core/java/android/view/contentcapture/MainContentCaptureSession.java - platform/frameworks/base - Gitiles

 /*
  * Copyright (C) 2018 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package android.view.contentcapture;

 import static android.view.contentcapture.ContentCaptureEvent.TYPE_SESSION_FINISHED;
 import static android.view.contentcapture.ContentCaptureEvent.TYPE_SESSION_STARTED;
 import static android.view.contentcapture.ContentCaptureEvent.TYPE_VIEW_APPEARED;
 import static android.view.contentcapture.ContentCaptureEvent.TYPE_VIEW_DISAPPEARED;
 import static android.view.contentcapture.ContentCaptureEvent.TYPE_VIEW_TEXT_CHANGED;
 import static android.view.contentcapture.ContentCaptureManager.DEBUG;
 import static android.view.contentcapture.ContentCaptureManager.VERBOSE;

 import static com.android.internal.util.function.pooled.PooledLambda.obtainMessage;

 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.pm.ParceledListSlice;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.IBinder;
 import android.os.IBinder.DeathRecipient;
 import android.os.RemoteException;
 import android.os.SystemClock;
 import android.util.Log;
 import android.util.TimeUtils;
 import android.view.autofill.AutofillId;
 import android.view.contentcapture.ViewNode.ViewStructureImpl;

 import com.android.internal.os.IResultReceiver;

 import java.io.PrintWriter;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicBoolean;

 /**
  * Main session associated with a context.
  *
  * <p>This session is created when the activity starts and finished when it stops; clients can use
  * it to create children activities.
  *
  * <p><b>NOTE: all methods in this class should return right away, or do the real work in a handler
  * thread. Hence, the only field that must be thread-safe is {@code mEnabled}, which is called at
  * the beginning of every method.
  *
  * @hide
  */
 public final class MainContentCaptureSession extends ContentCaptureSession {

     /**
      * Handler message used to flush the buffer.
      */
     private static final int MSG_FLUSH = 1;

     /**
      * Maximum number of events that are buffered before sent to the app.
      */
     // TODO(b/121044064): use settings
     private static final int MAX_BUFFER_SIZE = 100;

     /**
      * Frequency the buffer is flushed if stale.
      */
     // TODO(b/121044064): use settings
     private static final int FLUSHING_FREQUENCY_MS = 5_000;

     /**
      * Name of the {@link IResultReceiver} extra used to pass the binder interface to the service.
      * @hide
      */
     public static final String EXTRA_BINDER = "binder";

     @NonNull
     private final AtomicBoolean mDisabled;

     @NonNull
     private final Context mContext;

     @NonNull
     private final Handler mHandler;

     /**
      * Interface to the system_server binder object - it's only used to start the session (and
      * notify when the session is finished).
      */
     @Nullable
     private final IContentCaptureManager mSystemServerInterface;

     /**
      * Direct interface to the service binder object - it's used to send the events, including the
      * last ones (when the session is finished)
      */
     @Nullable
     private IContentCaptureDirectManager mDirectServiceInterface;
     @Nullable
     private DeathRecipient mDirectServiceVulture;

     private int mState = STATE_UNKNOWN;

     @Nullable
     private IBinder mApplicationToken;

     @Nullable
     private ComponentName mComponentName;

     /**
      * List of events held to be sent as a batch.
      */
     @Nullable
     private ArrayList<ContentCaptureEvent> mEvents;

     // Used just for debugging purposes (on dump)
     private long mNextFlush;

     // Lazily created on demand.
     private ContentCaptureSessionId mContentCaptureSessionId;

     /** @hide */
     protected MainContentCaptureSession(@NonNull Context context, @NonNull Handler handler,
             @Nullable IContentCaptureManager systemServerInterface,
             @NonNull AtomicBoolean disabled) {
         mContext = context;
         mHandler = handler;
         mSystemServerInterface = systemServerInterface;
         mDisabled = disabled;
     }

     @Override
     ContentCaptureSession newChild(@NonNull ContentCaptureContext clientContext) {
         final ContentCaptureSession child = new ChildContentCaptureSession(this, clientContext);
         notifyChildSessionStarted(mId, child.mId, clientContext);
         return child;
     }

     /**
      * Starts this session.
      *
      * @hide
      */
     void start(@NonNull IBinder applicationToken, @NonNull ComponentName activityComponent) {
         if (!isContentCaptureEnabled()) return;

         if (VERBOSE) {
             Log.v(mTag, "start(): token=" + applicationToken + ", comp="
                     + ComponentName.flattenToShortString(activityComponent));
         }

         mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleStartSession, this,
                 applicationToken, activityComponent));
     }

     @Override
     void flush() {
         mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleForceFlush, this));
     }

