gecko-dev/dom/svg/SVGSwitchElement.h
Kirk Steuber 7fdb378650 Bug 1359556 - Optimize cloneNode by preinitializing attribute and child arrays r=bz
Currently, attribute and child arrays (implemented in dom/base/nsAttrAndChildArray.h) start out empty. When cloning, the array ends up being resized multiple times in order to add the attributes and children that are being cloned from the original node. This would be quicker if the array was initialized to the correct size in the first place so that resizes are not necessary.

However, preallocating space for children is only necessary when performing a deep clone. Therefore, an additional parameter is being added to the Clone, CopyInnerTo, and CloneDocHelper methods to indicate whether preallocation of children should happen. Attributes are copied either way, so that part of the array is preallocated in both cases.

MozReview-Commit-ID: 3iVezeAKXnI

--HG--
extra : rebase_source : 9c3deec6d7aafd6411044d623d4863637b45fd58
2017-04-20 12:57:48 -07:00

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2.1 KiB
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/* -*- 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 mozilla_dom_SVGSwitchElement_h
#define mozilla_dom_SVGSwitchElement_h
#include "mozilla/dom/SVGGraphicsElement.h"
class nsSVGSwitchFrame;
nsresult NS_NewSVGSwitchElement(nsIContent **aResult,
already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
namespace mozilla {
namespace dom {
typedef SVGGraphicsElement SVGSwitchElementBase;
class SVGSwitchElement final : public SVGSwitchElementBase
{
friend class ::nsSVGSwitchFrame;
protected:
friend nsresult (::NS_NewSVGSwitchElement(nsIContent **aResult,
already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo));
explicit SVGSwitchElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
~SVGSwitchElement();
virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
public:
nsIContent * GetActiveChild() const
{ return mActiveChild; }
void MaybeInvalidate();
// interfaces:
NS_DECL_ISUPPORTS_INHERITED
NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(SVGSwitchElement,
SVGSwitchElementBase)
// nsINode
virtual nsresult InsertChildAt(nsIContent* aKid, uint32_t aIndex,
bool aNotify) override;
virtual void RemoveChildAt(uint32_t aIndex, bool aNotify) override;
// nsIContent
NS_IMETHOD_(bool) IsAttributeMapped(const nsIAtom* aAttribute) const override;
virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
bool aPreallocateChildren) const override;
private:
void UpdateActiveChild()
{ mActiveChild = FindActiveChild(); }
nsIContent* FindActiveChild() const;
// only this child will be displayed
nsCOMPtr<nsIContent> mActiveChild;
};
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_SVGSwitchElement_h