/*
** Copyright 2009, 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;
import com.android.internal.content.PackageMonitor;
import com.android.internal.os.HandlerCaller;
import com.android.internal.os.HandlerCaller.SomeArgs;
import android.accessibilityservice.AccessibilityService;
import android.accessibilityservice.AccessibilityServiceInfo;
import android.accessibilityservice.IAccessibilityServiceConnection;
import android.accessibilityservice.IEventListener;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.ServiceConnection;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.content.pm.ServiceInfo;
import android.database.ContentObserver;
import android.net.Uri;
import android.os.Binder;
import android.os.DeadObjectException;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.RemoteException;
import android.provider.Settings;
import android.text.TextUtils;
import android.text.TextUtils.SimpleStringSplitter;
import android.util.Config;
import android.util.Slog;
import android.util.SparseArray;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.IAccessibilityManager;
import android.view.accessibility.IAccessibilityManagerClient;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* This class is instantiated by the system as a system level service and can be
* accessed only by the system. The task of this service is to be a centralized
* event dispatch for {@link AccessibilityEvent}s generated across all processes
* on the device. Events are dispatched to {@link AccessibilityService}s.
*
* @hide
*/
public class AccessibilityManagerService extends IAccessibilityManager.Stub
implements HandlerCaller.Callback {
private static final String LOG_TAG = "AccessibilityManagerService";
private static int sIdCounter = 0;
private static final int OWN_PROCESS_ID = android.os.Process.myPid();
private static final int DO_SET_SERVICE_INFO = 10;
final HandlerCaller mCaller;
final Context mContext;
final Object mLock = new Object();
final List<Service> mServices = new ArrayList<Service>();
final List<IAccessibilityManagerClient> mClients =
new ArrayList<IAccessibilityManagerClient>();
final Map<ComponentName, Service> mComponentNameToServiceMap =
new HashMap<ComponentName, Service>();
private final List<ServiceInfo> mInstalledServices = new ArrayList<ServiceInfo>();
private final Set<ComponentName> mEnabledServices = new HashSet<ComponentName>();
private final SimpleStringSplitter mStringColonSplitter = new SimpleStringSplitter(':');
private PackageManager mPackageManager;
private int mHandledFeedbackTypes = 0;
private boolean mIsEnabled;
/**
* Handler for delayed event dispatch.
*/
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message message) {
Service service = (Service) message.obj;
int eventType = message.arg1;
synchronized (mLock) {
notifyEventListenerLocked(service, eventType);
AccessibilityEvent oldEvent = service.mPendingEvents.get(eventType);
service.mPendingEvents.remove(eventType);
tryRecycleLocked(oldEvent);
}
}
};
/**
* Creates a new instance.
*
* @param context A {@link Context} instance.
*/
AccessibilityManagerService(Context context) {
mContext = context;
mPackageManager = mContext.getPackageManager();
mCaller = new HandlerCaller(context, this);
registerPackageChangeAndBootCompletedBroadcastReceiver();
registerSettingsContentObservers();
}
/**
* Registers a {@link BroadcastReceiver} for the events of
* adding/changing/removing/restarting a package and boot completion.
