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Diffstat (limited to 'dom/svg/DOMSVGLength.h')
| -rw-r--r-- | dom/svg/DOMSVGLength.h | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/dom/svg/DOMSVGLength.h b/dom/svg/DOMSVGLength.h new file mode 100644 index 0000000000..9dc6096c65 --- /dev/null +++ b/dom/svg/DOMSVGLength.h @@ -0,0 +1,218 @@ +/* -*- 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_DOMSVGLENGTH_H_ +#define DOM_SVG_DOMSVGLENGTH_H_ + +#include "DOMSVGLengthList.h" +#include "nsCycleCollectionParticipant.h" +#include "nsDebug.h" +#include "nsTArray.h" +#include "SVGLength.h" +#include "mozilla/Attributes.h" +#include "nsWrapperCache.h" + +#define MOZ_SVG_LIST_INDEX_BIT_COUNT 22 // supports > 4 million list items + +namespace mozilla { + +class ErrorResult; + +namespace dom { +class SVGElement; + +/** + * 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 SVGAnimatedLength.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 + * SVGAnimatedLength 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 nsWrapperCache { + template <class T> + friend class AutoChangeLengthListNotifier; + + /** + * Ctor for creating the object returned by + * SVGAnimatedLength::ToDOMBaseVal/ToDOMAnimVal + */ + DOMSVGLength(SVGAnimatedLength* aVal, dom::SVGElement* aSVGElement, + bool aAnimVal); + + ~DOMSVGLength() { CleanupWeakRefs(); } + + public: + NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(DOMSVGLength) + NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(DOMSVGLength) + + /** + * 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(SVGAnimatedLength* aVal, + dom::SVGElement* 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(); + + /** + * Returns true if our attribute is animating. + */ + bool IsAnimating() const; + + /** + * In future, if this class is used for non-list lengths, this will be + * different to IsInList(). + */ + bool HasOwner() const { return !!mOwner; } + + /** + * 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 aUserUnitValue, ErrorResult& aRv); + float ValueInSpecifiedUnits(); + void SetValueInSpecifiedUnits(float aValue, ErrorResult& aRv); + void GetValueAsString(nsAString& aValue); + 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() { return mOwner; } + + JSObject* WrapObject(JSContext* aCx, + JS::Handle<JSObject*> aGivenProto) override; + + private: + dom::SVGElement* Element(); + + uint8_t AttrEnum() const { return mAttrEnum; } + + /** + * 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(); + + /** + * Some values have units that depend on style or layout so we may need to + * flush to ensure we get or set the right value in pixels. + */ + void FlushIfNeeded(); + +#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<nsISupports> mOwner; // Either a DOMSVGLengthList if we're in a list, + // an SVGElement if we're an attribute or null + + // 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 = 0.0f; +}; + +} // namespace dom +} // namespace mozilla + +#undef MOZ_SVG_LIST_INDEX_BIT_COUNT + +#endif // DOM_SVG_DOMSVGLENGTH_H_ |