core/java/android/service/autofill/AutoFillService.java - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2016 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.service.autofill;

 import static android.view.View.AUTO_FILL_FLAG_TYPE_FILL;
 import static android.view.View.AUTO_FILL_FLAG_TYPE_SAVE;

 import android.annotation.SdkConstant;
 import android.app.Activity;
 import android.app.Service;
 import android.app.assist.AssistStructure;
 import android.content.Intent;
 import android.os.Bundle;
 import android.os.CancellationSignal;
 import android.os.IBinder;
 import android.os.Looper;
 import android.os.Message;
 import android.util.Log;
 import android.view.autofill.AutoFillId;
 import android.view.autofill.Dataset;
 import android.view.autofill.FillResponse;

 import com.android.internal.os.HandlerCaller;
 import com.android.internal.os.SomeArgs;

 import java.io.FileDescriptor;
 import java.io.PrintWriter;
 import java.util.ArrayList;
 import java.util.List;

 //TODO(b/33197203): improve javadoc (of both class and methods); in particular, make sure the
 //life-cycle (and how state could be maintained on server-side) is well documented.

 /**
  * Top-level service of the current auto-fill service for a given user.
  *
  * <p>Apps providing auto-fill capabilities must extend this service.
  */
 public abstract class AutoFillService extends Service {

     private static final String TAG = "AutoFillService";
     static final boolean DEBUG = true; // TODO(b/33197203): set to false once stable

     // TODO(b/33197203): check for device's memory size instead of DEBUG?
     static final boolean DEBUG_PENDING_CALLBACKS = DEBUG;

     /**
      * The {@link Intent} that must be declared as handled by the service.
      * To be supported, the service must also require the
      * {@link android.Manifest.permission#BIND_AUTO_FILL} permission so
      * that other applications can not abuse it.
      */
     @SdkConstant(SdkConstant.SdkConstantType.SERVICE_ACTION)
     public static final String SERVICE_INTERFACE = "android.service.autofill.AutoFillService";

     /**
      * Name under which a AutoFillService component publishes information about itself.
      * This meta-data should reference an XML resource containing a
      * <code>&lt;{@link
      * android.R.styleable#AutoFillService autofill-service}&gt;</code> tag.
      * This is a a sample XML file configuring an AutoFillService:
      * <pre> &lt;autofill-service
      *     android:settingsActivity="foo.bar.SettingsActivity"
      *     . . .
      * /&gt;</pre>
      */
     public static final String SERVICE_META_DATA = "android.autofill";

     // Internal bundle keys.
     /** @hide */ public static final String KEY_CALLBACK = "callback";
     /** @hide */ public static final String KEY_SAVABLE_IDS = "savable_ids";
     /** @hide */ public static final String EXTRA_CRYPTO_OBJECT_ID = "crypto_object_id";

     // Prefix for public bundle keys.
     private static final String KEY_PREFIX = "android.service.autofill.extra.";

     /**
      * Key of the {@link Bundle} passed to methods such as
      * {@link #onSaveRequest(AssistStructure, Bundle, CancellationSignal, SaveCallback)}
      * containing the extras set by
      * {@link android.view.autofill.FillResponse.Builder#setExtras(Bundle)}.
      */
     public static final String EXTRA_RESPONSE_EXTRAS = KEY_PREFIX + "RESPONSE_EXTRAS";

     /**
      * Key of the {@link Bundle} passed to methods such as
      * {@link #onSaveRequest(AssistStructure, Bundle, CancellationSignal, SaveCallback)}
      * containing the extras set by
      * {@link android.view.autofill.Dataset.Builder#setExtras(Bundle)}.
      */
     public static final String EXTRA_DATASET_EXTRAS = KEY_PREFIX + "DATASET_EXTRAS";

     /**
      * Used to indicate the user selected an action that requires authentication.
      */
     public static final int FLAG_AUTHENTICATION_REQUESTED = 1 << 0;

     /**
      * Used to indicate the user authentication succeeded.
      */
     public static final int FLAG_AUTHENTICATION_SUCCESS = 1 << 1;

     /**
      * Used to indicate the user authentication failed.
      */
     public static final int FLAG_AUTHENTICATION_ERROR = 1 << 2;

     /**
      * Used when the service requested Fingerprint authentication but such option is not available.
      */
     public static final int FLAG_FINGERPRINT_AUTHENTICATION_NOT_AVAILABLE  = 1 << 3;

