dom/svg/SVGAnimatedPathSegList.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_SVGANIMATEDPATHSEGLIST_H_
   8 #define DOM_SVG_SVGANIMATEDPATHSEGLIST_H_
   9
  10 #include "mozilla/Attributes.h"
  11 #include "mozilla/MemoryReporting.h"
  12 #include "mozilla/SMILAttr.h"
  13 #include "mozilla/UniquePtr.h"
  14 #include "SVGPathData.h"
  15
  16 namespace mozilla {
  17
  18 class SMILValue;
  19
  20 namespace dom {
  21 class SVGAnimationElement;
  22 class SVGElement;
  23 }  // namespace dom
  24
  25 /**
  26  * Class SVGAnimatedPathSegList
  27  *
  28  * Despite the fact that no SVGAnimatedPathSegList 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  * SVGAnimatedPathData 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 SVGPathData objects,
  35  * which helps ensure that the DOM wrappers for SVGPathData objects' are always
  36  * kept in sync. This is vitally important (see the comment in
  37  * DOMSVGPathSegList::InternalListWillChangeTo) and frees consumers from having
  38  * to know or worry about wrappers (or forget about them!) for the most part.
  39  */
  40 class SVGAnimatedPathSegList final {
  41  public:
  42   SVGAnimatedPathSegList() = default;
  43
  44   SVGAnimatedPathSegList& operator=(const SVGAnimatedPathSegList& aOther) {
  45     mBaseVal = aOther.mBaseVal;
  46     if (aOther.mAnimVal) {
  47       mAnimVal = MakeUnique<SVGPathData>(*aOther.mAnimVal);
  48     }
  49     return *this;
  50   }
  51
  52   /**
  53    * Because it's so important that mBaseVal and its DOMSVGPathSegList wrapper
  54    * (if any) be kept in sync (see the comment in
  55    * DOMSVGPathSegList::InternalListWillChangeTo), this method returns a const
  56    * reference. Only our friend classes may get mutable references to mBaseVal.
  57    */
  58   const SVGPathData& GetBaseValue() const { return mBaseVal; }
  59
  60   nsresult SetBaseValueString(const nsAString& aValue);
  61
  62   void ClearBaseValue();
  63
  64   /**
  65    * const! See comment for GetBaseValue!
  66    */
  67   const SVGPathData& GetAnimValue() const {
  68     return mAnimVal ? *mAnimVal : mBaseVal;
  69   }
  70
  71   nsresult SetAnimValue(const SVGPathData& aNewAnimValue,
  72                         dom::SVGElement* aElement);
  73
  74   void ClearAnimValue(dom::SVGElement* aElement);
  75
  76   /**
  77    * Empty paths are not rendered.
  78    */
  79   bool IsRendered() const;
  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   size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const;
  93
  94  private:
  95   // mAnimVal is a pointer to allow us to determine if we're being animated or
  96   // not. Making it a non-pointer member and using mAnimVal.IsEmpty() to check
  97   // if we're animating is not an option, since that would break animation *to*
  98   // the empty string (<set to="">).
  99
 100   SVGPathData mBaseVal;
 101   UniquePtr<SVGPathData> mAnimVal;
 102
 103   struct SMILAnimatedPathSegList : public SMILAttr {
 104    public:
 105     SMILAnimatedPathSegList(SVGAnimatedPathSegList* aVal,
 106                             dom::SVGElement* aElement)
 107         : mVal(aVal), mElement(aElement) {}
 108
 109     // These will stay alive because a SMILAttr only lives as long
 110     // as the Compositing step, and DOM elements don't get a chance to
 111     // die during that.
 112     SVGAnimatedPathSegList* mVal;
 113     dom::SVGElement* mElement;
 114
 115     // SMILAttr methods
 116     nsresult ValueFromString(const nsAString& aStr,
 117                              const dom::SVGAnimationElement* aSrcElement,
 118                              SMILValue& aValue,
 119                              bool& aPreventCachingOfSandwich) const override;
 120     SMILValue GetBaseValue() const override;
 121     void ClearAnimValue() override;
 122     nsresult SetAnimValue(const SMILValue& aValue) override;
 123   };
 124 };
 125
 126 }  // namespace mozilla
 127
 128 #endif  // DOM_SVG_SVGANIMATEDPATHSEGLIST_H_