/* -*- 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_DOMSVGNUMBER_H__

#define MOZILLA_DOMSVGNUMBER_H__

#include "DOMSVGNumberList.h"

#include "nsCycleCollectionParticipant.h"

#include "nsTArray.h"

#include "mozilla/Attributes.h"

#include "mozilla/ErrorResult.h"

#include "nsWrapperCache.h"

class nsSVGElement;

#define MOZ_SVG_LIST_INDEX_BIT_COUNT 27 // supports > 134 million list items

namespace mozilla {

/**

 * Class DOMSVGNumber

 *

 * This class creates the DOM objects that wrap internal SVGNumber objects that

 * are in an SVGNumberList. It is also used to create the objects returned by

 * SVGSVGElement.createSVGNumber().

 *

 * For the DOM wrapper classes for non-list SVGNumber, see nsSVGNumber2.h.

 *

 * See the architecture comment in DOMSVGAnimatedNumberList.h.

 *

 * See the comment in DOMSVGLength.h (yes, LENGTH), which applies here too.

 */

class DOMSVGNumber final : public nsISupports

                         , public nsWrapperCache

{

  friend class AutoChangeNumberNotifier;

  ~DOMSVGNumber() {

    // Our mList'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 mList is null.

    if (mList) {

      mList->mItems[mListIndex] = nullptr;

    }

  }

public:

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGNumber)

  /**

   * Generic ctor for DOMSVGNumber objects that are created for an attribute.

   */

  DOMSVGNumber(DOMSVGNumberList *aList,

               uint8_t aAttrEnum,

               uint32_t aListIndex,

               bool aIsAnimValItem);

  /**

   * Ctor for creating the objects returned by SVGSVGElement.createSVGNumber(),

   * which do not initially belong to an attribute.

   */

  explicit DOMSVGNumber(nsISupports* aParent);

  /**

   * Create an unowned copy. The caller is responsible for the first AddRef().

   */

  DOMSVGNumber* Clone() {

    DOMSVGNumber *clone = new DOMSVGNumber(mParent);

    clone->mValue = ToSVGNumber();

    return clone;

  }

  bool IsInList() const {

    return !!mList;

  }

  /**

   * In future, if this class is used for non-list numbers, this will be

   * different to IsInList().

   */

  bool HasOwner() const {

    return !!mList;

  }

  /**

   * This method is called to notify this DOM object that it is being inserted

   * into a list, and give it the information it needs as a result.

   *

   * This object MUST NOT already belong to a list when this method is called.

   * That's not to say that script can't move these DOM objects between

   * lists - it can - it's just that the logic to handle that (and send out

   * the necessary notifications) is located elsewhere (in DOMSVGNumberList).)

   */

  void InsertingIntoList(DOMSVGNumberList *aList,

                         uint8_t aAttrEnum,

                         uint32_t aListIndex,

                         bool aIsAnimValItem);

  static uint32_t MaxListIndex() {

    return (1U << MOZ_SVG_LIST_INDEX_BIT_COUNT) - 1;

  }

  /// This method is called to notify this object that its list index changed.

  void UpdateListIndex(uint32_t aListIndex) {

    mListIndex = aListIndex;

  }

  /**

   * This method is called to notify this DOM object that it is about to be

   * removed from its current DOM list so that it can first make a copy of its

   * internal counterpart's value. (If it didn't do this, then it would

   * "lose" its value on being removed.)

   */

  void RemovingFromList();

  float ToSVGNumber();

  nsISupports* GetParentObject()

  {

    return mParent;

  }

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

  float Value();

  void SetValue(float aValue, ErrorResult& aRv);

private:

  nsSVGElement* Element() {

    return mList->Element();

  }

  uint8_t AttrEnum() const {

    return mAttrEnum;

  }

  /**

   * Get a reference to the internal SVGNumber list item that this DOM wrapper

   * object currently wraps.

   *

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

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

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

   * animVal items.

   */

  float& InternalItem();

#ifdef DEBUG

  bool IndexIsValid();

#endif

  RefPtr<DOMSVGNumberList> mList;

  nsCOMPtr<nsISupports> mParent;

  // Bounds for the following are checked in the ctor, so be sure to update

  // that if you change the capacity of any of the following.

  uint32_t mListIndex:MOZ_SVG_LIST_INDEX_BIT_COUNT;

  uint32_t mAttrEnum:4; // supports up to 16 attributes

  uint32_t mIsAnimValItem:1;

  // The following member is only used when we're not in a list:

  float mValue;

};

} // namespace mozilla

#undef MOZ_SVG_LIST_INDEX_BIT_COUNT

#endif // MOZILLA_DOMSVGNUMBER_H__