path: root/src/xmlpatterns/expr/qarithmeticexpression.cpp

/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qboolean_p.h"
#include "qbuiltintypes_p.h"
#include "qcommonsequencetypes_p.h"
#include "qemptysequence_p.h"
#include "qgenericsequencetype_p.h"
#include "qliteral_p.h"
#include "qpatternistlocale_p.h"
#include "qschemanumeric_p.h"
#include "quntypedatomicconverter_p.h"

#include "qarithmeticexpression_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

ArithmeticExpression::ArithmeticExpression(const Expression::Ptr &op1,
                                           const AtomicMathematician::Operator op,
                                           const Expression::Ptr &op2) : PairContainer(op1, op2)
                                                                       , m_op(op)
                                                                       , m_isCompat(false)
{
}

Item ArithmeticExpression::evaluateSingleton(const DynamicContext::Ptr &context) const
{
    const Item op1(m_operand1->evaluateSingleton(context));
    if(!op1)
        return Item();

    const Item op2(m_operand2->evaluateSingleton(context));
    if(!op2)
        return Item();

    return flexiblyCalculate(op1, m_op, op2, m_mather, context, this,
                             ReportContext::XPTY0004, m_isCompat);
}

/**
 * Since ArithmeticExpression::flexiblyCalculate() creates Expression instances
 * at runtime, we have the problem of having SourceLocationReflections for them
 * in the case that we run into a runtime error, since the locations are always
 * located at compile time.
 *
 * This class simply delegates the reflection over to an existing expression.
 *
 * I only managed to trigger this with "current() + 1", where current()
 * evaluates to an invalid representation for @c xs:double.
 *
 * @since 4.5
 * @author Frans Englich <frans.englich@nokia.com>
 */
class DelegatingReflectionExpression : public Literal
{
public:
    DelegatingReflectionExpression(const Item &item,
                                   const SourceLocationReflection *const reflection) : Literal(item)
                                                                                     , m_reflection(reflection)
    {
    }

    const SourceLocationReflection *actualReflection() const override
    {
        return m_reflection;
    }

private:
    const SourceLocationReflection *const m_reflection;
};

Item ArithmeticExpression::flexiblyCalculate(const Item &op1,
                                             const AtomicMathematician::Operator op,
                                             const Item &op2,
                                             const AtomicMathematician::Ptr &mather,
                                             const DynamicContext::Ptr &context,
                                             const SourceLocationReflection *const reflection,
                                             const ReportContext::ErrorCode code,
                                             const bool isCompat)
{
    if(mather)
        return mather->calculate(op1, op, op2, context);

    /* This is a very heavy code path. */
    Expression::Ptr a1(new DelegatingReflectionExpression(op1, reflection));
    Expression::Ptr a2(new DelegatingReflectionExpression(op2, reflection));

    const AtomicMathematician::Ptr ingela(fetchMathematician(a1, a2, op, true, context, reflection, code, isCompat));

    return ingela->calculate(a1->evaluateSingleton(context),
                             op,
                             a2->evaluateSingleton(context),
                             context);
}

Expression::Ptr ArithmeticExpression::typeCheck(const StaticContext::Ptr &context,
                                                const SequenceType::Ptr &reqType)
{
    m_isCompat = context->compatModeEnabled();

    const Expression::Ptr me(PairContainer::typeCheck(context, reqType));
    const ItemType::Ptr t1(m_operand1->staticType()->itemType());
    const ItemType::Ptr t2(m_operand2->staticType()->itemType());

    if(*CommonSequenceTypes::Empty == *t1 ||
       *CommonSequenceTypes::Empty == *t2)
    {
        return EmptySequence::create(this, context);
    }

    if(*BuiltinTypes::xsAnyAtomicType == *t1    ||
       *BuiltinTypes::xsAnyAtomicType == *t2    ||
       *BuiltinTypes::numeric == *t1            ||
       *BuiltinTypes::numeric == *t2)
    {
        /* The static type of (at least) one of the operands could not
         * be narrowed further than xs:anyAtomicType, so we do the operator
         * lookup at runtime. */
        return me;
    }

