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.launcher3.util;
  
  import android.os.Looper;
  import android.os.MessageQueue;
  
  import com.android.launcher3.Utilities;
  
  /**
   * Utility class to block execution until the UI looper is idle.
   */
  public class LooperIdleLock implements MessageQueue.IdleHandler, Runnable {
  
      private final Object mLock;
  
      private boolean mIsLocked;
  
      public LooperIdleLock(Object lock, Looper looper) {
          mLock = lock;
          mIsLocked = true;
          if (Utilities.ATLEAST_MARSHMALLOW) {
              looper.getQueue().addIdleHandler(this);
          } else {
              // Looper.myQueue() only gives the current queue. Move the execution to the UI thread
              // so that the IdleHandler is attached to the correct message queue.
              new LooperExecutor(looper).execute(this);
          }
      }
  
      @Override
      public void run() {
          Looper.myQueue().addIdleHandler(this);
      }
  
      @Override
      public boolean queueIdle() {
          synchronized (mLock) {
              mIsLocked = false;
              mLock.notify();
          }
          return false;
      }
  
      public boolean awaitLocked(long ms) {
          if (mIsLocked) {
              try {
                  // Just in case mFlushingWorkerThread changes but we aren't woken up,
                  // wait no longer than 1sec at a time
                  mLock.wait(ms);
              } catch (InterruptedException ex) {
                  // Ignore
              }
          }
          return mIsLocked;
      }
  }
  