gecko-dev/dom/base/nsAttrName.h

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5.1 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/. */
/*
* 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 "nsAtom.h"
#include "nsDOMString.h"
#define NS_ATTRNAME_NODEINFO_BIT 1
class nsAttrName {
public:
nsAttrName(const nsAttrName& aOther) : mBits(aOther.mBits) {
AddRefInternalName();
}
explicit nsAttrName(nsAtom* 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(nsAtom* 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);
}
nsAtom* Atom() const {
NS_ASSERTION(IsAtom(), "getting atom-value of nodeinfo-name");
return reinterpret_cast<nsAtom*>(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 AttrArray::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(const nsAtom* 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(const nsAtom* 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));
}
nsAtom* LocalName() const {
return IsAtom() ? Atom() : NodeInfo()->NameAtom();
}
nsAtom* 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(const nsAtom* 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