/* -*- 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_dom_SVGAnimatedTransformList_h #define mozilla_dom_SVGAnimatedTransformList_h #include "nsAutoPtr.h" #include "nsCOMPtr.h" #include "nsCycleCollectionParticipant.h" #include "nsSVGElement.h" #include "nsWrapperCache.h" #include "mozilla/Attributes.h" namespace mozilla { class DOMSVGTransformList; class nsSVGAnimatedTransformList; namespace dom { /** * Class SVGAnimatedTransformList * * This class is used to create the DOM tearoff objects that wrap internal * nsSVGAnimatedTransformList 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 DOMSVGTransformList and * DOMSVGTransform. * Our DOMSVGTransformList 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 SVGAnimatedTransformList final : public nsWrapperCache { friend class mozilla::DOMSVGTransformList; public: NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(SVGAnimatedTransformList) NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(SVGAnimatedTransformList) /** * Factory method to create and return a SVGAnimatedTransformList wrapper * for a given internal nsSVGAnimatedTransformList object. The factory takes * care of caching the object that it returns so that the same object can be * returned for the given nsSVGAnimatedTransformList 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 nsSVGAnimatedTransformList will naturally result in a new * SVGAnimatedTransformList being returned. */ static already_AddRefed<SVGAnimatedTransformList> GetDOMWrapper(nsSVGAnimatedTransformList *aList, nsSVGElement *aElement); /** * This method returns the SVGAnimatedTransformList wrapper for an internal * nsSVGAnimatedTransformList object if it currently has a wrapper. If it does * not, then nullptr is returned. */ static SVGAnimatedTransformList* GetDOMWrapperIfExists(nsSVGAnimatedTransformList *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 InternalBaseValListWillChangeLengthTo(uint32_t aNewLength); void InternalAnimValListWillChangeLengthTo(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; // WebIDL nsSVGElement* GetParentObject() const { return mElement; } virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override; // These aren't weak refs because mBaseVal and mAnimVal are weak already_AddRefed<DOMSVGTransformList> BaseVal(); already_AddRefed<DOMSVGTransformList> AnimVal(); private: /** * Only our static GetDOMWrapper() factory method may create objects of our * type. */ explicit SVGAnimatedTransformList(nsSVGElement *aElement) : mBaseVal(nullptr) , mAnimVal(nullptr) , mElement(aElement) { } ~SVGAnimatedTransformList(); /// Get a reference to this DOM wrapper object's internal counterpart. nsSVGAnimatedTransformList& InternalAList(); const nsSVGAnimatedTransformList& InternalAList() const; // Weak refs to our DOMSVGTransformList baseVal/animVal objects. These objects // are friends and take care of clearing these pointers when they die, making // these true weak references. DOMSVGTransformList *mBaseVal; DOMSVGTransformList *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<nsSVGElement> mElement; }; } // namespace dom } // namespace mozilla #endif // mozilla_dom_SVGAnimatedTransformList_h