service/voice/AlwaysOnHotwordDetector.java

/**
 * Copyright (C) 2014 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.voice;

import android.content.Intent;
import android.hardware.soundtrigger.IRecognitionStatusCallback;
import android.hardware.soundtrigger.KeyphraseEnrollmentInfo;
import android.hardware.soundtrigger.KeyphraseMetadata;
import android.hardware.soundtrigger.SoundTrigger;
import android.hardware.soundtrigger.SoundTrigger.ConfidenceLevel;
import android.hardware.soundtrigger.SoundTrigger.Keyphrase;
import android.hardware.soundtrigger.SoundTrigger.KeyphraseRecognitionExtra;
import android.hardware.soundtrigger.SoundTrigger.KeyphraseSoundModel;
import android.hardware.soundtrigger.SoundTrigger.ModuleProperties;
import android.hardware.soundtrigger.SoundTrigger.RecognitionConfig;
import android.os.Handler;
import android.os.Message;
import android.os.RemoteException;
import android.util.Slog;

import com.android.internal.app.IVoiceInteractionManagerService;

import java.util.List;

/**
 * A class that lets a VoiceInteractionService implementation interact with
 * always-on keyphrase detection APIs.
 */
public class AlwaysOnHotwordDetector {
    //---- States of Keyphrase availability. Return codes for getAvailability() ----//
    /**
     * Indicates that this hotword detector is no longer valid for any recognition
     * and should not be used anymore.
     */
    public static final int STATE_INVALID = -3;
    /**
     * Indicates that recognition for the given keyphrase is not available on the system
     * because of the hardware configuration.
     */
    public static final int STATE_HARDWARE_UNAVAILABLE = -2;
    /**
     * Indicates that recognition for the given keyphrase is not supported.
     */
    public static final int STATE_KEYPHRASE_UNSUPPORTED = -1;
    /**
     * Indicates that the given keyphrase is not enrolled.
     */
    public static final int STATE_KEYPHRASE_UNENROLLED = 1;
    /**
     * Indicates that the given keyphrase is currently enrolled and it's possible to start
     * recognition for it.
     */
    public static final int STATE_KEYPHRASE_ENROLLED = 2;

    // Keyphrase management actions. Used in getManageIntent() ----//
    /** Indicates that we need to enroll. */
    public static final int MANAGE_ACTION_ENROLL = 0;
    /** Indicates that we need to re-enroll. */
    public static final int MANAGE_ACTION_RE_ENROLL = 1;
    /** Indicates that we need to un-enroll. */
    public static final int MANAGE_ACTION_UN_ENROLL = 2;

    /**
     * Return codes for {@link #startRecognition(int)}, {@link #stopRecognition()}
     */
    public static final int STATUS_ERROR = SoundTrigger.STATUS_ERROR;
    public static final int STATUS_OK = SoundTrigger.STATUS_OK;

    //-- Flags for startRecogntion    ----//
    /** Empty flag for {@link #startRecognition(int)}. */
    public static final int RECOGNITION_FLAG_NONE = 0;
    /**
     * Recognition flag for {@link #startRecognition(int)} that indicates
     * whether the trigger audio for hotword needs to be captured.
     */
    public static final int RECOGNITION_FLAG_CAPTURE_TRIGGER_AUDIO = 0x1;

    //---- Recognition mode flags. Return codes for getSupportedRecognitionModes() ----//
    // Must be kept in sync with the related attribute defined as searchKeyphraseRecognitionFlags.

    /**
     * Simple recognition of the key phrase. Returned by {@link #getSupportedRecognitionModes()}
     */
    public static final int RECOGNITION_MODE_VOICE_TRIGGER
            = SoundTrigger.RECOGNITION_MODE_VOICE_TRIGGER;
    /**
     * Trigger only if one user is identified. Returned by {@link #getSupportedRecognitionModes()}
     */
    public static final int RECOGNITION_MODE_USER_IDENTIFICATION
            = SoundTrigger.RECOGNITION_MODE_USER_IDENTIFICATION;

    static final String TAG = "AlwaysOnHotwordDetector";

    private static final int MSG_HOTWORD_DETECTED = 1;
    private static final int MSG_DETECTION_STOPPED = 2;

    private final String mText;
    private final String mLocale;
    /**
     * The metadata of the Keyphrase, derived from the enrollment application.
     * This may be null if this keyphrase isn't supported by the enrollment application.
     */
    private final KeyphraseMetadata mKeyphraseMetadata;
    private final KeyphraseEnrollmentInfo mKeyphraseEnrollmentInfo;
    private final IVoiceInteractionService mVoiceInteractionService;
    private final IVoiceInteractionManagerService mModelManagementService;
    private final SoundTriggerListener mInternalCallback;
    private final Callback mExternalCallback;
    private final boolean mDisabled;
    private final Object mLock = new Object();

