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 art.test;
  
  import java.util.concurrent.locks.ReentrantLock;
  
  public class TestWatcher {
    // Lock to synchronize access to the static state of this class.
    private static final ReentrantLock lock = new ReentrantLock();
    private static volatile boolean criticalFailure = false;
    private static boolean reportingEnabled = true;
    private static boolean doingReport = false;
  
    private static void MonitorEnter() {
      lock.lock();
    }
  
    private static void MonitorExit() {
      // Need to do this manually since we need to notify critical failure but would deadlock if
      // waited for the unlock.
      if (!lock.isHeldByCurrentThread()) {
        NotifyCriticalFailure();
        throw new IllegalMonitorStateException("Locking error!");
      } else {
        lock.unlock();
      }
    }
  
    // Stops reporting. Must be paired with an EnableReporting call.
    public static void DisableReporting() {
      MonitorEnter();
      reportingEnabled = false;
    }
  
    // Stops reporting. Must be paired with a DisableReporting call.
    public static void EnableReporting() {
      reportingEnabled = true;
      MonitorExit();
    }
  
    public static void NotifyCriticalFailure() {
      criticalFailure = true;
    }
  
    public static void NotifyConstructed(Object o) {
      if (criticalFailure) {
        // Something went very wrong. We are probably trying to report it so don't get in the way.
        return;
      }
      MonitorEnter();
      // We could enter an infinite loop if println allocates (which it does) so we disable
      // reporting while we are doing a report. Since we are synchronized we won't miss any
      // allocations.
      if (reportingEnabled && !doingReport) {
        doingReport = true;
        System.out.println("Object allocated of type '" + o.getClass().getName() + "'");
        doingReport = false;
      }
      MonitorExit();
    }
  }
  