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Block a11y-changing key events from a11y services

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If the volume keys are being pressed to enable or disable
an accessibility service, the key events should not be
dispatched to accessibility services.

Bug: 62653966
Test: A11y CTS and unit tests. Adding a set of unit tests for
the expanded KeyboardInterceptor. Also verified that the
accessibility shortcut now works as designed with TalkBack.

Change-Id: Iaea58a5bfe6748d4b9a033f5b957e78298881c40
This commit is contained in:
Phil Weaver
2017-06-23 10:03:52 -07:00
parent 6f76e7f96d
commit 77287ab7d1
4 changed files with 376 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
services/accessibility/java/com/android/server/accessibility/AccessibilityInputFilter.java
View File

@@ -17,6 +17,7 @@
package com.android.server.accessibility;
import android.content.Context;
import android.os.Handler;
import android.os.PowerManager;
import android.util.Pools.SimplePool;
import android.util.Slog;
@@ -30,6 +31,8 @@ import android.view.MotionEvent;
import android.view.WindowManagerPolicy;
import android.view.accessibility.AccessibilityEvent;
import com.android.server.LocalServices;
/**
* This class is an input filter for implementing accessibility features such
* as display magnification and explore by touch.
@@ -425,7 +428,8 @@ class AccessibilityInputFilter extends InputFilter implements EventStreamTransfo
}
if ((mEnabledFeatures & FLAG_FEATURE_FILTER_KEY_EVENTS) != 0) {
mKeyboardInterceptor = new KeyboardInterceptor(mAms);
mKeyboardInterceptor = new KeyboardInterceptor(mAms,
LocalServices.getService(WindowManagerPolicy.class));
addFirstEventHandler(mKeyboardInterceptor);
}
}

4
services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
View File

@@ -102,6 +102,7 @@ import android.view.accessibility.IAccessibilityManagerClient;
import com.android.internal.R;
import com.android.internal.annotations.GuardedBy;
import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.content.PackageMonitor;
import com.android.internal.os.SomeArgs;
import com.android.internal.util.DumpUtils;
@@ -903,7 +904,8 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
}
}
boolean notifyKeyEvent(KeyEvent event, int policyFlags) {
@VisibleForTesting
public boolean notifyKeyEvent(KeyEvent event, int policyFlags) {
synchronized (mLock) {
List<Service> boundServices = getCurrentUserStateLocked().mBoundServices;
if (boundServices.isEmpty()) {

154
services/accessibility/java/com/android/server/accessibility/KeyboardInterceptor.java
View File