    /**
     * The sound model for the keyphrase, derived from the model management service
     * (IVoiceInteractionManagerService). May be null if the keyphrase isn't enrolled yet.
     */
    private KeyphraseSoundModel mEnrolledSoundModel;
    private boolean mInvalidated;

    /**
     * Callbacks for always-on hotword detection.
     */
    public interface Callback {
        /**
         * Called when the keyphrase is spoken.
         *
         * @param data Optional trigger audio data, if it was requested during
         *        {@link AlwaysOnHotwordDetector#startRecognition(int)}.
         */
        void onDetected(byte[] data);
        /**
         * Called when the detection for the associated keyphrase stops.
         */
        void onDetectionStopped();
    }

    /**
     * @param text The keyphrase text to get the detector for.
     * @param locale The java locale for the detector.
     * @param callback A non-null Callback for receiving the recognition events.
     * @param voiceInteractionService The current voice interaction service.
     * @param modelManagementService A service that allows management of sound models.
     *
     * @hide
     */
    public AlwaysOnHotwordDetector(String text, String locale, Callback callback,
            KeyphraseEnrollmentInfo keyphraseEnrollmentInfo,
            IVoiceInteractionService voiceInteractionService,
            IVoiceInteractionManagerService modelManagementService) {
        mInvalidated = false;
        mText = text;
        mLocale = locale;
        mKeyphraseEnrollmentInfo = keyphraseEnrollmentInfo;
        mKeyphraseMetadata = mKeyphraseEnrollmentInfo.getKeyphraseMetadata(text, locale);
        mExternalCallback = callback;
        mInternalCallback = new SoundTriggerListener(new MyHandler());
        mVoiceInteractionService = voiceInteractionService;
        mModelManagementService = modelManagementService;
        if (mKeyphraseMetadata != null) {
            mEnrolledSoundModel = internalGetKeyphraseSoundModelLocked(mKeyphraseMetadata.id);
        }
        int initialAvailability = internalGetAvailabilityLocked();
        mDisabled = (initialAvailability == STATE_HARDWARE_UNAVAILABLE)
                || (initialAvailability == STATE_KEYPHRASE_UNSUPPORTED);
    }

    /**
     * Gets the state of always-on hotword detection for the given keyphrase and locale
     * on this system.
     * Availability implies that the hardware on this system is capable of listening for
     * the given keyphrase or not. <p/>
     * If the return code is one of {@link #STATE_HARDWARE_UNAVAILABLE} or
     * {@link #STATE_KEYPHRASE_UNSUPPORTED}, no further interaction should be performed with this
     * detector. <br/>
     * If the state is {@link #STATE_KEYPHRASE_UNENROLLED} the caller may choose to begin
     * an enrollment flow for the keyphrase. <br/>
     * For {@value #STATE_KEYPHRASE_ENROLLED} a recognition can be started as desired. <br/>
     * If the return code is {@link #STATE_INVALID}, this detector is stale and must not be used.
     * A new detector should be obtained and used.
     *
     * @return Indicates if always-on hotword detection is available for the given keyphrase.
     *         The return code is one of {@link #STATE_HARDWARE_UNAVAILABLE},
     *         {@link #STATE_KEYPHRASE_UNSUPPORTED}, {@link #STATE_KEYPHRASE_UNENROLLED},
     *         {@link #STATE_KEYPHRASE_ENROLLED}, or {@link #STATE_INVALID}.
     */
    public int getAvailability() {
        synchronized (mLock) {
            return internalGetAvailabilityLocked();
        }
    }

