dom/base/nsTraversal.cpp

   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 #include "nsTraversal.h"
   8
   9 #include "nsError.h"
  10 #include "nsINode.h"
  11 #include "mozilla/AutoRestore.h"
  12 #include "mozilla/dom/NodeFilterBinding.h"
  13
  14 #include "nsGkAtoms.h"
  15
  16 using namespace mozilla;
  17 using namespace mozilla::dom;
  18
  19 nsTraversal::nsTraversal(nsINode* aRoot, uint32_t aWhatToShow,
  20                          NodeFilter* aFilter)
  21     : mRoot(aRoot),
  22       mWhatToShow(aWhatToShow),
  23       mFilter(aFilter),
  24       mInAcceptNode(false) {
  25   NS_ASSERTION(aRoot, "invalid root in call to nsTraversal constructor");
  26 }
  27
  28 nsTraversal::~nsTraversal() { /* destructor code */ }
  29
  30 /*
  31  * Tests if and how a node should be filtered. Uses mWhatToShow and
  32  * mFilter to test the node.
  33  * @param aNode     Node to test
  34  * @param aResult   Whether we succeeded
  35  * @returns         Filtervalue. See NodeFilter.webidl
  36  */
  37 int16_t nsTraversal::TestNode(nsINode* aNode, mozilla::ErrorResult& aResult,
  38                               nsCOMPtr<nsINode>* aUnskippedNode) {
  39   if (mInAcceptNode) {
  40     aResult.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
  41     return 0;
  42   }
  43
  44   uint16_t nodeType = aNode->NodeType();
  45
  46   if (nodeType <= 12 && !((1 << (nodeType - 1)) & mWhatToShow)) {
  47     return NodeFilter_Binding::FILTER_SKIP;
  48   }
  49
  50   if (aUnskippedNode) {
  51     *aUnskippedNode = aNode;
  52   }
  53
  54   if (!mFilter) {
  55     // No filter, just accept
  56     return NodeFilter_Binding::FILTER_ACCEPT;
  57   }
  58
  59   AutoRestore<bool> inAcceptNode(mInAcceptNode);
  60   mInAcceptNode = true;
  61   // No need to pass in an execution reason, since the generated default,
  62   // "NodeFilter.acceptNode", is pretty much exactly what we'd say anyway.
  63   return mFilter->AcceptNode(*aNode, aResult, nullptr,
  64                              CallbackObject::eRethrowExceptions);
  65 }