consistencychecker.cpp

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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)
 **********************************************************************/

#include "consistencychecker.h"
#include <memory>
#include <QCoreApplication>
#include <QFile>
#include <QMessageBox>
#include <QSqlDatabase>
#include <QtConcurrentRun>
#include <util/gui/util.h>
#include <util/sll/qtutil.h>
#include <util/sll/visitor.h>
#include <util/sys/paths.h>
#include <util/threads/coro.h>
#include <util/util.h>
#include "dumper.h"
#include "util.h"

namespace LC::Util::ConsistencyChecker
{
    namespace
    {
        struct Tr
        {
            Q_DECLARE_TR_FUNCTIONS (LC::Util::ConsistencyChecker)
        };

        CheckResult_t CheckSync (const QString& dbPath)
        {
            qDebug () << "checking" << dbPath;
            const auto& connName = GenConnectionName ("ConsistencyChecker_" + dbPath);

            auto db = QSqlDatabase::addDatabase ("QSQLITE"_qs, connName);
            const auto remGuard = MakeScopeGuard ([connName] { QSqlDatabase::removeDatabase (connName); });

            db.setDatabaseName (dbPath);
            if (!db.open ())
            {
                qWarning () << "cannot open the DB, but that's not the kind of errors we're solving.";
                return Succeeded {};
            }

            QSqlQuery pragma { db };
            static const auto checkQuery = qgetenv ("LC_THOROUGH_SQLITE_CHECK") == "1" ?
                    "PRAGMA integrity_check;"_qs :
                    "PRAGMA quick_check;"_qs;
            const auto isGood = pragma.exec (checkQuery) &&
                    pragma.next () &&
                    pragma.value (0) == "ok";
            qDebug () << "done checking" << dbPath << "; db is good?" << isGood;
            if (isGood)
                return Succeeded {};

            return Left { Failed {} };
        }

        Either<RecoverFailed, Void> CheckRecoverSpace (const QString& dbPath)
        {
            const QFileInfo fi { dbPath };
            const auto filesize = fi.size ();

            const auto available = static_cast<qint64> (GetSpaceInfo (dbPath).Available_);

            qDebug () << "db size:" << filesize
                    << "free space:" << available;
            if (available >= filesize)
                return Void {};

            return Left { RecoverNoSpace { .Available_ = available, .Expected_ = filesize } };
        }
    }

    Task<CheckResult_t> Check (QString dbPath)
    {
        co_return co_await QtConcurrent::run (CheckSync, dbPath);
    }

    Task<RecoverResult_t> Recover (QString dbPath)
    {
        co_await CheckRecoverSpace (dbPath);
        const auto& newPath = dbPath + ".new";
        if (QFile::exists (newPath))
            co_return Left { RecoverTargetExists { newPath } };

        const auto dumpProcResult = co_await DumpSqlite (dbPath, newPath);
        [[maybe_unused]] const auto dumpProcSuccess = co_await WithHandler (dumpProcResult,
                [] (const QString& msg) { return RecoverOtherFailure { msg }; });

        const auto oldSize = QFileInfo { dbPath }.size ();
        const auto newSize = QFileInfo { newPath }.size ();

        const auto& backupPath = dbPath + ".bak";
        if (!QFile::rename (dbPath, backupPath))
            co_return Left { RecoverTargetExists { backupPath } };

        // extremely unlikely if the previous rename succeeded
        while (!QFile::rename (newPath, dbPath))
        {
            qCritical () << "unable to rename" << newPath << "→" << dbPath;
            const auto& msg = Tr::tr ("Unable to rename %1 to %2. Please check %2 does not exist, and hit OK.")
                    .arg (newPath, dbPath);
            QMessageBox::critical (nullptr, "LeechCraft"_qs, msg);
        }

        co_return RecoverFinished { .OldFileSize_ = oldSize, .NewFileSize_ = newSize };
    }

    namespace
    {
        QString GetRecoverFailureMessage (const RecoverFailed& failure)
        {
            return Visit (failure,
                    [&] (RecoverNoSpace space)
                    {
                        return Tr::tr ("Not enough space available: "
                                    "%1 free while the restored file is expected to be around %2. "
                                    "Please either free some disk space on this partition "
                                    "and retry or cancel the restore process.")
                                .arg (MakePrettySize (space.Available_), MakePrettySize (space.Expected_));
                    },
                    [&] (const RecoverTargetExists& exists)
                    {
                        return Tr::tr ("Target file %1 already exists, please remove it manually and retry.")
                                .arg (FormatName (exists.Target_));
                    },
                    [&] (const RecoverOtherFailure& other)
                    {
                        return other.Message_;
                    });
        }
    }

    Task<RecoverResult_t> RecoverWithUserInteraction (QString dbPath, QString diaTitle)
    {
        while (true)
        {
            const auto result = co_await Recover (dbPath);
            if (result.IsRight ())
                co_return result;

            const auto& question = Tr::tr ("Unable to dump corrupted SQLite database %1.").arg (FormatName (dbPath)) +
                    "<br/><br/>"_qs +
                    GetRecoverFailureMessage (result.GetLeft ());
            if (QMessageBox::question (nullptr, diaTitle, question, QMessageBox::Retry | QMessageBox::Cancel) == QMessageBox::Cancel)
                co_return result;
        }
    }
}