src/Mod/Spreadsheet/App/Cell.cpp

// SPDX-License-Identifier: LGPL-2.1-or-later

/***************************************************************************
 *   Copyright (c) 2015 Eivind Kvedalen <eivind@kvedalen.name>             *
 *                                                                         *
 *   This file is part of the FreeCAD CAx development system.              *
 *                                                                         *
 *   This library is free software; you can redistribute it and/or         *
 *   modify it under the terms of the GNU Library General Public           *
 *   License as published by the Free Software Foundation; either          *
 *   version 2 of the License, or (at your option) any later version.      *
 *                                                                         *
 *   This library  is distributed in the hope that it will be useful,      *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU Library General Public License for more details.                  *
 *                                                                         *
 *   You should have received a copy of the GNU Library General Public     *
 *   License along with this library; see the file COPYING.LIB. If not,    *
 *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
 *   Suite 330, Boston, MA  02111-1307, USA                                *
 *                                                                         *
 ***************************************************************************/


#include <QLocale>
#include <boost/algorithm/string/predicate.hpp>
#include <boost/tokenizer.hpp>
#include <iomanip>
#include <sstream>


#include <App/ExpressionParser.h>
#include <Base/Console.h>
#include <Base/Quantity.h>
#include <Base/Reader.h>
#include <Base/UnitsApi.h>
#include <Base/Writer.h>

#include "Cell.h"
#include "Sheet.h"


FC_LOG_LEVEL_INIT("Spreadsheet", true, true)

#ifdef _MSC_VER
# define __func__ __FUNCTION__
# ifdef PropertySheet
#  undef PropertySheet  // Microsoft's #define conflicts with the use below
# endif
#endif

using namespace App;
using namespace Base;
using namespace Spreadsheet;

/////////////////////////////////////////////////////////

// expose the read() function for simpler partial xml reading in setExpression()
class ReaderPrivate: public Base::XMLReader
{
public:
    ReaderPrivate(const char* FileName, std::istream& is)
        : XMLReader(FileName, is)
    {}

    bool read()
    {
        return XMLReader::read();
    }
};

///////////////////////////////////////////////////////////

// clang-format off
const int Cell::EXPRESSION_SET       = 1;
const int Cell::ALIGNMENT_SET        = 4;
const int Cell::STYLE_SET            = 8;
const int Cell::BACKGROUND_COLOR_SET = 0x10;
const int Cell::FOREGROUND_COLOR_SET = 0x20;
const int Cell::DISPLAY_UNIT_SET     = 0x40;
const int Cell::COMPUTED_UNIT_SET    = 0x80;
const int Cell::ALIAS_SET            = 0x100;
const int Cell::SPANS_SET            = 0x200;
const int Cell::MARK_SET             = 0x40000000;
const int Cell::EXCEPTION_SET        = 0x20000000;
const int Cell::PARSE_EXCEPTION_SET  = 0x80000000;
const int Cell::RESOLVE_EXCEPTION_SET= 0x01000000;

/* Alignment */
const int Cell::ALIGNMENT_LEFT       = 0x01;
const int Cell::ALIGNMENT_HCENTER    = 0x02;
const int Cell::ALIGNMENT_RIGHT      = 0x04;
const int Cell::ALIGNMENT_HIMPLIED   = 0x08;
const int Cell::ALIGNMENT_HORIZONTAL = 0x0f;
const int Cell::ALIGNMENT_TOP        = 0x10;
const int Cell::ALIGNMENT_VCENTER    = 0x20;
const int Cell::ALIGNMENT_BOTTOM     = 0x40;
const int Cell::ALIGNMENT_VIMPLIED   = 0x80;
const int Cell::ALIGNMENT_VERTICAL   = 0xf0;
// clang-format on

/**
 * Construct a CellContent object.
 * @param _address  The address of the cell (i.e. row and column)
 * @param _owner    The spreadsheet that owns this cell.
 *
 */

Cell::Cell(const CellAddress& _address, PropertySheet* _owner)
    : address(_address)
    , owner(_owner)
    , used(0)
    , alignment(ALIGNMENT_HIMPLIED | ALIGNMENT_LEFT | ALIGNMENT_VIMPLIED | ALIGNMENT_VCENTER)
    , style()
    , foregroundColor(0, 0, 0, 1)
    , backgroundColor(1, 1, 1, 1)
    , displayUnit()
    , alias()
    , computedUnit()
    , rowSpan(1)
    , colSpan(1)
    , anchor()
{
    assert(address.isValid());
}