     @Override
     void onDestroy() {
         mHandler.sendMessage(
                 obtainMessage(MainContentCaptureSession::handleDestroySession, this));
     }

     private void handleStartSession(@NonNull IBinder token, @NonNull ComponentName componentName) {
         if (mState != STATE_UNKNOWN) {
             // TODO(b/111276913): revisit this scenario
             Log.w(mTag, "ignoring handleStartSession(" + token + ") while on state "
                     + getStateAsString(mState));
             return;
         }
         mState = STATE_WAITING_FOR_SERVER;
         mApplicationToken = token;
         mComponentName = componentName;

         if (VERBOSE) {
             Log.v(mTag, "handleStartSession(): token=" + token + ", act="
                     + getActivityDebugName() + ", id=" + mId);
         }
         final int flags = 0; // TODO(b/111276913): get proper flags

         try {
             mSystemServerInterface.startSession(mContext.getUserId(), mApplicationToken,
                     componentName, mId, flags, new IResultReceiver.Stub() {
                         @Override
                         public void send(int resultCode, Bundle resultData) {
                             IBinder binder = null;
                             if (resultData != null) {
                                 binder = resultData.getBinder(EXTRA_BINDER);
                                 if (binder == null) {
                                     Log.wtf(mTag, "No " + EXTRA_BINDER + " extra result");
                                     handleResetState();
                                     return;
                                 }
                             }
                             handleSessionStarted(resultCode, binder);
                         }
                     });
         } catch (RemoteException e) {
             Log.w(mTag, "Error starting session for " + componentName.flattenToShortString() + ": "
                     + e);
         }
     }

     /**
      * Callback from {@code system_server} after call to
      * {@link IContentCaptureManager#startSession(int, IBinder, ComponentName, String,
      * int, IResultReceiver)}.
      *
      * @param resultCode session state
      * @param binder handle to {@code IContentCaptureDirectManager}
      */
     private void handleSessionStarted(int resultCode, @Nullable IBinder binder) {
         mState = resultCode;
         if (binder != null) {
             mDirectServiceInterface = IContentCaptureDirectManager.Stub.asInterface(binder);
             mDirectServiceVulture = () -> {
                 Log.w(mTag, "Destroying session " + mId + " because service died");
                 destroy();
             };
             try {
                 binder.linkToDeath(mDirectServiceVulture, 0);
             } catch (RemoteException e) {
                 Log.w(mTag, "Failed to link to death on " + binder + ": " + e);
             }
         }
         if (resultCode == STATE_DISABLED || resultCode == STATE_DISABLED_DUPLICATED_ID) {
             mDisabled.set(true);
             handleResetSession(/* resetState= */ false);
         } else {
             mDisabled.set(false);
         }
         if (VERBOSE) {
             Log.v(mTag, "handleSessionStarted() result: code=" + resultCode + ", id=" + mId
                     + ", state=" + getStateAsString(mState) + ", disabled=" + mDisabled.get()
                     + ", binder=" + binder);
         }
     }

     private void handleSendEvent(@NonNull ContentCaptureEvent event, boolean forceFlush) {
         if (mEvents == null) {
             if (VERBOSE) {
                 Log.v(mTag, "Creating buffer for " + MAX_BUFFER_SIZE + " events");
             }
             mEvents = new ArrayList<>(MAX_BUFFER_SIZE);
         }

         if (!mEvents.isEmpty() && event.getType() == TYPE_VIEW_TEXT_CHANGED) {
             final ContentCaptureEvent lastEvent = mEvents.get(mEvents.size() - 1);

             // TODO(b/121045053): check if flags match
             if (lastEvent.getType() == TYPE_VIEW_TEXT_CHANGED
                     && lastEvent.getId().equals(event.getId())) {
                 if (VERBOSE) {
                     Log.v(mTag, "Buffering VIEW_TEXT_CHANGED event, updated text = "
                             + event.getText());
                 }
                 lastEvent.setText(event.getText());
             } else {
                 mEvents.add(event);
             }
         } else {
             mEvents.add(event);
         }

         final int numberEvents = mEvents.size();

         final boolean bufferEvent = numberEvents < MAX_BUFFER_SIZE;

         if (bufferEvent && !forceFlush) {
             handleScheduleFlush(/* checkExisting= */ true);
             return;
         }

         if (mState != STATE_ACTIVE) {
             // Callback from startSession hasn't been called yet - typically happens on system
             // apps that are started before the system service
             // TODO(b/111276913): try to ignore session while system is not ready / boot
             // not complete instead. Similarly, the manager service should return right away
             // when the user does not have a service set
             if (VERBOSE) {
                 Log.v(mTag, "Closing session for " + getActivityDebugName()
                         + " after " + numberEvents + " delayed events and state "
                         + getStateAsString(mState));
             }
             handleResetState();
             // TODO(b/111276913): blacklist activity / use special flag to indicate that
             // when it's launched again
             return;
         }

