gecko-dev/dom/base/TreeWalker.h

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=4 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/. */

/*
 * Implementation of DOM Traversal's TreeWalker
 */

#ifndef mozilla_dom_TreeWalker_h
#define mozilla_dom_TreeWalker_h

#include "nsISupports.h"
#include "nsTraversal.h"
#include "nsCOMPtr.h"
#include "nsTArray.h"
#include "nsCycleCollectionParticipant.h"

class nsINode;

namespace mozilla::dom {

class TreeWalker final : public nsISupports, public nsTraversal {
  virtual ~TreeWalker();

 public:
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  TreeWalker(nsINode* aRoot, uint32_t aWhatToShow, NodeFilter* aFilter);

  NS_DECL_CYCLE_COLLECTION_CLASS(TreeWalker)

  // WebIDL API
  nsINode* Root() const { return mRoot; }
  uint32_t WhatToShow() const { return mWhatToShow; }
  NodeFilter* GetFilter() { return mFilter; }
  nsINode* CurrentNode() const { return mCurrentNode; }
  void SetCurrentNode(nsINode& aNode, ErrorResult& aResult);
  // All our traversal methods return strong refs because filtering can
  // remove nodes from the tree.
  already_AddRefed<nsINode> ParentNode(ErrorResult& aResult);
  already_AddRefed<nsINode> FirstChild(ErrorResult& aResult);
  already_AddRefed<nsINode> LastChild(ErrorResult& aResult);
  already_AddRefed<nsINode> PreviousSibling(ErrorResult& aResult);
  already_AddRefed<nsINode> NextSibling(ErrorResult& aResult);
  already_AddRefed<nsINode> PreviousNode(ErrorResult& aResult);
  already_AddRefed<nsINode> NextNode(ErrorResult& aResult);

  bool WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto,
                  JS::MutableHandle<JSObject*> aReflector);

 private:
  nsCOMPtr<nsINode> mCurrentNode;

  /*
   * Implements FirstChild and LastChild which only vary in which direction
   * they search.
   * @param aReversed Controls whether we search forwards or backwards
   * @param aResult   Whether we threw or not.
   * @returns         The desired node. Null if no child is found
   */
  already_AddRefed<nsINode> FirstChildInternal(bool aReversed,
                                               ErrorResult& aResult);

  /*
   * Implements NextSibling and PreviousSibling which only vary in which
   * direction they search.
   * @param aReversed Controls whether we search forwards or backwards
   * @param aResult   Whether we threw or not.
   * @returns         The desired node. Null if no child is found
   */
  already_AddRefed<nsINode> NextSiblingInternal(bool aReversed,
                                                ErrorResult& aResult);
};

}  // namespace mozilla::dom

#endif  // mozilla_dom_TreeWalker_h