Source/WebCore/layout/integration/InlineIteratorBoxModernPath.h

/*
 * Copyright (C) 2019 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

#if ENABLE(LAYOUT_FORMATTING_CONTEXT)

#include "FontCascade.h"
#include "LayoutIntegrationInlineContent.h"
#include "TextBoxSelectableRange.h"

namespace WebCore {
namespace InlineIterator {

class BoxModernPath {
public:
    BoxModernPath(const LayoutIntegration::InlineContent& inlineContent)
        : m_inlineContent(&inlineContent)
    {
        setAtEnd();
    }
    BoxModernPath(const LayoutIntegration::InlineContent& inlineContent, size_t startIndex)
        : m_inlineContent(&inlineContent)
        , m_boxIndex(startIndex)
    {
    }

    bool isText() const { return !!box().text(); }
    bool isInlineBox() const { return box().isInlineBox(); }
    bool isRootInlineBox() const { return box().isRootInlineBox(); }

    FloatRect rect() const { return box().logicalRect(); }

    bool isHorizontal() const { return true; }
    bool dirOverride() const { return false; }
    bool isLineBreak() const { return box().isLineBreak(); }

    unsigned minimumCaretOffset() const { return isText() ? start() : 0; }
    unsigned maximumCaretOffset() const { return isText() ? end() : 1; }

    unsigned char bidiLevel() const { return 0; }

    bool hasHyphen() const { return box().text()->hasHyphen(); }
    StringView text() const { return box().text()->originalContent(); }
    unsigned start() const { return box().text()->start(); }
    unsigned end() const { return box().text()->end(); }
    unsigned length() const { return box().text()->length(); }

    // FIXME: Make a shared generic version of this.
    inline unsigned offsetForPosition(float x) const
    {
        if (isLineBreak())
            return 0;
        auto rect = this->rect();
        auto localX = x - rect.x();
        if (localX > rect.width())
            return length();
        if (localX < 0)
            return 0;

        bool includePartialGlyphs = true;
        return box().style().fontCascade().offsetForPosition(createTextRun(HyphenMode::Ignore), localX, includePartialGlyphs);
    }

    // FIXME: Make a shared generic version of this.
    float positionForOffset(unsigned offset) const
    {
        ASSERT(offset >= start());
        ASSERT(offset <= end());

        if (isLineBreak())
            return rect().x();

        auto endOffset = selectableRange().clamp(offset);

        LayoutRect selectionRect = LayoutRect(rect().x(), 0, 0, 0);
        TextRun textRun = createTextRun(HyphenMode::Ignore);
        box().style().fontCascade().adjustSelectionRectForText(textRun, selectionRect, 0, endOffset);
        return snapRectToDevicePixelsWithWritingDirection(selectionRect, renderer().document().deviceScaleFactor(), textRun.ltr()).maxX();
    }

    TextBoxSelectableRange selectableRange() const
    {
        return {
            start(),
            length(),
            box().text()->hasHyphen() ? box().style().hyphenString().length() : 0,
            box().isLineBreak()
        };
    }

    TextRun createTextRun() const
    {
        return createTextRun(HyphenMode::Include);
    };

    const RenderObject& renderer() const
    {
        return m_inlineContent->rendererForLayoutBox(box().layoutBox());
    }

    void traverseNextTextBox()
    {
        ASSERT(!atEnd());
        ASSERT(box().text());

        auto& layoutBox = box().layoutBox();

        traverseNextLeaf();

        if (!atEnd() && &layoutBox != &box().layoutBox())
            setAtEnd();

        ASSERT(atEnd() || box().text());
    }

    void traverseNextOnLine()
    {
        ASSERT(!atEnd());

        auto oldLineIndex = box().lineIndex();

        traverseNextLeaf();

        if (!atEnd() && oldLineIndex != box().lineIndex())
            setAtEnd();
    }

    void traversePreviousOnLine()
    {
        ASSERT(!atEnd());

        auto oldLineIndex = box().lineIndex();

        traversePreviousLeaf();

        if (!atEnd() && oldLineIndex != box().lineIndex())
            setAtEnd();
    }

    void traverseNextOnLineInLogicalOrder()
    {
        traverseNextOnLine();
    }

    void traversePreviousOnLineInLogicalOrder()
    {
        traversePreviousOnLine();
    }

    void traverseNextInlineBox()
    {
        ASSERT(box().isInlineBox());

        if (box().isLastBox()) {
            setAtEnd();
            return;
        }

        auto& layoutBox = box().layoutBox();
        do {
            traverseNextBox();
        } while (!atEnd() && &box().layoutBox() != &layoutBox);

        ASSERT(atEnd() || box().isInlineBox());
    }

    void traversePreviousInlineBox()
    {
        ASSERT(box().isInlineBox());

        if (box().isFirstBox()) {
            setAtEnd();
            return;
        }

        auto& layoutBox = box().layoutBox();
        do {
            traversePreviousBox();
        } while (!atEnd() && &box().layoutBox() != &layoutBox);

        ASSERT(atEnd() || box().isInlineBox());
    }

    bool operator==(const BoxModernPath& other) const { return m_inlineContent == other.m_inlineContent && m_boxIndex == other.m_boxIndex; }

    bool atEnd() const { return m_boxIndex == boxes().size(); }
    const InlineDisplay::Box& box() const { return boxes()[m_boxIndex]; }
    auto& inlineContent() const { return *m_inlineContent; }

private:
    void traverseNextBox()
    {
        ASSERT(!atEnd());
        ++m_boxIndex;
    }

    void traversePreviousBox()
    {
        ASSERT(!atEnd());
        m_boxIndex = m_boxIndex ? m_boxIndex - 1 : boxes().size();
    }

    void traverseNextLeaf()
    {
        do {
            traverseNextBox();
        } while (!atEnd() && box().isInlineBox());
    }

    void traversePreviousLeaf()
    {
        do {
            traversePreviousBox();
        } while (!atEnd() && box().isInlineBox());
    }

    void setAtEnd() { m_boxIndex = boxes().size(); }

    const LayoutIntegration::InlineContent::Boxes& boxes() const { return m_inlineContent->boxes; }
    const LayoutIntegration::Line& line() const { return m_inlineContent->lineForBox(box()); }

    enum class HyphenMode { Include, Ignore };
    TextRun createTextRun(HyphenMode hyphenMode) const
    {
        auto& style = box().style();
        auto expansion = box().expansion();
        auto rect = this->rect();
        auto xPos = rect.x() - (line().lineBoxLeft() + line().contentLeft());

        auto textForRun = [&] {
            if (hyphenMode == HyphenMode::Ignore || !hasHyphen())
                return text().toStringWithoutCopying();

            return makeString(text(), style.hyphenString());
        }();

        TextRun textRun { textForRun, xPos, expansion.horizontalExpansion, expansion.behavior };
        textRun.setTabSize(!style.collapseWhiteSpace(), style.tabSize());
        return textRun;
    };

    RefPtr<const LayoutIntegration::InlineContent> m_inlineContent;
    size_t m_boxIndex { 0 };
};

}
}

#endif