services/java/com/android/server/AccessibilityManagerService.java - LeafOS-Project/android_frameworks_base - Gitiles

 /*
  ** 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 boolean addClient(IAccessibilityManagerClient client) {
         synchronized (mLock) {
             mClients.add(client);
             return mIsEnabled;
         }
     }

     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);
             }
         }
     }
 }
	/*
	** 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 boolean addClient(IAccessibilityManagerClient client) {
	synchronized (mLock) {
	mClients.add(client);
	return mIsEnabled;
	}
	}

	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);
	}
	}
	}
	}