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       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* vim: set ts=8 sts=2 et sw=2 tw=80: */
       3             : /* This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : #ifndef MOZILLA_DOMSVGANIMATEDNUMBERLIST_H__
       8             : #define MOZILLA_DOMSVGANIMATEDNUMBERLIST_H__
       9             : 
      10             : #include "nsCOMPtr.h"
      11             : #include "nsCycleCollectionParticipant.h"
      12             : #include "nsSVGElement.h"
      13             : #include "nsWrapperCache.h"
      14             : #include "mozilla/Attributes.h"
      15             : 
      16             : namespace mozilla {
      17             : 
      18             : class DOMSVGNumberList;
      19             : class SVGAnimatedNumberList;
      20             : class SVGNumberList;
      21             : 
      22             : /**
      23             :  * Class DOMSVGAnimatedNumberList
      24             :  *
      25             :  * This class is used to create the DOM tearoff objects that wrap internal
      26             :  * SVGAnimatedNumberList objects.
      27             :  *
      28             :  * See the architecture comment in DOMSVGAnimatedLengthList.h (that's
      29             :  * LENGTH list). The comment for that class largly applies to this one too
      30             :  * and will go a long way to helping you understand the architecture here.
      31             :  *
      32             :  * This class is strongly intertwined with DOMSVGNumberList and DOMSVGNumber.
      33             :  * Our DOMSVGNumberList base and anim vals are friends and take care of nulling
      34             :  * out our pointers to them when they die (making our pointers to them true
      35             :  * weak refs).
      36             :  */
      37             : class DOMSVGAnimatedNumberList final : public nsISupports,
      38             :                                        public nsWrapperCache
      39             : {
      40             :   friend class DOMSVGNumberList;
      41             : 
      42             : public:
      43             :   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
      44           0 :   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGAnimatedNumberList)
      45             : 
      46             :   /**
      47             :    * Factory method to create and return a DOMSVGAnimatedNumberList wrapper
      48             :    * for a given internal SVGAnimatedNumberList object. The factory takes care
      49             :    * of caching the object that it returns so that the same object can be
      50             :    * returned for the given SVGAnimatedNumberList each time it is requested.
      51             :    * The cached object is only removed from the cache when it is destroyed due
      52             :    * to there being no more references to it or to any of its descendant
      53             :    * objects. If that happens, any subsequent call requesting the DOM wrapper
      54             :    * for the SVGAnimatedNumberList will naturally result in a new
      55             :    * DOMSVGAnimatedNumberList being returned.
      56             :    */
      57             :   static already_AddRefed<DOMSVGAnimatedNumberList>
      58             :     GetDOMWrapper(SVGAnimatedNumberList *aList,
      59             :                   nsSVGElement *aElement,
      60             :                   uint8_t aAttrEnum);
      61             : 
      62             :   /**
      63             :    * This method returns the DOMSVGAnimatedNumberList wrapper for an internal
      64             :    * SVGAnimatedNumberList object if it currently has a wrapper. If it does
      65             :    * not, then nullptr is returned.
      66             :    */
      67             :   static DOMSVGAnimatedNumberList*
      68             :     GetDOMWrapperIfExists(SVGAnimatedNumberList *aList);
      69             : 
      70             :   /**
      71             :    * Called by internal code to notify us when we need to sync the length of
      72             :    * our baseVal DOM list with its internal list. This is called just prior to
      73             :    * the length of the internal baseVal list being changed so that any DOM list
      74             :    * items that need to be removed from the DOM list can first get their values
      75             :    * from their internal counterpart.
      76             :    *
      77             :    * The only time this method could fail is on OOM when trying to increase the
      78             :    * length of the DOM list. If that happens then this method simply clears the
      79             :    * list and returns. Callers just proceed as normal, and we simply accept
      80             :    * that the DOM list will be empty (until successfully set to a new value).
      81             :    */
      82             :   void InternalBaseValListWillChangeTo(const SVGNumberList& aNewValue);
      83             :   void InternalAnimValListWillChangeTo(const SVGNumberList& aNewValue);
      84             : 
      85             :   /**
      86             :    * Returns true if our attribute is animating (in which case our animVal is
      87             :    * not simply a mirror of our baseVal).
      88             :    */
      89             :   bool IsAnimating() const;
      90             : 
      91             :   // WebIDL
      92           0 :   nsSVGElement* GetParentObject() const { return mElement; }
      93             :   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
      94             :   // These aren't weak refs because mBaseVal and mAnimVal are weak
      95             :   already_AddRefed<DOMSVGNumberList> BaseVal();
      96             :   already_AddRefed<DOMSVGNumberList> AnimVal();
      97             : 
      98             : private:
      99             : 
     100             :   /**
     101             :    * Only our static GetDOMWrapper() factory method may create objects of our
     102             :    * type.
     103             :    */
     104           0 :   DOMSVGAnimatedNumberList(nsSVGElement *aElement, uint8_t aAttrEnum)
     105           0 :     : mBaseVal(nullptr)
     106             :     , mAnimVal(nullptr)
     107             :     , mElement(aElement)
     108           0 :     , mAttrEnum(aAttrEnum)
     109             :   {
     110           0 :   }
     111             : 
     112             :   ~DOMSVGAnimatedNumberList();
     113             : 
     114             :   /// Get a reference to this DOM wrapper object's internal counterpart.
     115             :   SVGAnimatedNumberList& InternalAList();
     116             :   const SVGAnimatedNumberList& InternalAList() const;
     117             : 
     118             :   // Weak refs to our DOMSVGNumberList baseVal/animVal objects. These objects
     119             :   // are friends and take care of clearing these pointers when they die, making
     120             :   // these true weak references.
     121             :   DOMSVGNumberList *mBaseVal;
     122             :   DOMSVGNumberList *mAnimVal;
     123             : 
     124             :   // Strong ref to our element to keep it alive. We hold this not only for
     125             :   // ourself, but also for our base/animVal and all of their items.
     126             :   RefPtr<nsSVGElement> mElement;
     127             : 
     128             :   uint8_t mAttrEnum;
     129             : };
     130             : 
     131             : } // namespace mozilla
     132             : 
     133             : #endif // MOZILLA_DOMSVGANIMATEDNUMBERLIST_H__