1 files changed, 179 insertions, 0 deletions
diff --git a/dom/base/nsAttrName.h b/dom/base/nsAttrName.h
new file mode 100644
index 0000000000..5af01b028b
--- /dev/null
+++ b/dom/base/nsAttrName.h
@@ -0,0 +1,179 @@
+/* -*- 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