfo#recycle()
- // will wipe the data of the cached info.
- AccessibilityNodeInfo clone = AccessibilityNodeInfo.obtain(info);
- mCacheImpl.put(sourceId, clone);
- }
- }
- }
- /**
- * Clears the cache.
- */
- public void clear() {
- if (ENABLED) {
- synchronized(mLock) {
- if (DEBUG) {
- Log.i(LOG_TAG, "clear()");
- }
- // Recycle the nodes before clearing the cache.
- final int nodeCount = mCacheImpl.size();
- for (int i = 0; i < nodeCount; i++) {
- AccessibilityNodeInfo info = mCacheImpl.valueAt(i);
- info.recycle();
- }
- mCacheImpl.clear();
- }
- }
- }
- /**
- * Clears a subtree rooted at the node with the given id.
- *
- * @param rootNodeId The root id.
- */
- private void clearSubTreeLocked(long rootNodeId) {
- AccessibilityNodeInfo current = mCacheImpl.get(rootNodeId);
- if (current == null) {
- return;
- }
- mCacheImpl.remove(rootNodeId);
- SparseLongArray childNodeIds = current.getChildNodeIds();
- final int childCount = childNodeIds.size();
- for (int i = 0; i < childCount; i++) {
- final long childNodeId = childNodeIds.valueAt(i);
- clearSubTreeLocked(childNodeId);
- }
- }
- /**
- * We are enforcing the invariant for a single input focus.
- *
- * @param currentInputFocusId The current input focused node.
- */
- private void clearSubtreeWithOldInputFocusLocked(long currentInputFocusId) {
- final int cacheSize = mCacheImpl.size();
- for (int i = 0; i < cacheSize; i++) {
- AccessibilityNodeInfo info = mCacheImpl.valueAt(i);
- final long infoSourceId = info.getSourceNodeId();
- if (infoSourceId != currentInputFocusId && info.isFocused()) {
- clearSubTreeLocked(infoSourceId);
- return;
- }
- }
- }
- /**
- * We are enforcing the invariant for a single accessibility focus.
- *
- * @param currentAccessibilityFocusId The current input focused node.
- */
- private void clearSubtreeWithOldAccessibilityFocusLocked(long currentAccessibilityFocusId) {
- final int cacheSize = mCacheImpl.size();
- for (int i = 0; i < cacheSize; i++) {
- AccessibilityNodeInfo info = mCacheImpl.valueAt(i);
- final long infoSourceId = info.getSourceNodeId();
- if (infoSourceId != currentAccessibilityFocusId && info.isAccessibilityFocused()) {
- clearSubTreeLocked(infoSourceId);
- return;
- }
- }
- }
- /**
- * Check the integrity of the cache which is it does not have nodes
- * from more than one window, there are no duplicates, all nodes are
- * connected, there is a single input focused node, and there is a
- * single accessibility focused node.
- */
- private void checkIntegrity() {
- synchronized (mLock) {
- // Get the root.
- if (mCacheImpl.size() <= 0) {
- return;
- }
- // If the cache is a tree it does not matter from
- // which node we start to search for the root.
- AccessibilityNodeInfo root = mCacheImpl.valueAt(0);
- AccessibilityNodeInfo parent = root;
- while (parent != null) {
- root = parent;
- parent = mCacheImpl.get(parent.getParentNodeId());
- }
- // Traverse the tree and do some checks.
- final int windowId = root.getWindowId();
- AccessibilityNodeInfo accessFocus = null;
- AccessibilityNodeInfo inputFocus = null;
- HashSet<AccessibilityNodeInfo> seen = new HashSet<AccessibilityNodeInfo>();
- Queue<AccessibilityNodeInfo> fringe = new LinkedList<AccessibilityNodeInfo>();
- fringe.add(root);
- while (!fringe.isEmpty()) {
- AccessibilityNodeInfo current = fringe.poll();
- // Check for duplicates
- if (!seen.add(current)) {
- Log.e(LOG_TAG, "Duplicate node: " + current);
- return;
- }
- // Check for one accessibility focus.
- if (current.isAccessibilityFocused()) {
- if (accessFocus != null) {
- Log.e(LOG_TAG, "Duplicate accessibility focus:" + current);
- } else {
- accessFocus = current;
- }
- }
- // Check for one input focus.
- if (current.isFocused()) {
- if (inputFocus != null) {
- Log.e(LOG_TAG, "Duplicate input focus: " + current);
- } else {
- inputFocus = current;
- }
- }
- SparseLongArray childIds = current.getChildNodeIds();
- final int childCount = childIds.size();
- for (int i = 0; i < childCount; i++) {
- final long childId = childIds.valueAt(i);
- AccessibilityNodeInfo child = mCacheImpl.get(childId);
- if (child != null) {
- fringe.add(child);
- }
- }
- }
- // Check for disconnected nodes or ones from another window.
- final int cacheSize = mCacheImpl.size();
- for (int i = 0; i < cacheSize; i++) {
- AccessibilityNodeInfo info = mCacheImpl.valueAt(i);
- if (!seen.contains(info)) {
- if (info.getWindowId() == windowId) {
- Log.e(LOG_TAG, "Disconneced node: ");
- } else {
- Log.e(LOG_TAG, "Node from: " + info.getWindowId() + " not from:"
- + windowId + " " + info);
- }
- }
- }
- }
- }
- }