dom/base/TreeWalker.h
author Sylvestre Ledru <sledru@mozilla.com>
Thu, 17 Aug 2017 11:13:01 +0200
changeset 648192 c236dfe7dc98c387219d7cb45d0693560db708fd
parent 605172 6a629adbb62a299d7208373d1c6f375149d2afdb
permissions -rw-r--r--
indent all (with js specific coding style) MozReview-Commit-ID: LU1md2wyB8

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

#ifndef mozilla_dom_TreeWalker_h
#define mozilla_dom_TreeWalker_h

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

class nsINode;
class nsIDOMNode;

namespace mozilla {
namespace dom {

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

public:
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_NSIDOMTREEWALKER

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

  NS_DECL_CYCLE_COLLECTION_CLASS(TreeWalker)

  // WebIDL API
  nsINode* Root() const { return mRoot; }
  uint32_t WhatToShow() const { return mWhatToShow; }
  already_AddRefed<NodeFilter> GetFilter()
  {
    return mFilter.ToWebIDLCallback();
  }
  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);

  // Implementation for our various XPCOM getters
  typedef already_AddRefed<nsINode> (TreeWalker::*NodeGetter)(ErrorResult&);
  inline nsresult ImplNodeGetter(NodeGetter aGetter, nsIDOMNode** aRetval)
  {
    mozilla::ErrorResult rv;
    nsCOMPtr<nsINode> node = (this->*aGetter)(rv);
    if (rv.Failed()) {
      return rv.StealNSResult();
    }
    *aRetval = node ? node.forget().take()->AsDOMNode() : nullptr;
    return NS_OK;
  }
};

} // namespace dom
} // namespace mozilla

#endif // mozilla_dom_TreeWalker_h