Cell::Cell(PropertySheet* _owner, const Cell& other)
    : address(other.address)
    , owner(_owner)
    , used(other.used)
    , expression(other.expression ? other.expression->copy() : nullptr)
    , alignment(other.alignment)
    , style(other.style)
    , foregroundColor(other.foregroundColor)
    , backgroundColor(other.backgroundColor)
    , displayUnit(other.displayUnit)
    , computedUnit(other.computedUnit)
    , rowSpan(other.rowSpan)
    , colSpan(other.colSpan)
{
    setUsed(MARK_SET, false);
    setAlias(other.alias);
    setDirty();
}

Cell& Cell::operator=(const Cell& rhs)
{
    PropertySheet::AtomicPropertyChange signaller(*owner);

    address = rhs.address;

    setExpression(App::ExpressionPtr(rhs.expression ? rhs.expression->copy() : nullptr));
    setAlignment(rhs.alignment);
    setStyle(rhs.style);
    setBackground(rhs.backgroundColor);
    setForeground(rhs.foregroundColor);
    setDisplayUnit(rhs.displayUnit.stringRep);
    setComputedUnit(rhs.computedUnit);
    setAlias(rhs.alias);
    setSpans(rhs.rowSpan, rhs.colSpan);

    setUsed(MARK_SET, false);
    setDirty();

    signaller.tryInvoke();
    return *this;
}

/**
 * Destroy a CellContent object.
 *
 */

Cell::~Cell() = default;

/**
 * Set the expression tree to \a expr.
 *
 */

void Cell::setExpression(App::ExpressionPtr&& expr)
{
    PropertySheet::AtomicPropertyChange signaller(*owner);

    owner->setDirty(address);

    /* Remove dependencies */
    owner->removeDependencies(address);

    if (expr && !expr->comment.empty()) {
        if (!boost::starts_with(expr->comment, "<Cell ")) {
            FC_WARN(
                "Unknown style of cell " << owner->sheet()->getFullName() << '.' << address.toString()
            );
        }
        else {
            try {
                std::istringstream in(expr->comment);
                ReaderPrivate reader("<memory>", in);
                reader.read();
                restore(reader, true);
            }
            catch (Base::Exception& e) {
                e.reportException();
                FC_ERR(
                    "Failed to restore style of cell " << owner->sheet()->getFullName() << '.'
                                                       << address.toString() << ": " << e.what()
                );
            }
        }
        expr->comment.clear();
    }

    expression = std::move(expr);
    setUsed(EXPRESSION_SET, !!expression);

    /* Update dependencies */
    owner->addDependencies(address);

    signaller.tryInvoke();
}

/**
 * Get the expression tree.
 *
 */

const App::Expression* Cell::getExpression(bool withFormat) const
{
    if (withFormat && expression) {
        if ((used
             & (ALIGNMENT_SET | STYLE_SET | FOREGROUND_COLOR_SET | BACKGROUND_COLOR_SET
                | DISPLAY_UNIT_SET | ALIAS_SET | SPANS_SET))) {
            std::ostringstream ss;
            save(ss, "", true);
            expression->comment = ss.str();
        }
    }
    return expression.get();
}

/**
 * Get string content.
 *
 */

bool Cell::getStringContent(std::string& s, bool persistent) const
{
    if (expression) {
        s.clear();
        if (expression->hasComponent()) {
            s = "=" + expression->toString(persistent);
        }
        else if (freecad_cast<App::StringExpression*>(expression.get())) {
            s = static_cast<App::StringExpression*>(expression.get())->getText();
            s = "'" + s;
        }
        else if (freecad_cast<App::ConstantExpression*>(expression.get())) {
            s = "=" + expression->toString();
        }
        else if (freecad_cast<App::NumberExpression*>(expression.get())) {
            s = expression->toString();
        }
        else {
            s = "=" + expression->toString(persistent);
        }

        return true;
    }
    else {
        s = "";
        return false;
    }
}

void Cell::afterRestore()
{
    auto expr = freecad_cast<StringExpression*>(expression.get());
    if (expr) {
        setContent(expr->getText().c_str());
    }
}

