content: /*
   * 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;
  
  import static android.os.Process.THREAD_PRIORITY_DISPLAY;
  
  import android.os.Handler;
  import android.os.Trace;
  
  /**
   * Thread for handling all legacy window animations, or anything that's directly impacting
   * animations like starting windows or traversals.
   */
  public final class AnimationThread extends ServiceThread {
      private static AnimationThread sInstance;
      private static Handler sHandler;
  
      private AnimationThread() {
          super("android.anim", THREAD_PRIORITY_DISPLAY, false /*allowIo*/);
      }
  
      private static void ensureThreadLocked() {
          if (sInstance == null) {
              sInstance = new AnimationThread();
              sInstance.start();
              sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_WINDOW_MANAGER);
              sHandler = new Handler(sInstance.getLooper());
          }
      }
  
      public static AnimationThread get() {
          synchronized (AnimationThread.class) {
              ensureThreadLocked();
              return sInstance;
          }
      }
  
      public static Handler getHandler() {
          synchronized (AnimationThread.class) {
              ensureThreadLocked();
              return sHandler;
          }
      }
  }
  