text: /*
   * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
   * 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.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT HOLDER OR 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 <AK/FixedArray.h>
  #include <AK/InlineLinkedList.h>
  #include <AK/RefCounted.h>
  #include <AK/RefPtr.h>
  #include <AK/Weakable.h>
  #include <Kernel/Lock.h>
  
  class Inode;
  class PhysicalPage;
  
  class VMObject : public RefCounted<VMObject>
      , public Weakable<VMObject>
      , public InlineLinkedListNode<VMObject> {
      friend class MemoryManager;
      friend class Region;
  
  public:
      virtual ~VMObject();
  
      virtual NonnullRefPtr<VMObject> clone() = 0;
  
      virtual bool is_anonymous() const { return false; }
      virtual bool is_purgeable() const { return false; }
      virtual bool is_inode() const { return false; }
  
      size_t page_count() const { return m_physical_pages.size(); }
      const FixedArray<RefPtr<PhysicalPage>>& physical_pages() const { return m_physical_pages; }
      FixedArray<RefPtr<PhysicalPage>>& physical_pages() { return m_physical_pages; }
  
      size_t size() const { return m_physical_pages.size() * PAGE_SIZE; }
  
      // For InlineLinkedListNode
      VMObject* m_next { nullptr };
      VMObject* m_prev { nullptr };
  
  protected:
      explicit VMObject(size_t);
      explicit VMObject(const VMObject&);
  
      template<typename Callback>
      void for_each_region(Callback);
  
      FixedArray<RefPtr<PhysicalPage>> m_physical_pages;
      Lock m_paging_lock { "VMObject" };
  
  private:
      VMObject& operator=(const VMObject&) = delete;
      VMObject& operator=(VMObject&&) = delete;
      VMObject(VMObject&&) = delete;
  };
  