android/net/wifi/rtt/WifiRttManager.java

package android.net.wifi.rtt;

import static android.Manifest.permission.ACCESS_COARSE_LOCATION;
import static android.Manifest.permission.ACCESS_WIFI_STATE;
import static android.Manifest.permission.CHANGE_WIFI_STATE;
import static android.Manifest.permission.LOCATION_HARDWARE;

import android.annotation.Nullable;
import android.annotation.RequiresPermission;
import android.annotation.SdkConstant;
import android.annotation.SystemApi;
import android.annotation.SystemService;
import android.content.Context;
import android.os.Binder;
import android.os.Handler;
import android.os.Looper;
import android.os.RemoteException;
import android.os.WorkSource;
import android.util.Log;

import java.util.List;

/**
 * This class provides the primary API for measuring distance (range) to other devices using the
 * IEEE 802.11mc Wi-Fi Round Trip Time (RTT) technology.
 * <p>
 * The devices which can be ranged include:
 * <li>Access Points (APs)
 * <li>Wi-Fi Aware peers
 * <p>
 * Ranging requests are triggered using
 * {@link #startRanging(RangingRequest, RangingResultCallback, Handler)}. Results (in case of
 * successful operation) are returned in the {@link RangingResultCallback#onRangingResults(List)}
 * callback.
 * <p>
 *     Wi-Fi RTT may not be usable at some points, e.g. when Wi-Fi is disabled. To validate that
 *     the functionality is available use the {@link #isAvailable()} function. To track
 *     changes in RTT usability register for the {@link #ACTION_WIFI_RTT_STATE_CHANGED}
 *     broadcast. Note that this broadcast is not sticky - you should register for it and then
 *     check the above API to avoid a race condition.
 *
 * @hide RTT_API
 */
@SystemService(Context.WIFI_RTT2_SERVICE)
public class WifiRttManager {
    private static final String TAG = "WifiRttManager";
    private static final boolean VDBG = false;

    private final Context mContext;
    private final IWifiRttManager mService;

    /**
     * Broadcast intent action to indicate that the state of Wi-Fi RTT availability has changed.
     * Use the {@link #isAvailable()} to query the current status.
     * This broadcast is <b>not</b> sticky, use the {@link #isAvailable()} API after registering
     * the broadcast to check the current state of Wi-Fi RTT.
     * <p>Note: The broadcast is only delivered to registered receivers - no manifest registered
     * components will be launched.
     */
    @SdkConstant(SdkConstant.SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_WIFI_RTT_STATE_CHANGED =
            "android.net.wifi.rtt.action.WIFI_RTT_STATE_CHANGED";

    /** @hide */
    public WifiRttManager(Context context, IWifiRttManager service) {
        mContext = context;
        mService = service;
    }

    /**
     * Returns the current status of RTT API: whether or not RTT is available. To track
     * changes in the state of RTT API register for the
     * {@link #ACTION_WIFI_RTT_STATE_CHANGED} broadcast.
     *
     * @return A boolean indicating whether the app can use the RTT API at this time (true) or
     * not (false).
     */
    public boolean isAvailable() {
        try {
            return mService.isAvailable();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    /**
     * Initiate a request to range to a set of devices specified in the {@link RangingRequest}.
     * Results will be returned in the {@link RangingResultCallback} set of callbacks.
     *
     * @param request  A request specifying a set of devices whose distance measurements are
     *                 requested.
     * @param callback A callback for the result of the ranging request.
     * @param handler  The Handler on whose thread to execute the callbacks of the {@code
     *                 callback} object. If a null is provided then the application's main thread
     *                 will be used.
     */
    @RequiresPermission(allOf = {ACCESS_COARSE_LOCATION, CHANGE_WIFI_STATE, ACCESS_WIFI_STATE})
    public void startRanging(RangingRequest request, RangingResultCallback callback,
            @Nullable Handler handler) {
        startRanging(null, request, callback, handler);
    }

    /**
     * Initiate a request to range to a set of devices specified in the {@link RangingRequest}.
     * Results will be returned in the {@link RangingResultCallback} set of callbacks.
     *
     * @param workSource A mechanism to specify an alternative work-source for the request.
     * @param request  A request specifying a set of devices whose distance measurements are
     *                 requested.
     * @param callback A callback for the result of the ranging request.
     * @param handler  The Handler on whose thread to execute the callbacks of the {@code
     *                 callback} object. If a null is provided then the application's main thread
     *                 will be used.
     *
     * @hide (@SystemApi)
     */
    @RequiresPermission(allOf = {LOCATION_HARDWARE, ACCESS_COARSE_LOCATION, CHANGE_WIFI_STATE,
            ACCESS_WIFI_STATE})
    public void startRanging(@Nullable WorkSource workSource, RangingRequest request,
            RangingResultCallback callback, @Nullable Handler handler) {
        if (VDBG) {
            Log.v(TAG, "startRanging: workSource=" + workSource + ", request=" + request
                    + ", callback=" + callback + ", handler=" + handler);
        }

        Looper looper = (handler == null) ? Looper.getMainLooper() : handler.getLooper();
        Binder binder = new Binder();
        try {
            mService.startRanging(binder, mContext.getOpPackageName(), workSource, request,
                    new RttCallbackProxy(looper, callback));
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    /**
     * Cancel all ranging requests for the specified work sources. The requests have been requested
     * using {@link #startRanging(WorkSource, RangingRequest, RangingResultCallback, Handler)}.
     *
     * @param workSource The work-sources of the requesters.
     *
     * @hide (@SystemApi)
     */
    @RequiresPermission(allOf = {LOCATION_HARDWARE})
    public void cancelRanging(WorkSource workSource) {
        if (VDBG) {
            Log.v(TAG, "cancelRanging: workSource=" + workSource);
        }

        try {
            mService.cancelRanging(workSource);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    private static class RttCallbackProxy extends IRttCallback.Stub {
        private final Handler mHandler;
        private final RangingResultCallback mCallback;

        RttCallbackProxy(Looper looper, RangingResultCallback callback) {
            mHandler = new Handler(looper);
            mCallback = callback;
        }

        @Override
        public void onRangingFailure(int status) throws RemoteException {
            if (VDBG) Log.v(TAG, "RttCallbackProxy: onRangingFailure: status=" + status);
            mHandler.post(() -> {
               mCallback.onRangingFailure(status);
            });
        }

        @Override
        public void onRangingResults(List<RangingResult> results) throws RemoteException {
            if (VDBG) Log.v(TAG, "RttCallbackProxy: onRanginResults: results=" + results);
            mHandler.post(() -> {
               mCallback.onRangingResults(results);
            });
        }
    }
}