     // Handler messages.
     private static final int MSG_CONNECT = 1;
     private static final int MSG_DISCONNECT = 2;
     private static final int MSG_AUTO_FILL_ACTIVITY = 3;
     private static final int MSG_AUTHENTICATE_FILL_RESPONSE = 4;
     private static final int MSG_AUTHENTICATE_DATASET = 5;

     private final IAutoFillService mInterface = new IAutoFillService.Stub() {

         @Override
         public void autoFill(AssistStructure structure, IAutoFillServerCallback callback,
                 Bundle extras, int flags) {
             mHandlerCaller
                     .obtainMessageIOOO(MSG_AUTO_FILL_ACTIVITY, flags, structure, extras, callback)
                     .sendToTarget();
         }

         @Override
         public void authenticateFillResponse(Bundle extras, int flags) {
             final Message msg = mHandlerCaller.obtainMessage(MSG_AUTHENTICATE_FILL_RESPONSE);
             msg.arg1 = flags;
             msg.obj = extras;
             mHandlerCaller.sendMessage(msg);
         }

         @Override
         public void authenticateDataset(Bundle extras, int flags) {
             final Message msg = mHandlerCaller.obtainMessage(MSG_AUTHENTICATE_DATASET);
             msg.arg1 = flags;
             msg.obj = extras;
             mHandlerCaller.sendMessage(msg);
         }

         @Override
         public void onConnected() {
             mHandlerCaller.sendMessage(mHandlerCaller.obtainMessage(MSG_CONNECT));
         }

         @Override
         public void onDisconnected() {
             mHandlerCaller.sendMessage(mHandlerCaller.obtainMessage(MSG_DISCONNECT));
         }
     };

     private final HandlerCaller.Callback mHandlerCallback = new HandlerCaller.Callback() {

         @Override
         public void executeMessage(Message msg) {
             switch (msg.what) {
                 case MSG_CONNECT: {
                     onConnected();
                     break;
                 } case MSG_AUTO_FILL_ACTIVITY: {
                     final SomeArgs args = (SomeArgs) msg.obj;
                     final int flags = msg.arg1;
                     final AssistStructure structure = (AssistStructure) args.arg1;
                     final Bundle extras = (Bundle) args.arg2;
                     final IAutoFillServerCallback callback = (IAutoFillServerCallback) args.arg3;
                     requestAutoFill(callback, structure, extras, flags);
                     break;
                 } case MSG_AUTHENTICATE_FILL_RESPONSE: {
                     final int flags = msg.arg1;
                     final Bundle extras = (Bundle) msg.obj;
                     onFillResponseAuthenticationRequest(extras, flags);
                     break;
                 } case MSG_AUTHENTICATE_DATASET: {
                     final int flags = msg.arg1;
                     final Bundle extras = (Bundle) msg.obj;
                     onDatasetAuthenticationRequest(extras, flags);
                     break;
                 } case MSG_DISCONNECT: {
                     onDisconnected();
                     break;
                 } default: {
                     Log.w(TAG, "MyCallbacks received invalid message type: " + msg);
                 }
             }
         }
     };

     private HandlerCaller mHandlerCaller;

     // User for debugging purposes
     private final List<CallbackHelper.Dumpable> mPendingCallbacks =
             DEBUG_PENDING_CALLBACKS ? new ArrayList<>() : null;

     /**
      * {@inheritDoc}
      *
      * <strong>NOTE: </strong>if overridden, it must call {@code super.onCreate()}.
      */
     @Override
     public void onCreate() {
         super.onCreate();

         mHandlerCaller = new HandlerCaller(null, Looper.getMainLooper(), mHandlerCallback, true);
     }

     @Override
     public final IBinder onBind(Intent intent) {
         if (SERVICE_INTERFACE.equals(intent.getAction())) {
             return mInterface.asBinder();
         }
         Log.w(TAG, "Tried to bind to wrong intent: " + intent);
         return null;
     }

     /**
      * Called when the Android system connects to service.
      *
      * <p>You should generally do initialization here rather than in {@link #onCreate}.
      */
     public void onConnected() {
         if (DEBUG) Log.d(TAG, "onConnected()");
     }

