[1/X] Introduce CompanionDeviceServiceConnector

/*

 * Copyright (C) 2022 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.companion;

import static android.content.Context.BIND_IMPORTANT;

import android.annotation.NonNull;

import android.annotation.Nullable;

import android.annotation.SuppressLint;

import android.annotation.UserIdInt;

import android.companion.AssociationInfo;

import android.companion.CompanionDeviceService;

import android.companion.ICompanionDeviceService;

import android.content.ComponentName;

import android.content.Context;

import android.content.Intent;

import android.os.IBinder;

import android.util.Log;

import com.android.internal.infra.ServiceConnector;

/**

 * Manages a connection (binding) to an instance of {@link CompanionDeviceService} running in the

 * application process.

 */

@SuppressLint("LongLogTag")

class CompanionDeviceServiceConnector extends ServiceConnector.Impl<ICompanionDeviceService> {

    private static final String TAG = "CompanionDevice_ServiceConnector";

    private static final boolean DEBUG = false;

    private static final int BINDING_FLAGS = BIND_IMPORTANT;

    /** Listener for changes to the state of the {@link CompanionDeviceServiceConnector}  */

    interface Listener {

        void onBindingDied(@UserIdInt int userId, @NonNull String packageName);

    }

    private final @UserIdInt int mUserId;

    private final @NonNull ComponentName mComponentName;

    private @Nullable Listener mListener;

    CompanionDeviceServiceConnector(@NonNull Context context, @UserIdInt int userId,

            @NonNull ComponentName componentName) {

        super(context, buildIntent(componentName), BINDING_FLAGS, userId, null);

        mUserId = userId;

        mComponentName = componentName;

    }

    void setListener(@Nullable Listener listener) {

        mListener = listener;

    }

    void postOnDeviceAppeared(@NonNull AssociationInfo associationInfo) {

        post(companionService -> companionService.onDeviceAppeared(associationInfo));

    }

    void postOnDeviceDisappeared(@NonNull AssociationInfo associationInfo) {

        post(companionService -> companionService.onDeviceDisappeared(associationInfo));

    }

    /**

     * Post "unbind" job, which will run *after* all previously posted jobs complete.

     *

     * IMPORTANT: use this method instead of invoking {@link ServiceConnector#unbind()} directly,

     * because the latter may cause previously posted callback, such as

     * {@link ICompanionDeviceService#onDeviceDisappeared(AssociationInfo)} to be dropped.

     */

    void postUnbind() {

        post(it -> unbind());

    }

    @Override

    protected void onServiceConnectionStatusChanged(

            @NonNull ICompanionDeviceService service, boolean isConnected) {

        if (DEBUG) {

            Log.d(TAG, "onServiceConnection_StatusChanged() " + mComponentName.toShortString()

                    + " connected=" + isConnected);

        }

    }

    @Override

    public void onBindingDied(@NonNull ComponentName name) {

        // IMPORTANT: call super!

        super.onBindingDied(name);

        if (DEBUG) Log.d(TAG, "onBindingDied() " + mComponentName.toShortString());

        mListener.onBindingDied(mUserId, mComponentName.getPackageName());

    }

    @Override

    protected ICompanionDeviceService binderAsInterface(@NonNull IBinder service) {

        return ICompanionDeviceService.Stub.asInterface(service);

    }

    @Override

    protected long getAutoDisconnectTimeoutMs() {

        // Do NOT auto-disconnect.

        return -1;

    }

    private static @NonNull Intent buildIntent(@NonNull ComponentName componentName) {

        return new Intent(CompanionDeviceService.SERVICE_INTERFACE)

                .setComponent(componentName);

    }

}