*/
private void registerPackageChangeAndBootCompletedBroadcastReceiver() {
Context context = mContext;
PackageMonitor monitor = new PackageMonitor() {
@Override
public void onSomePackagesChanged() {
synchronized (mLock) {
populateAccessibilityServiceListLocked();
manageServicesLocked();
}
}
@Override
public boolean onHandleForceStop(Intent intent, String[] packages,
int uid, boolean doit) {
synchronized (mLock) {
boolean changed = false;
Iterator<ComponentName> it = mEnabledServices.iterator();
while (it.hasNext()) {
ComponentName comp = it.next();
String compPkg = comp.getPackageName();
for (String pkg : packages) {
if (compPkg.equals(pkg)) {
if (!doit) {
return true;
}
it.remove();
changed = true;
}
}
}
if (changed) {
it = mEnabledServices.iterator();
StringBuilder str = new StringBuilder();
while (it.hasNext()) {
if (str.length() > 0) {
str.append(':');
}
str.append(it.next().flattenToShortString());
}
Settings.Secure.putString(mContext.getContentResolver(),
Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES,
str.toString());
manageServicesLocked();
}
return false;
}
}
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction() == Intent.ACTION_BOOT_COMPLETED) {
synchronized (mLock) {
populateAccessibilityServiceListLocked();
// get the accessibility enabled setting on boot
mIsEnabled = Settings.Secure.getInt(mContext.getContentResolver(),
Settings.Secure.ACCESSIBILITY_ENABLED, 0) == 1;
// if accessibility is enabled inform our clients we are on
if (mIsEnabled) {
updateClientsLocked();
}
manageServicesLocked();
}
return;
}
super.onReceive(context, intent);
}
};
// package changes
monitor.register(context, true);
// boot completed
IntentFilter bootFiler = new IntentFilter(Intent.ACTION_BOOT_COMPLETED);
mContext.registerReceiver(monitor, bootFiler);
}
/**
* {@link ContentObserver}s for {@link Settings.Secure#ACCESSIBILITY_ENABLED}
* and {@link Settings.Secure#ENABLED_ACCESSIBILITY_SERVICES} settings.
*/
private void registerSettingsContentObservers() {
ContentResolver contentResolver = mContext.getContentResolver();
Uri enabledUri = Settings.Secure.getUriFor(Settings.Secure.ACCESSIBILITY_ENABLED);
contentResolver.registerContentObserver(enabledUri, false,
new ContentObserver(new Handler()) {
@Override
public void onChange(boolean selfChange) {
super.onChange(selfChange);
mIsEnabled = Settings.Secure.getInt(mContext.getContentResolver(),
Settings.Secure.ACCESSIBILITY_ENABLED, 0) == 1;
synchronized (mLock) {
if (mIsEnabled) {
manageServicesLocked();
} else {
unbindAllServicesLocked();
}
updateClientsLocked();
}
}
});
Uri providersUri =
Settings.Secure.getUriFor(Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES);
contentResolver.registerContentObserver(providersUri, false,
new ContentObserver(new Handler()) {
@Override
public void onChange(boolean selfChange) {
super.onChange(selfChange);
synchronized (mLock) {
manageServicesLocked();
}
}
});
}
public void addClient(IAccessibilityManagerClient client) {
synchronized (mLock) {
try {
client.setEnabled(mIsEnabled);
mClients.add(client);
} catch (RemoteException re) {
Slog.w(LOG_TAG, "Dead AccessibilityManagerClient: " + client, re);
}
}
}
public boolean sendAccessibilityEvent(AccessibilityEvent event) {
synchronized (mLock) {
notifyAccessibilityServicesDelayedLocked(event, false);
notifyAccessibilityServicesDelayedLocked(event, true);
}
// event not scheduled for dispatch => recycle
if (mHandledFeedbackTypes == 0) {
event.recycle();
} else {
mHandledFeedbackTypes = 0;
}
return (OWN_PROCESS_ID != Binder.getCallingPid());
}
public List<ServiceInfo> getAccessibilityServiceList() {
synchronized (mLock) {
return mInstalledServices;
}
}
public void interrupt() {
synchronized (mLock) {
for (int i = 0, count = mServices.size(); i < count; i++) {
Service service = mServices.get(i);
try {
service.mServiceInterface.onInterrupt();
} catch (RemoteException re) {
if (re instanceof DeadObjectException) {
Slog.w(LOG_TAG, "Dead " + service.mService + ". Cleaning up.");
if (removeDeadServiceLocked(service)) {
count--;
i--;
}
} else {
Slog.e(LOG_TAG, "Error during sending interrupt request to "
+ service.mService, re);
}
}
}
}
}
public void executeMessage(Message message) {
switch (message.what) {
case DO_SET_SERVICE_INFO:
SomeArgs arguments = ((SomeArgs) message.obj);
AccessibilityServiceInfo info = (AccessibilityServiceInfo) arguments.arg1;
Service service = (Service) arguments.arg2;
synchronized (mLock) {
service.mEventTypes = info.eventTypes;
service.mFeedbackType = info.feedbackType;
String[] packageNames = info.packageNames;
if (packageNames != null) {
service.mPackageNames.addAll(Arrays.asList(packageNames));
}
service.mNotificationTimeout = info.notificationTimeout;
service.mIsDefault = (info.flags & AccessibilityServiceInfo.DEFAULT) != 0;
}
return;
default:
Slog.w(LOG_TAG, "Unknown message type: " + message.what);
}
}
/**
* Populates the cached list of installed {@link AccessibilityService}s.
