regexp.h

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/**********************************************************************
 * LeechCraft - modular cross-platform feature rich internet client.
 * Copyright (C) 2006-2014  Georg Rudoy
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE or copy at https://www.boost.org/LICENSE_1_0.txt)
 **********************************************************************/

#pragma once

#include "sllconfig.h"
#include <memory>
#include <QString>
#include <QMetaType>
#include <QRegularExpression>
#include "visitor.h"

namespace LC::Util
{
    // TODO mark this deprecated once Qt6 port is complete
    class UTIL_SLL_API RegExp
    {
        QRegularExpression Rx_;
    public:
        static bool IsFast ();

        RegExp () = default;
        RegExp (const QString&, Qt::CaseSensitivity);

        bool Matches (const QString&) const;
        bool Matches (const QByteArray&) const;

        QString GetPattern () const;
        Qt::CaseSensitivity GetCaseSensitivity () const;
    };

    struct StopReplace {};

    struct ReplaceAdvance
    {
        qsizetype Shift_;

        explicit ReplaceAdvance (qsizetype shift)
        : Shift_ { std::max<qsizetype> (shift, 1) }
        {
        }
    };

    using ReplacerResult = std::variant<StopReplace, ReplaceAdvance>;

    template<typename R>
    void ReplaceByRegexp (QString& body,
            const QRegularExpression& rx,
            R&& replacer)
        requires requires { { replacer (body, QRegularExpressionMatch {}) } -> std::convertible_to<ReplacerResult>; }
    {
        int pos = 0;
        bool keepGoing = true;
        while (keepGoing)
        {
            const auto& match = rx.match (body, pos);
            if (!match.hasMatch ())
                return;

            Util::Visit (ReplacerResult { replacer (body, match) },
                    [&] (StopReplace) { keepGoing = false; },
                    [&] (ReplaceAdvance adv) { pos = match.capturedStart (0) + adv.Shift_; });
        }
    }
}

UTIL_SLL_API QDataStream& operator<< (QDataStream&, const LC::Util::RegExp&);
UTIL_SLL_API QDataStream& operator>> (QDataStream&, LC::Util::RegExp&);

Q_DECLARE_METATYPE (LC::Util::RegExp)