Coverage Report

Created: 2018-09-25 14:53

/src/mozilla-central/dom/svg/DOMSVGAnimatedNumberList.h
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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 * License, v. 2.0. If a copy of the MPL was not distributed with this
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 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef MOZILLA_DOMSVGANIMATEDNUMBERLIST_H__
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#define MOZILLA_DOMSVGANIMATEDNUMBERLIST_H__
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#include "nsCOMPtr.h"
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#include "nsCycleCollectionParticipant.h"
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#include "nsSVGElement.h"
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#include "nsWrapperCache.h"
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#include "mozilla/Attributes.h"
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namespace mozilla {
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class DOMSVGNumberList;
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class SVGAnimatedNumberList;
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class SVGNumberList;
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/**
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 * Class DOMSVGAnimatedNumberList
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 *
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 * This class is used to create the DOM tearoff objects that wrap internal
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 * SVGAnimatedNumberList objects.
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 *
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 * See the architecture comment in DOMSVGAnimatedLengthList.h (that's
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 * LENGTH list). The comment for that class largly applies to this one too
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 * and will go a long way to helping you understand the architecture here.
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 *
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 * This class is strongly intertwined with DOMSVGNumberList and DOMSVGNumber.
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 * Our DOMSVGNumberList base and anim vals are friends and take care of nulling
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 * out our pointers to them when they die (making our pointers to them true
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 * weak refs).
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 */
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class DOMSVGAnimatedNumberList final : public nsISupports,
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                                       public nsWrapperCache
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{
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  friend class DOMSVGNumberList;
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public:
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  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
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  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGAnimatedNumberList)
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  /**
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   * Factory method to create and return a DOMSVGAnimatedNumberList wrapper
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   * for a given internal SVGAnimatedNumberList object. The factory takes care
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   * of caching the object that it returns so that the same object can be
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   * returned for the given SVGAnimatedNumberList each time it is requested.
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   * The cached object is only removed from the cache when it is destroyed due
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   * to there being no more references to it or to any of its descendant
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   * objects. If that happens, any subsequent call requesting the DOM wrapper
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   * for the SVGAnimatedNumberList will naturally result in a new
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   * DOMSVGAnimatedNumberList being returned.
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   */
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  static already_AddRefed<DOMSVGAnimatedNumberList>
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    GetDOMWrapper(SVGAnimatedNumberList *aList,
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                  nsSVGElement *aElement,
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                  uint8_t aAttrEnum);
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  /**
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   * This method returns the DOMSVGAnimatedNumberList wrapper for an internal
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   * SVGAnimatedNumberList object if it currently has a wrapper. If it does
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   * not, then nullptr is returned.
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   */
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  static DOMSVGAnimatedNumberList*
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    GetDOMWrapperIfExists(SVGAnimatedNumberList *aList);
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  /**
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   * Called by internal code to notify us when we need to sync the length of
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   * our baseVal DOM list with its internal list. This is called just prior to
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   * the length of the internal baseVal list being changed so that any DOM list
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   * items that need to be removed from the DOM list can first get their values
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   * from their internal counterpart.
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   *
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   * The only time this method could fail is on OOM when trying to increase the
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   * length of the DOM list. If that happens then this method simply clears the
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   * list and returns. Callers just proceed as normal, and we simply accept
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   * that the DOM list will be empty (until successfully set to a new value).
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   */
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  void InternalBaseValListWillChangeTo(const SVGNumberList& aNewValue);
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  void InternalAnimValListWillChangeTo(const SVGNumberList& aNewValue);
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  /**
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   * Returns true if our attribute is animating (in which case our animVal is
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   * not simply a mirror of our baseVal).
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   */
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  bool IsAnimating() const;
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  // WebIDL
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  nsSVGElement* GetParentObject() const { return mElement; }
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  virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
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  // These aren't weak refs because mBaseVal and mAnimVal are weak
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  already_AddRefed<DOMSVGNumberList> BaseVal();
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  already_AddRefed<DOMSVGNumberList> AnimVal();
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private:
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  /**
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   * Only our static GetDOMWrapper() factory method may create objects of our
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   * type.
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   */
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  DOMSVGAnimatedNumberList(nsSVGElement *aElement, uint8_t aAttrEnum)
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    : mBaseVal(nullptr)
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    , mAnimVal(nullptr)
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    , mElement(aElement)
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    , mAttrEnum(aAttrEnum)
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  {
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  }
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  ~DOMSVGAnimatedNumberList();
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  /// Get a reference to this DOM wrapper object's internal counterpart.
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  SVGAnimatedNumberList& InternalAList();
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  const SVGAnimatedNumberList& InternalAList() const;
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  // Weak refs to our DOMSVGNumberList baseVal/animVal objects. These objects
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  // are friends and take care of clearing these pointers when they die, making
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  // these true weak references.
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  DOMSVGNumberList *mBaseVal;
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  DOMSVGNumberList *mAnimVal;
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  // Strong ref to our element to keep it alive. We hold this not only for
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  // ourself, but also for our base/animVal and all of their items.
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  RefPtr<nsSVGElement> mElement;
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  uint8_t mAttrEnum;
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};
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} // namespace mozilla
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#endif // MOZILLA_DOMSVGANIMATEDNUMBERLIST_H__