content: /*
   * Copyright (C) 2013 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;
  
  import android.os.Handler;
  import android.os.HandlerExecutor;
  import android.os.Trace;
  
  import java.util.concurrent.Executor;
  
  /**
   * Shared singleton I/O thread for the system.  This is a thread for non-background
   * service operations that can potential block briefly on network IO operations
   * (not waiting for data itself, but communicating with network daemons).
   */
  public final class IoThread extends ServiceThread {
      private static IoThread sInstance;
      private static Handler sHandler;
      private static HandlerExecutor sHandlerExecutor;
  
      private IoThread() {
          super("android.io", android.os.Process.THREAD_PRIORITY_DEFAULT, true /*allowIo*/);
      }
  
      private static void ensureThreadLocked() {
          if (sInstance == null) {
              sInstance = new IoThread();
              sInstance.start();
              sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_SYSTEM_SERVER);
              sHandler = new Handler(sInstance.getLooper());
              sHandlerExecutor = new HandlerExecutor(sHandler);
          }
      }
  
      public static IoThread get() {
          synchronized (IoThread.class) {
              ensureThreadLocked();
              return sInstance;
          }
      }
  
      public static Handler getHandler() {
          synchronized (IoThread.class) {
              ensureThreadLocked();
              return sHandler;
          }
      }
  
      public static Executor getExecutor() {
          synchronized (IoThread.class) {
              ensureThreadLocked();
              return sHandlerExecutor;
          }
      }
  }
  