@@ -16,19 +16,52 @@
package com.android.server.accessibility;
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
import android.util.Pools;
import android.util.Slog;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.WindowManagerPolicy;
import android.view.accessibility.AccessibilityEvent;
/**
* Intercepts key events and forwards them to accessibility manager service.
*/
public class KeyboardInterceptor implements EventStreamTransformation {
private EventStreamTransformation mNext;
private AccessibilityManagerService mAms;
public class KeyboardInterceptor implements EventStreamTransformation, Handler.Callback {
private static final int MESSAGE_PROCESS_QUEUED_EVENTS = 1;
private static final String LOG_TAG = "KeyboardInterceptor";
public KeyboardInterceptor(AccessibilityManagerService service) {
private final AccessibilityManagerService mAms;
private final WindowManagerPolicy mPolicy;
private final Handler mHandler;
private EventStreamTransformation mNext;
private KeyEventHolder mEventQueueStart;
private KeyEventHolder mEventQueueEnd;
/**
* @param service The service to notify of key events
* @param policy The policy to check for keys that may affect a11y
*/
public KeyboardInterceptor(AccessibilityManagerService service, WindowManagerPolicy policy) {
mAms = service;
mPolicy = policy;
mHandler = new Handler(this);
}
/**
* @param service The service to notify of key events
* @param policy The policy to check for keys that may affect a11y
* @param handler The handler to use. Only used for testing.
*/
public KeyboardInterceptor(AccessibilityManagerService service, WindowManagerPolicy policy,
Handler handler) {
// Can't combine the constructors without making at least mHandler non-final.
mAms = service;
mPolicy = policy;
mHandler = handler;
}
@Override
@@ -40,6 +73,19 @@ public class KeyboardInterceptor implements EventStreamTransformation {
@Override
public void onKeyEvent(KeyEvent event, int policyFlags) {
/*
* Certain keys have system-level behavior that affects accessibility services.
* Let that behavior settle before handling the keys
*/
long eventDelay = getEventDelay(event, policyFlags);
if (eventDelay < 0) {
return;
}
if ((eventDelay > 0) || (mEventQueueStart != null)) {
addEventToQueue(event, policyFlags, eventDelay);
return;
}
mAms.notifyKeyEvent(event, policyFlags);
}
@@ -65,4 +111,104 @@ public class KeyboardInterceptor implements EventStreamTransformation {
@Override
public void onDestroy() {
}
@Override
public boolean handleMessage(Message msg) {
if (msg.what != MESSAGE_PROCESS_QUEUED_EVENTS) {
Slog.e(LOG_TAG, "Unexpected message type");
return false;
}
processQueuedEvents();
if (mEventQueueStart != null) {
scheduleProcessQueuedEvents();
}
return true;
}
private void addEventToQueue(KeyEvent event, int policyFlags, long delay) {
long dispatchTime = SystemClock.uptimeMillis() + delay;
if (mEventQueueStart == null) {
mEventQueueEnd = mEventQueueStart =
KeyEventHolder.obtain(event, policyFlags, dispatchTime);
scheduleProcessQueuedEvents();
return;
}
final KeyEventHolder holder = KeyEventHolder.obtain(event, policyFlags, dispatchTime);
holder.next = mEventQueueStart;
mEventQueueStart.previous = holder;
mEventQueueStart = holder;
}
private void scheduleProcessQueuedEvents() {
if (!mHandler.sendEmptyMessageAtTime(
MESSAGE_PROCESS_QUEUED_EVENTS, mEventQueueEnd.dispatchTime)) {
Slog.e(LOG_TAG, "Failed to schedule key event");
};
}
private void processQueuedEvents() {
final long currentTime = SystemClock.uptimeMillis();
while ((mEventQueueEnd != null) && (mEventQueueEnd.dispatchTime <= currentTime)) {
final long eventDelay = getEventDelay(mEventQueueEnd.event, mEventQueueEnd.policyFlags);
if (eventDelay > 0) {
// Reschedule the event
mEventQueueEnd.dispatchTime = currentTime + eventDelay;
return;
}
// We'll either send or drop the event
if (eventDelay == 0) {
mAms.notifyKeyEvent(mEventQueueEnd.event, mEventQueueEnd.policyFlags);
}
final KeyEventHolder eventToBeRecycled = mEventQueueEnd;
mEventQueueEnd = mEventQueueEnd.previous;
if (mEventQueueEnd != null) {
mEventQueueEnd.next = null;
}
eventToBeRecycled.recycle();
if (mEventQueueEnd == null) {
mEventQueueStart = null;
}
}
}
private long getEventDelay(KeyEvent event, int policyFlags) {
int keyCode = event.getKeyCode();
if ((keyCode == KeyEvent.KEYCODE_VOLUME_DOWN) || (keyCode == KeyEvent.KEYCODE_VOLUME_UP)) {
return mPolicy.interceptKeyBeforeDispatching(null, event, policyFlags);
}
return 0;
}
private static class KeyEventHolder {
private static final int MAX_POOL_SIZE = 32;
private static final Pools.SimplePool<KeyEventHolder> sPool =
new Pools.SimplePool<>(MAX_POOL_SIZE);
public int policyFlags;
public long dispatchTime;
public KeyEvent event;
public KeyEventHolder next;
public KeyEventHolder previous;
public static KeyEventHolder obtain(KeyEvent event, int policyFlags, long dispatchTime) {
KeyEventHolder holder = sPool.acquire();
if (holder == null) {
holder = new KeyEventHolder();
}
holder.event = KeyEvent.obtain(event);
holder.policyFlags = policyFlags;
holder.dispatchTime = dispatchTime;
return holder;
}
public void recycle() {
event.recycle();
event = null;
policyFlags = 0;
dispatchTime = 0;
next = null;
previous = null;
sPool.release(this);
}
}
}

218
services/tests/servicestests/src/com/android/server/accessibility/KeyboardInterceptorTest.java Normal file
View File

