// -*- c++ -*-
/*  This file is part of the KDE libraries
    Copyright (C) 2000 David Faure <faure@kde.org>
                  2000 Carsten Pfeiffer <pfeiffer@kde.org>
                  2001 Malte Starostik <malte.starostik@t-online.de>

    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., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
*/

#include "previewjob.h"

#if defined(Q_OS_UNIX) && !defined(Q_OS_ANDROID)
#define WITH_SHM 1
#else
#define WITH_SHM 0
#endif

#if WITH_SHM
#include <sys/ipc.h>
#include <sys/shm.h>
#endif

#include <limits>

#include <QDir>
#include <QFile>
#include <QImage>
#include <QPixmap>
#include <QTimer>
#include <QRegExp>
#include <qtemporaryfile.h>
#include <qsavefile.h>

#include <QCryptographicHash>

#include <kfileitem.h>
#include <kservicetypetrader.h>
#include <kservice.h>
#include <ksharedconfig.h>
#include <QLinkedList>
#include <kconfiggroup.h>
#include <kprotocolinfo.h>
#include <qmimedatabase.h>
#include <qstandardpaths.h>
#include <KMountPoint>

#include <algorithm>

#include "job_p.h"

namespace KIO
{
struct PreviewItem;
}
using namespace KIO;

struct KIO::PreviewItem {
    KFileItem item;
    KService::Ptr plugin;
};

class KIO::PreviewJobPrivate: public KIO::JobPrivate
{
public:
    PreviewJobPrivate(const KFileItemList &items, const QSize &size)
        : initialItems(items),
          width(size.width()),
          height(size.height()),
          cacheWidth(width),
          cacheHeight(height),
          bScale(true),
          bSave(true),
          ignoreMaximumSize(false),
          sequenceIndex(0),
          succeeded(false),
          maximumLocalSize(0),
          maximumRemoteSize(0),
          iconSize(0),
          iconAlpha(70),
          shmid(-1),
          shmaddr(nullptr)
    {
        // http://specifications.freedesktop.org/thumbnail-spec/thumbnail-spec-latest.html#DIRECTORY
        thumbRoot = QStandardPaths::writableLocation(QStandardPaths::GenericCacheLocation) + QLatin1String("/thumbnails/");
    }

    enum { STATE_STATORIG, // if the thumbnail exists
           STATE_GETORIG, // if we create it
           STATE_CREATETHUMB // thumbnail:/ slave
         } state;

    KFileItemList initialItems;
    QStringList enabledPlugins;
    // Some plugins support remote URLs, <protocol, mimetypes>
    QHash<QString, QStringList> m_remoteProtocolPlugins;
    // Our todo list :)
    // We remove the first item at every step, so use QLinkedList
    QLinkedList<PreviewItem> items;
    // The current item
    PreviewItem currentItem;
    // The modification time of that URL
    QDateTime tOrig;
    // Path to thumbnail cache for the current size
    QString thumbPath;
    // Original URL of current item in RFC2396 format
    // (file:///path/to/a%20file instead of file:/path/to/a file)
    QByteArray origName;
    // Thumbnail file name for current item
    QString thumbName;
    // Size of thumbnail
    int width;
    int height;
    // Unscaled size of thumbnail (128 or 256 if cache is enabled)
    int cacheWidth;
    int cacheHeight;
    // Whether the thumbnail should be scaled
    bool bScale;
    // Whether we should save the thumbnail
    bool bSave;
    bool ignoreMaximumSize;
    int sequenceIndex;
    bool succeeded;
    // If the file to create a thumb for was a temp file, this is its name
    QString tempName;
    KIO::filesize_t maximumLocalSize;
    KIO::filesize_t maximumRemoteSize;
    // the size for the icon overlay
    int iconSize;
    // the transparency of the blended mimetype icon
    int iconAlpha;
    // Shared memory segment Id. The segment is allocated to a size
    // of extent x extent x 4 (32 bit image) on first need.
    int shmid;
    // And the data area
    uchar *shmaddr;
    // Root of thumbnail cache
    QString thumbRoot;

    void getOrCreateThumbnail();
    bool statResultThumbnail();
    void createThumbnail(const QString &);
    void cleanupTempFile();
    void determineNextFile();
    void emitPreview(const QImage &thumb);

    void startPreview();
    void slotThumbData(KIO::Job *, const QByteArray &);