void Cell::setContent(const char* value)
{
    PropertySheet::AtomicPropertyChange signaller(*owner);
    ExpressionPtr newExpr;

    clearException();
    if (value) {
        Sheet* sheet = owner->sheet();
        if (sheet && sheet->isRestoring()) {
            if (value[0] == '\0' || (value[0] == '\'' && value[1] == '\0')) {
                return;
            }
            expression = std::make_unique<App::StringExpression>(sheet, value);
            setUsed(EXPRESSION_SET, true);
            return;
        }
        if (*value == '=') {
            try {
                newExpr = ExpressionPtr(App::ExpressionParser::parse(sheet, value + 1));
            }
            catch (Base::Exception& e) {
                newExpr = std::make_unique<App::StringExpression>(sheet, value);
                setParseException(e.what());
            }
        }
        else if (*value == '\'') {
            if (value[1] == '\0') {
                value = nullptr;
            }
            else {
                newExpr = std::make_unique<App::StringExpression>(sheet, value + 1);
            }
        }
        else if (*value != '\0') {
            // check if value is just a number
            char* end;
            errno = 0;
            const double float_value = strtod(value, &end);
            if (errno == 0) {
                const bool isEndEmpty = *end == '\0' || strspn(end, " \t\n\r") == strlen(end);
                if (isEndEmpty) {
                    newExpr = std::make_unique<App::NumberExpression>(sheet, Quantity(float_value));
                }
            }

            // if not a float, check if it is a quantity or compatible fraction
            const bool isStartingWithNumber = value != end;
            if (!newExpr && isStartingWithNumber) {
                try {
                    ExpressionPtr parsedExpr(App::ExpressionParser::parse(sheet, value));

                    if (const auto fraction = freecad_cast<OperatorExpression*>(parsedExpr.get())) {
                        if (fraction->getOperator() == OperatorExpression::UNIT) {
                            const auto left = freecad_cast<NumberExpression*>(fraction->getLeft());
                            const auto right = freecad_cast<UnitExpression*>(fraction->getRight());
                            if (left && right) {
                                newExpr = std::move(parsedExpr);
                            }
                        }
                        else if (fraction->getOperator() == OperatorExpression::DIV) {
                            // only the following types of fractions are ok:
                            //     1/2, 1m/2, 1/2s, 1m/2s, 1/m

                            // check for numbers in (de)nominator
                            const bool isNumberNom = freecad_cast<NumberExpression*>(
                                fraction->getLeft()
                            );
                            const bool isNumberDenom = freecad_cast<NumberExpression*>(
                                fraction->getRight()
                            );

                            // check for numbers with units in (de)nominator
                            const auto opNom = freecad_cast<OperatorExpression*>(fraction->getLeft());
                            const auto opDenom = freecad_cast<OperatorExpression*>(
                                fraction->getRight()
                            );
                            const bool isQuantityNom = opNom
                                && opNom->getOperator() == OperatorExpression::UNIT;
                            const bool isQuantityDenom = opDenom
                                && opDenom->getOperator() == OperatorExpression::UNIT;

                            // check for units in denomainator
                            const auto uDenom = freecad_cast<UnitExpression*>(fraction->getRight());
                            const bool isUnitDenom = uDenom && uDenom->is<UnitExpression>();

                            const bool isNomValid = isNumberNom || isQuantityNom;
                            const bool isDenomValid = isNumberDenom || isQuantityDenom || isUnitDenom;
                            if (isNomValid && isDenomValid) {
                                newExpr = std::move(parsedExpr);
                            }
                        }
                    }
                    else if (const auto number = freecad_cast<NumberExpression*>(parsedExpr.get())) {
                        // NumbersExpressions can accept more than can be parsed with strtod.
                        //   Example: 12.34 and 12,34 are both valid NumberExpressions
                        newExpr = std::move(parsedExpr);
                    }
                }
                catch (...) {
                }
            }
        }

        if (!newExpr && value && *value != '\0') {
            newExpr = std::make_unique<App::StringExpression>(sheet, value);
        }

        // trying to add an empty string will make newExpr = nullptr
    }

    // set expression, or delete the current expression by setting nullptr if empty string was
    // entered
    setExpression(std::move(newExpr));
    signaller.tryInvoke();
}