*/
private void populateAccessibilityServiceListLocked() {
mInstalledServices.clear();
List<ResolveInfo> installedServices = mPackageManager.queryIntentServices(
new Intent(AccessibilityService.SERVICE_INTERFACE), PackageManager.GET_SERVICES);
for (int i = 0, count = installedServices.size(); i < count; i++) {
mInstalledServices.add(installedServices.get(i).serviceInfo);
}
}
/**
* Performs {@link AccessibilityService}s delayed notification. The delay is configurable
* and denotes the period after the last event before notifying the service.
*
* @param event The event.
* @param isDefault True to notify default listeners, not default services.
*/
private void notifyAccessibilityServicesDelayedLocked(AccessibilityEvent event,
boolean isDefault) {
try {
for (int i = 0, count = mServices.size(); i < count; i++) {
Service service = mServices.get(i);
if (service.mIsDefault == isDefault) {
if (canDispathEventLocked(service, event, mHandledFeedbackTypes)) {
mHandledFeedbackTypes |= service.mFeedbackType;
notifyAccessibilityServiceDelayedLocked(service, event);
}
}
}
} catch (IndexOutOfBoundsException oobe) {
// An out of bounds exception can happen if services are going away
// as the for loop is running. If that happens, just bail because
// there are no more services to notify.
return;
}
}
/**
* Performs an {@link AccessibilityService} delayed notification. The delay is configurable
* and denotes the period after the last event before notifying the service.
*
* @param service The service.
* @param event The event.
*/
private void notifyAccessibilityServiceDelayedLocked(Service service,
AccessibilityEvent event) {
synchronized (mLock) {
int eventType = event.getEventType();
AccessibilityEvent oldEvent = service.mPendingEvents.get(eventType);
service.mPendingEvents.put(eventType, event);
int what = eventType | (service.mId << 16);
if (oldEvent != null) {
mHandler.removeMessages(what);
tryRecycleLocked(oldEvent);
}
Message message = mHandler.obtainMessage(what, service);
message.arg1 = event.getEventType();
mHandler.sendMessageDelayed(message, service.mNotificationTimeout);
}
}
/**
* Recycles an event if it can be safely recycled. The condition is that no
* not notified service is interested in the event.
*
* @param event The event.
*/
private void tryRecycleLocked(AccessibilityEvent event) {
if (event == null) {
return;
}
int eventType = event.getEventType();
List<Service> services = mServices;
// linear in the number of service which is not large
for (int i = 0, count = services.size(); i < count; i++) {
Service service = services.get(i);
if (service.mPendingEvents.get(eventType) == event) {
return;
}
}
event.recycle();
}
/**
* Notifies a service for a scheduled event given the event type.
*
* @param service The service.
* @param eventType The type of the event to dispatch.
