/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 */

/* arena allocation for the frame tree and closely-related objects */

#ifndef nsPresArena_h___

#define nsPresArena_h___

#include "mozilla/ArenaAllocator.h"

#include "mozilla/ArenaObjectID.h"

#include "mozilla/ArenaRefPtr.h"

#include "mozilla/Assertions.h"

#include "mozilla/MemoryChecking.h" // Note: Do not remove this, needed for MOZ_HAVE_MEM_CHECKS below

#include "mozilla/MemoryReporting.h"

#include <stdint.h>

#include "nscore.h"

#include "nsDataHashtable.h"

#include "nsHashKeys.h"

#include "nsTArray.h"

#include "nsTHashtable.h"

class nsWindowSizes;

class nsPresArena {

public:

  nsPresArena();

  ~nsPresArena();

  /**

   * Pool allocation with recycler lists indexed by frame-type ID.

   * Every aID must always be used with the same object size, aSize.

   */

  void* AllocateByFrameID(nsQueryFrame::FrameIID aID, size_t aSize)

  {

    return Allocate(aID, aSize);

  }

  void FreeByFrameID(nsQueryFrame::FrameIID aID, void* aPtr)

  {

    Free(aID, aPtr);

  }

  /**

   * Pool allocation with recycler lists indexed by object-type ID (see above).

   * Every aID must always be used with the same object size, aSize.

   */

  void* AllocateByObjectID(mozilla::ArenaObjectID aID, size_t aSize)

  {

    return Allocate(aID, aSize);

  }

  void FreeByObjectID(mozilla::ArenaObjectID aID, void* aPtr)

  {

    Free(aID, aPtr);

  }

  void* AllocateByCustomID(uint32_t aID, size_t aSize)

  {

    return Allocate(aID, aSize);

  }

  void FreeByCustomID(uint32_t aID, void* ptr)

  {

    Free(aID, ptr);

  }

  /**

   * Register an ArenaRefPtr to be cleared when this arena is about to

   * be destroyed.

   *

   * (Defined in ArenaRefPtrInlines.h.)

   *

   * @param aPtr The ArenaRefPtr to clear.

   * @param aObjectID The ArenaObjectID value that uniquely identifies

   *   the type of object the ArenaRefPtr holds.

   */

  template<typename T>

  void RegisterArenaRefPtr(mozilla::ArenaRefPtr<T>* aPtr);

  /**

   * Deregister an ArenaRefPtr that was previously registered with

   * RegisterArenaRefPtr.

   */

  template<typename T>

  void DeregisterArenaRefPtr(mozilla::ArenaRefPtr<T>* aPtr)

  {

    MOZ_ASSERT(mArenaRefPtrs.Contains(aPtr));

    mArenaRefPtrs.Remove(aPtr);

  }

  /**

   * Clears all currently registered ArenaRefPtrs.  This will be called during

   * the destructor, but can be called by users of nsPresArena who want to

   * ensure arena-allocated objects are released earlier.

   */

  void ClearArenaRefPtrs();

  /**

   * Clears all currently registered ArenaRefPtrs for the given ArenaObjectID.

   * This is called when we reconstruct the rule tree so that ComputedStyles

   * pointing into the old rule tree aren't released afterwards, triggering an

   * assertion in ~ComputedStyle.

   */

  void ClearArenaRefPtrs(mozilla::ArenaObjectID aObjectID);

  /**

   * Increment nsWindowSizes with sizes of interesting objects allocated in this

   * arena.

   */

  void AddSizeOfExcludingThis(nsWindowSizes& aWindowSizes) const;

  void Check() {

    mPool.Check();

  }

private:

  void* Allocate(uint32_t aCode, size_t aSize);

  void Free(uint32_t aCode, void* aPtr);

  inline void ClearArenaRefPtrWithoutDeregistering(

      void* aPtr,

      mozilla::ArenaObjectID aObjectID);

  class FreeList

  {

  public:

    nsTArray<void *> mEntries;

    size_t mEntrySize;

    size_t mEntriesEverAllocated;

    FreeList()

      : mEntrySize(0)

      , mEntriesEverAllocated(0)

    {}

    size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const

    { return mEntries.ShallowSizeOfExcludingThis(aMallocSizeOf); }

  };

  FreeList mFreeLists[mozilla::eArenaObjectID_COUNT];

  mozilla::ArenaAllocator<8192, 8> mPool;

  nsDataHashtable<nsPtrHashKey<void>, mozilla::ArenaObjectID> mArenaRefPtrs;

};

#endif