gecko-dev/dom/base/nsTraversal.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * 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/. */

#include "nsTraversal.h"

#include "nsError.h"
#include "nsINode.h"
#include "mozilla/AutoRestore.h"
#include "mozilla/dom/NodeFilterBinding.h"

#include "nsGkAtoms.h"

using namespace mozilla;
using namespace mozilla::dom;

nsTraversal::nsTraversal(nsINode* aRoot, uint32_t aWhatToShow,
                         NodeFilter* aFilter)
    : mRoot(aRoot),
      mWhatToShow(aWhatToShow),
      mFilter(aFilter),
      mInAcceptNode(false) {
  NS_ASSERTION(aRoot, "invalid root in call to nsTraversal constructor");
}

nsTraversal::~nsTraversal() { /* destructor code */
}

/*
 * Tests if and how a node should be filtered. Uses mWhatToShow and
 * mFilter to test the node.
 * @param aNode     Node to test
 * @param aResult   Whether we succeeded
 * @returns         Filtervalue. See NodeFilter.webidl
 */
int16_t nsTraversal::TestNode(nsINode* aNode, mozilla::ErrorResult& aResult) {
  if (mInAcceptNode) {
    aResult.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
    return 0;
  }

  uint16_t nodeType = aNode->NodeType();

  if (nodeType <= 12 && !((1 << (nodeType - 1)) & mWhatToShow)) {
    return NodeFilter_Binding::FILTER_SKIP;
  }

  if (!mFilter) {
    // No filter, just accept
    return NodeFilter_Binding::FILTER_ACCEPT;
  }

  AutoRestore<bool> inAcceptNode(mInAcceptNode);
  mInAcceptNode = true;
  // No need to pass in an execution reason, since the generated default,
  // "NodeFilter.acceptNode", is pretty much exactly what we'd say anyway.
  return mFilter->AcceptNode(*aNode, aResult, nullptr,
                             CallbackObject::eRethrowExceptions);
}