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SVGAnimatedPointList.h (4307B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef DOM_SVG_SVGANIMATEDPOINTLIST_H_
      8 #define DOM_SVG_SVGANIMATEDPOINTLIST_H_
      9 
     10 #include "SVGPointList.h"
     11 #include "mozilla/SMILAttr.h"
     12 #include "mozilla/UniquePtr.h"
     13 
     14 namespace mozilla {
     15 
     16 class SMILValue;
     17 
     18 namespace dom {
     19 class DOMSVGPoint;
     20 class DOMSVGPointList;
     21 class SVGAnimationElement;
     22 class SVGElement;
     23 }  // namespace dom
     24 
     25 /**
     26 * Class SVGAnimatedPointList
     27 *
     28 * Despite the fact that no SVGAnimatedPointList interface or objects exist
     29 * in the SVG specification (unlike e.g. SVGAnimated*Length*List), we
     30 * nevertheless have this internal class. (Note that there is an
     31 * SVGAnimatedPoints interface, but that's quite different to
     32 * SVGAnimatedLengthList since it is inherited by elements, as opposed to
     33 * elements having members of that type.) The reason that we have this class is
     34 * to provide a single locked down point of entry to the SVGPointList objects,
     35 * which helps ensure that the DOM wrappers for SVGPointList objects' are
     36 * always kept in sync. This is vitally important (see the comment in
     37 * DOMSVGPointList::InternalListWillChangeTo) and frees consumers from having
     38 * to know or worry about wrappers (or forget about them!) for the most part.
     39 */
     40 class SVGAnimatedPointList {
     41  // friends so that they can get write access to mBaseVal and mAnimVal
     42  friend class dom::DOMSVGPoint;
     43  friend class dom::DOMSVGPointList;
     44 
     45 public:
     46  SVGAnimatedPointList() = default;
     47 
     48  SVGAnimatedPointList& operator=(const SVGAnimatedPointList& aOther) {
     49    mBaseVal = aOther.mBaseVal;
     50    if (aOther.mAnimVal) {
     51      mAnimVal = MakeUnique<SVGPointList>(*aOther.mAnimVal);
     52    }
     53    return *this;
     54  }
     55 
     56  /**
     57   * Because it's so important that mBaseVal and its DOMSVGPointList wrapper
     58   * (if any) be kept in sync (see the comment in
     59   * DOMSVGPointList::InternalListWillChangeTo), this method returns a const
     60   * reference. Only our friend classes may get mutable references to mBaseVal.
     61   */
     62  const SVGPointList& GetBaseValue() const { return mBaseVal; }
     63 
     64  nsresult SetBaseValueString(const nsAString& aValue);
     65 
     66  void ClearBaseValue();
     67 
     68  /**
     69   * const! See comment for GetBaseValue!
     70   */
     71  const SVGPointList& GetAnimValue() const {
     72    return mAnimVal ? *mAnimVal : mBaseVal;
     73  }
     74 
     75  nsresult SetAnimValue(const SVGPointList& aNewAnimValue,
     76                        dom::SVGElement* aElement);
     77 
     78  void ClearAnimValue(dom::SVGElement* aElement);
     79 
     80  /**
     81   * Needed for correct DOM wrapper construction since GetAnimValue may
     82   * actually return the baseVal!
     83   */
     84  void* GetBaseValKey() const { return (void*)&mBaseVal; }
     85  void* GetAnimValKey() const { return (void*)&mAnimVal; }
     86 
     87  bool IsAnimating() const { return !!mAnimVal; }
     88 
     89  UniquePtr<SMILAttr> ToSMILAttr(dom::SVGElement* aElement);
     90 
     91 private:
     92  // mAnimVal is a pointer to allow us to determine if we're being animated or
     93  // not. Making it a non-pointer member and using mAnimVal.IsEmpty() to check
     94  // if we're animating is not an option, since that would break animation *to*
     95  // the empty string (<set to="">).
     96 
     97  SVGPointList mBaseVal;
     98  UniquePtr<SVGPointList> mAnimVal;
     99 
    100  struct SMILAnimatedPointList : public SMILAttr {
    101   public:
    102    SMILAnimatedPointList(SVGAnimatedPointList* aVal, dom::SVGElement* aElement)
    103        : mVal(aVal), mElement(aElement) {}
    104 
    105    // These will stay alive because a SMILAttr only lives as long
    106    // as the Compositing step, and DOM elements don't get a chance to
    107    // die during that.
    108    SVGAnimatedPointList* mVal;
    109    dom::SVGElement* mElement;
    110 
    111    // SMILAttr methods
    112    nsresult ValueFromString(const nsAString& aStr,
    113                             const dom::SVGAnimationElement* aSrcElement,
    114                             SMILValue& aValue,
    115                             bool& aPreventCachingOfSandwich) const override;
    116    SMILValue GetBaseValue() const override;
    117    void ClearAnimValue() override;
    118    nsresult SetAnimValue(const SMILValue& aValue) override;
    119  };
    120 };
    121 
    122 }  // namespace mozilla
    123 
    124 #endif  // DOM_SVG_SVGANIMATEDPOINTLIST_H_