    /**
     * Gets the recognition modes supported by the associated keyphrase.
     *
     * @throws UnsupportedOperationException if the keyphrase itself isn't supported.
     *         Callers should check the availability by calling {@link #getAvailability()}
     *         before calling this method to avoid this exception.
     */
    public int getSupportedRecognitionModes() {
        synchronized (mLock) {
            return getSupportedRecognitionModesLocked();
        }
    }

    private int getSupportedRecognitionModesLocked() {
        if (mDisabled) {
            throw new UnsupportedOperationException(
                    "Getting supported recognition modes for the keyphrase is not supported");
        }

        return mKeyphraseMetadata.recognitionModeFlags;
    }

    /**
     * Starts recognition for the associated keyphrase.
     *
     * @param recognitionFlags The flags to control the recognition properties.
     *        The allowed flags are {@link #RECOGNITION_FLAG_NONE} and
     *        {@link #RECOGNITION_FLAG_CAPTURE_TRIGGER_AUDIO}.
     * @return {@link #STATUS_OK} if the call succeeds, an error code otherwise.
     * @throws UnsupportedOperationException if the recognition isn't supported.
     *         Callers should check the availability by calling {@link #getAvailability()}
     *         before calling this method to avoid this exception.
     */
    public int startRecognition(int recognitionFlags) {
        synchronized (mLock) {
            return startRecognitionLocked(recognitionFlags);
        }
    }

    private int startRecognitionLocked(int recognitionFlags) {
        if (internalGetAvailabilityLocked() != STATE_KEYPHRASE_ENROLLED) {
            throw new UnsupportedOperationException(
                    "Recognition for the given keyphrase is not supported");
        }

        KeyphraseRecognitionExtra[] recognitionExtra = new KeyphraseRecognitionExtra[1];
        // TODO: Do we need to do something about the confidence level here?
        recognitionExtra[0] = new KeyphraseRecognitionExtra(mKeyphraseMetadata.id,
                mKeyphraseMetadata.recognitionModeFlags, new ConfidenceLevel[0]);
        boolean captureTriggerAudio =
                (recognitionFlags & RECOGNITION_FLAG_CAPTURE_TRIGGER_AUDIO) != 0;
        int code = STATUS_ERROR;
        try {
            code = mModelManagementService.startRecognition(mVoiceInteractionService,
                    mKeyphraseMetadata.id, mEnrolledSoundModel, mInternalCallback,
                    new RecognitionConfig(
                            captureTriggerAudio, recognitionExtra, null /* additional data */));
        } catch (RemoteException e) {
            Slog.w(TAG, "RemoteException in startRecognition!");
        }
        if (code != STATUS_OK) {
            Slog.w(TAG, "startRecognition() failed with error code " + code);
        }
        return code;
    }

    /**
     * Stops recognition for the associated keyphrase.
     *
     * @return {@link #STATUS_OK} if the call succeeds, an error code otherwise.
     * @throws UnsupportedOperationException if the recognition isn't supported.
     *         Callers should check the availability by calling {@link #getAvailability()}
     *         before calling this method to avoid this exception.
     */
    public int stopRecognition() {
        synchronized (mLock) {
            return stopRecognitionLocked();
        }
    }

    private int stopRecognitionLocked() {
        if (internalGetAvailabilityLocked() != STATE_KEYPHRASE_ENROLLED) {
            throw new UnsupportedOperationException(
                    "Recognition for the given keyphrase is not supported");
        }

        int code = STATUS_ERROR;
        try {
            code = mModelManagementService.stopRecognition(
                    mVoiceInteractionService, mKeyphraseMetadata.id, mInternalCallback);
        } catch (RemoteException e) {
            Slog.w(TAG, "RemoteException in stopRecognition!");
        }

        if (code != STATUS_OK) {
            Slog.w(TAG, "stopRecognition() failed with error code " + code);
        }
        return code;
    }

