/* -*- 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_DOMSVGPATHSEGLIST_H_ #define DOM_SVG_DOMSVGPATHSEGLIST_H_ #include "mozAutoDocUpdate.h" #include "nsCycleCollectionParticipant.h" #include "nsDebug.h" #include "nsTArray.h" #include "SVGPathData.h" // IWYU pragma: keep #include "mozilla/Attributes.h" #include "mozilla/RefPtr.h" #include "mozilla/dom/SVGElement.h" namespace mozilla { class ErrorResult; class SVGAnimatedPathSegList; namespace dom { class DOMSVGPathSeg; class SVGPathElement; //---------------------------------------------------------------------- // Helper class: AutoChangePathSegListNotifier // Stack-based helper class to pair calls to WillChangePathSegList and // DidChangePathSegList. Used by DOMSVGPathSeg and DOMSVGPathSegList. template class MOZ_RAII AutoChangePathSegListNotifier : public mozAutoDocUpdate { public: explicit AutoChangePathSegListNotifier(T* aValue) : mozAutoDocUpdate(aValue->Element()->GetComposedDoc(), true), mValue(aValue) { MOZ_ASSERT(mValue, "Expecting non-null value"); mEmptyOrOldValue = mValue->Element()->WillChangePathSegList(*this); } ~AutoChangePathSegListNotifier() { mValue->Element()->DidChangePathSegList(mEmptyOrOldValue, *this); if (mValue->AttrIsAnimating()) { mValue->Element()->AnimationNeedsResample(); } } private: T* const mValue; nsAttrValue mEmptyOrOldValue; }; /** * Class DOMSVGPathSegList * * This class is used to create the DOM tearoff objects that wrap internal * SVGPathData objects. * * See the architecture comment in DOMSVGAnimatedLengthList.h first (that's * LENGTH list), then continue reading the remainder of this comment. * * The architecture of this class is very similar to that of DOMSVGLengthList * except that, since there is no nsIDOMSVGAnimatedPathSegList interface * in SVG, we have no parent DOMSVGAnimatedPathSegList (unlike DOMSVGLengthList * which has a parent DOMSVGAnimatedLengthList class). (There is an * SVGAnimatedPathData interface, but that is quite different to * DOMSVGAnimatedLengthList, since it is inherited by elements rather than * elements having members of that type.) As a consequence, much of the logic * that would otherwise be in DOMSVGAnimatedPathSegList (and is in * DOMSVGAnimatedLengthList) is contained in this class. * * This class is strongly intertwined with DOMSVGPathSeg. Our DOMSVGPathSeg * items are friends of us and responsible for nulling out our pointers to * them when they die. * * Our DOM items are created lazily on demand as and when script requests them. */ class DOMSVGPathSegList final : public nsISupports, public nsWrapperCache { template friend class AutoChangePathSegListNotifier; friend class DOMSVGPathSeg; public: NS_DECL_CYCLE_COLLECTING_ISUPPORTS NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGPathSegList) JSObject* WrapObject(JSContext* cx, JS::Handle aGivenProto) override; nsISupports* GetParentObject() { return static_cast(mElement); } /** * Factory method to create and return a DOMSVGPathSegList wrapper * for a given internal SVGPathData object. The factory takes care * of caching the object that it returns so that the same object can be * returned for the given SVGPathData 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 SVGPathData will naturally result in a new * DOMSVGPathSegList being returned. * * It's unfortunate that aList is a void* instead of a typed argument. This * is because the mBaseVal and mAnimVal members of SVGAnimatedPathSegList are * of different types - a plain SVGPathData, and a SVGPathData*. We * use the addresses of these members as the key for the hash table, and * clearly SVGPathData* and a SVGPathData** are not the same type. */ static already_AddRefed GetDOMWrapper( void* aList, dom::SVGPathElement* aElement); /** * This method returns the DOMSVGPathSegList wrapper for an internal * SVGPathData object if it currently has a wrapper. If it does * not, then nullptr is returned. */ static DOMSVGPathSegList* GetDOMWrapperIfExists(void* aList); /** * This will normally be the same as InternalList().CountItems(), except if * we've hit OOM, in which case our length will be zero. */ uint32_t LengthNoFlush() const { MOZ_ASSERT( mItems.Length() == 0 || mItems.Length() == InternalList().CountItems(), "DOM wrapper's list length is out of sync"); return mItems.Length(); } /** * WATCH OUT! If you add code to call this on a baseVal