gecko-dev/dom/svg/DOMSVGAnimatedNumberList.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_DOMSVGANIMATEDNUMBERLIST_H_
#define DOM_SVG_DOMSVGANIMATEDNUMBERLIST_H_
#include "nsCycleCollectionParticipant.h"
#include "SVGElement.h"
#include "nsWrapperCache.h"
#include "mozilla/Attributes.h"
#include "mozilla/RefPtr.h"
namespace mozilla {
class SVGAnimatedNumberList;
class SVGNumberList;
namespace dom {
class DOMSVGNumberList;
/**
* Class DOMSVGAnimatedNumberList
*
* This class is used to create the DOM tearoff objects that wrap internal
* SVGAnimatedNumberList objects.
*
* See the architecture comment in DOMSVGAnimatedLengthList.h (that's
* LENGTH list). The comment for that class largly applies to this one too
* and will go a long way to helping you understand the architecture here.
*
* This class is strongly intertwined with DOMSVGNumberList and DOMSVGNumber.
* Our DOMSVGNumberList base and anim vals are friends and take care of nulling
* out our pointers to them when they die (making our pointers to them true
* weak refs).
*/
class DOMSVGAnimatedNumberList final : public nsWrapperCache {
friend class DOMSVGNumberList;
public:
NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(DOMSVGAnimatedNumberList)
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(DOMSVGAnimatedNumberList)
/**
* Factory method to create and return a DOMSVGAnimatedNumberList wrapper
* for a given internal SVGAnimatedNumberList object. The factory takes care
* of caching the object that it returns so that the same object can be
* returned for the given SVGAnimatedNumberList each time it is requested.
* The cached object is only removed from the cache when it is destroyed due
* to there being no more references to it or to any of its descendant
* objects. If that happens, any subsequent call requesting the DOM wrapper
* for the SVGAnimatedNumberList will naturally result in a new
* DOMSVGAnimatedNumberList being returned.
*/
static already_AddRefed<DOMSVGAnimatedNumberList> GetDOMWrapper(
SVGAnimatedNumberList* aList, dom::SVGElement* aElement,
uint8_t aAttrEnum);
/**
* This method returns the DOMSVGAnimatedNumberList wrapper for an internal
* SVGAnimatedNumberList object if it currently has a wrapper. If it does
* not, then nullptr is returned.
*/
static DOMSVGAnimatedNumberList* GetDOMWrapperIfExists(
SVGAnimatedNumberList* aList);
/**
* Called by internal code to notify us when we need to sync the length of
* our baseVal DOM list with its internal list. This is called just prior to
* the length of the internal baseVal list being changed so that any DOM list
* items that need to be removed from the DOM list can first get their values
* from their internal counterpart.
*
* The only time this method could fail is on OOM when trying to increase the
* length of the DOM list. If that happens then this method simply clears the
* list and returns. Callers just proceed as normal, and we simply accept
* that the DOM list will be empty (until successfully set to a new value).
*/
void InternalBaseValListWillChangeTo(const SVGNumberList& aNewValue);
void InternalAnimValListWillChangeTo(const SVGNumberList& aNewValue);
/**
* Returns true if our attribute is animating (in which case our animVal is
* not simply a mirror of our baseVal).
*/
bool IsAnimating() const;
// WebIDL
dom::SVGElement* GetParentObject() const { return mElement; }
JSObject* WrapObject(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto) override;
// These aren't weak refs because mBaseVal and mAnimVal are weak
already_AddRefed<DOMSVGNumberList> BaseVal();
already_AddRefed<DOMSVGNumberList> AnimVal();
private:
/**
* Only our static GetDOMWrapper() factory method may create objects of our
* type.
*/
DOMSVGAnimatedNumberList(dom::SVGElement* aElement, uint8_t aAttrEnum)
: mBaseVal(nullptr),
mAnimVal(nullptr),
mElement(aElement),
mAttrEnum(aAttrEnum) {}
~DOMSVGAnimatedNumberList();
/// Get a reference to this DOM wrapper object's internal counterpart.
SVGAnimatedNumberList& InternalAList();
const SVGAnimatedNumberList& InternalAList() const;
// Weak refs to our DOMSVGNumberList baseVal/animVal objects. These objects
// are friends and take care of clearing these pointers when they die, making
// these true weak references.
DOMSVGNumberList* mBaseVal;
DOMSVGNumberList* mAnimVal;
// Strong ref to our element to keep it alive. We hold this not only for
// ourself, but also for our base/animVal and all of their items.
RefPtr<dom::SVGElement> mElement;
uint8_t mAttrEnum;
};
} // namespace dom
} // namespace mozilla
#endif // DOM_SVG_DOMSVGANIMATEDNUMBERLIST_H_