         handleForceFlush();
     }

     private void handleScheduleFlush(boolean checkExisting) {
         if (checkExisting && mHandler.hasMessages(MSG_FLUSH)) {
             // "Renew" the flush message by removing the previous one
             mHandler.removeMessages(MSG_FLUSH);
         }
         mNextFlush = SystemClock.elapsedRealtime() + FLUSHING_FREQUENCY_MS;
         if (VERBOSE) {
             Log.v(mTag, "Scheduled to flush in " + FLUSHING_FREQUENCY_MS + "ms: " + mNextFlush);
         }
         mHandler.sendMessageDelayed(
                 obtainMessage(MainContentCaptureSession::handleFlushIfNeeded, this)
                 .setWhat(MSG_FLUSH), FLUSHING_FREQUENCY_MS);
     }

     private void handleFlushIfNeeded() {
         if (mEvents.isEmpty()) {
             if (VERBOSE) Log.v(mTag, "Nothing to flush");
             return;
         }
         handleForceFlush();
     }

     private void handleForceFlush() {
         if (mEvents == null) return;

         if (mDirectServiceInterface == null) {
             if (DEBUG) Log.d(mTag, "handleForceFlush(): hold your horses, client not ready yet!");
             if (!mHandler.hasMessages(MSG_FLUSH)) {
                 handleScheduleFlush(/* checkExisting= */ false);
             }
             return;
         }

         final int numberEvents = mEvents.size();
         try {
             if (DEBUG) {
                 Log.d(mTag, "Flushing " + numberEvents + " event(s) for " + getActivityDebugName());
             }
             mHandler.removeMessages(MSG_FLUSH);

             final ParceledListSlice<ContentCaptureEvent> events = handleClearEvents();
             mDirectServiceInterface.sendEvents(events);
         } catch (RemoteException e) {
             Log.w(mTag, "Error sending " + numberEvents + " for " + getActivityDebugName()
                     + ": " + e);
         }
     }

     /**
      * Resets the buffer and return a {@link ParceledListSlice} with the previous events.
      */
     @NonNull
     private ParceledListSlice<ContentCaptureEvent> handleClearEvents() {
         // NOTE: we must save a reference to the current mEvents and then set it to to null,
         // otherwise clearing it would clear it in the receiving side if the service is also local.
         final List<ContentCaptureEvent> events = mEvents == null
                 ? Collections.emptyList()
                 : mEvents;
         mEvents = null;
         return new ParceledListSlice<>(events);
     }

     private void handleDestroySession() {
         if (DEBUG) {
             Log.d(mTag, "Destroying session (ctx=" + mContext + ", id=" + mId + ") with "
                     + (mEvents == null ? 0 : mEvents.size()) + " event(s) for "
                     + getActivityDebugName());
         }

         try {
             mSystemServerInterface.finishSession(mContext.getUserId(), mId);
         } catch (RemoteException e) {
             Log.e(mTag, "Error destroying system-service session " + mId + " for "
                     + getActivityDebugName() + ": " + e);
         }
     }

     private void handleResetState() {
         handleResetSession(/* resetState= */ true);
     }

     // TODO(b/121033016): once we support multiple sessions, we might need to move some of these
     // clearings out.
     private void handleResetSession(boolean resetState) {
         if (resetState) {
             mState = STATE_UNKNOWN;
         }

         // TODO(b/121033016): must reset children (which currently is owned by superclass)

         mContentCaptureSessionId = null;
         mApplicationToken = null;
         mComponentName = null;
         mEvents = null;
         if (mDirectServiceInterface != null) {
             mDirectServiceInterface.asBinder().unlinkToDeath(mDirectServiceVulture, 0);
         }
         mDirectServiceInterface = null;
         mHandler.removeMessages(MSG_FLUSH);
     }

     @Override
     void internalNotifyViewAppeared(@NonNull ViewStructureImpl node) {
         notifyViewAppeared(mId, node);
     }

     @Override
     void internalNotifyViewDisappeared(@NonNull AutofillId id) {
         notifyViewDisappeared(mId, id);
     }

     @Override
     void internalNotifyViewTextChanged(@NonNull AutofillId id, @Nullable CharSequence text,
             int flags) {
         notifyViewTextChanged(mId, id, text, flags);
     }

     @Override
     boolean isContentCaptureEnabled() {
         return super.isContentCaptureEnabled() && mSystemServerInterface != null
                 && !mDisabled.get();
     }

