/* -*- 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/. */

#ifndef MOZILLA_DOMSVGLENGTHLIST_H__

#define MOZILLA_DOMSVGLENGTHLIST_H__

#include "DOMSVGAnimatedLengthList.h"

#include "nsCycleCollectionParticipant.h"

#include "nsDebug.h"

#include "nsTArray.h"

#include "SVGLengthList.h"

#include "mozilla/Attributes.h"

#include "mozilla/ErrorResult.h"

class nsSVGElement;

namespace mozilla {

class DOMSVGLength;

/**

 * Class DOMSVGLengthList

 *

 * This class is used to create the DOM tearoff objects that wrap internal

 * SVGLengthList objects.

 *

 * See the architecture comment in DOMSVGAnimatedLengthList.h.

 *

 * This class is strongly intertwined with DOMSVGAnimatedLengthList and

 * DOMSVGLength. We are a friend of DOMSVGAnimatedLengthList, and are

 * responsible for nulling out our DOMSVGAnimatedLengthList's pointer to us

 * when we die, essentially making its pointer to us a weak pointer. Similarly,

 * our DOMSVGLength items are friends of us and responsible for nulling out our

 * pointers to them.

 *

 * Our DOM items are created lazily on demand as and when script requests them.

 */

class DOMSVGLengthList final : public nsISupports,

                               public nsWrapperCache

{

  friend class AutoChangeLengthListNotifier;

  friend class DOMSVGLength;

  ~DOMSVGLengthList() {

    // Our mAList's weak ref to us must be nulled out when we die. If GC has

    // unlinked us using the cycle collector code, then that has already

    // happened, and mAList is null.

    if (mAList) {

      ( IsAnimValList() ? mAList->mAnimVal : mAList->mBaseVal ) = nullptr;

    }

  }

public:

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGLengthList)

  DOMSVGLengthList(DOMSVGAnimatedLengthList *aAList,

                   const SVGLengthList &aInternalList)

    : mAList(aAList)

  {

    // aInternalList must be passed in explicitly because we can't use

    // InternalList() here. (Because it depends on IsAnimValList, which depends

    // on this object having been assigned to aAList's mBaseVal or mAnimVal,

    // which hasn't happened yet.)

    InternalListLengthWillChange(aInternalList.Length()); // Sync mItems

  }

  virtual JSObject* WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto) override;

  nsISupports* GetParentObject()

  {

    return static_cast<nsIContent*>(Element());

  }

  /**

   * This will normally be the same as InternalList().Length(), except if we've

   * hit OOM in which case our length will be zero.

   */

  uint32_t LengthNoFlush() const {

    MOZ_ASSERT(mItems.Length() == 0 ||

               mItems.Length() == InternalList().Length(),

               "DOM wrapper's list length is out of sync");

    return mItems.Length();

  }

  /// Called to notify us to synchronize our length and detach excess items.

  void InternalListLengthWillChange(uint32_t aNewLength);

  /**

   * Returns true if our attribute is animating (in which case our animVal is

   * not simply a mirror of our baseVal).

   */

  bool IsAnimating() const {

    return mAList->IsAnimating();

  }

  /**

   * Returns true if there is an animated list mirroring the base list.

   */

  bool AnimListMirrorsBaseList() const {

    return mAList->mAnimVal && !mAList->IsAnimating();

  }

  uint32_t NumberOfItems() const

  {

    if (IsAnimValList()) {

      Element()->FlushAnimations();

    }

    return LengthNoFlush();

  }

  void Clear(ErrorResult& aError);

  already_AddRefed<DOMSVGLength> Initialize(DOMSVGLength& newItem,

                                            ErrorResult& error);

  already_AddRefed<DOMSVGLength> GetItem(uint32_t index,

                                         ErrorResult& error);

  already_AddRefed<DOMSVGLength> IndexedGetter(uint32_t index, bool& found,

                                               ErrorResult& error);

  already_AddRefed<DOMSVGLength> InsertItemBefore(DOMSVGLength& newItem,

                                                  uint32_t index,

                                                  ErrorResult& error);

  already_AddRefed<DOMSVGLength> ReplaceItem(DOMSVGLength& newItem,

                                             uint32_t index,

                                             ErrorResult& error);

  already_AddRefed<DOMSVGLength> RemoveItem(uint32_t index,

                                            ErrorResult& error);

  already_AddRefed<DOMSVGLength> AppendItem(DOMSVGLength& newItem,

                                            ErrorResult& error)

  {

    return InsertItemBefore(newItem, LengthNoFlush(), error);

  }

  uint32_t Length() const

  {

    return NumberOfItems();

  }

private:

  nsSVGElement* Element() const {

    return mAList->mElement;

  }

  uint8_t AttrEnum() const {

    return mAList->mAttrEnum;

  }

  uint8_t Axis() const {

    return mAList->mAxis;

  }

  /// Used to determine if this list is the baseVal or animVal list.

  bool IsAnimValList() const {

    MOZ_ASSERT(this == mAList->mBaseVal || this == mAList->mAnimVal,

               "Calling IsAnimValList() too early?!");

    return this == mAList->mAnimVal;

  }

  /**

   * Get a reference to this object's corresponding internal SVGLengthList.

   *

   * To simplify the code we just have this one method for obtaining both

   * baseVal and animVal internal lists. This means that animVal lists don't

   * get const protection, but our setter methods guard against changing

   * animVal lists.

   */

  SVGLengthList& InternalList() const;

  /// Returns the DOMSVGLength at aIndex, creating it if necessary.

  already_AddRefed<DOMSVGLength> GetItemAt(uint32_t aIndex);

  void MaybeInsertNullInAnimValListAt(uint32_t aIndex);

  void MaybeRemoveItemFromAnimValListAt(uint32_t aIndex);

  // Weak refs to our DOMSVGLength items. The items are friends and take care

  // of clearing our pointer to them when they die.

  FallibleTArray<DOMSVGLength*> mItems;

  RefPtr<DOMSVGAnimatedLengthList> mAList;

};

} // namespace mozilla

#endif // MOZILLA_DOMSVGLENGTHLIST_H__