/**
 * Set alignment of this cell. Alignment is the or'ed value of
 * vertical and horizontal alignment, given by the constants
 * defined in the class.
 *
 */

void Cell::setAlignment(int _alignment)
{
    if (_alignment != alignment) {
        PropertySheet::AtomicPropertyChange signaller(*owner);

        alignment = _alignment;
        setUsed(
            ALIGNMENT_SET,
            alignment != (ALIGNMENT_HIMPLIED | ALIGNMENT_LEFT | ALIGNMENT_VIMPLIED | ALIGNMENT_VCENTER)
        );
        setDirty();
        signaller.tryInvoke();
    }
}

/**
 * Get alignment.
 *
 */

bool Cell::getAlignment(int& _alignment) const
{
    _alignment = alignment;
    return isUsed(ALIGNMENT_SET);
}

/**
 * Set style to the given set \a _style.
 *
 */

void Cell::setStyle(const std::set<std::string>& _style)
{
    if (_style != style) {
        PropertySheet::AtomicPropertyChange signaller(*owner);

        style = _style;
        setUsed(STYLE_SET, !style.empty());
        setDirty();

        signaller.tryInvoke();
    }
}

/**
 * Get the style of the cell.
 *
 */

bool Cell::getStyle(std::set<std::string>& _style) const
{
    _style = style;
    return isUsed(STYLE_SET);
}

/**
 * Set foreground (i.e text) color of the cell to \a color.
 *
 */

void Cell::setForeground(const Base::Color& color)
{
    if (color != foregroundColor) {
        PropertySheet::AtomicPropertyChange signaller(*owner);

        foregroundColor = color;
        setUsed(FOREGROUND_COLOR_SET, foregroundColor != Base::Color(0, 0, 0, 1));
        setDirty();

        signaller.tryInvoke();
    }
}

/**
 * Get foreground color of the cell.
 *
 */

bool Cell::getForeground(Base::Color& color) const
{
    color = foregroundColor;
    return isUsed(FOREGROUND_COLOR_SET);
}

/**
 * Set background color of the cell to \a color.
 *
 */

void Cell::setBackground(const Base::Color& color)
{
    if (color != backgroundColor) {
        PropertySheet::AtomicPropertyChange signaller(*owner);

        backgroundColor = color;
        setUsed(BACKGROUND_COLOR_SET, backgroundColor != Base::Color(1, 1, 1, 0));
        setDirty();

        signaller.tryInvoke();
    }
}

/**
 * Get the background color of the cell into \a color.
 *
 * @returns true if the background color was previously set.
 *
 */

bool Cell::getBackground(Base::Color& color) const
{
    color = backgroundColor;
    return isUsed(BACKGROUND_COLOR_SET);
}

/**
 * Set the display unit for the cell.
 *
 */

void Cell::setDisplayUnit(const std::string& unit)
{
    DisplayUnit newDisplayUnit;
    if (!unit.empty()) {
        std::shared_ptr<App::UnitExpression> e(
            ExpressionParser::parseUnit(owner->sheet(), unit.c_str())
        );

        if (!e) {
            throw Base::UnitsMismatchError("Invalid unit");
        }
        newDisplayUnit = DisplayUnit(unit, e->getUnit(), e->getScaler());
    }

    if (newDisplayUnit != displayUnit) {
        PropertySheet::AtomicPropertyChange signaller(*owner);

        displayUnit = std::move(newDisplayUnit);
        setUsed(DISPLAY_UNIT_SET, !displayUnit.isEmpty());
        setDirty();

        signaller.tryInvoke();
    }
}

/**
 * Get the display unit for the cell into unit.
 *
 * @returns true if the display unit was previously set.
 *
 */

bool Cell::getDisplayUnit(DisplayUnit& unit) const
{
    unit = displayUnit;
    return isUsed(DISPLAY_UNIT_SET);
}

void Cell::setAlias(const std::string& n)
{
    if (alias != n) {
        PropertySheet::AtomicPropertyChange signaller(*owner);

        owner->revAliasProp.erase(alias);

