tor-browser

DOMSVGPoint.h (6730B)

---

/* -*- 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_DOMSVGPOINT_H_
#define DOM_SVG_DOMSVGPOINT_H_

#include "DOMSVGPointList.h"
#include "SVGPoint.h"
#include "mozilla/dom/SVGSVGElement.h"
#include "mozilla/gfx/2D.h"
#include "nsCycleCollectionParticipant.h"
#include "nsDebug.h"
#include "nsWrapperCache.h"

#define MOZ_SVG_LIST_INDEX_BIT_COUNT 29

namespace mozilla::dom {
struct DOMMatrix2DInit;

/**
* Class DOMSVGPoint
*
* This class creates the DOM objects that wrap internal SVGPoint objects that
* are in an SVGPointList. It is also used to create the objects returned by
* SVGSVGElement.createSVGPoint() and other functions that return DOM SVGPoint
* objects.
*
* See the architecture comment in DOMSVGPointList.h for an overview of the
* important points regarding these DOM wrapper structures.
*
* See the architecture comment in DOMSVGLength.h (yes, LENGTH) for an overview
* of the important points regarding how this specific class works.
*/
class DOMSVGPoint final : public nsWrapperCache {
 template <class T>
 friend class AutoChangePointListNotifier;

 using Point = gfx::Point;

public:
 /**
  * Generic ctor for DOMSVGPoint objects that are created for an attribute.
  */
 DOMSVGPoint(DOMSVGPointList* aList, uint32_t aListIndex, bool aIsAnimValItem)
     : mVal(nullptr),
       mOwner(aList),
       mListIndex(aListIndex),
       mIsAnimValItem(aIsAnimValItem),
       mIsTranslatePoint(false),
       mIsInTearoffTable(false) {
   // These shifts are in sync with the members.
   MOZ_ASSERT(aList && aListIndex <= MaxListIndex(), "bad arg");

   MOZ_ASSERT(IndexIsValid(), "Bad index for DOMSVGPoint!");
 }

 // Constructor for unowned points and SVGSVGElement.createSVGPoint
 explicit DOMSVGPoint(const Point& aPt)
     : mListIndex(0),
       mIsAnimValItem(false),
       mIsTranslatePoint(false),
       mIsInTearoffTable(false) {
   // In this case we own mVal
   mVal = new SVGPoint(aPt.x, aPt.y);
 }

private:
 // The translate of an SVGSVGElement
 DOMSVGPoint(SVGPoint* aPt, SVGSVGElement* aSVGSVGElement)
     : mVal(aPt),
       mOwner(ToSupports(aSVGSVGElement)),
       mListIndex(0),
       mIsAnimValItem(false),
       mIsTranslatePoint(true),
       mIsInTearoffTable(false) {}

 virtual ~DOMSVGPoint() { CleanupWeakRefs(); }

public:
 NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(DOMSVGPoint)
 NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(DOMSVGPoint)

 static already_AddRefed<DOMSVGPoint> GetTranslateTearOff(
     SVGPoint* aVal, SVGSVGElement* aSVGSVGElement);

 bool IsInList() const { return HasOwner() && !IsTranslatePoint(); }

 /**
  * "Owner" here means that the instance has an
  * internal counterpart from which it gets its values. (A better name may
  * be HasWrappee().)
  */
 bool HasOwner() const { return !!mOwner; }

 bool IsTranslatePoint() const { return mIsTranslatePoint; }

 void DidChangeTranslate();

 /**
  * 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 DOMSVGPointList).)
  */
 void InsertingIntoList(DOMSVGPointList* aList, 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();

 SVGPoint ToSVGPoint() { return InternalItem(); }

 // WebIDL
 float X();
 void SetX(float aX, ErrorResult& rv);
 float Y();
 void SetY(float aY, ErrorResult& rv);
 already_AddRefed<DOMSVGPoint> MatrixTransform(const DOMMatrix2DInit& aMatrix,
                                               ErrorResult& aRv);

 nsISupports* GetParentObject() { return Element(); }

 /**
  * Returns true if our attribute is animating (in which case our animVal is
  * not simply a mirror of our baseVal).
  */
 bool AttrIsAnimating() const;

 JSObject* WrapObject(JSContext* cx,
                      JS::Handle<JSObject*> aGivenProto) override;

 DOMSVGPoint* Copy() { return new DOMSVGPoint(InternalItem()); }

private:
#ifdef DEBUG
 bool IndexIsValid();
#endif

 SVGElement* Element();

 /**
  * 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();

 /**
  * Get a reference to the internal SVGPoint list item that this DOM wrapper
  * object currently wraps.
  */
 SVGPoint& InternalItem();

 SVGPoint* mVal;              // If mIsTranslatePoint is true, the element owns
                              // the value. Otherwise we do.
 RefPtr<nsISupports> mOwner;  // If mIsTranslatePoint is true, this is an
                              // SVGSVGElement, if we're unowned it's null, or
                              // we're in a list and it's a DOMSVGPointList

 // 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 mIsAnimValItem : 1;     // True if We're the animated value of a list
 uint32_t mIsTranslatePoint : 1;  // true iff our owner is a SVGSVGElement

 // Tracks whether we're in the tearoff table. Initialized to false in the
 // ctor, but then immediately set to true if/when we're added to the table
 // (not all instances are).  Updated to false when we're removed from the
 // table (at which point we're being destructed or soon-to-be destructed).
 uint32_t mIsInTearoffTable : 1;
};

}  // namespace mozilla::dom

#undef MOZ_SVG_LIST_INDEX_BIT_COUNT

#endif  // DOM_SVG_DOMSVGPOINT_H_