content: /*
   * Copyright (C) 2019 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.systemcaptions;
  
  import android.annotation.Nullable;
  import android.content.ComponentName;
  import android.content.Context;
  import android.content.Intent;
  import android.content.ServiceConnection;
  import android.os.Handler;
  import android.os.IBinder;
  import android.os.Looper;
  import android.os.UserHandle;
  import android.util.Slog;
  
  import com.android.internal.annotations.GuardedBy;
  
  /** Manages the connection to the remote system captions manager service. */
  final class RemoteSystemCaptionsManagerService {
  
      private static final String TAG = RemoteSystemCaptionsManagerService.class.getSimpleName();
  
      private static final String SERVICE_INTERFACE =
              "android.service.systemcaptions.SystemCaptionsManagerService";
  
      private final Object mLock = new Object();
  
      private final Context mContext;
      private final Intent mIntent;
      private final ComponentName mComponentName;
      private final int mUserId;
      private final boolean mVerbose;
      private final Handler mHandler;
  
      private final RemoteServiceConnection mServiceConnection = new RemoteServiceConnection();
  
      @GuardedBy("mLock")
      @Nullable private IBinder mService;
  
      @GuardedBy("mLock")
      private boolean mBinding = false;
  
      @GuardedBy("mLock")
      private boolean mDestroyed = false;
  
      RemoteSystemCaptionsManagerService(
              Context context, ComponentName componentName, int userId, boolean verbose) {
          mContext = context;
          mComponentName = componentName;
          mUserId = userId;
          mVerbose = verbose;
          mIntent = new Intent(SERVICE_INTERFACE).setComponent(componentName);
          mHandler = new Handler(Looper.getMainLooper());
      }
  
      void initialize() {
          if (mVerbose) {
              Slog.v(TAG, "initialize()");
          }
          ensureBound();
      }
  
      void destroy() {
          if (mVerbose) {
              Slog.v(TAG, "destroy()");
          }
  
          synchronized (mLock) {
              if (mDestroyed) {
                  if (mVerbose) {
                      Slog.v(TAG, "destroy(): Already destroyed");
                  }
                  return;
              }
              mDestroyed = true;
              ensureUnboundLocked();
          }
      }
  
      boolean isDestroyed() {
          synchronized (mLock) {
              return mDestroyed;
          }
      }
  
      private void ensureBound() {
          synchronized (mLock) {
              if (mService != null || mBinding) {
                  return;
              }
  
              if (mVerbose) {
                  Slog.v(TAG, "ensureBound(): binding");
              }
              mBinding = true;
  
              int flags = Context.BIND_AUTO_CREATE | Context.BIND_FOREGROUND_SERVICE;
              boolean willBind = mContext.bindServiceAsUser(mIntent, mServiceConnection, flags,
                      mHandler, new UserHandle(mUserId));
              if (!willBind) {
                  Slog.w(TAG, "Could not bind to " + mIntent + " with flags " + flags);
                  mBinding = false;
                  mService = null;
              }
          }
      }
  
      @GuardedBy("mLock")
      private void ensureUnboundLocked() {
          if (mService == null && !mBinding) {
              return;
          }
  
          mBinding = false;
          mService = null;
  
          if (mVerbose) {
              Slog.v(TAG, "ensureUnbound(): unbinding");
          }
          mContext.unbindService(mServiceConnection);
      }
  
      private class RemoteServiceConnection implements ServiceConnection {
          @Override
          public void onServiceConnected(ComponentName name, IBinder service) {
              synchronized (mLock) {
                  if (mVerbose) {
                      Slog.v(TAG, "onServiceConnected()");
                  }
                  if (mDestroyed || !mBinding) {
                      Slog.wtf(TAG, "onServiceConnected() dispatched after unbindService");
                      return;
                  }
                  mBinding = false;
                  mService = service;
              }
          }
  
          @Override
          public void onServiceDisconnected(ComponentName name) {
              synchronized (mLock) {
                  if (mVerbose) {
                      Slog.v(TAG, "onServiceDisconnected()");
                  }
                  mBinding = true;
                  mService = null;
              }
          }
      }
  }
  