dom/base/TreeWalker.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=4 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /*
   8  * Implementation of DOM Traversal's TreeWalker
   9  */
  10
  11 #ifndef mozilla_dom_TreeWalker_h
  12 #define mozilla_dom_TreeWalker_h
  13
  14 #include "nsISupports.h"
  15 #include "nsTraversal.h"
  16 #include "nsCOMPtr.h"
  17 #include "nsTArray.h"
  18 #include "nsCycleCollectionParticipant.h"
  19
  20 class nsINode;
  21
  22 namespace mozilla::dom {
  23
  24 class TreeWalker final : public nsISupports, public nsTraversal {
  25   virtual ~TreeWalker();
  26
  27  public:
  28   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  29
  30   TreeWalker(nsINode* aRoot, uint32_t aWhatToShow, NodeFilter* aFilter);
  31
  32   NS_DECL_CYCLE_COLLECTION_CLASS(TreeWalker)
  33
  34   // WebIDL API
  35   nsINode* Root() const { return mRoot; }
  36   uint32_t WhatToShow() const { return mWhatToShow; }
  37   NodeFilter* GetFilter() { return mFilter; }
  38   nsINode* CurrentNode() const { return mCurrentNode; }
  39   void SetCurrentNode(nsINode& aNode, ErrorResult& aResult);
  40   // All our traversal methods return strong refs because filtering can
  41   // remove nodes from the tree.
  42   already_AddRefed<nsINode> ParentNode(ErrorResult& aResult);
  43   already_AddRefed<nsINode> FirstChild(ErrorResult& aResult);
  44   already_AddRefed<nsINode> LastChild(ErrorResult& aResult);
  45   already_AddRefed<nsINode> PreviousSibling(ErrorResult& aResult);
  46   already_AddRefed<nsINode> NextSibling(ErrorResult& aResult);
  47   already_AddRefed<nsINode> PreviousNode(ErrorResult& aResult);
  48   already_AddRefed<nsINode> NextNode(ErrorResult& aResult);
  49
  50   bool WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto,
  51                   JS::MutableHandle<JSObject*> aReflector);
  52
  53  private:
  54   nsCOMPtr<nsINode> mCurrentNode;
  55
  56   /*
  57    * Implements FirstChild and LastChild which only vary in which direction
  58    * they search.
  59    * @param aReversed Controls whether we search forwards or backwards
  60    * @param aResult   Whether we threw or not.
  61    * @returns         The desired node. Null if no child is found
  62    */
  63   already_AddRefed<nsINode> FirstChildInternal(bool aReversed,
  64                                                ErrorResult& aResult);
  65
  66   /*
  67    * Implements NextSibling and PreviousSibling which only vary in which
  68    * direction they search.
  69    * @param aReversed Controls whether we search forwards or backwards
  70    * @param aResult   Whether we threw or not.
  71    * @returns         The desired node. Null if no child is found
  72    */
  73   already_AddRefed<nsINode> NextSiblingInternal(bool aReversed,
  74                                                 ErrorResult& aResult);
  75 };
  76
  77 }  // namespace mozilla::dom
  78
  79 #endif  // mozilla_dom_TreeWalker_h