*/
private void notifyEventListenerLocked(Service service, int eventType) {
IEventListener listener = service.mServiceInterface;
AccessibilityEvent event = service.mPendingEvents.get(eventType);
try {
listener.onAccessibilityEvent(event);
if (Config.DEBUG) {
Slog.i(LOG_TAG, "Event " + event + " sent to " + listener);
}
} catch (RemoteException re) {
if (re instanceof DeadObjectException) {
Slog.w(LOG_TAG, "Dead " + service.mService + ". Cleaning up.");
synchronized (mLock) {
removeDeadServiceLocked(service);
}
} else {
Slog.e(LOG_TAG, "Error during sending " + event + " to " + service.mService, re);
}
}
}
/**
* Removes a dead service.
*
* @param service The service.
* @return True if the service was removed, false otherwise.
*/
private boolean removeDeadServiceLocked(Service service) {
mServices.remove(service);
mHandler.removeMessages(service.mId);
if (Config.DEBUG) {
Slog.i(LOG_TAG, "Dead service " + service.mService + " removed");
}
if (mServices.isEmpty()) {
mIsEnabled = false;
updateClientsLocked();
}
return true;
}
/**
* Determines if given event can be dispatched to a service based on the package of the
* event source and already notified services for that event type. Specifically, a
* service is notified if it is interested in events from the package and no other service
* providing the same feedback type has been notified. Exception are services the
* provide generic feedback (feedback type left as a safety net for unforeseen feedback
* types) which are always notified.
*
* @param service The potential receiver.
* @param event The event.
* @param handledFeedbackTypes The feedback types for which services have been notified.
* @return True if the listener should be notified, false otherwise.
*/
private boolean canDispathEventLocked(Service service, AccessibilityEvent event,
int handledFeedbackTypes) {
if (!service.isConfigured()) {
return false;
}
if (!service.mService.isBinderAlive()) {
removeDeadServiceLocked(service);
return false;
}
int eventType = event.getEventType();
if ((service.mEventTypes & eventType) != eventType) {
return false;
}
Set<String> packageNames = service.mPackageNames;
CharSequence packageName = event.getPackageName();
if (packageNames.isEmpty() || packageNames.contains(packageName)) {
int feedbackType = service.mFeedbackType;
if ((handledFeedbackTypes & feedbackType) != feedbackType
|| feedbackType == AccessibilityServiceInfo.FEEDBACK_GENERIC) {
return true;
}
}
return false;
}
/**
* Manages services by starting enabled ones and stopping disabled ones.
*/
private void manageServicesLocked() {
populateEnabledServicesLocked(mEnabledServices);
updateServicesStateLocked(mInstalledServices, mEnabledServices);
}
/**
* Unbinds all bound services.
*/
private void unbindAllServicesLocked() {
List<Service> services = mServices;
for (int i = 0, count = services.size(); i < count; i++) {
Service service = services.get(i);
service.unbind();
mComponentNameToServiceMap.remove(service.mComponentName);
}
services.clear();
}
/**
* Populates a list with the {@link ComponentName}s of all enabled
* {@link AccessibilityService}s.
*
* @param enabledServices The list.
*/
private void populateEnabledServicesLocked(Set<ComponentName> enabledServices) {
enabledServices.clear();
String servicesValue = Settings.Secure.getString(mContext.getContentResolver(),
Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES);
if (servicesValue != null) {
TextUtils.SimpleStringSplitter splitter = mStringColonSplitter;
splitter.setString(servicesValue);
while (splitter.hasNext()) {
String str = splitter.next();
if (str == null || str.length() <= 0) {
continue;
}
ComponentName enabledService = ComponentName.unflattenFromString(str);
if (enabledService != null) {
enabledServices.add(enabledService);
}
}
}
}
/**
* Updates the state of each service by starting (or keeping running) enabled ones and
* stopping the rest.
*
* @param installedServices All installed {@link AccessibilityService}s.
* @param enabledServices The {@link ComponentName}s of the enabled services.
