gecko-dev/dom/svg/DOMSVGNumber.h

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/* -*- 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 DOM_SVG_DOMSVGNUMBER_H_
#define DOM_SVG_DOMSVGNUMBER_H_
#include "DOMSVGNumberList.h"
#include "nsCOMPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "nsTArray.h"
#include "mozilla/Attributes.h"
#include "mozilla/RefPtr.h"
#include "nsWrapperCache.h"
#define MOZ_SVG_LIST_INDEX_BIT_COUNT 27 // supports > 134 million list items
namespace mozilla {
class ErrorResult;
namespace dom {
class SVGElement;
class SVGSVGElement;
/**
* 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 SVGAnimatedNumber.h.
*
* See the architecture comment in DOMSVGAnimatedNumberList.h.
*
* See the comment in DOMSVGLength.h (yes, LENGTH), which applies here too.
*/
class DOMSVGNumber final : public nsWrapperCache {
template <class T>
friend class AutoChangeNumberListNotifier;
~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_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(DOMSVGNumber)
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_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(SVGSVGElement* aParent);
private:
explicit DOMSVGNumber(nsISupports* aParent);
public:
/**
* 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; }
/**
* Returns true if our attribute is animating.
*/
bool IsAnimating() const { return mList && mList->IsAnimating(); }
/**
* 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; }
JSObject* WrapObject(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto) override;
float Value();
void SetValue(float aValue, ErrorResult& aRv);
private:
dom::SVGElement* 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 dom
} // namespace mozilla
#undef MOZ_SVG_LIST_INDEX_BIT_COUNT
#endif // DOM_SVG_DOMSVGNUMBER_H_