        // Update owner
        if (!n.empty()) {
            owner->aliasProp[address] = n;
            owner->revAliasProp[n] = address;
        }
        else {
            owner->aliasProp.erase(address);
        }

        if (!alias.empty()) {
            // The property may have been added in Sheet::updateAlias
            auto* docObj = static_cast<App::DocumentObject*>(owner->getContainer());
            docObj->removeDynamicProperty(alias.c_str());
        }

        alias = n;

        setUsed(ALIAS_SET, !alias.empty());
        setDirty();

        signaller.tryInvoke();
    }
}

bool Cell::getAlias(std::string& n) const
{
    n = alias;
    return isUsed(ALIAS_SET);
}

/**
 * Set the computed unit for the cell to \a unit.
 *
 */

void Cell::setComputedUnit(const Base::Unit& unit)
{
    PropertySheet::AtomicPropertyChange signaller(*owner);

    computedUnit = unit;
    setUsed(COMPUTED_UNIT_SET, computedUnit != Unit::One);
    setDirty();

    signaller.tryInvoke();
}

/**
 * Get the computed unit into \a unit.
 *
 * @returns true if the computed unit was previously set.
 *
 */

bool Cell::getComputedUnit(Base::Unit& unit) const
{
    unit = computedUnit;
    return isUsed(COMPUTED_UNIT_SET);
}

/**
 * Set the cell's row and column span to \a rows and \a columns. This
 * is done when cells are merged.
 *
 */

void Cell::setSpans(int rows, int columns)
{
    if (rows != rowSpan || columns != colSpan) {
        PropertySheet::AtomicPropertyChange signaller(*owner);

        rowSpan = (rows == -1 ? 1 : rows);
        colSpan = (columns == -1 ? 1 : columns);
        setUsed(SPANS_SET, (rowSpan != 1 || colSpan != 1));
        setDirty();
        signaller.tryInvoke();
    }
}

/**
 * Get the row and column spans for the cell into \a rows and \a columns.
 *
 */

bool Cell::getSpans(int& rows, int& columns) const
{
    rows = rowSpan;
    columns = colSpan;
    return isUsed(SPANS_SET);
}

void Cell::setException(const std::string& e, bool silent)
{
    if (!silent && !e.empty() && owner && owner->sheet()) {
        FC_ERR(owner->sheet()->getFullName() << '.' << address.toString() << ": " << e);
    }
    exceptionStr = e;
    setUsed(EXCEPTION_SET);
}

void Cell::setParseException(const std::string& e)
{
    if (!e.empty() && owner && owner->sheet()) {
        FC_ERR(owner->sheet()->getFullName() << '.' << address.toString() << ": " << e);
    }
    exceptionStr = e;
    setUsed(PARSE_EXCEPTION_SET);
}

void Cell::setResolveException(const std::string& e)
{
    if (!e.empty() && owner && owner->sheet()) {
        FC_LOG(owner->sheet()->getFullName() << '.' << address.toString() << ": " << e);
    }
    exceptionStr = e;
    setUsed(RESOLVE_EXCEPTION_SET);
}

void Cell::clearResolveException()
{
    setUsed(RESOLVE_EXCEPTION_SET, false);
}

void Cell::clearException()
{
    exceptionStr.clear();
    setUsed(EXCEPTION_SET, false);
    setUsed(RESOLVE_EXCEPTION_SET, false);
    setUsed(PARSE_EXCEPTION_SET, false);
}

void Cell::clearDirty()
{
    if (owner) {
        owner->clearDirty(address);
    }
}

void Cell::setDirty()
{
    if (owner) {
        owner->setDirty(address);
    }
}

