1 files changed, 308 insertions, 0 deletions
diff --git a/dom/base/NodeInfo.h b/dom/base/NodeInfo.h
new file mode 100644
index 0000000000..3060597ffb
--- /dev/null
+++ b/dom/base/NodeInfo.h
@@ -0,0 +1,308 @@
+/* -*- 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 a prefix/namespace/localName triple; a single
+ * nodeinfo is shared by all elements in a document that have that
+ * prefix, namespace, and localName.
+ *
+ * nsNodeInfoManagers are internal objects that manage a list of
+ * NodeInfos, every document object should hold a strong reference to
+ * a nsNodeInfoManager and every NodeInfo also holds a strong reference
+ * to their owning manager. When a NodeInfo is no longer used it will
+ * automatically remove itself from its owner manager, and when all
+ * NodeInfos have been removed from a nsNodeInfoManager and all external
+ * references are released the nsNodeInfoManager deletes itself.
+ */
+
+#ifndef mozilla_dom_NodeInfo_h___
+#define mozilla_dom_NodeInfo_h___
+
+#include "nsCycleCollectionParticipant.h"
+#include "mozilla/dom/NameSpaceConstants.h"
+#include "nsString.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Maybe.h"
+#include "nsAtom.h"
+#include "nsHashKeys.h"
+
+class nsNodeInfoManager;
+
+namespace mozilla::dom {
+
+class Document;
+
+class NodeInfo final {
+ public:
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(NodeInfo)
+  NS_DECL_CYCLE_COLLECTION_SKIPPABLE_NATIVE_CLASS_WITH_CUSTOM_DELETE(NodeInfo)
+
+  /*
+   * Get the name from this node as a string, this does not include the prefix.
+   *
+   * For the HTML element "<body>" this will return "body" and for the XML
+   * element "<html:body>" this will return "body".
+   */
+  void GetName(nsAString& aName) const;
+
+  /*
+   * Get the name from this node as an atom, this does not include the prefix.
+   * This function never returns a null atom.
+   *
+   * For the HTML element "<body>" this will return the "body" atom and for
+   * the XML element "<html:body>" this will return the "body" atom.
+   */
+  nsAtom* NameAtom() const { return mInner.mName; }
+
+  /*
+   * Get the qualified name from this node as a string, the qualified name
+   * includes the prefix, if one exists.
+   *
+   * For the HTML element "<body>" this will return "body" and for the XML
+   * element "<html:body>" this will return "html:body".
+   */
+  const nsString& QualifiedName() const { return mQualifiedName; }
+
+  /*
+   * Returns the node's nodeName as defined in DOM Core
+   */
+  const nsString& NodeName() const { return mNodeName; }
+
+  /*
+   * Returns the node's localName as defined in DOM Core
+   */
+  const nsString& LocalName() const { return mLocalName; }
+
+  /*
+   * Get the prefix from this node as a string.
+   *
+   * For the HTML element "<body>" this will return a null string and for
+   * the XML element "<html:body>" this will return the string "html".
+   */
+  void GetPrefix(nsAString& aPrefix) const;
+
+  /*
+   * Get the prefix from this node as an atom.
+   *
+   * For the HTML element "<body>" this will return a null atom and for
+   * the XML element "<html:body>" this will return the "html" atom.
+   */
+  nsAtom* GetPrefixAtom() const { return mInner.mPrefix; }
+
+  /*
+   * Get the namespace URI for a node, if the node has a namespace URI.
+   */
+  void GetNamespaceURI(nsAString& aNameSpaceURI) const;
+
+  /*
+   * Get the namespace ID for a node if the node has a namespace, if not this
+   * returns kNameSpaceID_None.
+   */
+  int32_t NamespaceID() const { return mInner.mNamespaceID; }
+
+  /*
+   * Get the nodetype for the node. Returns the values specified in Node
+   * for Node.nodeType
+   */
+  uint16_t NodeType() const { return mInner.mNodeType; }
+
+  /*
+   * Get the extra name, used by PIs and DocTypes, for the node.
+   */
+  nsAtom* GetExtraName() const { return mInner.mExtraName; }
+
+  /**
+   * Get the owning node info manager. Only to be used inside Gecko, you can't
+   * really do anything with the pointer outside Gecko anyway.
+   */
+  nsNodeInfoManager* NodeInfoManager() const { return mOwnerManager; }
+
+  /*
+   * Utility functions that can be used to check if a nodeinfo holds a specific
+   * name, name and prefix, name and prefix and namespace ID, or just
+   * namespace ID.
+   */
+  inline bool Equals(NodeInfo* aNodeInfo) const;
+
+  bool NameAndNamespaceEquals(NodeInfo* aNodeInfo) const;
+
+  bool Equals(const nsAtom* aNameAtom) const {
+    return mInner.mName == aNameAtom;
+  }
+
+  bool Equals(const nsAtom* aNameAtom, const nsAtom* aPrefixAtom) const {
+    return (mInner.mName == aNameAtom) && (mInner.mPrefix == aPrefixAtom);
+  }
+
+  bool Equals(const nsAtom* aNameAtom, int32_t aNamespaceID) const {
+    return ((mInner.mName == aNameAtom) &&
+            (mInner.mNamespaceID == aNamespaceID));
+  }
+
+  bool Equals(const nsAtom* aNameAtom, const nsAtom* aPrefixAtom,
+              int32_t aNamespaceID) const {
+    return ((mInner.mName == aNameAtom) && (mInner.mPrefix == aPrefixAtom) &&
+            (mInner.mNamespaceID == aNamespaceID));
+  }
+
+  bool NamespaceEquals(int32_t aNamespaceID) const {
+    return mInner.mNamespaceID == aNamespaceID;
+  }
+
+  inline bool Equals(const nsAString& aName) const;
+
+  inline bool Equals(const nsAString& aName, const nsAString& aPrefix) const;
+
+  inline bool Equals(const nsAString& aName, int32_t aNamespaceID) const;
+
+  inline bool Equals(const nsAString& aName, const nsAString& aPrefix,
+                     int32_t aNamespaceID) const;
+
+  bool NamespaceEquals(const nsAString& aNamespaceURI) const;
+
+  inline bool QualifiedNameEquals(const nsAtom* aNameAtom) const;
+
+  bool QualifiedNameEquals(const nsAString& aQualifiedName) const {
+    return mQualifiedName == aQualifiedName;
+  }
+
+  /*
+   * Retrieve a pointer to the document that owns this node info.