    Q_DECLARE_PUBLIC(PreviewJob)
};

#ifndef KIOWIDGETS_NO_DEPRECATED
PreviewJob::PreviewJob(const KFileItemList &items, int width, int height,
                       int iconSize, int iconAlpha, bool scale, bool save,
                       const QStringList *enabledPlugins)
    : KIO::Job(*new PreviewJobPrivate(items, QSize(width, height ? height : width)))
{
    Q_D(PreviewJob);
    d->enabledPlugins = enabledPlugins ? *enabledPlugins : availablePlugins();
    d->iconSize = iconSize;
    d->iconAlpha = iconAlpha;
    d->bScale = scale;
    d->bSave = save && scale;

    // Return to event loop first, determineNextFile() might delete this;
    QTimer::singleShot(0, this, SLOT(startPreview()));
}
#endif

PreviewJob::PreviewJob(const KFileItemList &items,
                       const QSize &size,
                       const QStringList *enabledPlugins) :
    KIO::Job(*new PreviewJobPrivate(items, size))
{
    Q_D(PreviewJob);

    if (enabledPlugins) {
        d->enabledPlugins = *enabledPlugins;
    } else {
        const KConfigGroup globalConfig(KSharedConfig::openConfig(), "PreviewSettings");
        d->enabledPlugins = globalConfig.readEntry("Plugins", QStringList {
                                                                  QStringLiteral("directorythumbnail"),
                                                                  QStringLiteral("imagethumbnail"),
                                                                  QStringLiteral("jpegthumbnail")});
    }

    // Return to event loop first, determineNextFile() might delete this;
    QTimer::singleShot(0, this, SLOT(startPreview()));
}

PreviewJob::~PreviewJob()
{
#if WITH_SHM
    Q_D(PreviewJob);
    if (d->shmaddr) {
        shmdt((char *)d->shmaddr);
        shmctl(d->shmid, IPC_RMID, nullptr);
    }
#endif
}

void PreviewJob::setOverlayIconSize(int size)
{
    Q_D(PreviewJob);
    d->iconSize = size;
}

int PreviewJob::overlayIconSize() const
{
    Q_D(const PreviewJob);
    return d->iconSize;
}

void PreviewJob::setOverlayIconAlpha(int alpha)
{
    Q_D(PreviewJob);
    d->iconAlpha = qBound(0, alpha, 255);
}

int PreviewJob::overlayIconAlpha() const
{
    Q_D(const PreviewJob);
    return d->iconAlpha;
}

void PreviewJob::setScaleType(ScaleType type)
{
    Q_D(PreviewJob);
    switch (type) {
    case Unscaled:
        d->bScale = false;
        d->bSave = false;
        break;
    case Scaled:
        d->bScale = true;
        d->bSave = false;
        break;
    case ScaledAndCached:
        d->bScale = true;
        d->bSave = true;
        break;
    default:
        break;
    }
}

PreviewJob::ScaleType PreviewJob::scaleType() const
{
    Q_D(const PreviewJob);
    if (d->bScale) {
        return d->bSave ? ScaledAndCached : Scaled;
    }
    return Unscaled;
}

void PreviewJobPrivate::startPreview()
{
    Q_Q(PreviewJob);
    // Load the list of plugins to determine which mimetypes are supported
    const KService::List plugins = KServiceTypeTrader::self()->query(QStringLiteral("ThumbCreator"));
    QMap<QString, KService::Ptr> mimeMap;
    QHash<QString, QHash<QString, KService::Ptr> > protocolMap;