/**
 * Move the cell to a new position given by \a _row and \a _col.
 *
 */

void Cell::moveAbsolute(CellAddress newAddress)
{
    address = newAddress;
}

/**
 * Restore cell contents from \a reader.
 *
 */

void Cell::restore(Base::XMLReader& reader, bool checkAlias)
{
    const char* style = reader.hasAttribute("style") ? reader.getAttribute<const char*>("style")
                                                     : nullptr;
    const char* alignment = reader.hasAttribute("alignment")
        ? reader.getAttribute<const char*>("alignment")
        : nullptr;
    const char* content = reader.hasAttribute("content")
        ? reader.getAttribute<const char*>("content")
        : "";
    const char* foregroundColor = reader.hasAttribute("foregroundColor")
        ? reader.getAttribute<const char*>("foregroundColor")
        : nullptr;
    const char* backgroundColor = reader.hasAttribute("backgroundColor")
        ? reader.getAttribute<const char*>("backgroundColor")
        : nullptr;
    const char* displayUnit = reader.hasAttribute("displayUnit")
        ? reader.getAttribute<const char*>("displayUnit")
        : nullptr;
    const char* alias = reader.hasAttribute("alias") ? reader.getAttribute<const char*>("alias")
                                                     : nullptr;
    const char* rowSpan = reader.hasAttribute("rowSpan")
        ? reader.getAttribute<const char*>("rowSpan")
        : nullptr;
    const char* colSpan = reader.hasAttribute("colSpan")
        ? reader.getAttribute<const char*>("colSpan")
        : nullptr;

    // Don't trigger multiple updates below; wait until everything is loaded by calling unfreeze()
    // below.
    PropertySheet::AtomicPropertyChange signaller(*owner);

    if (content) {
        setContent(content);
    }
    if (style) {
        using namespace boost;
        std::set<std::string> styleSet;

        escaped_list_separator<char> e('\0', '|', '\0');
        std::string line = std::string(style);
        tokenizer<escaped_list_separator<char>> tok(line, e);

        for (tokenizer<escaped_list_separator<char>>::iterator i = tok.begin(); i != tok.end(); ++i) {
            styleSet.insert(*i);
        }
        setStyle(styleSet);
    }
    if (alignment) {
        int alignmentCode = 0;
        using namespace boost;

        escaped_list_separator<char> e('\0', '|', '\0');
        std::string line = std::string(alignment);
        tokenizer<escaped_list_separator<char>> tok(line, e);

        for (tokenizer<escaped_list_separator<char>>::iterator i = tok.begin(); i != tok.end(); ++i) {
            alignmentCode = decodeAlignment(*i, alignmentCode);
        }

        setAlignment(alignmentCode);
    }
    if (foregroundColor) {
        Base::Color color = decodeColor(foregroundColor, Base::Color(0, 0, 0, 1));

        setForeground(color);
    }
    if (backgroundColor) {
        Base::Color color = decodeColor(backgroundColor, Base::Color(1, 1, 1, 1));

        setBackground(color);
    }
    if (displayUnit) {
        setDisplayUnit(displayUnit);
    }
    if (alias && (!checkAlias || !owner->revAliasProp.count(alias))) {
        setAlias(alias);
    }

    if (rowSpan || colSpan) {
        int rs = rowSpan ? atoi(rowSpan) : 1;
        int cs = colSpan ? atoi(colSpan) : 1;

        setSpans(rs, cs);
    }
}

/**
 * Save cell contents into \a writer.
 *
 */

void Cell::save(Base::Writer& writer) const
{
    save(writer.Stream(), writer.ind(), false);
}

void Cell::save(std::ostream& os, const char* indent, bool noContent) const
{
    if (!isUsed()) {
        return;
    }

    os << indent << "<Cell ";

    if (!noContent) {
        os << "address=\"" << address.toString() << "\" ";

        if (isUsed(EXPRESSION_SET)) {
            std::string content;
            getStringContent(content, true);
            os << "content=\"" << App::Property::encodeAttribute(content) << "\" ";
        }
    }

    if (isUsed(ALIGNMENT_SET)) {
        os << "alignment=\"" << encodeAlignment(alignment) << "\" ";
    }

    if (isUsed(STYLE_SET)) {
        os << "style=\"" << encodeStyle(style) << "\" ";
    }

    if (isUsed(FOREGROUND_COLOR_SET)) {
        os << "foregroundColor=\"" << encodeColor(foregroundColor) << "\" ";
    }

    if (isUsed(BACKGROUND_COLOR_SET)) {
        os << "backgroundColor=\"" << encodeColor(backgroundColor) << "\" ";
    }

    if (isUsed(DISPLAY_UNIT_SET)) {
        os << "displayUnit=\"" << App::Property::encodeAttribute(displayUnit.stringRep) << "\" ";
    }

    if (isUsed(ALIAS_SET)) {
        os << "alias=\"" << App::Property::encodeAttribute(alias) << "\" ";
    }

    if (isUsed(SPANS_SET)) {
        os << "rowSpan=\"" << rowSpan << "\" ";
        os << "colSpan=\"" << colSpan << "\" ";
    }

    os << "/>";
    if (!noContent) {
        os << std::endl;
    }
}

/**
 * Update the \a used member variable with mask (bitwise or'ed).
 *
 */

void Cell::setUsed(int mask, bool state)
{
    if (state) {
        used |= mask;
    }
    else {
        used &= ~mask;
    }
}

