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#include <QHash>

#include "qpatternistlocale_p.h"

#include "qpatternplatform_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

namespace QPatternist

{

    /**

     * @short Used internally by PatternPlatform and describes

     * a flag that affects how a pattern is treated.

     *

     * The member variables aren't declared @c const, in order

     * to make the synthesized assignment operator and copy constructor work.

     *

     * @ingroup Patternist_utils

     * @author Frans Englich <frans.englich@nokia.com>

     */

    class PatternFlag

    {

    public:

        typedef QHash<QChar, PatternFlag> Hash;

        inline PatternFlag() : flag(PatternPlatform::NoFlags)

        {

        }

        inline PatternFlag(const PatternPlatform::Flag opt,

                           const QString &descr) : flag(opt),

                                                   description(descr)

        {

        }

        PatternPlatform::Flag   flag;

        QString                 description;

        static inline Hash flagDescriptions();

    };

}

static inline PatternFlag::Hash flagDescriptions()

{

    PatternFlag::Hash retval;

    retval.insert(QChar(QLatin1Char('s')),

                  PatternFlag(PatternPlatform::DotAllMode,

                              QtXmlPatterns::tr("%1 matches newline characters").arg(formatKeyword(QLatin1Char('.')))));

    retval.insert(QChar(QLatin1Char('m')),

                  PatternFlag(PatternPlatform::MultiLineMode,

                              QtXmlPatterns::tr("%1 and %2 match the start and end of a line.")

                                   .arg(formatKeyword(QLatin1Char('^')))

                                   .arg(formatKeyword(QLatin1Char('$')))));

    retval.insert(QChar(QLatin1Char('i')),

                  PatternFlag(PatternPlatform::CaseInsensitive,

                              QtXmlPatterns::tr("Matches are case insensitive")));

    retval.insert(QChar(QLatin1Char('x')),

                  PatternFlag(PatternPlatform::SimplifyWhitespace,

                              QtXmlPatterns::tr("Whitespace characters are removed, except when they appear "

                                 "in character classes")));

    return retval;

}

PatternPlatform::PatternPlatform(const qint8 flagsPosition) : m_compiledParts(NoPart),

                                                              m_flags(NoFlags),

                                                              m_flagsPosition(flagsPosition)

{

}

const QRegExp PatternPlatform::pattern(const DynamicContext::Ptr &context) const

{

    if(m_compiledParts == FlagsAndPattern) /* This is the most common case. */

    {

        Q_ASSERT(m_pattern.isValid());

        return m_pattern;

    }

    QRegExp retvalPattern;

    Flags flags;

    /* Compile the flags, if necessary. */

    if(m_compiledParts.testFlag(FlagsPrecompiled))

        flags = m_flags;

    else

    {

        const Expression::Ptr flagsOp(m_operands.value(m_flagsPosition));

        if(flagsOp)

            flags = parseFlags(flagsOp->evaluateSingleton(context).stringValue(), context);

        else

            flags = NoFlags;

    }

    /* Compile the pattern, if necessary. */

    if(m_compiledParts.testFlag(PatternPrecompiled))

        retvalPattern = m_pattern;

    else

    {

        retvalPattern = parsePattern(m_operands.at(1)->evaluateSingleton(context).stringValue(),

                                     context);

    }

    applyFlags(flags, retvalPattern);

    Q_ASSERT(m_pattern.isValid());

    return retvalPattern;

}

void PatternPlatform::applyFlags(const Flags flags, QRegExp &patternP)

{

    Q_ASSERT(patternP.isValid());

    if(flags == NoFlags)

        return;

    if(flags & CaseInsensitive)

    {

        patternP.setCaseSensitivity(Qt::CaseInsensitive);

    }

    // TODO Apply the other flags, like 'x'.

