dom/base/FilteredNodeIterator.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 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 a generic filtered iterator over nodes.
   9  */
  10
  11 #ifndef mozilla_dom_FilteredNodeIterator_h
  12 #define mozilla_dom_FilteredNodeIterator_h
  13
  14 #include "nsINode.h"
  15
  16 namespace mozilla::dom {
  17
  18 template <typename T, typename Iter>
  19 class FilteredNodeIterator : public Iter {
  20  public:
  21   explicit FilteredNodeIterator(const nsINode& aNode) : Iter(aNode) {
  22     EnsureValid();
  23   }
  24
  25   FilteredNodeIterator& begin() { return *this; }
  26   using Iter::end;
  27
  28   void operator++() {
  29     Iter::operator++();
  30     EnsureValid();
  31   }
  32
  33   using Iter::operator!=;
  34
  35   T* operator*() {
  36     nsINode* node = Iter::operator*();
  37     MOZ_ASSERT(!node || T::FromNode(node));
  38     return static_cast<T*>(node);
  39   }
  40
  41  private:
  42   void EnsureValid() {
  43     while (true) {
  44       nsINode* node = Iter::operator*();
  45       if (!node || T::FromNode(node)) {
  46         return;
  47       }
  48       Iter::operator++();
  49     }
  50   }
  51
  52   FilteredNodeIterator() : Iter() {}
  53 };
  54
  55 }  // namespace mozilla::dom
  56
  57 #endif  // mozilla_dom_FilteredNodeIterator.h