content: /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.weex.tracing;
  
  import org.apache.weex.utils.WXLogUtils;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  /**
   * Created by moxun on 2017/6/2.
   */
  
  public class Stopwatch {
    private static final ThreadLocal<Stopwatch> sThreadLocal = new ThreadLocal<>();
    private long startNanos;
    private List<ProcessEvent> splits = new ArrayList<>();
    private long startMillis;
  
    private static void prepare() {
      if (sThreadLocal.get() == null) {
        sThreadLocal.set(new Stopwatch());
      }
    }
  
    public static void tick() {
      if (WXTracing.isAvailable()) {
        try {
          prepare();
          if (sThreadLocal.get().startNanos != 0L) {
            WXLogUtils.w("Stopwatch", "Stopwatch is not reset");
          }
          sThreadLocal.get().startNanos = System.nanoTime();
          sThreadLocal.get().startMillis = System.currentTimeMillis();
        } catch (Throwable t) {
          t.printStackTrace();
        }
      }
    }
  
    public static void split(String fname) {
      if (WXTracing.isAvailable()) {
        try {
          ProcessEvent event = new ProcessEvent();
          long start = sThreadLocal.get().startMillis;
          double millis = tackAndTick();
          event.fname = fname;
          event.duration = millis;
          event.startMillis = start;
          sThreadLocal.get().splits.add(event);
        } catch (Throwable throwable) {
          throwable.printStackTrace();
        }
      }
    }
  
    public static List<ProcessEvent> getProcessEvents() {
      if (WXTracing.isAvailable()) {
        tack();
        List<ProcessEvent> existedEvents = sThreadLocal.get().splits;
        sThreadLocal.get().splits = new ArrayList<>();
        return existedEvents;
      } else {
        return Collections.emptyList();
      }
    }
  
    public static double tack() {
      if (WXTracing.isAvailable()) {
        try {
          long startNanos = sThreadLocal.get().startNanos;
          if (startNanos == 0L) {
            WXLogUtils.w("Stopwatch", "Should call Stopwatch.tick() before Stopwatch.tack() called");
          }
          long nanos = System.nanoTime() - startNanos;
          sThreadLocal.get().startNanos = 0L;
          return nanosToMillis(nanos);
        } catch (Throwable throwable) {
          throwable.printStackTrace();
        }
      }
      return -1;
    }
  
    public static long lastTickStamp() {
      if (WXTracing.isAvailable()) {
        try {
          return sThreadLocal.get().startMillis;
        } catch (Throwable t) {
          t.printStackTrace();
        }
      }
      return -1;
    }
  
    public static double tackAndTick() {
      double ms = tack();
      tick();
      return ms;
    }
  
    public static double nanosToMillis(long nanos) {
      return nanos / 1000000.0;
    }
  
    public static double millisUntilNow(long startNanos) {
      return nanosToMillis(System.nanoTime() - startNanos);
    }
  
    public static class ProcessEvent {
      public String fname;
      public double duration;
      public long startMillis;
    }
  }
  