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/*
* Copyright (C) 2020 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "BoundaryPoint.h"
#include "ContainerNode.h"
namespace WebCore {
template PartialOrdering treeOrder<Tree>(const BoundaryPoint&, const BoundaryPoint&);
template PartialOrdering treeOrder< ShadowIncludingTree >(const BoundaryPoint&, const BoundaryPoint&);
template PartialOrdering treeOrder<ComposedTree>(const BoundaryPoint&, const BoundaryPoint&);
std::optional<BoundaryPoint> makeBoundaryPointBeforeNode(Node& node)
{
auto parent = node.parentNode();
if (!parent)
return std::nullopt;
return BoundaryPoint { *parent, node.computeNodeIndex() };
}
std::optional<BoundaryPoint> makeBoundaryPointAfterNode(Node& node)
{
auto parent = node.parentNode();
if (!parent)
return std::nullopt;
return BoundaryPoint { *parent, node.computeNodeIndex() + 1 };
}
static bool isOffsetBeforeChild(ContainerNode& container, unsigned offset, Node& child)
{
if (!offset)
return true;
// If the container is not the parent, the child is part of a shadow tree, which we sort between offset 0 and offset 1.
if (child.parentNode() != &container)
return false;
unsigned currentOffset = 0;
for (auto currentChild = container.firstChild(); currentChild && currentChild != &child; currentChild = currentChild->nextSibling()) {
if (offset <= ++currentOffset)
return true;
}
return false;
}
// FIXME: Once we move to C++20, replace with the C++20 <=> operator.
// FIXME: This could return std::strong_ordering if we had that, or the equivalent.
static PartialOrdering order(unsigned a, unsigned b)
{
if (a < b)
return PartialOrdering::less;
if (a > b)
return PartialOrdering::greater;
return PartialOrdering::equivalent;
}
template<TreeType treeType> PartialOrdering treeOrder(const BoundaryPoint& a, const BoundaryPoint& b)
{
if (a.container.ptr() == b.container.ptr())
return order(a.offset, b.offset);
for (auto ancestor = b.container.ptr(); ancestor; ) {
auto nextAncestor = parent<treeType>(*ancestor);
if (nextAncestor == a.container.ptr())
return isOffsetBeforeChild(*nextAncestor, a.offset, *ancestor) ? PartialOrdering::less : PartialOrdering::greater;
ancestor = nextAncestor;
}
for (auto ancestor = a.container.ptr(); ancestor; ) {
auto nextAncestor = parent<treeType>(*ancestor);
if (nextAncestor == b.container.ptr())
return isOffsetBeforeChild(*nextAncestor, b.offset, *ancestor) ? PartialOrdering::greater : PartialOrdering::less;
ancestor = nextAncestor;
}
return treeOrder<treeType>(a.container, b.container);
}
PartialOrdering treeOrderForTesting(TreeType type, const BoundaryPoint& a, const BoundaryPoint& b)
{
switch (type) {
case Tree:
return treeOrder<Tree>(a, b);
case ShadowIncludingTree:
return treeOrder<ShadowIncludingTree>(a, b);
case ComposedTree:
return treeOrder<ComposedTree>(a, b);
}
ASSERT_NOT_REACHED();
return PartialOrdering::unordered;
}
TextStream& operator<<(TextStream& stream, const BoundaryPoint& boundaryPoint)
{
TextStream::GroupScope scope(stream);
stream << "BoundaryPoint ";
stream.dumpProperty("node", boundaryPoint.container->debugDescription());
stream.dumpProperty("offset", boundaryPoint.offset);
return stream;
}
}