Source/core/layout/TextRunConstructor.cpp

/*
 * Copyright (C) 2013 Google 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:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
 * OWNER OR 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 "core/layout/TextRunConstructor.h"

#include "core/layout/LayoutText.h"
#include "core/layout/api/LineLayoutItem.h"
#include "core/layout/api/LineLayoutText.h"
#include "platform/text/BidiTextRun.h"

namespace blink {

template <typename CharacterType>
static inline TextRun constructTextRunInternal(const Font& font, const CharacterType* characters, int length, const ComputedStyle& style, TextDirection direction)
{
    TextRun::ExpansionBehavior expansion = TextRun::AllowTrailingExpansion | TextRun::ForbidLeadingExpansion;
    bool directionalOverride = style.rtlOrdering() == VisualOrder;
    TextRun run(characters, length, 0, 0, expansion, direction, directionalOverride);
    return run;
}

template <typename CharacterType>
static inline TextRun constructTextRunInternal(const Font& font, const CharacterType* characters, int length, const ComputedStyle& style, TextDirection direction, TextRunFlags flags)
{
    TextDirection textDirection = direction;
    bool directionalOverride = style.rtlOrdering() == VisualOrder;
    if (flags != DefaultTextRunFlags) {
        if (flags & RespectDirection)
            textDirection = style.direction();
        if (flags & RespectDirectionOverride)
            directionalOverride |= isOverride(style.unicodeBidi());
    }

    TextRun::ExpansionBehavior expansion = TextRun::AllowTrailingExpansion | TextRun::ForbidLeadingExpansion;
    TextRun run(characters, length, 0, 0, expansion, textDirection, directionalOverride);
    return run;
}

TextRun constructTextRun(const Font& font, const LChar* characters, int length, const ComputedStyle& style, TextDirection direction)
{
    return constructTextRunInternal(font, characters, length, style, direction);
}

TextRun constructTextRun(const Font& font, const UChar* characters, int length, const ComputedStyle& style, TextDirection direction)
{
    return constructTextRunInternal(font, characters, length, style, direction);
}

TextRun constructTextRun(const Font& font, const LayoutText* text, unsigned offset, unsigned length, const ComputedStyle& style, TextDirection direction)
{
    ASSERT(offset + length <= text->textLength());
    if (text->hasEmptyText())
        return constructTextRunInternal(font, static_cast<const LChar*>(nullptr), 0, style, direction);
    if (text->is8Bit())
        return constructTextRunInternal(font, text->characters8() + offset, length, style, direction);
    return constructTextRunInternal(font, text->characters16() + offset, length, style, direction);
}

TextRun constructTextRun(const Font& font, const String& string, const ComputedStyle& style, TextDirection direction, TextRunFlags flags)
{
    unsigned length = string.length();
    if (!length)
        return constructTextRunInternal(font, static_cast<const LChar*>(nullptr), length, style, direction, flags);
    if (string.is8Bit())
        return constructTextRunInternal(font, string.characters8(), length, style, direction, flags);
    return constructTextRunInternal(font, string.characters16(), length, style, direction, flags);
}

TextRun constructTextRun(const Font& font, const String& string, const ComputedStyle& style, TextRunFlags flags)
{
    return constructTextRun(font, string, style, string.isEmpty() || string.is8Bit() ? LTR : determineDirectionality(string), flags);
}

TextRun constructTextRun(const Font& font, const LineLayoutText text, unsigned offset, unsigned length, const ComputedStyle& style)
{
    ASSERT(offset + length <= text.textLength());
    if (text.hasEmptyText())
        return constructTextRunInternal(font, static_cast<const LChar*>(nullptr), 0, style, LTR);
    if (text.is8Bit())
        return constructTextRunInternal(font, text.characters8() + offset, length, style, LTR);

    TextRun run = constructTextRunInternal(font, text.characters16() + offset, length, style, LTR);
    run.setDirection(directionForRun(run));
    return run;
}

} // namespace blink