     // TODO(b/121033016): refactor "notifyXXXX" methods below to a common "Buffer" object that is
     // shared between ActivityContentCaptureSession and ChildContentCaptureSession objects. Such
     // change should also get get rid of the "internalNotifyXXXX" methods above
     void notifyChildSessionStarted(@NonNull String parentSessionId,
             @NonNull String childSessionId, @NonNull ContentCaptureContext clientContext) {
         mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleSendEvent, this,
                 new ContentCaptureEvent(childSessionId, TYPE_SESSION_STARTED)
                         .setParentSessionId(parentSessionId)
                         .setClientContext(clientContext),
                         /* forceFlush= */ false));
     }

     void notifyChildSessionFinished(@NonNull String parentSessionId,
             @NonNull String childSessionId) {
         mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleSendEvent, this,
                 new ContentCaptureEvent(childSessionId, TYPE_SESSION_FINISHED)
                         .setParentSessionId(parentSessionId), /* forceFlush= */ false));
     }

     void notifyViewAppeared(@NonNull String sessionId, @NonNull ViewStructureImpl node) {
         mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleSendEvent, this,
                 new ContentCaptureEvent(sessionId, TYPE_VIEW_APPEARED)
                         .setViewNode(node.mNode), /* forceFlush= */ false));
     }

     void notifyViewDisappeared(@NonNull String sessionId, @NonNull AutofillId id) {
         mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleSendEvent, this,
                 new ContentCaptureEvent(sessionId, TYPE_VIEW_DISAPPEARED).setAutofillId(id),
                         /* forceFlush= */ false));
     }

     void notifyViewTextChanged(@NonNull String sessionId, @NonNull AutofillId id,
             @Nullable CharSequence text, int flags) {
         mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleSendEvent, this,
                 new ContentCaptureEvent(sessionId, TYPE_VIEW_TEXT_CHANGED, flags).setAutofillId(id)
                         .setText(text), /* forceFlush= */ false));
     }

     @Override
     void dump(@NonNull String prefix, @NonNull PrintWriter pw) {
         pw.print(prefix); pw.print("id: "); pw.println(mId);
         pw.print(prefix); pw.print("mContext: "); pw.println(mContext);
         pw.print(prefix); pw.print("user: "); pw.println(mContext.getUserId());
         if (mSystemServerInterface != null) {
             pw.print(prefix); pw.print("mSystemServerInterface: ");
             pw.println(mSystemServerInterface);
         }
         if (mDirectServiceInterface != null) {
             pw.print(prefix); pw.print("mDirectServiceInterface: ");
             pw.println(mDirectServiceInterface);
         }
         pw.print(prefix); pw.print("mDisabled: "); pw.println(mDisabled.get());
         pw.print(prefix); pw.print("isEnabled(): "); pw.println(isContentCaptureEnabled());
         if (mContentCaptureSessionId != null) {
             pw.print(prefix); pw.print("public id: "); pw.println(mContentCaptureSessionId);
         }
         pw.print(prefix); pw.print("state: "); pw.print(mState); pw.print(" (");
         pw.print(getStateAsString(mState)); pw.println(")");
         if (mApplicationToken != null) {
             pw.print(prefix); pw.print("app token: "); pw.println(mApplicationToken);
         }
         if (mComponentName != null) {
             pw.print(prefix); pw.print("component name: ");
             pw.println(mComponentName.flattenToShortString());
         }
         if (mEvents != null && !mEvents.isEmpty()) {
             final int numberEvents = mEvents.size();
             pw.print(prefix); pw.print("buffered events: "); pw.print(numberEvents);
             pw.print('/'); pw.println(MAX_BUFFER_SIZE);
             if (VERBOSE && numberEvents > 0) {
                 final String prefix3 = prefix + "  ";
                 for (int i = 0; i < numberEvents; i++) {
                     final ContentCaptureEvent event = mEvents.get(i);
                     pw.print(prefix3); pw.print(i); pw.print(": "); event.dump(pw);
                     pw.println();
                 }
             }
             pw.print(prefix); pw.print("flush frequency: "); pw.println(FLUSHING_FREQUENCY_MS);
             pw.print(prefix); pw.print("next flush: ");
             TimeUtils.formatDuration(mNextFlush - SystemClock.elapsedRealtime(), pw); pw.println();
         }
         super.dump(prefix, pw);
     }

