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Diffstat (limited to 'dom/svg/DOMSVGPointList.h')
| -rw-r--r-- | dom/svg/DOMSVGPointList.h | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/dom/svg/DOMSVGPointList.h b/dom/svg/DOMSVGPointList.h new file mode 100644 index 0000000000..36c0d653ef --- /dev/null +++ b/dom/svg/DOMSVGPointList.h @@ -0,0 +1,260 @@ +/* -*- 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_DOMSVGPOINTLIST_H_ +#define DOM_SVG_DOMSVGPOINTLIST_H_ + +#include "mozAutoDocUpdate.h" +#include "nsCycleCollectionParticipant.h" +#include "nsDebug.h" +#include "nsTArray.h" +#include "SVGPointList.h" // IWYU pragma: keep +#include "mozilla/Attributes.h" +#include "mozilla/RefPtr.h" + +// {61812ad1-c078-4cd1-87e6-bc1c1b8d7284} +#define MOZILLA_DOMSVGPOINTLIST_IID \ + { \ + 0x61812ad1, 0xc078, 0x4cd1, { \ + 0x87, 0xe6, 0xbc, 0x1c, 0x1b, 0x8d, 0x72, 0x84 \ + } \ + } + +namespace mozilla { + +class ErrorResult; +class SVGAnimatedPointList; + +namespace dom { + +class DOMSVGPoint; +class SVGElement; + +//---------------------------------------------------------------------- +// Helper class: AutoChangePointListNotifier +// Stack-based helper class to pair calls to WillChangePointList and +// DidChangePointList. Used by DOMSVGPoint and DOMSVGPointList. +template <class T> +class MOZ_RAII AutoChangePointListNotifier { + public: + explicit AutoChangePointListNotifier(T* aValue) : mValue(aValue) { + MOZ_ASSERT(mValue, "Expecting non-null value"); + if (mValue->IsInList()) { + mUpdateBatch.emplace(mValue->Element()->GetComposedDoc(), true); + mEmptyOrOldValue = + mValue->Element()->WillChangePointList(mUpdateBatch.ref()); + } + } + + ~AutoChangePointListNotifier() { + if (mValue->IsInList()) { + mValue->Element()->DidChangePointList(mEmptyOrOldValue, + mUpdateBatch.ref()); + if (mValue->AttrIsAnimating()) { + mValue->Element()->AnimationNeedsResample(); + } + } + } + + private: + Maybe<mozAutoDocUpdate> mUpdateBatch; + T* const mValue; + nsAttrValue mEmptyOrOldValue; +}; + +/** + * Class DOMSVGPointList + * + * This class is used to create the DOM tearoff objects that wrap internal + * SVGPointList 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 nsIDOMSVGAnimatedPointList interface + * in SVG, we have no parent DOMSVGAnimatedPointList (unlike DOMSVGLengthList + * which has a parent DOMSVGAnimatedLengthList class). (There is an + * SVGAnimatedPoints 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 DOMSVGAnimatedPointList (and is in + * DOMSVGAnimatedLengthList) is contained in this class. + * + * This class is strongly intertwined with DOMSVGPoint. Our DOMSVGPoint + * 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 DOMSVGPointList final : public nsISupports, public nsWrapperCache { + template <class T> + friend class AutoChangePointListNotifier; + friend class DOMSVGPoint; + + public: + NS_DECLARE_STATIC_IID_ACCESSOR(MOZILLA_DOMSVGPOINTLIST_IID) + NS_DECL_CYCLE_COLLECTING_ISUPPORTS + NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGPointList) + + JSObject* WrapObject(JSContext* cx, + JS::Handle<JSObject*> aGivenProto) override; + + nsISupports* GetParentObject() { return static_cast<nsIContent*>(mElement); } + + /** + * Factory method to create and return a DOMSVGPointList wrapper + * for a given internal SVGPointList object. The factory takes care + * of caching the object that it returns so that the same object can be + * returned for the given SVGPointList 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 SVGPointList will naturally result in a new + * DOMSVGPointList being returned. + * + * It's unfortunate that aList is a void* instead of a typed argument. This + * is because the mBaseVal and mAnimVal members of SVGAnimatedPointList are + * of different types - a plain SVGPointList, and a SVGPointList*. We + * use the addresses of these members as the key for the hash table, and + * clearly SVGPointList* and a SVGPointList** are not the same type. + */ + static already_AddRefed<DOMSVGPointList> GetDOMWrapper( + void* aList, dom::SVGElement* aElement, bool aIsAnimValList); + + /** + * This method returns the DOMSVGPointList wrapper for an internal + * SVGPointList object if it currently has a wrapper. If it does + * not, then nullptr is returned. + */ + static DOMSVGPointList* GetDOMWrapperIfExists(void* aList); + + /** + * This will normally be the same as InternalList().Length(), 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().Length(), + "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 SVGPointList& aNewValue); + + /* + * We need this so that templates that work on lists and elements can check + * ownership where elements may be not be in a list. + */ + bool IsInList() const { return true; } + + /** + * 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<DOMSVGPoint> Initialize(DOMSVGPoint& aNewItem, + ErrorResult& aError); + already_AddRefed<DOMSVGPoint> GetItem(uint32_t index, ErrorResult& error); + already_AddRefed<DOMSVGPoint> IndexedGetter(uint32_t index, bool& found, + ErrorResult& error); + already_AddRefed<DOMSVGPoint> InsertItemBefore(DOMSVGPoint& aNewItem, + uint32_t aIndex, + ErrorResult& aError); + already_AddRefed<DOMSVGPoint> ReplaceItem(DOMSVGPoint& aNewItem, + uint32_t aIndex, + ErrorResult& aError); + already_AddRefed<DOMSVGPoint> RemoveItem(uint32_t aIndex, + ErrorResult& aError); + already_AddRefed<DOMSVGPoint> AppendItem(DOMSVGPoint& 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. + */ + DOMSVGPointList(dom::SVGElement* aElement, bool aIsAnimValList) + : mElement(aElement), mIsAnimValList(aIsAnimValList) { + InternalListWillChangeTo(InternalList()); // Sync mItems + } + + ~DOMSVGPointList(); + + 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 SVGPointList. + * + * 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. + */ + SVGPointList& InternalList() const; + + SVGAnimatedPointList& InternalAList() const; + + /// Returns the DOMSVGPoint at aIndex, creating it if necessary. + already_AddRefed<DOMSVGPoint> GetItemAt(uint32_t aIndex); + + void MaybeInsertNullInAnimValListAt(uint32_t aIndex); + void MaybeRemoveItemFromAnimValListAt(uint32_t aIndex); + + void RemoveFromTearoffTable(); + + // Weak refs to our DOMSVGPoint items. The items are friends and take care + // of clearing our pointer to them when they die. + FallibleTArray<DOMSVGPoint*> mItems; + + // Strong ref to our element to keep it alive. We hold this not only for + // ourself, but also for our DOMSVGPoint items too. + RefPtr<dom::SVGElement> mElement; + + bool mIsAnimValList; +}; + +NS_DEFINE_STATIC_IID_ACCESSOR(DOMSVGPointList, MOZILLA_DOMSVGPOINTLIST_IID) + +} // namespace dom +} // namespace mozilla + +#endif // DOM_SVG_DOMSVGPOINTLIST_H_ |