/**
 * Determine whether the bits in \a mask are set in the \a used member variable.
 *
 */

bool Cell::isUsed(int mask) const
{
    return (used & mask) == mask;
}

/**
 * Determine if the any of the contents of the cell is set a non-default value.
 *
 */

bool Cell::isUsed() const
{
    return used != 0;
}

void Cell::visit(App::ExpressionVisitor& v)
{
    if (expression) {
        expression->visit(v);
    }
}

/**
 * Decode alignment into its internal value.
 *
 * @param itemStr   Alignment as a string
 * @param alignment Current alignment. This is or'ed with the one in \a itemStr.
 *
 * @returns New alignment.
 *
 */

int Cell::decodeAlignment(const std::string& itemStr, int alignment)
{
    if (itemStr == "himplied") {
        if (!(alignment & ALIGNMENT_HORIZONTAL)) {
            alignment |= ALIGNMENT_LEFT;
        }
        alignment |= Cell::ALIGNMENT_HIMPLIED;
    }
    else if (itemStr == "left") {
        alignment = (alignment & ~Cell::ALIGNMENT_HORIZONTAL) | Cell::ALIGNMENT_LEFT;
    }
    else if (itemStr == "center") {
        alignment = (alignment & ~Cell::ALIGNMENT_HORIZONTAL) | Cell::ALIGNMENT_HCENTER;
    }
    else if (itemStr == "right") {
        alignment = (alignment & ~Cell::ALIGNMENT_HORIZONTAL) | Cell::ALIGNMENT_RIGHT;
    }
    else if (itemStr == "vimplied") {
        if (!(alignment & ALIGNMENT_VERTICAL)) {
            alignment |= ALIGNMENT_VCENTER;
        }
        alignment |= Cell::ALIGNMENT_VIMPLIED;
    }
    else if (itemStr == "top") {
        alignment = (alignment & ~Cell::ALIGNMENT_VERTICAL) | Cell::ALIGNMENT_TOP;
    }
    else if (itemStr == "vcenter") {
        alignment = (alignment & ~Cell::ALIGNMENT_VERTICAL) | Cell::ALIGNMENT_VCENTER;
    }
    else if (itemStr == "bottom") {
        alignment = (alignment & ~Cell::ALIGNMENT_VERTICAL) | Cell::ALIGNMENT_BOTTOM;
    }
    else if (!itemStr.empty()) {
        throw Base::ValueError("Invalid alignment.");
    }

    return alignment;
}

/**
 * Encode internal alignment value as a string.
 *
 * @param alignment Alignment as a binary value.
 *
 * @returns Alignment represented as a string.
 *
 */

std::string Cell::encodeAlignment(int alignment)
{
    std::string s;

    if (alignment & Cell::ALIGNMENT_LEFT) {
        s += "left";
    }
    if (alignment & Cell::ALIGNMENT_HCENTER) {
        s += "center";
    }
    if (alignment & Cell::ALIGNMENT_RIGHT) {
        s += "right";
    }
    if (alignment & Cell::ALIGNMENT_HIMPLIED) {
        s += "|himplied";
    }

    if (alignment & Cell::ALIGNMENT_VERTICAL) {
        s += "|";
    }

    if (alignment & Cell::ALIGNMENT_TOP) {
        s += "top";
    }
    if (alignment & Cell::ALIGNMENT_VCENTER) {
        s += "vcenter";
    }
    if (alignment & Cell::ALIGNMENT_BOTTOM) {
        s += "bottom";
    }
    if (alignment & Cell::ALIGNMENT_VIMPLIED) {
        s += "|vimplied";
    }

    return s;
}

/**
 * Encode \a color as a \#rrggbbaa string.
 *
 * @param color Color to encode.
 *
 * @returns String with encoded color.
 *
 */

std::string Cell::encodeColor(const Base::Color& color)
{
    std::stringstream tmp;

