Merge "Define CarrierPrivilegesTracker for tracking CarrierPrivileged UIDs." into rvc-dev

/*

 * Copyright (C) 2020 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.android.internal.telephony;

import android.annotation.NonNull;

import android.os.Handler;

import android.os.Looper;

import android.os.Message;

import android.os.Registrant;

import android.os.RegistrantList;

import android.util.Log;

/**

 * CarrierPrivilegesTracker will track the Carrier Privileges for a specific {@link Phone}.

 * Registered Telephony entities will receive notifications when the UIDs with these privileges

 * change.

 */

public class CarrierPrivilegesTracker extends Handler {

    private static final String TAG = CarrierPrivilegesTracker.class.getSimpleName();

    /**

     * Action to register a Registrant with this Tracker.

     * obj: Registrant that will be notified of Carrier Privileged UID changes.

     */

    private static final int ACTION_REGISTER_LISTENER = 1;

    /**

     * Action to unregister a Registrant with this Tracker.

     * obj: Handler used by the Registrant that will be removed.

     */

    private static final int ACTION_UNREGISTER_LISTENER = 2;

    private final RegistrantList mRegistrantList;

    private int[] mPrivilegedUids;

    public CarrierPrivilegesTracker(@NonNull Looper looper) {

        super(looper);

        mRegistrantList = new RegistrantList();

        mPrivilegedUids = new int[0];

    }

    @Override

    public void handleMessage(Message msg) {

        switch (msg.what) {

            case ACTION_REGISTER_LISTENER: {

                handleRegisterListener((Registrant) msg.obj);

                break;

            }

            case ACTION_UNREGISTER_LISTENER: {

                handleUnregisterListener((Handler) msg.obj);

                break;

            }

            default: {

                Log.e(TAG, "Received unknown msg type: " + msg.what);

                break;

            }

        }

    }

    private void handleRegisterListener(Registrant registrant) {

        mRegistrantList.add(registrant);

        registrant.notifyResult(mPrivilegedUids);

    }

    private void handleUnregisterListener(Handler handler) {

        mRegistrantList.remove(handler);

    }

    /**

     * Registers the given Registrant with this tracker.

     *

     * <p>After being registered, the Registrant will be notified with the current Carrier

     * Privileged UIDs for this Phone.

     *

     * @hide

     */

    public void registerCarrierPrivilegesListener(Handler h, int what, Object obj) {

        sendMessage(obtainMessage(ACTION_REGISTER_LISTENER, new Registrant(h, what, obj)));

    }

    /**

     * Unregisters the given listener with this tracker.

     *

     * @hide

     */

    public void unregisterCarrierPrivilegesListener(Handler handler) {

        sendMessage(obtainMessage(ACTION_UNREGISTER_LISTENER, handler));

    }

}