     /**
      * Gets a string that can be used to identify the activity on logging statements.
      */
     private String getActivityDebugName() {
         return mComponentName == null ? mContext.getPackageName()
                 : mComponentName.flattenToShortString();
     }
 }
	/*
	* Copyright (C) 2018 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package android.view.contentcapture;

	import static android.view.contentcapture.ContentCaptureEvent.TYPE_SESSION_FINISHED;
	import static android.view.contentcapture.ContentCaptureEvent.TYPE_SESSION_STARTED;
	import static android.view.contentcapture.ContentCaptureEvent.TYPE_VIEW_APPEARED;
	import static android.view.contentcapture.ContentCaptureEvent.TYPE_VIEW_DISAPPEARED;
	import static android.view.contentcapture.ContentCaptureEvent.TYPE_VIEW_TEXT_CHANGED;
	import static android.view.contentcapture.ContentCaptureManager.DEBUG;
	import static android.view.contentcapture.ContentCaptureManager.VERBOSE;

	import static com.android.internal.util.function.pooled.PooledLambda.obtainMessage;

	import android.annotation.NonNull;
	import android.annotation.Nullable;
	import android.content.ComponentName;
	import android.content.Context;
	import android.content.pm.ParceledListSlice;
	import android.os.Bundle;
	import android.os.Handler;
	import android.os.IBinder;
	import android.os.IBinder.DeathRecipient;
	import android.os.RemoteException;
	import android.os.SystemClock;
	import android.util.Log;
	import android.util.TimeUtils;
	import android.view.autofill.AutofillId;
	import android.view.contentcapture.ViewNode.ViewStructureImpl;

	import com.android.internal.os.IResultReceiver;

	import java.io.PrintWriter;
	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.List;
	import java.util.concurrent.atomic.AtomicBoolean;

	/**
	* Main session associated with a context.
	*
	* <p>This session is created when the activity starts and finished when it stops; clients can use
	* it to create children activities.
	*
	* <p><b>NOTE: all methods in this class should return right away, or do the real work in a handler
	* thread. Hence, the only field that must be thread-safe is {@code mEnabled}, which is called at
	* the beginning of every method.
	*
	* @hide
	*/
	public final class MainContentCaptureSession extends ContentCaptureSession {

	/**
	* Handler message used to flush the buffer.
	*/
	private static final int MSG_FLUSH = 1;

	/**
	* Maximum number of events that are buffered before sent to the app.
	*/
	// TODO(b/121044064): use settings
	private static final int MAX_BUFFER_SIZE = 100;

	/**
	* Frequency the buffer is flushed if stale.
	*/
	// TODO(b/121044064): use settings
	private static final int FLUSHING_FREQUENCY_MS = 5_000;

	/**
	* Name of the {@link IResultReceiver} extra used to pass the binder interface to the service.
	* @hide
	*/
	public static final String EXTRA_BINDER = "binder";

	@NonNull
	private final AtomicBoolean mDisabled;

	@NonNull
	private final Context mContext;

	@NonNull
	private final Handler mHandler;

	/**
	* Interface to the system_server binder object - it's only used to start the session (and
	* notify when the session is finished).
	*/
	@Nullable
	private final IContentCaptureManager mSystemServerInterface;

	/**
	* Direct interface to the service binder object - it's used to send the events, including the
	* last ones (when the session is finished)
	*/
	@Nullable
	private IContentCaptureDirectManager mDirectServiceInterface;
	@Nullable
	private DeathRecipient mDirectServiceVulture;

	private int mState = STATE_UNKNOWN;

	@Nullable
	private IBinder mApplicationToken;

	@Nullable
	private ComponentName mComponentName;

	/**
	* List of events held to be sent as a batch.
	*/
	@Nullable
	private ArrayList<ContentCaptureEvent> mEvents;

	// Used just for debugging purposes (on dump)
	private long mNextFlush;

	// Lazily created on demand.
	private ContentCaptureSessionId mContentCaptureSessionId;

	/** @hide */
	protected MainContentCaptureSession(@NonNull Context context, @NonNull Handler handler,
	@Nullable IContentCaptureManager systemServerInterface,
	@NonNull AtomicBoolean disabled) {
	mContext = context;
	mHandler = handler;
	mSystemServerInterface = systemServerInterface;
	mDisabled = disabled;
	}

	@Override
	ContentCaptureSession newChild(@NonNull ContentCaptureContext clientContext) {
	final ContentCaptureSession child = new ChildContentCaptureSession(this, clientContext);
	notifyChildSessionStarted(mId, child.mId, clientContext);
	return child;
	}

	/**
	* Starts this session.
	*
	* @hide
	*/
	void start(@NonNull IBinder applicationToken, @NonNull ComponentName activityComponent) {
	if (!isContentCaptureEnabled()) return;

	if (VERBOSE) {
	Log.v(mTag, "start(): token=" + applicationToken + ", comp="
	+ ComponentName.flattenToShortString(activityComponent));
	}

	mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleStartSession, this,
	applicationToken, activityComponent));
	}