@@ -0,0 +1,218 @@
/*
* Copyright (C) 2017 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 com.android.server.accessibility;
import static junit.framework.Assert.assertTrue;
import static org.hamcrest.CoreMatchers.nullValue;
import static org.junit.Assert.assertFalse;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Matchers.anyObject;
import static org.mockito.Matchers.isNull;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
import static org.mockito.hamcrest.MockitoHamcrest.argThat;
import org.hamcrest.BaseMatcher;
import org.hamcrest.Description;
import org.hamcrest.TypeSafeMatcher;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InOrder;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.MockitoAnnotations;
import android.os.Looper;
import android.support.test.runner.AndroidJUnit4;
import android.view.KeyEvent;
import android.view.WindowManagerPolicy;
import android.view.WindowManagerPolicy.WindowState;
/**
* Tests for KeyboardInterceptor
*/
@RunWith(AndroidJUnit4.class)
public class KeyboardInterceptorTest {
private KeyboardInterceptor mInterceptor;
private MessageCapturingHandler mHandler = new MessageCapturingHandler(
msg -> mInterceptor.handleMessage(msg));
@Mock AccessibilityManagerService mMockAms;
@Mock WindowManagerPolicy mMockPolicy;
@BeforeClass
public static void oneTimeInitialization() {
if (Looper.myLooper() == null) {
Looper.prepare();
}
}
@Before
public void setUp() {
MockitoAnnotations.initMocks(this);
mInterceptor = new KeyboardInterceptor(mMockAms, mMockPolicy, mHandler);
}
@Test
public void whenNonspecialKeyArrives_withNothingInQueue_eventGoesToAms() {
KeyEvent event = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_0);
mInterceptor.onKeyEvent(event, 0);
verify(mMockAms).notifyKeyEvent(argThat(matchesKeyEvent(event)), eq(0));
}
@Test
public void whenVolumeKeyArrives_andPolicySaysUseIt_eventGoesToAms() {
KeyEvent event = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_VOLUME_DOWN);
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(event)), eq(0))).thenReturn(0L);
mInterceptor.onKeyEvent(event, 0);
verify(mMockAms).notifyKeyEvent(argThat(matchesKeyEvent(event)), eq(0));
}
@Test
public void whenVolumeKeyArrives_andPolicySaysDropIt_eventDropped() {
KeyEvent event = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_VOLUME_UP);
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(event)), eq(0))).thenReturn(-1L);
mInterceptor.onKeyEvent(event, 0);
verify(mMockAms, times(0)).notifyKeyEvent(anyObject(), anyInt());
assertFalse(mHandler.hasMessages());
}
@Test
public void whenVolumeKeyArrives_andPolicySaysDelayThenUse_eventQueuedThenSentToAms() {
KeyEvent event = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_VOLUME_UP);
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(event)), eq(0))).thenReturn(150L);
mInterceptor.onKeyEvent(event, 0);
assertTrue(mHandler.hasMessages());
verify(mMockAms, times(0)).notifyKeyEvent(anyObject(), anyInt());
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(event)), eq(0))).thenReturn(0L);
mHandler.sendAllMessages();
verify(mMockAms).notifyKeyEvent(argThat(matchesKeyEvent(event)), eq(0));
}
@Test
public void whenVolumeKeyArrives_andPolicySaysDelayThenDrop_eventQueuedThenDropped() {
KeyEvent event = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_VOLUME_DOWN);
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(event)), eq(0))).thenReturn(150L);
mInterceptor.onKeyEvent(event, 0);
assertTrue(mHandler.hasMessages());
verify(mMockAms, times(0)).notifyKeyEvent(anyObject(), anyInt());
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(event)), eq(0))).thenReturn(-1L);
mHandler.sendAllMessages();
verify(mMockAms, times(0)).notifyKeyEvent(anyObject(), anyInt());
}
@Test
public void whenSomeEventsGetDelayed_allEventsStillInOrder() {
KeyEvent[] events = {new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_0),
new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_VOLUME_UP),
new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_A),
new KeyEvent(KeyEvent.ACTION_UP, KeyEvent.KEYCODE_VOLUME_UP),
new KeyEvent(KeyEvent.ACTION_UP, KeyEvent.KEYCODE_0)};
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(events[1])), eq(0))).thenReturn(150L);
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(events[3])), eq(0))).thenReturn(75L);
for (KeyEvent event : events) {
mInterceptor.onKeyEvent(event, 0);
}
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(events[1])), eq(0))).thenReturn(0L);
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(events[3])), eq(0))).thenReturn(0L);
mHandler.sendAllMessages();
InOrder inOrder = Mockito.inOrder(mMockAms);
for (KeyEvent event : events) {
inOrder.verify(mMockAms).notifyKeyEvent(argThat(matchesKeyEvent(event)), eq(0));
}
}
@Test
public void whenSomeEventsGetDropped_otherEventsStillInOrder() {
KeyEvent[] events = {new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_0),
new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_VOLUME_UP),
new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_A),
new KeyEvent(KeyEvent.ACTION_UP, KeyEvent.KEYCODE_VOLUME_UP),
new KeyEvent(KeyEvent.ACTION_UP, KeyEvent.KEYCODE_0)};
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(events[1])), eq(0))).thenReturn(150L);
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(events[3])), eq(0))).thenReturn(75L);
for (KeyEvent event : events) {
mInterceptor.onKeyEvent(event, 0);
}
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(events[1])), eq(0))).thenReturn(-1L);
when(mMockPolicy.interceptKeyBeforeDispatching((WindowState) argThat(nullValue()),
argThat(matchesKeyEvent(events[3])), eq(0))).thenReturn(-1L);
mHandler.sendAllMessages();
InOrder inOrder = Mockito.inOrder(mMockAms);
for (KeyEvent event : events) {
if ((event == events[1]) || (event == events[3])) continue;
inOrder.verify(mMockAms).notifyKeyEvent(argThat(matchesKeyEvent(event)), eq(0));
}
}
private static KeyEventMatcher matchesKeyEvent(KeyEvent event) {
return new KeyEventMatcher(event);
}
private static class KeyEventMatcher extends TypeSafeMatcher<KeyEvent> {
private KeyEvent mEventToMatch;
public KeyEventMatcher(KeyEvent eventToMatch) {
mEventToMatch = eventToMatch;
}
@Override
protected boolean matchesSafely(KeyEvent item) {
return (mEventToMatch.getKeyCode() == item.getKeyCode())
&& (mEventToMatch.getAction() == item.getAction());
}
@Override
public void describeTo(Description description) {
description.appendText("Matches key event");
}
}
}