     /**
      * Called by the Android system do decide if an {@link Activity} can be auto-filled by the
      * service.
      *
      * <p>Service must call one of the {@link FillCallback} methods (like
      * {@link FillCallback#onSuccess(FillResponse)} or {@link FillCallback#onFailure(CharSequence)})
      * to notify the result of the request.
      *
      * @param structure {@link Activity}'s view structure.
      * @param data bundle containing additional arguments set by the Android system (currently none)
      * or data passed by the service on previous calls to fullfill other sections of this activity
      * (see {@link FillResponse} Javadoc for examples of multiple-sections requests).
      * @param cancellationSignal signal for observing cancel requests.
      * @param callback object used to notify the result of the request.
      */
     public abstract void onFillRequest(AssistStructure structure,
             Bundle data, CancellationSignal cancellationSignal, FillCallback callback);

     /**
      * Called when user requests service to save the fields of an {@link Activity}.
      *
      * <p>Service must call one of the {@link SaveCallback} methods (like
      * {@link SaveCallback#onSuccess(AutoFillId[])} or {@link SaveCallback#onFailure(CharSequence)})
      * to notify the result of the request.
      *
      * @param structure {@link Activity}'s view structure.
      * @param data bundle containing additional arguments set by the Android system (currently none)
      * or data passed by the service in the {@link FillResponse} that originated this call.
      * @param cancellationSignal signal for observing cancel requests.
      * @param callback object used to notify the result of the request.
      */
     public abstract void onSaveRequest(AssistStructure structure,
             Bundle data, CancellationSignal cancellationSignal, SaveCallback callback);

     /**
      * Called as result of the user action for a {@link FillResponse} that required authentication.
      *
      * <p>When the {@link FillResponse} required authentication through
      * {@link android.view.autofill.FillResponse.Builder#requiresCustomAuthentication(Bundle, int)}, this
      * call indicates the user is requesting the service to authenticate him/her (and {@code flags}
      * contains {@link #FLAG_AUTHENTICATION_REQUESTED}), and {@code extras} contains the
      * {@link Bundle} passed to that method.
      *
      * <p>When the {@link FillResponse} required authentication through
      * {@link android.view.autofill.FillResponse.Builder#requiresFingerprintAuthentication(
      * android.hardware.fingerprint.FingerprintManager.CryptoObject, Bundle, int)},
      * {@code flags} this call contains the result of the fingerprint authentication (such as
      * {@link #FLAG_AUTHENTICATION_SUCCESS}, {@link #FLAG_AUTHENTICATION_ERROR}, and
      * {@link #FLAG_FINGERPRINT_AUTHENTICATION_NOT_AVAILABLE}) and {@code extras} contains the
      * {@link Bundle} passed to that method.
      */
     public void onFillResponseAuthenticationRequest(@SuppressWarnings("unused") Bundle extras,
             int flags) {
         if (DEBUG) Log.d(TAG, "onFillResponseAuthenticationRequest(): flags=" + flags);
     }

     /**
      * Called as result of the user action for a {@link Dataset} that required authentication.
      *
      * <p>When the {@link Dataset} required authentication through
      * {@link android.view.autofill.Dataset.Builder#requiresCustomAuthentication(Bundle, int)}, this
      * call indicates the user is requesting the service to authenticate him/her (and {@code flags}
      * contains {@link #FLAG_AUTHENTICATION_REQUESTED}), and {@code extras} contains the
      * {@link Bundle} passed to that method.
      *
      * <p>When the {@link Dataset} required authentication through
      * {@link android.view.autofill.Dataset.Builder#requiresFingerprintAuthentication(
      * android.hardware.fingerprint.FingerprintManager.CryptoObject, Bundle, int)},
      * {@code flags} this call contains the result of the fingerprint authentication (such as
      * {@link #FLAG_AUTHENTICATION_SUCCESS}, {@link #FLAG_AUTHENTICATION_ERROR}, and
      * {@link #FLAG_FINGERPRINT_AUTHENTICATION_NOT_AVAILABLE}) and {@code extras} contains the
      * {@link Bundle} passed to that method.
      */
     public void onDatasetAuthenticationRequest(@SuppressWarnings("unused") Bundle extras,
             int flags) {
         if (DEBUG) Log.d(TAG, "onDatasetAuthenticationRequest(): flags=" + flags);
     }

