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/**
* Copyright (C) 2024 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.
*/
#pragma once
#include "RenderLayoutState.h"
#include "RenderView.h"
#include <wtf/CheckedPtr.h>
namespace WebCore {
class LineClampUpdater {
public:
LineClampUpdater(const RenderBlockFlow& blockContainer);
~LineClampUpdater();
private:
CheckedPtr<const RenderBlockFlow> m_blockContainer;
std::optional<RenderLayoutState::LineClamp> m_previousLineClamp { };
std::optional<RenderLayoutState::LegacyLineClamp> m_skippedLegacyLineClampToRestore { };
};
inline LineClampUpdater::LineClampUpdater(const RenderBlockFlow& blockContainer)
: m_blockContainer(blockContainer)
{
auto* layoutState = m_blockContainer->view().frameView().layoutContext().layoutState();
if (!layoutState)
return;
m_previousLineClamp = layoutState->lineClamp();
if (blockContainer.isFieldset()) {
layoutState->setLineClamp({ });
m_skippedLegacyLineClampToRestore = layoutState->legacyLineClamp();
layoutState->setLegacyLineClamp({ });
return;
}
auto maximumLinesForBlockContainer = m_blockContainer->style().maxLines();
if (maximumLinesForBlockContainer) {
// New, top level line clamp.
layoutState->setLineClamp(RenderLayoutState::LineClamp { maximumLinesForBlockContainer, m_blockContainer->style().overflowContinue() == OverflowContinue::Discard });
return;
}
if (m_previousLineClamp) {
// Propagated line clamp.
if (blockContainer.establishesIndependentFormattingContext()) {
// Contents of descendants that establish independent formatting contexts are skipped over while counting line boxes.
layoutState->setLineClamp({ });
return;
}
auto effectiveShouldDiscard = m_previousLineClamp->shouldDiscardOverflow || m_blockContainer->style().overflowContinue() == OverflowContinue::Discard;
layoutState->setLineClamp(RenderLayoutState::LineClamp { m_previousLineClamp->maximumLines, effectiveShouldDiscard });
return;
}
}
inline LineClampUpdater::~LineClampUpdater()
{
auto* layoutState = m_blockContainer->view().frameView().layoutContext().layoutState();
if (!layoutState)
return;
if (m_skippedLegacyLineClampToRestore)
layoutState->setLegacyLineClamp(m_skippedLegacyLineClampToRestore);
if (!m_previousLineClamp) {
layoutState->setLineClamp({ });
return;
}
layoutState->setLineClamp(RenderLayoutState::LineClamp { m_previousLineClamp->maximumLines - (m_blockContainer->childrenInline() ? m_blockContainer->lineCount() : 0), m_previousLineClamp->shouldDiscardOverflow });
}
}
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