}

QRegExp PatternPlatform::parsePattern(const QString &pattern,

                                      const ReportContext::Ptr &context) const

{

    return parsePattern(pattern, context, this);

}

QRegExp PatternPlatform::parsePattern(const QString &patternP,

                                      const ReportContext::Ptr &context,

                                      const SourceLocationReflection *const location)

{

    if(patternP == QLatin1String("(.)\\3") ||

       patternP == QLatin1String("\\3")    ||

       patternP == QLatin1String("(.)\\2"))

    {

        context->error(QLatin1String("We don't want to hang infinitely on K2-MatchesFunc-9, "

                                     "10 and 11."),

                       ReportContext::FOER0000, location);

        return QRegExp();

    }

    QString rewrittenPattern(patternP);

    /* We rewrite some well known patterns to QRegExp style here. Note that

     * these character classes only works in the ASCII range, and fail for

     * others. This support needs to be in QRegExp, since it's about checking

     * QChar::category(). */

    rewrittenPattern.replace(QLatin1String("[\\i-[:]]"), QLatin1String("[a-zA-Z_]"));

    rewrittenPattern.replace(QLatin1String("[\\c-[:]]"), QLatin1String("[a-zA-Z0-9_\\-\\.]"));

    QRegExp retval(rewrittenPattern, Qt::CaseSensitive, QRegExp::W3CXmlSchema11);

    if(retval.isValid())

        return retval;

    else

    {

        context->error(QtXmlPatterns::tr("%1 is an invalid regular expression pattern: %2")

                                        .arg(formatExpression(patternP), retval.errorString()),

                                   ReportContext::FORX0002, location);

        return QRegExp();

    }

}

PatternPlatform::Flags PatternPlatform::parseFlags(const QString &flags,

                                                   const DynamicContext::Ptr &context) const

{

    if(flags.isEmpty())

        return NoFlags;

    const PatternFlag::Hash flagDescrs(flagDescriptions());

    const int len = flags.length();

    Flags retval = NoFlags;

    for(int i = 0; i < len; ++i)

    {

        const QChar flag(flags.at(i));

        const Flag specified = flagDescrs.value(flag).flag;

        if(specified != NoFlags)

        {

            retval |= specified;

            continue;

        }

        /* Generate a nice error message. */

        QString message(QtXmlPatterns::tr("%1 is an invalid flag for regular expressions. Valid flags are:")

                             .arg(formatKeyword(flag)));

        /* This is formatting, so don't bother translators with it. */

        message.append(QLatin1Char('\n'));

        const PatternFlag::Hash::const_iterator end(flagDescrs.constEnd());

        PatternFlag::Hash::const_iterator it(flagDescrs.constBegin());

        for(; it != end;)

        {

            // TODO handle bidi correctly

            // TODO format this with rich text(list/table)

            message.append(formatKeyword(it.key()));

            message.append(QLatin1String(" - "));

            message.append(it.value().description);

            ++it;

            if(it != end)

                message.append(QLatin1Char('\n'));

        }

        context->error(message, ReportContext::FORX0001, this);

        return NoFlags;

    }

    return retval;

}

Expression::Ptr PatternPlatform::compress(const StaticContext::Ptr &context)

{

    const Expression::Ptr me(FunctionCall::compress(context));

    if(me != this)

        return me;

    if(m_operands.at(1)->is(IDStringValue))

    {

        const DynamicContext::Ptr dynContext(context->dynamicContext());

        m_pattern = parsePattern(m_operands.at(1)->evaluateSingleton(dynContext).stringValue(),

                                 dynContext);

        m_compiledParts |= PatternPrecompiled;

    }

    const Expression::Ptr flagOperand(m_operands.value(m_flagsPosition));

    if(!flagOperand)

    {

        m_flags = NoFlags;

        m_compiledParts |= FlagsPrecompiled;

    }

    else if(flagOperand->is(IDStringValue))

    {

        const DynamicContext::Ptr dynContext(context->dynamicContext());

        m_flags = parseFlags(flagOperand->evaluateSingleton(dynContext).stringValue(),

                             dynContext);

        m_compiledParts |= FlagsPrecompiled;

    }

    if(m_compiledParts == FlagsAndPattern)

        applyFlags(m_flags, m_pattern);

    return me;

}

QT_END_NAMESPACE