     // TODO(b/33197203): make it final and create another method classes could extend so it's
     // guaranteed to dump the pending callbacks?
     @Override
     protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
         if (mPendingCallbacks != null) {
             pw.print("Number of pending callbacks: "); pw.println(mPendingCallbacks.size());
             final String prefix = "  ";
             for (int i = 0; i < mPendingCallbacks.size(); i++) {
                 final CallbackHelper.Dumpable cb = mPendingCallbacks.get(i);
                 pw.print('#'); pw.print(i + 1); pw.println(':');
                 cb.dump(prefix, pw);
             }
             pw.println();
         } else {
             pw.println("Dumping disabled");
         }
     }

     private void requestAutoFill(IAutoFillServerCallback callback, AssistStructure structure,
             Bundle data, int flags) {
         switch (flags) {
             case AUTO_FILL_FLAG_TYPE_FILL:
                 final FillCallback fillCallback = new FillCallback(callback);
                 if (DEBUG_PENDING_CALLBACKS) {
                     addPendingCallback(fillCallback);
                 }
                 // TODO(b/33197203): hook up the cancelationSignal
                 onFillRequest(structure, data, new CancellationSignal(), fillCallback);
                 break;
             case AUTO_FILL_FLAG_TYPE_SAVE:
                 final SaveCallback saveCallback = new SaveCallback(callback);
                 if (DEBUG_PENDING_CALLBACKS) {
                     addPendingCallback(saveCallback);
                 }
                 // TODO(b/33197203): hook up the cancelationSignal
                 onSaveRequest(structure, data, new CancellationSignal(), saveCallback);
                 break;
             default:
                 Log.w(TAG, "invalid flag on requestAutoFill(): " + flags);
         }
     }

     private void addPendingCallback(CallbackHelper.Dumpable callback) {
         if (mPendingCallbacks == null) {
             // Shouldn't happend since call is controlled by DEBUG_PENDING_CALLBACKS guard.
             Log.wtf(TAG, "addPendingCallback(): mPendingCallbacks not set");
             return;
         }

         if (DEBUG) Log.d(TAG, "Adding pending callback: " + callback);

         callback.setFinalizer(() -> {
             if (DEBUG) Log.d(TAG, "Removing pending callback: " + callback);
             mPendingCallbacks.remove(callback);
         });
         mPendingCallbacks.add(callback);
     }

     /**
      * Called when the Android system disconnects from the service.
      *
      * <p> At this point this service may no longer be an active {@link AutoFillService}.
      */
     public void onDisconnected() {
         if (DEBUG) Log.d(TAG, "onDisconnected()");
     }
 }
	/*
	* Copyright (C) 2016 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.service.autofill;

	import static android.view.View.AUTO_FILL_FLAG_TYPE_FILL;
	import static android.view.View.AUTO_FILL_FLAG_TYPE_SAVE;

	import android.annotation.SdkConstant;
	import android.app.Activity;
	import android.app.Service;
	import android.app.assist.AssistStructure;
	import android.content.Intent;
	import android.os.Bundle;
	import android.os.CancellationSignal;
	import android.os.IBinder;
	import android.os.Looper;
	import android.os.Message;
	import android.util.Log;
	import android.view.autofill.AutoFillId;
	import android.view.autofill.Dataset;
	import android.view.autofill.FillResponse;

	import com.android.internal.os.HandlerCaller;
	import com.android.internal.os.SomeArgs;

	import java.io.FileDescriptor;
	import java.io.PrintWriter;
	import java.util.ArrayList;
	import java.util.List;

	//TODO(b/33197203): improve javadoc (of both class and methods); in particular, make sure the
	//life-cycle (and how state could be maintained on server-side) is well documented.

	/**
	* Top-level service of the current auto-fill service for a given user.
	*
	* <p>Apps providing auto-fill capabilities must extend this service.
	*/
	public abstract class AutoFillService extends Service {

	private static final String TAG = "AutoFillService";
	static final boolean DEBUG = true; // TODO(b/33197203): set to false once stable

	// TODO(b/33197203): check for device's memory size instead of DEBUG?
	static final boolean DEBUG_PENDING_CALLBACKS = DEBUG;

	/**
	* The {@link Intent} that must be declared as handled by the service.
	* To be supported, the service must also require the
	* {@link android.Manifest.permission#BIND_AUTO_FILL} permission so
	* that other applications can not abuse it.
	*/
	@SdkConstant(SdkConstant.SdkConstantType.SERVICE_ACTION)
	public static final String SERVICE_INTERFACE = "android.service.autofill.AutoFillService";

