dom/base/NodeIterator.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   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 NodeIterator
   9  */
  10
  11 #ifndef mozilla_dom_NodeIterator_h
  12 #define mozilla_dom_NodeIterator_h
  13
  14 #include "nsTraversal.h"
  15 #include "nsCycleCollectionParticipant.h"
  16 #include "nsStubMutationObserver.h"
  17
  18 class nsINode;
  19
  20 namespace mozilla::dom {
  21
  22 class NodeIterator final : public nsStubMutationObserver, public nsTraversal {
  23  public:
  24   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  25
  26   NodeIterator(nsINode* aRoot, uint32_t aWhatToShow, NodeFilter* aFilter);
  27
  28   NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
  29
  30   NS_DECL_CYCLE_COLLECTION_CLASS(NodeIterator)
  31
  32   // WebIDL API
  33   nsINode* Root() const { return mRoot; }
  34   nsINode* GetReferenceNode() const { return mPointer.mNode; }
  35   bool PointerBeforeReferenceNode() const { return mPointer.mBeforeNode; }
  36   uint32_t WhatToShow() const { return mWhatToShow; }
  37   NodeFilter* GetFilter() { return mFilter; }
  38   already_AddRefed<nsINode> NextNode(ErrorResult& aResult) {
  39     return NextOrPrevNode(&NodePointer::MoveToNext, aResult);
  40   }
  41   already_AddRefed<nsINode> PreviousNode(ErrorResult& aResult) {
  42     return NextOrPrevNode(&NodePointer::MoveToPrevious, aResult);
  43   }
  44   void Detach();
  45
  46   bool WrapObject(JSContext* cx, JS::Handle<JSObject*> aGivenProto,
  47                   JS::MutableHandle<JSObject*> aReflector);
  48
  49  private:
  50   virtual ~NodeIterator();
  51
  52   struct NodePointer {
  53     NodePointer() : mNode(nullptr), mBeforeNode(false) {}
  54     NodePointer(nsINode* aNode, bool aBeforeNode);
  55
  56     typedef bool (NodePointer::*MoveToMethodType)(nsINode*);
  57     bool MoveToNext(nsINode* aRoot);
  58     bool MoveToPrevious(nsINode* aRoot);
  59
  60     bool MoveForward(nsINode* aRoot, nsINode* aNode);
  61     void MoveBackward(nsINode* aParent, nsINode* aNode);
  62
  63     void AdjustAfterRemoval(nsINode* aRoot, nsINode* aContainer,
  64                             nsIContent* aChild, nsIContent* aPreviousSibling);
  65
  66     void Clear() { mNode = nullptr; }
  67
  68     nsINode* mNode;
  69     bool mBeforeNode;
  70   };
  71
  72   // Have to return a strong ref, because the act of testing the node can
  73   // remove it from the DOM so we're holding the only ref to it.
  74   already_AddRefed<nsINode> NextOrPrevNode(NodePointer::MoveToMethodType aMove,
  75                                            ErrorResult& aResult);
  76
  77   NodePointer mPointer;
  78   NodePointer mWorkingPointer;
  79 };
  80
  81 }  // namespace mozilla::dom
  82
  83 #endif  // mozilla_dom_NodeIterator_h