gecko-dev/dom/svg/SVGAnimatedNumberList.h

/* -*- 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_SVGANIMATEDNUMBERLIST_H_
#define DOM_SVG_SVGANIMATEDNUMBERLIST_H_

#include "mozilla/Attributes.h"
#include "mozilla/SMILAttr.h"
#include "mozilla/UniquePtr.h"
#include "SVGNumberList.h"

namespace mozilla {

class SMILValue;

namespace dom {
class SVGAnimationElement;
class SVGElement;
}  // namespace dom

/**
 * Class SVGAnimatedNumberList
 *
 * This class is very different to the SVG DOM interface of the same name found
 * in the SVG specification. This is a lightweight internal class - see
 * DOMSVGAnimatedNumberList for the heavier DOM class that wraps instances of
 * this class and implements the SVG specification's SVGAnimatedNumberList DOM
 * interface.
 *
 * Except where noted otherwise, this class' methods take care of keeping the
 * appropriate DOM wrappers in sync (see the comment in
 * DOMSVGAnimatedNumberList::InternalBaseValListWillChangeTo) so that their
 * consumers don't need to concern themselves with that.
 */
class SVGAnimatedNumberList {
  // friends so that they can get write access to mBaseVal
  friend class dom::DOMSVGNumber;
  friend class dom::DOMSVGNumberList;

 public:
  SVGAnimatedNumberList() = default;

  SVGAnimatedNumberList& operator=(const SVGAnimatedNumberList& aOther) {
    mIsBaseSet = aOther.mIsBaseSet;
    mBaseVal = aOther.mBaseVal;
    if (aOther.mAnimVal) {
      mAnimVal = MakeUnique<SVGNumberList>(*aOther.mAnimVal);
    }
    return *this;
  }

  /**
   * Because it's so important that mBaseVal and its DOMSVGNumberList wrapper
   * (if any) be kept in sync (see the comment in
   * DOMSVGAnimatedNumberList::InternalBaseValListWillChangeTo), this method
   * returns a const reference. Only our friend classes may get mutable
   * references to mBaseVal.
   */
  const SVGNumberList& GetBaseValue() const { return mBaseVal; }

  nsresult SetBaseValueString(const nsAString& aValue);

  void ClearBaseValue(uint32_t aAttrEnum);

  const SVGNumberList& GetAnimValue() const {
    return mAnimVal ? *mAnimVal : mBaseVal;
  }

  nsresult SetAnimValue(const SVGNumberList& aNewAnimValue,
                        dom::SVGElement* aElement, uint32_t aAttrEnum);

  void ClearAnimValue(dom::SVGElement* aElement, uint32_t aAttrEnum);

  // Returns true if the animated value of this list has been explicitly
  // set (either by animation, or by taking on the base value which has been
  // explicitly set by markup or a DOM call), false otherwise.
  // If this returns false, the animated value is still valid, that is,
  // usable, and represents the default base value of the attribute.
  bool IsExplicitlySet() const { return !!mAnimVal || mIsBaseSet; }

  bool IsAnimating() const { return !!mAnimVal; }

  UniquePtr<SMILAttr> ToSMILAttr(dom::SVGElement* aSVGElement,
                                 uint8_t aAttrEnum);

 private:
  // mAnimVal is a pointer to allow us to determine if we're being animated or
  // not. Making it a non-pointer member and using mAnimVal.IsEmpty() to check
  // if we're animating is not an option, since that would break animation *to*
  // the empty string (<set to="">).

  SVGNumberList mBaseVal;
  UniquePtr<SVGNumberList> mAnimVal;
  bool mIsBaseSet = false;

  struct SMILAnimatedNumberList : public SMILAttr {
   public:
    SMILAnimatedNumberList(SVGAnimatedNumberList* aVal,
                           dom::SVGElement* aSVGElement, uint8_t aAttrEnum)
        : mVal(aVal), mElement(aSVGElement), mAttrEnum(aAttrEnum) {}

    // These will stay alive because a SMILAttr only lives as long
    // as the Compositing step, and DOM elements don't get a chance to
    // die during that.
    SVGAnimatedNumberList* mVal;
    dom::SVGElement* mElement;
    uint8_t mAttrEnum;

    // SMILAttr methods
    nsresult ValueFromString(const nsAString& aStr,
                             const dom::SVGAnimationElement* aSrcElement,
                             SMILValue& aValue,
                             bool& aPreventCachingOfSandwich) const override;
    SMILValue GetBaseValue() const override;
    void ClearAnimValue() override;
    nsresult SetAnimValue(const SMILValue& aValue) override;
  };
};

}  // namespace mozilla

#endif  // DOM_SVG_SVGANIMATEDNUMBERLIST_H_