    m_mather = fetchMathematician(m_operand1, m_operand2, m_op, true, context, this,
                                  ReportContext::XPTY0004, m_isCompat);

    return me;
}

AtomicMathematician::Ptr
ArithmeticExpression::fetchMathematician(Expression::Ptr &op1,
                                         Expression::Ptr &op2,
                                         const AtomicMathematician::Operator op,
                                         const bool issueError,
                                         const ReportContext::Ptr &context,
                                         const SourceLocationReflection *const reflection,
                                         const ReportContext::ErrorCode code,
                                         const bool isCompat)
{
    ItemType::Ptr t1(op1->staticType()->itemType());
    ItemType::Ptr t2(op2->staticType()->itemType());

    if(BuiltinTypes::xsUntypedAtomic->xdtTypeMatches(t1)
       || (isCompat && (BuiltinTypes::xsString->xdtTypeMatches(t1)
                        || BuiltinTypes::xsDecimal->xdtTypeMatches(t1))))
    {
        op1 = Expression::Ptr(new UntypedAtomicConverter(op1, BuiltinTypes::xsDouble));
        /* The types might have changed, reload. */
        t1 = op1->staticType()->itemType();
    }

    if(BuiltinTypes::xsUntypedAtomic->xdtTypeMatches(t2)
       || (isCompat && (BuiltinTypes::xsString->xdtTypeMatches(t1)
                        || BuiltinTypes::xsDecimal->xdtTypeMatches(t1))))
    {
        op2 = Expression::Ptr(new UntypedAtomicConverter(op2, BuiltinTypes::xsDouble));
        /* The types might have changed, reload. */
        t2 = op2->staticType()->itemType();
    }

    const AtomicMathematicianLocator::Ptr locator
        (static_cast<const AtomicType *>(t1.data())->mathematicianLocator());

    if(!locator)
    {
        if(!issueError)
            return AtomicMathematician::Ptr();

        context->error(QtXmlPatterns::tr(
                       "Operator %1 cannot be used on type %2.")
                       .arg(formatKeyword(AtomicMathematician::displayName(op)))
                       .arg(formatType(context->namePool(), t1)),
                       code, reflection);
        return AtomicMathematician::Ptr();
    }

    const AtomicMathematician::Ptr comp
        (static_cast<const AtomicType *>(t2.data())->accept(locator, op, reflection));

    if(comp)
        return comp;

    if(!issueError)
        return AtomicMathematician::Ptr();

    context->error(QtXmlPatterns::tr("Operator %1 cannot be used on "
                                     "atomic values of type %2 and %3.")
                   .arg(formatKeyword(AtomicMathematician::displayName(op)))
                   .arg(formatType(context->namePool(), t1))
                   .arg(formatType(context->namePool(), t2)),
                   code, reflection);
    return AtomicMathematician::Ptr();
}

SequenceType::Ptr ArithmeticExpression::staticType() const
{
    Cardinality card;

    /* These variables are important because they ensure staticType() only
     * gets called once from this function. Before, this lead to strange
     * semi-infinite recursion involving many arithmetic expressions. */
    const SequenceType::Ptr st1(m_operand1->staticType());
    const SequenceType::Ptr st2(m_operand2->staticType());

    if(st1->cardinality().allowsEmpty() ||
       st2->cardinality().allowsEmpty())
    {
        card = Cardinality::zeroOrOne();
    }
    else
        card = Cardinality::exactlyOne();

    if(m_op == AtomicMathematician::IDiv)
        return makeGenericSequenceType(BuiltinTypes::xsInteger, card);

    const ItemType::Ptr t1(st1->itemType());
    const ItemType::Ptr t2(st2->itemType());
    ItemType::Ptr returnType;

