services/core/java/com/android/server/broadcastradio/BroadcastRadioService.java

/**
 * Copyright (C) 2017 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.server.broadcastradio;

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.radio.IRadioService;
import android.hardware.radio.ITuner;
import android.hardware.radio.ITunerCallback;
import android.hardware.radio.RadioManager;
import android.os.ParcelableException;

import com.android.server.SystemService;

import java.util.List;

public class BroadcastRadioService extends SystemService {
    private final ServiceImpl mServiceImpl = new ServiceImpl();

    /**
     * This field is used by native code, do not access or modify.
     */
    private final long mNativeContext = nativeInit();

    private final Object mLock = new Object();
    private List<RadioManager.ModuleProperties> mModules = null;

    public BroadcastRadioService(Context context) {
        super(context);
    }

    @Override
    protected void finalize() throws Throwable {
        nativeFinalize(mNativeContext);
        super.finalize();
    }

    private native long nativeInit();
    private native void nativeFinalize(long nativeContext);
    private native List<RadioManager.ModuleProperties> nativeLoadModules(long nativeContext);
    private native Tuner nativeOpenTuner(long nativeContext, int moduleId,
            RadioManager.BandConfig config, boolean withAudio, ITunerCallback callback);

    @Override
    public void onStart() {
        publishBinderService(Context.RADIO_SERVICE, mServiceImpl);
    }

    private class ServiceImpl extends IRadioService.Stub {
        private void enforcePolicyAccess() {
            if (PackageManager.PERMISSION_GRANTED != getContext().checkCallingPermission(
                    Manifest.permission.ACCESS_BROADCAST_RADIO)) {
                throw new SecurityException("ACCESS_BROADCAST_RADIO permission not granted");
            }
        }

        @Override
        public List<RadioManager.ModuleProperties> listModules() {
            enforcePolicyAccess();
            synchronized (mLock) {
                if (mModules != null) return mModules;

                mModules = nativeLoadModules(mNativeContext);
                if (mModules == null) {
                    throw new ParcelableException(new NullPointerException(
                            "couldn't load radio modules"));
                }

                return mModules;
            }
        }

        @Override
        public ITuner openTuner(int moduleId, RadioManager.BandConfig bandConfig,
                boolean withAudio, ITunerCallback callback) {
            enforcePolicyAccess();
            if (callback == null) {
                throw new IllegalArgumentException("Callback must not be empty");
            }
            synchronized (mLock) {
                return nativeOpenTuner(mNativeContext, moduleId, bandConfig, withAudio, callback);
            }
        }
    }
}