	@Override
	void flush() {
	mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleForceFlush, this));
	}

	@Override
	void onDestroy() {
	mHandler.sendMessage(
	obtainMessage(MainContentCaptureSession::handleDestroySession, this));
	}

	private void handleStartSession(@NonNull IBinder token, @NonNull ComponentName componentName) {
	if (mState != STATE_UNKNOWN) {
	// TODO(b/111276913): revisit this scenario
	Log.w(mTag, "ignoring handleStartSession(" + token + ") while on state "
	+ getStateAsString(mState));
	return;
	}
	mState = STATE_WAITING_FOR_SERVER;
	mApplicationToken = token;
	mComponentName = componentName;

	if (VERBOSE) {
	Log.v(mTag, "handleStartSession(): token=" + token + ", act="
	+ getActivityDebugName() + ", id=" + mId);
	}
	final int flags = 0; // TODO(b/111276913): get proper flags

	try {
	mSystemServerInterface.startSession(mContext.getUserId(), mApplicationToken,
	componentName, mId, flags, new IResultReceiver.Stub() {
	@Override
	public void send(int resultCode, Bundle resultData) {
	IBinder binder = null;
	if (resultData != null) {
	binder = resultData.getBinder(EXTRA_BINDER);
	if (binder == null) {
	Log.wtf(mTag, "No " + EXTRA_BINDER + " extra result");
	handleResetState();
	return;
	}
	}
	handleSessionStarted(resultCode, binder);
	}
	});
	} catch (RemoteException e) {
	Log.w(mTag, "Error starting session for " + componentName.flattenToShortString() + ": "
	+ e);
	}
	}

	/**
	* Callback from {@code system_server} after call to
	* {@link IContentCaptureManager#startSession(int, IBinder, ComponentName, String,
	* int, IResultReceiver)}.
	*
	* @param resultCode session state
	* @param binder handle to {@code IContentCaptureDirectManager}
	*/
	private void handleSessionStarted(int resultCode, @Nullable IBinder binder) {
	mState = resultCode;
	if (binder != null) {
	mDirectServiceInterface = IContentCaptureDirectManager.Stub.asInterface(binder);
	mDirectServiceVulture = () -> {
	Log.w(mTag, "Destroying session " + mId + " because service died");
	destroy();
	};
	try {
	binder.linkToDeath(mDirectServiceVulture, 0);
	} catch (RemoteException e) {
	Log.w(mTag, "Failed to link to death on " + binder + ": " + e);
	}
	}
	if (resultCode == STATE_DISABLED \|\| resultCode == STATE_DISABLED_DUPLICATED_ID) {
	mDisabled.set(true);
	handleResetSession(/* resetState= */ false);
	} else {
	mDisabled.set(false);
	}
	if (VERBOSE) {
	Log.v(mTag, "handleSessionStarted() result: code=" + resultCode + ", id=" + mId
	+ ", state=" + getStateAsString(mState) + ", disabled=" + mDisabled.get()
	+ ", binder=" + binder);
	}
	}

	private void handleSendEvent(@NonNull ContentCaptureEvent event, boolean forceFlush) {
	if (mEvents == null) {
	if (VERBOSE) {
	Log.v(mTag, "Creating buffer for " + MAX_BUFFER_SIZE + " events");
	}
	mEvents = new ArrayList<>(MAX_BUFFER_SIZE);
	}

	if (!mEvents.isEmpty() && event.getType() == TYPE_VIEW_TEXT_CHANGED) {
	final ContentCaptureEvent lastEvent = mEvents.get(mEvents.size() - 1);

	// TODO(b/121045053): check if flags match
	if (lastEvent.getType() == TYPE_VIEW_TEXT_CHANGED
	&& lastEvent.getId().equals(event.getId())) {
	if (VERBOSE) {
	Log.v(mTag, "Buffering VIEW_TEXT_CHANGED event, updated text = "
	+ event.getText());
	}
	lastEvent.setText(event.getText());
	} else {
	mEvents.add(event);
	}
	} else {
	mEvents.add(event);
	}

	final int numberEvents = mEvents.size();

	final boolean bufferEvent = numberEvents < MAX_BUFFER_SIZE;

	if (bufferEvent && !forceFlush) {
	handleScheduleFlush(/* checkExisting= */ true);
	return;
	}

