text: /*
   * Copyright (C) 2010, 2016 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1.  Redistributions of source code must retain the above copyright
   *     notice, this list of conditions and the following disclaimer. 
   * 2.  Redistributions in binary form must reproduce the above copyright
   *     notice, this list of conditions and the following disclaimer in the
   *     documentation and/or other materials provided with the distribution. 
   * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
   *     its contributors may be used to endorse or promote products derived
   *     from this software without specific prior written permission. 
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
   * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #pragma once
  
  #include "HeapTimer.h"
  #include <wtf/RefPtr.h>
  
  #if USE(CF)
  #include <CoreFoundation/CoreFoundation.h>
  #endif
  
  namespace JSC {
  
  class FullGCActivityCallback;
  class Heap;
  
  class JS_EXPORT_PRIVATE GCActivityCallback : public HeapTimer {
  public:
      static RefPtr<FullGCActivityCallback> createFullTimer(Heap*);
      static RefPtr<GCActivityCallback> createEdenTimer(Heap*);
  
      GCActivityCallback(Heap*);
  
      void doWork() override;
  
      virtual void doCollection() = 0;
  
      virtual void didAllocate(size_t);
      virtual void willCollect();
      virtual void cancel();
      bool isEnabled() const { return m_enabled; }
      void setEnabled(bool enabled) { m_enabled = enabled; }
  
      static bool s_shouldCreateGCTimer;
  
  #if USE(CF) || USE(GLIB)
      double nextFireTime() const { return m_nextFireTime; }
  #endif
  
  protected:
      virtual double lastGCLength() = 0;
      virtual double gcTimeSlice(size_t bytes) = 0;
      virtual double deathRate() = 0;
  
  #if USE(CF)
      GCActivityCallback(VM* vm)
          : HeapTimer(vm)
          , m_enabled(true)
          , m_delay(s_decade)
      {
      }
  #elif USE(GLIB)
      GCActivityCallback(VM* vm)
          : HeapTimer(vm)
          , m_enabled(true)
          , m_delay(s_decade)
      {
      }
  #else
      GCActivityCallback(VM* vm)
          : HeapTimer(vm)
          , m_enabled(true)
      {
      }
  #endif
  
      bool m_enabled;
  
  #if USE(CF) || USE(GLIB)
  protected:
      void cancelTimer();
      void scheduleTimer(double);
  
  private:
      double m_delay;
      double m_nextFireTime { 0 };
  #endif
  };
  
  } // namespace JSC
  