/* -*- 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_DOMSVGLENGTH_H__ #define MOZILLA_DOMSVGLENGTH_H__ #include "DOMSVGLengthList.h" #include "nsCycleCollectionParticipant.h" #include "nsDebug.h" #include "nsIDOMSVGLength.h" #include "nsTArray.h" #include "SVGLength.h" #include "mozilla/Attributes.h" #include "nsWrapperCache.h" class nsSVGElement; // We make DOMSVGLength a pseudo-interface to allow us to QI to it in order to // check that the objects that scripts pass to DOMSVGLengthList methods are our // *native* length objects. // // {A8468350-7F7B-4976-9A7E-3765A1DADF9A} #define MOZILLA_DOMSVGLENGTH_IID \ { 0xA8468350, 0x7F7B, 0x4976, { 0x9A, 0x7E, 0x37, 0x65, 0xA1, 0xDA, 0xDF, 0x9A } } #define MOZ_SVG_LIST_INDEX_BIT_COUNT 22 // supports > 4 million list items namespace mozilla { class ErrorResult; /** * Class DOMSVGLength * * This class creates the DOM objects that wrap internal SVGLength objects that * are in an SVGLengthList. It is also used to create the objects returned by * SVGSVGElement.createSVGLength(). * * For the DOM wrapper classes for non-list SVGLength, see nsSVGLength2.h. * * See the architecture comment in DOMSVGAnimatedLengthList.h. * * This class is strongly intertwined with DOMSVGAnimatedLengthList and * DOMSVGLengthList. We are a friend of DOMSVGLengthList, and are responsible * for nulling out our DOMSVGLengthList's pointer to us when we die, making it * a real weak pointer. * * When objects of this type are in a DOMSVGLengthList they belong to an * attribute. While they belong to an attribute, the objects' values come from * their corresponding internal SVGLength objects in the internal SVGLengthList * objects for the attribute. Getting and setting values of a DOMSVGLength * requires reading and writing to its internal SVGLength. However, if the * DOMSVGLength is detached from its DOMSVGLengthList then it first makes a * copy of its internal SVGLength's value and unit so that it doesn't appear to * "lose" its value from script's perspective on being removed from the list. * This means that these DOM tearoffs have space to store these values, even * though they're not used in the common case. * * Objects of this type are also used to reflect the baseVal and animVal of * a single, non-list SVGLength attribute. Getting and settings values of the * DOMSVGLength in this case requires reading and writing to the corresponding * nsSVGLength2 object. * * This class also stores its current list index, attribute enum, and whether * it belongs to a baseVal or animVal list. This is so that objects of this * type can find their corresponding internal SVGLength. * * To use these classes for <length> attributes as well as <list-of-length> * attributes, we would need to take a bit from mListIndex and use that to * indicate whether the object belongs to a list or non-list attribute, then * if-else as appropriate. The bug for doing that work is: * https://bugzilla.mozilla.org/show_bug.cgi?id=571734 */ class DOMSVGLength final : public nsIDOMSVGLength, public nsWrapperCache { friend class AutoChangeLengthNotifier; /** * Ctor for creating the object returned by nsSVGLength2::ToDOMBaseVal/ToDOMAnimVal */ DOMSVGLength(nsSVGLength2* aVal, nsSVGElement* aSVGElement, bool aAnimVal); ~DOMSVGLength(); public: NS_DECLARE_STATIC_IID_ACCESSOR(MOZILLA_DOMSVGLENGTH_IID) NS_DECL_CYCLE_COLLECTING_ISUPPORTS NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGLength) NS_DECL_NSIDOMSVGLENGTH /** * Generic ctor for DOMSVGLength objects that are created for an attribute. */ DOMSVGLength(DOMSVGLengthList *aList, uint8_t aAttrEnum, uint32_t aListIndex, bool aIsAnimValItem); /** * Ctor for creating the objects returned by SVGSVGElement.createSVGLength(), * which do not initially belong to an attribute. */ DOMSVGLength(); static already_AddRefed<DOMSVGLength> GetTearOff(nsSVGLength2* aVal, nsSVGElement* aSVGElement, bool aAnimVal); /** * Create an unowned copy of a length that is owned or is reflecting a single * attribute. The caller is responsible for the first AddRef(). */ DOMSVGLength* Copy(); bool IsInList() const { return !!mList; } /** * In future, if this class is used for non-list lengths, this will be * different to IsInList(). */ bool HasOwner() const { return !!mList; } /** * Returns whether this length object is reflecting a single SVG element * attribute. This includes the baseVal or animVal of SVGRectElement.x, for * example, but not an item in an SVGLengthList, such as those in the * baseVal or animVal of SVGTextElement.x. */ bool IsReflectingAttribute() const { return mVal; } /** * This method is called to notify this DOM object that it is being inserted * into a list, and give it the information it needs as a result. * * This object MUST NOT already belong to a list when this method is called. * That's not to say that script can't move these DOM objects between * lists - it can - it's just that the logic to handle that (and send out * the necessary notifications) is located elsewhere (in DOMSVGLengthList).) */ void InsertingIntoList(DOMSVGLengthList *aList, uint8_t aAttrEnum, uint32_t aListIndex, bool aIsAnimValItem); static uint32_t MaxListIndex() { return (1U << MOZ_SVG_LIST_INDEX_BIT_COUNT) - 1; } /// This method is called to notify this object that its list index changed. void UpdateListIndex(uint32_t aListIndex) { mListIndex = aListIndex; } /** * This method is called to notify this DOM object that it is about to be * removed from its current DOM list so that it can first make a copy of its * internal counterpart's values. (If it didn't do this, then it would * "lose" its value on being removed.) */ void RemovingFromList(); SVGLength ToSVGLength(); // WebIDL uint16_t UnitType(); float GetValue(ErrorResult& aRv); void SetValue(float aValue, ErrorResult& aRv); float ValueInSpecifiedUnits(); void SetValueInSpecifiedUnits(float aValue, ErrorResult& aRv); // The XPCOM GetValueAsString is good void SetValueAsString(const nsAString& aValue, ErrorResult& aRv); void NewValueSpecifiedUnits(uint16_t aUnit, float aValue, ErrorResult& aRv); void ConvertToSpecifiedUnits(uint16_t aUnit, ErrorResult& aRv); nsISupports* GetParentObject() const { auto svgElement = mList ? Element() : mSVGElement.get(); return static_cast<nsIDOMSVGElement*> (svgElement); } JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override; private: nsSVGElement* Element() const { return mList->Element(); } uint8_t AttrEnum() const { return mAttrEnum; } /** * Get the axis that this length lies along. This method must only be called * when this object is associated with an element (HasOwner() returns true). */ uint8_t Axis() const { return mList->Axis(); } /** * Get a reference to the internal SVGLength list item that this DOM wrapper * object currently wraps. * * To simplify the code we just have this one method for obtaining both * baseVal and animVal internal items. This means that animVal items don't * get const protection, but then our setter methods guard against changing * animVal items. */ SVGLength& InternalItem(); #ifdef DEBUG bool IndexIsValid(); #endif /** * Clears soon-to-be-invalid weak references in external objects that were * set up during the creation of this object. This should be called during * destruction and during cycle collection. */ void CleanupWeakRefs(); RefPtr<DOMSVGLengthList> mList; // Bounds for the following are checked in the ctor, so be sure to update // that if you change the capacity of any of the following. uint32_t mListIndex:MOZ_SVG_LIST_INDEX_BIT_COUNT; uint32_t mAttrEnum:4; // supports up to 16 attributes uint32_t mIsAnimValItem:1; // The following members are only used when we're not in a list: uint32_t mUnit:5; // can handle 31 units (the 10 SVG 1.1 units + rem, vw, vh, wm, calc + future additions) float mValue; // The following members are only used when we have an nsSVGLength2 nsSVGLength2* mVal; // kept alive because it belongs to mSVGElement RefPtr<nsSVGElement> mSVGElement; }; NS_DEFINE_STATIC_IID_ACCESSOR(DOMSVGLength, MOZILLA_DOMSVGLENGTH_IID) } // namespace mozilla #undef MOZ_SVG_LIST_INDEX_BIT_COUNT #endif // MOZILLA_DOMSVGLENGTH_H__