	if (mState != STATE_ACTIVE) {
	// Callback from startSession hasn't been called yet - typically happens on system
	// apps that are started before the system service
	// TODO(b/111276913): try to ignore session while system is not ready / boot
	// not complete instead. Similarly, the manager service should return right away
	// when the user does not have a service set
	if (VERBOSE) {
	Log.v(mTag, "Closing session for " + getActivityDebugName()
	+ " after " + numberEvents + " delayed events and state "
	+ getStateAsString(mState));
	}
	handleResetState();
	// TODO(b/111276913): blacklist activity / use special flag to indicate that
	// when it's launched again
	return;
	}

	handleForceFlush();
	}

	private void handleScheduleFlush(boolean checkExisting) {
	if (checkExisting && mHandler.hasMessages(MSG_FLUSH)) {
	// "Renew" the flush message by removing the previous one
	mHandler.removeMessages(MSG_FLUSH);
	}
	mNextFlush = SystemClock.elapsedRealtime() + FLUSHING_FREQUENCY_MS;
	if (VERBOSE) {
	Log.v(mTag, "Scheduled to flush in " + FLUSHING_FREQUENCY_MS + "ms: " + mNextFlush);
	}
	mHandler.sendMessageDelayed(
	obtainMessage(MainContentCaptureSession::handleFlushIfNeeded, this)
	.setWhat(MSG_FLUSH), FLUSHING_FREQUENCY_MS);
	}

	private void handleFlushIfNeeded() {
	if (mEvents.isEmpty()) {
	if (VERBOSE) Log.v(mTag, "Nothing to flush");
	return;
	}
	handleForceFlush();
	}

	private void handleForceFlush() {
	if (mEvents == null) return;

	if (mDirectServiceInterface == null) {
	if (DEBUG) Log.d(mTag, "handleForceFlush(): hold your horses, client not ready yet!");
	if (!mHandler.hasMessages(MSG_FLUSH)) {
	handleScheduleFlush(/* checkExisting= */ false);
	}
	return;
	}

	final int numberEvents = mEvents.size();
	try {
	if (DEBUG) {
	Log.d(mTag, "Flushing " + numberEvents + " event(s) for " + getActivityDebugName());
	}
	mHandler.removeMessages(MSG_FLUSH);

	final ParceledListSlice<ContentCaptureEvent> events = handleClearEvents();
	mDirectServiceInterface.sendEvents(events);
	} catch (RemoteException e) {
	Log.w(mTag, "Error sending " + numberEvents + " for " + getActivityDebugName()
	+ ": " + e);
	}
	}

	/**
	* Resets the buffer and return a {@link ParceledListSlice} with the previous events.
	*/
	@NonNull
	private ParceledListSlice<ContentCaptureEvent> handleClearEvents() {
	// NOTE: we must save a reference to the current mEvents and then set it to to null,
	// otherwise clearing it would clear it in the receiving side if the service is also local.
	final List<ContentCaptureEvent> events = mEvents == null
	? Collections.emptyList()
	: mEvents;
	mEvents = null;
	return new ParceledListSlice<>(events);
	}

	private void handleDestroySession() {
	if (DEBUG) {
	Log.d(mTag, "Destroying session (ctx=" + mContext + ", id=" + mId + ") with "
	+ (mEvents == null ? 0 : mEvents.size()) + " event(s) for "
	+ getActivityDebugName());
	}

	try {
	mSystemServerInterface.finishSession(mContext.getUserId(), mId);
	} catch (RemoteException e) {
	Log.e(mTag, "Error destroying system-service session " + mId + " for "
	+ getActivityDebugName() + ": " + e);
	}
	}

	private void handleResetState() {
	handleResetSession(/* resetState= */ true);
	}

	// TODO(b/121033016): once we support multiple sessions, we might need to move some of these
	// clearings out.
	private void handleResetSession(boolean resetState) {
	if (resetState) {
	mState = STATE_UNKNOWN;
	}

	// TODO(b/121033016): must reset children (which currently is owned by superclass)

	mContentCaptureSessionId = null;
	mApplicationToken = null;
	mComponentName = null;
	mEvents = null;
	if (mDirectServiceInterface != null) {
	mDirectServiceInterface.asBinder().unlinkToDeath(mDirectServiceVulture, 0);
	}
	mDirectServiceInterface = null;
	mHandler.removeMessages(MSG_FLUSH);
	}

	@Override
	void internalNotifyViewAppeared(@NonNull ViewStructureImpl node) {
	notifyViewAppeared(mId, node);
	}

	@Override
	void internalNotifyViewDisappeared(@NonNull AutofillId id) {
	notifyViewDisappeared(mId, id);
	}

	@Override
	void internalNotifyViewTextChanged(@NonNull AutofillId id, @Nullable CharSequence text,
	int flags) {
	notifyViewTextChanged(mId, id, text, flags);
	}

	@Override
	boolean isContentCaptureEnabled() {
	return super.isContentCaptureEnabled() && mSystemServerInterface != null
	&& !mDisabled.get();
	}