+   */
+  Document* GetDocument() const { return mDocument; }
+
+ private:
+  NodeInfo() = delete;
+  NodeInfo(const NodeInfo& aOther) = delete;
+
+  // NodeInfo is only constructed by nsNodeInfoManager which is a friend class.
+  // aName and aOwnerManager may not be null.
+  NodeInfo(nsAtom* aName, nsAtom* aPrefix, int32_t aNamespaceID,
+           uint16_t aNodeType, nsAtom* aExtraName,
+           nsNodeInfoManager* aOwnerManager);
+
+  ~NodeInfo();
+
+ public:
+  bool CanSkip();
+
+  /**
+   * This method gets called by the cycle collector when it's time to delete
+   * this object.
+   */
+  void DeleteCycleCollectable();
+
+ protected:
+  /*
+   * NodeInfoInner is used for two things:
+   *
+   *   1. as a member in nsNodeInfo for holding the name, prefix and
+   *      namespace ID
+   *   2. as the hash key in the hash table in nsNodeInfoManager
+   *
+   * NodeInfoInner does not do any kind of reference counting,
+   * that's up to the user of this class. Since NodeInfoInner is
+   * typically used as a member of NodeInfo, the hash table doesn't
+   * need to delete the keys. When the value (NodeInfo) is deleted
+   * the key is automatically deleted.
+   */
+
+  class NodeInfoInner {
+   public:
+    NodeInfoInner()
+        : mName(nullptr),
+          mPrefix(nullptr),
+          mNamespaceID(kNameSpaceID_Unknown),
+          mNodeType(0),
+          mNameString(nullptr),
+          mExtraName(nullptr),
+          mHash() {}
+    NodeInfoInner(nsAtom* aName, nsAtom* aPrefix, int32_t aNamespaceID,
+                  uint16_t aNodeType, nsAtom* aExtraName)
+        : mName(aName),
+          mPrefix(aPrefix),
+          mNamespaceID(aNamespaceID),
+          mNodeType(aNodeType),
+          mNameString(nullptr),
+          mExtraName(aExtraName),
+          mHash() {}
+    NodeInfoInner(const nsAString& aTmpName, nsAtom* aPrefix,
+                  int32_t aNamespaceID, uint16_t aNodeType)
+        : mName(nullptr),
+          mPrefix(aPrefix),
+          mNamespaceID(aNamespaceID),
+          mNodeType(aNodeType),
+          mNameString(&aTmpName),
+          mExtraName(nullptr),
+          mHash() {}
+
+    bool operator==(const NodeInfoInner& aOther) const {
+      if (mPrefix != aOther.mPrefix || mNamespaceID != aOther.mNamespaceID ||
+          mNodeType != aOther.mNodeType || mExtraName != aOther.mExtraName) {
+        return false;
+      }
+
+      if (mName) {
+        if (aOther.mName) {
+          return mName == aOther.mName;
+        }
+        return mName->Equals(*(aOther.mNameString));
+      }
+
+      if (aOther.mName) {
+        return aOther.mName->Equals(*(mNameString));
+      }
+
+      return mNameString->Equals(*(aOther.mNameString));
+    }
+
+    uint32_t Hash() const {
+      if (!mHash) {
+        mHash.emplace(mName ? mName->hash()
+                            : mozilla::HashString(*mNameString));
+      }
+      return mHash.value();
+    }
+
+    nsAtom* const MOZ_OWNING_REF mName;
+    nsAtom* MOZ_OWNING_REF mPrefix;
+    int32_t mNamespaceID;
+    uint16_t mNodeType;  // As defined by Node.nodeType
+    const nsAString* const mNameString;
+    nsAtom* MOZ_OWNING_REF mExtraName;  // Only used by PIs and DocTypes
+    mutable mozilla::Maybe<const uint32_t> mHash;
+  };
+
+  // nsNodeInfoManager needs to pass mInner to the hash table.
+  friend class ::nsNodeInfoManager;
+
+  // This is a non-owning reference, but it's safe since it's set to nullptr
+  // by nsNodeInfoManager::DropDocumentReference when the document is destroyed.
+  Document* MOZ_NON_OWNING_REF mDocument;  // Cache of mOwnerManager->mDocument
+
+  NodeInfoInner mInner;
+
+  RefPtr<nsNodeInfoManager> mOwnerManager;
+
+  /*
+   * Members for various functions of mName+mPrefix that we can be
+   * asked to compute.
+   */
+
+  // Qualified name
+  nsString mQualifiedName;
+
+  // nodeName for the node.
+  nsString mNodeName;
+
+  // localName for the node. This is either equal to mInner.mName, or a
+  // void string, depending on mInner.mNodeType.
+  nsString mLocalName;
+};
+
+}  // namespace mozilla::dom
+
+#endif /* mozilla_dom_NodeInfo_h___ */