	/**
	* Name under which a AutoFillService component publishes information about itself.
	* This meta-data should reference an XML resource containing a
	* <code><{@link
	* android.R.styleable#AutoFillService autofill-service}></code> tag.
	* This is a a sample XML file configuring an AutoFillService:
	* <pre> <autofill-service
	* android:settingsActivity="foo.bar.SettingsActivity"
	* . . .
	* /></pre>
	*/
	public static final String SERVICE_META_DATA = "android.autofill";

	// Internal bundle keys.
	/** @hide */ public static final String KEY_CALLBACK = "callback";
	/** @hide */ public static final String KEY_SAVABLE_IDS = "savable_ids";
	/** @hide */ public static final String EXTRA_CRYPTO_OBJECT_ID = "crypto_object_id";

	// Prefix for public bundle keys.
	private static final String KEY_PREFIX = "android.service.autofill.extra.";

	/**
	* Key of the {@link Bundle} passed to methods such as
	* {@link #onSaveRequest(AssistStructure, Bundle, CancellationSignal, SaveCallback)}
	* containing the extras set by
	* {@link android.view.autofill.FillResponse.Builder#setExtras(Bundle)}.
	*/
	public static final String EXTRA_RESPONSE_EXTRAS = KEY_PREFIX + "RESPONSE_EXTRAS";

	/**
	* Key of the {@link Bundle} passed to methods such as
	* {@link #onSaveRequest(AssistStructure, Bundle, CancellationSignal, SaveCallback)}
	* containing the extras set by
	* {@link android.view.autofill.Dataset.Builder#setExtras(Bundle)}.
	*/
	public static final String EXTRA_DATASET_EXTRAS = KEY_PREFIX + "DATASET_EXTRAS";

	/**
	* Used to indicate the user selected an action that requires authentication.
	*/
	public static final int FLAG_AUTHENTICATION_REQUESTED = 1 << 0;

	/**
	* Used to indicate the user authentication succeeded.
	*/
	public static final int FLAG_AUTHENTICATION_SUCCESS = 1 << 1;

	/**
	* Used to indicate the user authentication failed.
	*/
	public static final int FLAG_AUTHENTICATION_ERROR = 1 << 2;

	/**
	* Used when the service requested Fingerprint authentication but such option is not available.
	*/
	public static final int FLAG_FINGERPRINT_AUTHENTICATION_NOT_AVAILABLE = 1 << 3;

	// Handler messages.
	private static final int MSG_CONNECT = 1;
	private static final int MSG_DISCONNECT = 2;
	private static final int MSG_AUTO_FILL_ACTIVITY = 3;
	private static final int MSG_AUTHENTICATE_FILL_RESPONSE = 4;
	private static final int MSG_AUTHENTICATE_DATASET = 5;

	private final IAutoFillService mInterface = new IAutoFillService.Stub() {

	@Override
	public void autoFill(AssistStructure structure, IAutoFillServerCallback callback,
	Bundle extras, int flags) {
	mHandlerCaller
	.obtainMessageIOOO(MSG_AUTO_FILL_ACTIVITY, flags, structure, extras, callback)
	.sendToTarget();
	}

	@Override
	public void authenticateFillResponse(Bundle extras, int flags) {
	final Message msg = mHandlerCaller.obtainMessage(MSG_AUTHENTICATE_FILL_RESPONSE);
	msg.arg1 = flags;
	msg.obj = extras;
	mHandlerCaller.sendMessage(msg);
	}

	@Override
	public void authenticateDataset(Bundle extras, int flags) {
	final Message msg = mHandlerCaller.obtainMessage(MSG_AUTHENTICATE_DATASET);
	msg.arg1 = flags;
	msg.obj = extras;
	mHandlerCaller.sendMessage(msg);
	}

	@Override
	public void onConnected() {
	mHandlerCaller.sendMessage(mHandlerCaller.obtainMessage(MSG_CONNECT));
	}

	@Override
	public void onDisconnected() {
	mHandlerCaller.sendMessage(mHandlerCaller.obtainMessage(MSG_DISCONNECT));
	}
	};

	private final HandlerCaller.Callback mHandlerCallback = new HandlerCaller.Callback() {

