dom/svg/SVGAnimatedPointList.h

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