tor-browser

nsAttrName.h (5218B)

---

/* -*- 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