	@Override
	public void executeMessage(Message msg) {
	switch (msg.what) {
	case MSG_CONNECT: {
	onConnected();
	break;
	} case MSG_AUTO_FILL_ACTIVITY: {
	final SomeArgs args = (SomeArgs) msg.obj;
	final int flags = msg.arg1;
	final AssistStructure structure = (AssistStructure) args.arg1;
	final Bundle extras = (Bundle) args.arg2;
	final IAutoFillServerCallback callback = (IAutoFillServerCallback) args.arg3;
	requestAutoFill(callback, structure, extras, flags);
	break;
	} case MSG_AUTHENTICATE_FILL_RESPONSE: {
	final int flags = msg.arg1;
	final Bundle extras = (Bundle) msg.obj;
	onFillResponseAuthenticationRequest(extras, flags);
	break;
	} case MSG_AUTHENTICATE_DATASET: {
	final int flags = msg.arg1;
	final Bundle extras = (Bundle) msg.obj;
	onDatasetAuthenticationRequest(extras, flags);
	break;
	} case MSG_DISCONNECT: {
	onDisconnected();
	break;
	} default: {
	Log.w(TAG, "MyCallbacks received invalid message type: " + msg);
	}
	}
	}
	};

	private HandlerCaller mHandlerCaller;

	// User for debugging purposes
	private final List<CallbackHelper.Dumpable> mPendingCallbacks =
	DEBUG_PENDING_CALLBACKS ? new ArrayList<>() : null;

	/**
	* {@inheritDoc}
	*
	* <strong>NOTE: </strong>if overridden, it must call {@code super.onCreate()}.
	*/
	@Override
	public void onCreate() {
	super.onCreate();

	mHandlerCaller = new HandlerCaller(null, Looper.getMainLooper(), mHandlerCallback, true);
	}

	@Override
	public final IBinder onBind(Intent intent) {
	if (SERVICE_INTERFACE.equals(intent.getAction())) {
	return mInterface.asBinder();
	}
	Log.w(TAG, "Tried to bind to wrong intent: " + intent);
	return null;
	}

	/**
	* Called when the Android system connects to service.
	*
	* <p>You should generally do initialization here rather than in {@link #onCreate}.
	*/
	public void onConnected() {
	if (DEBUG) Log.d(TAG, "onConnected()");
	}

	/**
	* Called by the Android system do decide if an {@link Activity} can be auto-filled by the
	* service.
	*
	* <p>Service must call one of the {@link FillCallback} methods (like
	* {@link FillCallback#onSuccess(FillResponse)} or {@link FillCallback#onFailure(CharSequence)})
	* to notify the result of the request.
	*
	* @param structure {@link Activity}'s view structure.
	* @param data bundle containing additional arguments set by the Android system (currently none)
	* or data passed by the service on previous calls to fullfill other sections of this activity
	* (see {@link FillResponse} Javadoc for examples of multiple-sections requests).
	* @param cancellationSignal signal for observing cancel requests.
	* @param callback object used to notify the result of the request.
	*/
	public abstract void onFillRequest(AssistStructure structure,
	Bundle data, CancellationSignal cancellationSignal, FillCallback callback);

	/**
	* Called when user requests service to save the fields of an {@link Activity}.
	*
	* <p>Service must call one of the {@link SaveCallback} methods (like
	* {@link SaveCallback#onSuccess(AutoFillId[])} or {@link SaveCallback#onFailure(CharSequence)})
	* to notify the result of the request.
	*
	* @param structure {@link Activity}'s view structure.
	* @param data bundle containing additional arguments set by the Android system (currently none)
	* or data passed by the service in the {@link FillResponse} that originated this call.
	* @param cancellationSignal signal for observing cancel requests.
	* @param callback object used to notify the result of the request.
	*/
	public abstract void onSaveRequest(AssistStructure structure,
	Bundle data, CancellationSignal cancellationSignal, SaveCallback callback);

	/**
	* Called as result of the user action for a {@link FillResponse} that required authentication.
	*
	* <p>When the {@link FillResponse} required authentication through
	* {@link android.view.autofill.FillResponse.Builder#requiresCustomAuthentication(Bundle, int)}, this
	* call indicates the user is requesting the service to authenticate him/her (and {@code flags}
	* contains {@link #FLAG_AUTHENTICATION_REQUESTED}), and {@code extras} contains the
	* {@link Bundle} passed to that method.
	*
	* <p>When the {@link FillResponse} required authentication through
	* {@link android.view.autofill.FillResponse.Builder#requiresFingerprintAuthentication(
	* android.hardware.fingerprint.FingerprintManager.CryptoObject, Bundle, int)},
	* {@code flags} this call contains the result of the fingerprint authentication (such as
	* {@link #FLAG_AUTHENTICATION_SUCCESS}, {@link #FLAG_AUTHENTICATION_ERROR}, and
	* {@link #FLAG_FINGERPRINT_AUTHENTICATION_NOT_AVAILABLE}) and {@code extras} contains the
	* {@link Bundle} passed to that method.
	*/
	public void onFillResponseAuthenticationRequest(@SuppressWarnings("unused") Bundle extras,
	int flags) {
	if (DEBUG) Log.d(TAG, "onFillResponseAuthenticationRequest(): flags=" + flags);
	}