    /**
     * Gets an intent to manage the associated keyphrase.
     *
     * @param action The manage action that needs to be performed.
     *        One of {@link #MANAGE_ACTION_ENROLL}, {@link #MANAGE_ACTION_RE_ENROLL} or
     *        {@link #MANAGE_ACTION_UN_ENROLL}.
     * @return An {@link Intent} to manage the given keyphrase.
     * @throws UnsupportedOperationException if managing they keyphrase isn't supported.
     *         Callers should check the availability by calling {@link #getAvailability()}
     *         before calling this method to avoid this exception.
     */
    public Intent getManageIntent(int action) {
        if (mDisabled) {
            throw new UnsupportedOperationException(
                    "Managing the given keyphrase is not supported");
        }
        if (action != MANAGE_ACTION_ENROLL
                && action != MANAGE_ACTION_RE_ENROLL
                && action != MANAGE_ACTION_UN_ENROLL) {
            throw new IllegalArgumentException("Invalid action specified " + action);
        }

        return mKeyphraseEnrollmentInfo.getManageKeyphraseIntent(action, mText, mLocale);
    }

    private int internalGetAvailabilityLocked() {
        if (mInvalidated) {
            return STATE_INVALID;
        }

        ModuleProperties dspModuleProperties = null;
        try {
            dspModuleProperties =
                    mModelManagementService.getDspModuleProperties(mVoiceInteractionService);
        } catch (RemoteException e) {
            Slog.w(TAG, "RemoteException in getDspProperties!");
        }
        // No DSP available
        if (dspModuleProperties == null) {
            return STATE_HARDWARE_UNAVAILABLE;
        }
        // No enrollment application supports this keyphrase/locale
        if (mKeyphraseMetadata == null) {
            return STATE_KEYPHRASE_UNSUPPORTED;
        }

        // This keyphrase hasn't been enrolled.
        if (mEnrolledSoundModel == null) {
            return STATE_KEYPHRASE_UNENROLLED;
        }
        return STATE_KEYPHRASE_ENROLLED;
    }

    /**
     * Invalidates this hotword detector so that any future calls to this result
     * in an IllegalStateException.
     *
     * @hide
     */
    void invalidate() {
        synchronized (mLock) {
            mInvalidated = true;
        }
    }

    /**
     * Reloads the sound models from the service.
     *
     * @hide
     */
    void onSoundModelsChanged() {
        synchronized (mLock) {
            // TODO: This should stop the recognition if it was using an enrolled sound model
            // that's no longer available.
            if (mKeyphraseMetadata != null) {
                mEnrolledSoundModel = internalGetKeyphraseSoundModelLocked(mKeyphraseMetadata.id);
            }
        }
    }

    /**
     * @return The corresponding {@link KeyphraseSoundModel} or null if none is found.
     */
    private KeyphraseSoundModel internalGetKeyphraseSoundModelLocked(int keyphraseId) {
        List<KeyphraseSoundModel> soundModels;
        try {
            soundModels = mModelManagementService
                    .listRegisteredKeyphraseSoundModels(mVoiceInteractionService);
            if (soundModels == null || soundModels.isEmpty()) {
                Slog.i(TAG, "No available sound models for keyphrase ID: " + keyphraseId);
                return null;
            }
            for (KeyphraseSoundModel soundModel : soundModels) {
                if (soundModel.keyphrases == null) {
                    continue;
                }
                for (Keyphrase keyphrase : soundModel.keyphrases) {
                    if (keyphrase.id == keyphraseId) {
                        return soundModel;
                    }
                }
            }
        } catch (RemoteException e) {
            Slog.w(TAG, "RemoteException in listRegisteredKeyphraseSoundModels!");
        }
        return null;
    }

    /** @hide */
    static final class SoundTriggerListener extends IRecognitionStatusCallback.Stub {
        private final Handler mHandler;

        public SoundTriggerListener(Handler handler) {
            mHandler = handler;
        }

        @Override
        public void onDetected(byte[] data) {
            Slog.i(TAG, "onDetected");
            Message message = Message.obtain(mHandler, MSG_HOTWORD_DETECTED);
            message.obj = data;
            message.sendToTarget();
        }

        @Override
        public void onDetectionStopped() {
            Slog.i(TAG, "onDetectionStopped");
            mHandler.sendEmptyMessage(MSG_DETECTION_STOPPED);
        }
    }

    class MyHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case MSG_HOTWORD_DETECTED:
                    mExternalCallback.onDetected((byte[]) msg.obj);
                    break;
                case MSG_DETECTION_STOPPED:
                    mExternalCallback.onDetectionStopped();
                default:
                    super.handleMessage(msg);
            }
        }
    }
}