    tmp << "#" << std::hex << std::setw(2) << std::setfill('0') << int(color.r * 255.0) << std::hex
        << std::setw(2) << std::setfill('0') << int(color.g * 255.0) << std::hex << std::setw(2)
        << std::setfill('0') << int(color.b * 255.0) << std::hex << std::setw(2)
        << std::setfill('0') << int(color.a * 255.0);

    return tmp.str();
}

/**
 * Encode set of styles as a string.
 *
 * @param style Set of string describing the style.
 *
 * @returns Set encoded as a string.
 *
 */

std::string Cell::encodeStyle(const std::set<std::string>& style)
{
    std::string s;
    std::set<std::string>::const_iterator j = style.begin();
    std::set<std::string>::const_iterator j_end = style.end();

    while (j != j_end) {
        s += *j;
        ++j;
        if (j != j_end) {
            s += "|";
        }
    }

    return s;
}

/**
 * Decode a string of the format \#rrggbb or \#rrggbbaa into a Color.
 *
 * @param color        The color to decode.
 * @param defaultColor A default color in case the decoding fails.
 *
 * @returns Decoded color.
 *
 */

Base::Color Cell::decodeColor(const std::string& color, const Base::Color& defaultColor)
{
    if (color.size() == 7 || color.size() == 9) {
        Base::Color c;

        if (color[0] != '#') {
            return defaultColor;
        }
        unsigned int value = strtoul(color.c_str() + 1, nullptr, 16);

        if (color.size() == 7) {
            value = (value << 8) | 0xff;
        }

        c.setPackedValue(value);
        return c;
    }
    else {
        return defaultColor;
    }
}

// roughly based on Spreadsheet/Gui/SheetModel.cpp
std::string Cell::getFormattedQuantity()
{
    QString qFormatted;
    App::CellAddress thisCell = getAddress();
    Property* prop = owner->sheet()->getPropertyByName(thisCell.toString().c_str());

    if (prop->isDerivedFrom<App::PropertyString>()) {
        const App::PropertyString* stringProp = static_cast<const App::PropertyString*>(prop);
        qFormatted = QString::fromUtf8(stringProp->getValue());
    }
    else if (prop->isDerivedFrom<App::PropertyQuantity>()) {
        double rawVal = static_cast<App::PropertyQuantity*>(prop)->getValue();
        const App::PropertyQuantity* floatProp = static_cast<const App::PropertyQuantity*>(prop);
        DisplayUnit du;
        bool hasDisplayUnit = getDisplayUnit(du);
        double duScale = du.scaler;
        const Base::Unit& computedUnit = floatProp->getUnit();
        qFormatted = QLocale().toString(rawVal, 'f', Base::UnitsApi::getDecimals());
        if (hasDisplayUnit) {
            if (computedUnit == Unit::One || computedUnit == du.unit) {
                QString number
                    = QLocale().toString(rawVal / duScale, 'f', Base::UnitsApi::getDecimals());
                qFormatted = number + QString::fromStdString(" " + displayUnit.stringRep);
            }
        }
    }
    else if (prop->isDerivedFrom<App::PropertyFloat>()) {
        double rawVal = static_cast<const App::PropertyFloat*>(prop)->getValue();
        DisplayUnit du;
        bool hasDisplayUnit = getDisplayUnit(du);
        double duScale = du.scaler;
        qFormatted = QLocale().toString(rawVal, 'f', Base::UnitsApi::getDecimals());
        if (hasDisplayUnit) {
            QString number = QLocale().toString(rawVal / duScale, 'f', Base::UnitsApi::getDecimals());
            qFormatted = number + QString::fromStdString(" " + displayUnit.stringRep);
        }
    }
    else if (prop->isDerivedFrom<App::PropertyInteger>()) {
        double rawVal = static_cast<const App::PropertyInteger*>(prop)->getValue();
        DisplayUnit du;
        bool hasDisplayUnit = getDisplayUnit(du);
        double duScale = du.scaler;
        int iRawVal = std::round(rawVal);
        qFormatted = QLocale().toString(iRawVal);
        if (hasDisplayUnit) {
            QString number = QLocale().toString(rawVal / duScale, 'f', Base::UnitsApi::getDecimals());
            qFormatted = number + QString::fromStdString(" " + displayUnit.stringRep);
        }
    }
    return qFormatted.toStdString();
}