wrapper, then you * must also call it on the animVal wrapper too if necessary!! See other * callers! * * Called by internal code to notify us when we need to sync the length of * this DOM list with its internal list. This is called immediately prior to * the length of the internal list being changed so that any DOM list items * that need to be removed from the DOM list can first copy 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 InternalListWillChangeTo(const SVGPathData& aNewValue); /** * Returns true if our attribute is animating (in which case our animVal is * not simply a mirror of our baseVal). */ bool AttrIsAnimating() const; /** * Returns true if there is an animated list mirroring the base list. */ bool AnimListMirrorsBaseList() const; uint32_t NumberOfItems() const { if (IsAnimValList()) { Element()->FlushAnimations(); } return LengthNoFlush(); } void Clear(ErrorResult& aError); already_AddRefed Initialize(DOMSVGPathSeg& aNewItem, ErrorResult& aError); already_AddRefed GetItem(uint32_t index, ErrorResult& error); already_AddRefed IndexedGetter(uint32_t index, bool& found, ErrorResult& error); already_AddRefed InsertItemBefore(DOMSVGPathSeg& aNewItem, uint32_t aIndex, ErrorResult& aError); already_AddRefed ReplaceItem(DOMSVGPathSeg& aNewItem, uint32_t aIndex, ErrorResult& aError); already_AddRefed RemoveItem(uint32_t aIndex, ErrorResult& aError); already_AddRefed AppendItem(DOMSVGPathSeg& aNewItem, ErrorResult& aError) { return InsertItemBefore(aNewItem, LengthNoFlush(), aError); } uint32_t Length() const { return NumberOfItems(); } private: /** * Only our static GetDOMWrapper() factory method may create objects of our * type. */ DOMSVGPathSegList(dom::SVGElement* aElement, bool aIsAnimValList) : mElement(aElement), mIsAnimValList(aIsAnimValList) { InternalListWillChangeTo(InternalList()); // Sync mItems } ~DOMSVGPathSegList(); dom::SVGElement* Element() const { return mElement.get(); } /// Used to determine if this list is the baseVal or animVal list. bool IsAnimValList() const { return mIsAnimValList; } /** * Get a reference to this object's corresponding internal SVGPathData. * * To simplify the code we just have this one method for obtaining both * base val and anim val internal lists. This means that anim val lists don't * get const protection, but our setter methods guard against changing * anim val lists. */ SVGPathData& InternalList() const; SVGAnimatedPathSegList& InternalAList() const; /// Creates an instance of the appropriate DOMSVGPathSeg sub-class for // aIndex, if it doesn't already exist, and then returns it. already_AddRefed GetItemAt(uint32_t aIndex); void MaybeInsertNullInAnimValListAt(uint32_t aIndex, uint32_t aInternalIndex, uint32_t aArgCountForItem); void MaybeRemoveItemFromAnimValListAt(uint32_t aIndex, int32_t aArgCountForItem); // Calls UpdateListIndex on all elements in |mItems| that satisfy ItemAt(), // from |aStartingIndex| to the end of |mItems|. Also adjusts // |mItems.mInternalDataIndex| by the requested amount. void UpdateListIndicesFromIndex(uint32_t aStartingIndex, int32_t aInternalDataIndexDelta); DOMSVGPathSeg*& ItemAt(uint32_t aIndex) { return mItems[aIndex].mItem; } void RemoveFromTearoffTable(); /** * This struct is used in our array of mItems to provide us with somewhere to * store the indexes into the internal SVGPathData of the internal seg data * that our DOMSVGPathSeg items wrap (the internal segment data is or varying * length, so we can't just use the index of our DOMSVGPathSeg items * themselves). The reason that we have this separate struct rather than * just storing the internal indexes in the DOMSVGPathSeg items is because we * want to create the DOMSVGPathSeg items lazily on demand. */ struct ItemProxy { ItemProxy() : mItem(nullptr), mInternalDataIndex(0) {} ItemProxy(DOMSVGPathSeg* aItem, uint32_t aInternalDataIndex) : mItem(aItem), mInternalDataIndex(aInternalDataIndex) {} DOMSVGPathSeg* mItem; uint32_t mInternalDataIndex; }; // Weak refs to our DOMSVGPathSeg items. The items are friends and take care // of clearing our pointer to them when they die. FallibleTArray mItems; // Strong ref to our element to keep it alive. We hold this not only for // ourself, but also for our DOMSVGPathSeg items too. RefPtr mElement; bool mIsAnimValList; }; } // namespace dom } // namespace mozilla #endif // DOM_SVG_DOMSVGPATHSEGLIST_H_