	/**
	* Called as result of the user action for a {@link Dataset} that required authentication.
	*
	* <p>When the {@link Dataset} required authentication through
	* {@link android.view.autofill.Dataset.Builder#requiresCustomAuthentication(Bundle, int)}, this
	* call indicates the user is requesting the service to authenticate him/her (and {@code flags}
	* contains {@link #FLAG_AUTHENTICATION_REQUESTED}), and {@code extras} contains the
	* {@link Bundle} passed to that method.
	*
	* <p>When the {@link Dataset} required authentication through
	* {@link android.view.autofill.Dataset.Builder#requiresFingerprintAuthentication(
	* android.hardware.fingerprint.FingerprintManager.CryptoObject, Bundle, int)},
	* {@code flags} this call contains the result of the fingerprint authentication (such as
	* {@link #FLAG_AUTHENTICATION_SUCCESS}, {@link #FLAG_AUTHENTICATION_ERROR}, and
	* {@link #FLAG_FINGERPRINT_AUTHENTICATION_NOT_AVAILABLE}) and {@code extras} contains the
	* {@link Bundle} passed to that method.
	*/
	public void onDatasetAuthenticationRequest(@SuppressWarnings("unused") Bundle extras,
	int flags) {
	if (DEBUG) Log.d(TAG, "onDatasetAuthenticationRequest(): flags=" + flags);
	}

	// TODO(b/33197203): make it final and create another method classes could extend so it's
	// guaranteed to dump the pending callbacks?
	@Override
	protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
	if (mPendingCallbacks != null) {
	pw.print("Number of pending callbacks: "); pw.println(mPendingCallbacks.size());
	final String prefix = " ";
	for (int i = 0; i < mPendingCallbacks.size(); i++) {
	final CallbackHelper.Dumpable cb = mPendingCallbacks.get(i);
	pw.print('#'); pw.print(i + 1); pw.println(':');
	cb.dump(prefix, pw);
	}
	pw.println();
	} else {
	pw.println("Dumping disabled");
	}
	}

	private void requestAutoFill(IAutoFillServerCallback callback, AssistStructure structure,
	Bundle data, int flags) {
	switch (flags) {
	case AUTO_FILL_FLAG_TYPE_FILL:
	final FillCallback fillCallback = new FillCallback(callback);
	if (DEBUG_PENDING_CALLBACKS) {
	addPendingCallback(fillCallback);
	}
	// TODO(b/33197203): hook up the cancelationSignal
	onFillRequest(structure, data, new CancellationSignal(), fillCallback);
	break;
	case AUTO_FILL_FLAG_TYPE_SAVE:
	final SaveCallback saveCallback = new SaveCallback(callback);
	if (DEBUG_PENDING_CALLBACKS) {
	addPendingCallback(saveCallback);
	}
	// TODO(b/33197203): hook up the cancelationSignal
	onSaveRequest(structure, data, new CancellationSignal(), saveCallback);
	break;
	default:
	Log.w(TAG, "invalid flag on requestAutoFill(): " + flags);
	}
	}

	private void addPendingCallback(CallbackHelper.Dumpable callback) {
	if (mPendingCallbacks == null) {
	// Shouldn't happend since call is controlled by DEBUG_PENDING_CALLBACKS guard.
	Log.wtf(TAG, "addPendingCallback(): mPendingCallbacks not set");
	return;
	}

	if (DEBUG) Log.d(TAG, "Adding pending callback: " + callback);

	callback.setFinalizer(() -> {
	if (DEBUG) Log.d(TAG, "Removing pending callback: " + callback);
	mPendingCallbacks.remove(callback);
	});
	mPendingCallbacks.add(callback);
	}

	/**
	* Called when the Android system disconnects from the service.
	*
	* <p> At this point this service may no longer be an active {@link AutoFillService}.
	*/
	public void onDisconnected() {
	if (DEBUG) Log.d(TAG, "onDisconnected()");
	}
	}