gecko-dev/dom/html/HTMLDivElement.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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1.8 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 HTMLDivElement_h___
#define HTMLDivElement_h___
#include "mozilla/Attributes.h"
#include "nsGenericHTMLElement.h"
namespace mozilla {
namespace dom {
class HTMLDivElement final : public nsGenericHTMLElement
{
public:
explicit HTMLDivElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
: nsGenericHTMLElement(aNodeInfo)
{
}
void GetAlign(DOMString& aAlign)
{
GetHTMLAttr(nsGkAtoms::align, aAlign);
}
void SetAlign(const nsAString& aAlign, mozilla::ErrorResult& aError)
{
SetHTMLAttr(nsGkAtoms::align, aAlign, aError);
}
virtual bool ParseAttribute(int32_t aNamespaceID,
nsIAtom* aAttribute,
const nsAString& aValue,
nsAttrValue& aResult) override;
NS_IMETHOD_(bool) IsAttributeMapped(const nsIAtom* aAttribute) const override;
virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
bool aPreallocateChildren) const override;
protected:
virtual ~HTMLDivElement();
virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
private:
static void MapAttributesIntoRule(const nsMappedAttributes* aAttributes,
GenericSpecifiedValues* aGenericData);
};
} // namespace dom
} // namespace mozilla
#endif /* HTMLDivElement_h___ */