*/
private void updateServicesStateLocked(List<ServiceInfo> installedServices,
Set<ComponentName> enabledServices) {
Map<ComponentName, Service> componentNameToServiceMap = mComponentNameToServiceMap;
List<Service> services = mServices;
boolean isEnabled = mIsEnabled;
for (int i = 0, count = installedServices.size(); i < count; i++) {
ServiceInfo intalledService = installedServices.get(i);
ComponentName componentName = new ComponentName(intalledService.packageName,
intalledService.name);
Service service = componentNameToServiceMap.get(componentName);
if (isEnabled && enabledServices.contains(componentName)) {
if (service == null) {
new Service(componentName).bind();
}
} else {
if (service != null) {
service.unbind();
componentNameToServiceMap.remove(componentName);
services.remove(service);
}
}
}
}
/**
* Updates the state of {@link android.view.accessibility.AccessibilityManager} clients.
*/
private void updateClientsLocked() {
for (int i = 0, count = mClients.size(); i < count; i++) {
try {
mClients.get(i).setEnabled(mIsEnabled);
} catch (RemoteException re) {
mClients.remove(i);
count--;
i--;
}
}
}
/**
* This class represents an accessibility service. It stores all per service
* data required for the service management, provides API for starting/stopping the
* service and is responsible for adding/removing the service in the data structures
* for service management. The class also exposes configuration interface that is
* passed to the service it represents as soon it is bound. It also serves as the
* connection for the service.
*/
class Service extends IAccessibilityServiceConnection.Stub implements ServiceConnection {
int mId = 0;
IBinder mService;
IEventListener mServiceInterface;
int mEventTypes;
int mFeedbackType;
Set<String> mPackageNames = new HashSet<String>();
boolean mIsDefault;
long mNotificationTimeout;
boolean mIsActive;
ComponentName mComponentName;
Intent mIntent;
// the events pending events to be dispatched to this service
final SparseArray<AccessibilityEvent> mPendingEvents =
new SparseArray<AccessibilityEvent>();
Service(ComponentName componentName) {
mId = sIdCounter++;
mComponentName = componentName;
mIntent = new Intent().setComponent(mComponentName);
mIntent.putExtra(Intent.EXTRA_CLIENT_LABEL,
com.android.internal.R.string.accessibility_binding_label);
mIntent.putExtra(Intent.EXTRA_CLIENT_INTENT, PendingIntent.getActivity(
mContext, 0, new Intent(Settings.ACTION_ACCESSIBILITY_SETTINGS), 0));
}
/**
* Binds to the accessibility service.
*/
public void bind() {
if (mService == null) {
mContext.bindService(mIntent, this, Context.BIND_AUTO_CREATE);
}
}
/**
* Unbinds form the accessibility service and removes it from the data
* structures for service management.
*/
public void unbind() {
if (mService != null) {
mContext.unbindService(this);
}
}
/**
* Returns if the service is configured i.e. at least event types of interest
* and feedback type must be set.
*
* @return True if the service is configured, false otherwise.
*/
public boolean isConfigured() {
return (mEventTypes != 0 && mFeedbackType != 0);
}
public void setServiceInfo(AccessibilityServiceInfo info) {
mCaller.obtainMessageOO(DO_SET_SERVICE_INFO, info, this).sendToTarget();
}
public void onServiceConnected(ComponentName componentName, IBinder service) {
mService = service;
mServiceInterface = IEventListener.Stub.asInterface(service);
try {
mServiceInterface.setConnection(this);
synchronized (mLock) {
if (!mServices.contains(this)) {
mServices.add(this);
mComponentNameToServiceMap.put(componentName, this);
}
}
} catch (RemoteException re) {
Slog.w(LOG_TAG, "Error while setting Controller for service: " + service, re);
}
}
public void onServiceDisconnected(ComponentName componentName) {
synchronized (mLock) {
Service service = mComponentNameToServiceMap.remove(componentName);
mServices.remove(service);
}
}
}
}