    /* Please, make this beautiful? */
    if(BuiltinTypes::xsTime->xdtTypeMatches(t1) ||
       BuiltinTypes::xsDate->xdtTypeMatches(t1) ||
       BuiltinTypes::xsDateTime->xdtTypeMatches(t1))
    {
        if(BuiltinTypes::xsDuration->xdtTypeMatches(t2))
            returnType = t1;
        else
            returnType = BuiltinTypes::xsDayTimeDuration;
    }
    else if(BuiltinTypes::xsYearMonthDuration->xdtTypeMatches(t1))
    {
        if(m_op == AtomicMathematician::Div &&
           BuiltinTypes::xsYearMonthDuration->xdtTypeMatches(t2))
        {
            returnType = BuiltinTypes::xsDecimal;
        }
        else if(BuiltinTypes::numeric->xdtTypeMatches(t2))
            returnType = BuiltinTypes::xsYearMonthDuration;
        else
            returnType = t2;
    }
    else if(BuiltinTypes::xsYearMonthDuration->xdtTypeMatches(t2))
    {
        returnType = BuiltinTypes::xsYearMonthDuration;
    }
    else if(BuiltinTypes::xsDayTimeDuration->xdtTypeMatches(t1))
    {
        if(m_op == AtomicMathematician::Div &&
           BuiltinTypes::xsDayTimeDuration->xdtTypeMatches(t2))
        {
            returnType = BuiltinTypes::xsDecimal;
        }
        else if(BuiltinTypes::numeric->xdtTypeMatches(t2))
            returnType = BuiltinTypes::xsDayTimeDuration;
        else
            returnType = t2;
    }
    else if(BuiltinTypes::xsDayTimeDuration->xdtTypeMatches(t2))
    {
        returnType = BuiltinTypes::xsDayTimeDuration;
    }
    else if(BuiltinTypes::xsDouble->xdtTypeMatches(t1) ||
            BuiltinTypes::xsDouble->xdtTypeMatches(t2))
    {
        returnType = BuiltinTypes::xsDouble;
    }
    else if(BuiltinTypes::xsFloat->xdtTypeMatches(t1) ||
            BuiltinTypes::xsFloat->xdtTypeMatches(t2))
    {
        if(m_isCompat)
            returnType = BuiltinTypes::xsFloat;
        else
            returnType = BuiltinTypes::xsDouble;
    }
    else if(BuiltinTypes::xsInteger->xdtTypeMatches(t1) &&
            BuiltinTypes::xsInteger->xdtTypeMatches(t2))
    {
        if(m_isCompat)
            returnType = BuiltinTypes::xsDouble;
        else
        {
            /* "A div B  numeric  numeric  op:numeric-divide(A, B)
             * numeric; but xs:decimal if both operands are xs:integer" */
            if(m_op == AtomicMathematician::Div)
                returnType = BuiltinTypes::xsDecimal;
            else
                returnType = BuiltinTypes::xsInteger;
        }
    }
    else if(m_isCompat && (BuiltinTypes::xsInteger->xdtTypeMatches(t1) &&
                           BuiltinTypes::xsInteger->xdtTypeMatches(t2)))
    {
        returnType = BuiltinTypes::xsDouble;
    }
    else
    {
        /* If typeCheck() has been called, our operands conform to expectedOperandTypes(), and
         * the types are hence either xs:decimals, or xs:anyAtomicType(meaning the static type could
         * not be inferred), or empty-sequence(). So we use the union of the two types. The combinations
         * could also be wrong.*/
        returnType = t1 | t2;

        /* However, if we're called before typeCheck(), we could potentially have nodes, so we need to make
         * sure that the type is at least atomic. */
        if(!BuiltinTypes::xsAnyAtomicType->xdtTypeMatches(returnType))
            returnType = BuiltinTypes::xsAnyAtomicType;
    }

    return makeGenericSequenceType(returnType, card);
}

SequenceType::List ArithmeticExpression::expectedOperandTypes() const
{
    SequenceType::List result;
    result.append(CommonSequenceTypes::ZeroOrOneAtomicType);
    result.append(CommonSequenceTypes::ZeroOrOneAtomicType);
    return result;
}

ExpressionVisitorResult::Ptr ArithmeticExpression::accept(const ExpressionVisitor::Ptr &visitor) const
{
    return visitor->visit(this);
}

QT_END_NAMESPACE