gecko-dev/dom/base/nsAttrName.h

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5.2 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/. */
/*
* Class that represents the name (nodeinfo or atom) of an attribute;
* using nodeinfos all the time is too slow, so we use atoms when we
* can.
*/
#ifndef nsAttrName_h___
#define nsAttrName_h___
#include "mozilla/dom/NodeInfo.h"
#include "nsIAtom.h"
#include "nsDOMString.h"
#define NS_ATTRNAME_NODEINFO_BIT 1
class nsAttrName
{
public:
nsAttrName(const nsAttrName& aOther)
: mBits(aOther.mBits)
{
AddRefInternalName();
}
explicit nsAttrName(nsIAtom* aAtom)
: mBits(reinterpret_cast<uintptr_t>(aAtom))
{
NS_ASSERTION(aAtom, "null atom-name in nsAttrName");
NS_ADDREF(aAtom);
}
explicit nsAttrName(mozilla::dom::NodeInfo* aNodeInfo)
{
NS_ASSERTION(aNodeInfo, "null nodeinfo-name in nsAttrName");
if (aNodeInfo->NamespaceEquals(kNameSpaceID_None)) {
mBits = reinterpret_cast<uintptr_t>(aNodeInfo->NameAtom());
NS_ADDREF(aNodeInfo->NameAtom());
}
else {
mBits = reinterpret_cast<uintptr_t>(aNodeInfo) |
NS_ATTRNAME_NODEINFO_BIT;
NS_ADDREF(aNodeInfo);
}
}
~nsAttrName()
{
ReleaseInternalName();
}
void SetTo(mozilla::dom::NodeInfo* aNodeInfo)
{
NS_ASSERTION(aNodeInfo, "null nodeinfo-name in nsAttrName");
ReleaseInternalName();
if (aNodeInfo->NamespaceEquals(kNameSpaceID_None)) {
mBits = reinterpret_cast<uintptr_t>(aNodeInfo->NameAtom());
NS_ADDREF(aNodeInfo->NameAtom());
}
else {
mBits = reinterpret_cast<uintptr_t>(aNodeInfo) |
NS_ATTRNAME_NODEINFO_BIT;
NS_ADDREF(aNodeInfo);
}
}
void SetTo(nsIAtom* aAtom)
{
NS_ASSERTION(aAtom, "null atom-name in nsAttrName");
ReleaseInternalName();
mBits = reinterpret_cast<uintptr_t>(aAtom);
NS_ADDREF(aAtom);
}
bool IsAtom() const
{
return !(mBits & NS_ATTRNAME_NODEINFO_BIT);
}
mozilla::dom::NodeInfo* NodeInfo() const
{
NS_ASSERTION(!IsAtom(), "getting nodeinfo-value of atom-name");
return reinterpret_cast<mozilla::dom::NodeInfo*>(mBits & ~NS_ATTRNAME_NODEINFO_BIT);
}
nsIAtom* Atom() const
{
NS_ASSERTION(IsAtom(), "getting atom-value of nodeinfo-name");
return reinterpret_cast<nsIAtom*>(mBits);
}
bool Equals(const nsAttrName& aOther) const
{
return mBits == aOther.mBits;
}
// Faster comparison in the case we know the namespace is null
// Note that some callers such as nsAttrAndChildArray::IndexOfAttr() will
// call this function on nsAttrName structs with 0 mBits, so no attempt
// must be made to do anything with mBits besides comparing it with the
// incoming aAtom argument.
bool Equals(nsIAtom* aAtom) const
{
return reinterpret_cast<uintptr_t>(aAtom) == mBits;
}
// And the same but without forcing callers to atomize
bool Equals(const nsAString& aLocalName) const
{
return IsAtom() && Atom()->Equals(aLocalName);
}
bool Equals(nsIAtom* aLocalName, int32_t aNamespaceID) const
{
if (aNamespaceID == kNameSpaceID_None) {
return Equals(aLocalName);
}
return !IsAtom() && NodeInfo()->Equals(aLocalName, aNamespaceID);
}
bool Equals(mozilla::dom::NodeInfo* aNodeInfo) const
{
return Equals(aNodeInfo->NameAtom(), aNodeInfo->NamespaceID());
}
int32_t NamespaceID() const
{
return IsAtom() ? kNameSpaceID_None : NodeInfo()->NamespaceID();
}
int32_t NamespaceEquals(int32_t aNamespaceID) const
{
return aNamespaceID == kNameSpaceID_None ?
IsAtom() :
(!IsAtom() && NodeInfo()->NamespaceEquals(aNamespaceID));
}
nsIAtom* LocalName() const
{
return IsAtom() ? Atom() : NodeInfo()->NameAtom();
}
nsIAtom* GetPrefix() const
{
return IsAtom() ? nullptr : NodeInfo()->GetPrefixAtom();
}
bool QualifiedNameEquals(const nsAString& aName) const
{
return IsAtom() ? Atom()->Equals(aName) :
NodeInfo()->QualifiedNameEquals(aName);
}
void GetQualifiedName(nsAString& aStr) const
{
if (IsAtom()) {
Atom()->ToString(aStr);
}
else {
aStr = NodeInfo()->QualifiedName();
}
}
#ifdef MOZILLA_INTERNAL_API
void GetPrefix(nsAString& aStr) const
{
if (IsAtom()) {
SetDOMStringToNull(aStr);
}
else {
NodeInfo()->GetPrefix(aStr);
}
}
#endif
uint32_t HashValue() const
{
// mBits and uint32_t might have different size. This should silence
// any warnings or compile-errors. This is what the implementation of
// NS_PTR_TO_INT32 does to take care of the same problem.
return mBits - 0;
}
bool IsSmaller(nsIAtom* aOther) const
{
return mBits < reinterpret_cast<uintptr_t>(aOther);
}
private:
void AddRefInternalName()
{
if (IsAtom()) {
NS_ADDREF(Atom());
} else {
NS_ADDREF(NodeInfo());
}
}
void ReleaseInternalName()
{
if (IsAtom()) {
Atom()->Release();
} else {
NodeInfo()->Release();
}
}
uintptr_t mBits;
};
#endif