	// TODO(b/121033016): refactor "notifyXXXX" methods below to a common "Buffer" object that is
	// shared between ActivityContentCaptureSession and ChildContentCaptureSession objects. Such
	// change should also get get rid of the "internalNotifyXXXX" methods above
	void notifyChildSessionStarted(@NonNull String parentSessionId,
	@NonNull String childSessionId, @NonNull ContentCaptureContext clientContext) {
	mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleSendEvent, this,
	new ContentCaptureEvent(childSessionId, TYPE_SESSION_STARTED)
	.setParentSessionId(parentSessionId)
	.setClientContext(clientContext),
	/* forceFlush= */ false));
	}

	void notifyChildSessionFinished(@NonNull String parentSessionId,
	@NonNull String childSessionId) {
	mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleSendEvent, this,
	new ContentCaptureEvent(childSessionId, TYPE_SESSION_FINISHED)
	.setParentSessionId(parentSessionId), /* forceFlush= */ false));
	}

	void notifyViewAppeared(@NonNull String sessionId, @NonNull ViewStructureImpl node) {
	mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleSendEvent, this,
	new ContentCaptureEvent(sessionId, TYPE_VIEW_APPEARED)
	.setViewNode(node.mNode), /* forceFlush= */ false));
	}

	void notifyViewDisappeared(@NonNull String sessionId, @NonNull AutofillId id) {
	mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleSendEvent, this,
	new ContentCaptureEvent(sessionId, TYPE_VIEW_DISAPPEARED).setAutofillId(id),
	/* forceFlush= */ false));
	}

	void notifyViewTextChanged(@NonNull String sessionId, @NonNull AutofillId id,
	@Nullable CharSequence text, int flags) {
	mHandler.sendMessage(obtainMessage(MainContentCaptureSession::handleSendEvent, this,
	new ContentCaptureEvent(sessionId, TYPE_VIEW_TEXT_CHANGED, flags).setAutofillId(id)
	.setText(text), /* forceFlush= */ false));
	}

	@Override
	void dump(@NonNull String prefix, @NonNull PrintWriter pw) {
	pw.print(prefix); pw.print("id: "); pw.println(mId);
	pw.print(prefix); pw.print("mContext: "); pw.println(mContext);
	pw.print(prefix); pw.print("user: "); pw.println(mContext.getUserId());
	if (mSystemServerInterface != null) {
	pw.print(prefix); pw.print("mSystemServerInterface: ");
	pw.println(mSystemServerInterface);
	}
	if (mDirectServiceInterface != null) {
	pw.print(prefix); pw.print("mDirectServiceInterface: ");
	pw.println(mDirectServiceInterface);
	}
	pw.print(prefix); pw.print("mDisabled: "); pw.println(mDisabled.get());
	pw.print(prefix); pw.print("isEnabled(): "); pw.println(isContentCaptureEnabled());
	if (mContentCaptureSessionId != null) {
	pw.print(prefix); pw.print("public id: "); pw.println(mContentCaptureSessionId);
	}
	pw.print(prefix); pw.print("state: "); pw.print(mState); pw.print(" (");
	pw.print(getStateAsString(mState)); pw.println(")");
	if (mApplicationToken != null) {
	pw.print(prefix); pw.print("app token: "); pw.println(mApplicationToken);
	}
	if (mComponentName != null) {
	pw.print(prefix); pw.print("component name: ");
	pw.println(mComponentName.flattenToShortString());
	}
	if (mEvents != null && !mEvents.isEmpty()) {
	final int numberEvents = mEvents.size();
	pw.print(prefix); pw.print("buffered events: "); pw.print(numberEvents);
	pw.print('/'); pw.println(MAX_BUFFER_SIZE);
	if (VERBOSE && numberEvents > 0) {
	final String prefix3 = prefix + " ";
	for (int i = 0; i < numberEvents; i++) {
	final ContentCaptureEvent event = mEvents.get(i);
	pw.print(prefix3); pw.print(i); pw.print(": "); event.dump(pw);
	pw.println();
	}
	}
	pw.print(prefix); pw.print("flush frequency: "); pw.println(FLUSHING_FREQUENCY_MS);
	pw.print(prefix); pw.print("next flush: ");
	TimeUtils.formatDuration(mNextFlush - SystemClock.elapsedRealtime(), pw); pw.println();
	}
	super.dump(prefix, pw);
	}

	/**
	* Gets a string that can be used to identify the activity on logging statements.
	*/
	private String getActivityDebugName() {
	return mComponentName == null ? mContext.getPackageName()
	: mComponentName.flattenToShortString();
	}
	}