    for (KService::List::ConstIterator it = plugins.constBegin(); it != plugins.constEnd(); ++it) {
        QStringList protocols = (*it)->property(QStringLiteral("X-KDE-Protocols")).toStringList();
        const QString p = (*it)->property(QStringLiteral("X-KDE-Protocol")).toString();
        if (!p.isEmpty()) {
            protocols.append(p);
        }
        foreach (const QString &protocol, protocols) {
            // We cannot use mimeTypes() here, it doesn't support groups such as: text/*
            const QStringList mtypes = (*it)->serviceTypes();
            // Add supported mimetype for this protocol
            QStringList &_ms = m_remoteProtocolPlugins[protocol];
            foreach (const QString &_m, mtypes) {
                if (_m != QLatin1String("ThumbCreator")) {
                    protocolMap[protocol].insert(_m, *it);
                    if (!_ms.contains(_m)) {
                        _ms.append(_m);
                    }
                }
            }
        }
        if (enabledPlugins.contains((*it)->desktopEntryName())) {
            const QStringList mimeTypes = (*it)->serviceTypes();
            for (QStringList::ConstIterator mt = mimeTypes.constBegin(); mt != mimeTypes.constEnd(); ++mt) {
                if (*mt != QLatin1String("ThumbCreator")) {
                    mimeMap.insert(*mt, *it);
                }
            }
        }
    }

    const auto mountsList = KMountPoint::currentMountPoints();
    KMountPoint::List encryptedMountsList;
    const auto thumbRootMount = mountsList.findByPath(thumbRoot);

    std::copy_if(mountsList.begin(), mountsList.end(),
                 std::back_inserter(encryptedMountsList),
                 [&thumbRootMount] (KMountPoint::Ptr mount) {
                     return (thumbRootMount != mount) &&
                            (mount->mountType() == QLatin1String("fuse.cryfs") ||
                             mount->mountType() == QLatin1String("fuse.encfs"));
                 });

    // Look for images and store the items in our todo list :)
    bool bNeedCache = false;
    KFileItemList::const_iterator kit = initialItems.constBegin();
    const KFileItemList::const_iterator kend = initialItems.constEnd();
    for (; kit != kend; ++kit) {
        PreviewItem item;
        item.item = *kit;

        if (encryptedMountsList.findByPath(item.item.localPath())) {
            continue;
        }

        const QString mimeType = item.item.mimetype();
        KService::Ptr plugin(nullptr);

        // look for protocol-specific thumbnail plugins first
        QHash<QString, QHash<QString, KService::Ptr> >::const_iterator it = protocolMap.constFind(item.item.url().scheme());
        if (it != protocolMap.constEnd()) {
            plugin = it.value().value(mimeType);
        }

        if (!plugin) {
            QMap<QString, KService::Ptr>::ConstIterator pluginIt = mimeMap.constFind(mimeType);
            if (pluginIt == mimeMap.constEnd()) {
                QString groupMimeType = mimeType;
                groupMimeType.replace(QRegExp(QStringLiteral("/.*")), QStringLiteral("/*"));
                pluginIt = mimeMap.constFind(groupMimeType);

                if (pluginIt == mimeMap.constEnd()) {
                    QMimeDatabase db;
                    // check mime type inheritance, resolve aliases
                    const QMimeType mimeInfo = db.mimeTypeForName(mimeType);
                    if (mimeInfo.isValid()) {
                        const QStringList parentMimeTypes = mimeInfo.allAncestors();
                        for (const QString &parentMimeType : parentMimeTypes) {
                            pluginIt = mimeMap.constFind(parentMimeType);
                            if (pluginIt != mimeMap.constEnd()) {
                                break;
                            }
                        }
                    }
                }
            }

            if (pluginIt != mimeMap.constEnd()) {
                plugin = *pluginIt;
            }
        }

        if (plugin) {
            item.plugin = plugin;
            items.append(item);
            if (!bNeedCache && bSave && plugin->property(QStringLiteral("CacheThumbnail")).toBool()) {
                const QUrl url = (*kit).url();
                if (!url.isLocalFile() ||
                        !url.adjusted(QUrl::RemoveFilename).toLocalFile().startsWith(thumbRoot)) {
                    bNeedCache = true;
                }
            }
        } else {
            emit q->failed(*kit);
        }
    }

    KConfigGroup cg(KSharedConfig::openConfig(), "PreviewSettings");
    maximumLocalSize = cg.readEntry("MaximumSize", std::numeric_limits<KIO::filesize_t>::max());
    maximumRemoteSize = cg.readEntry("MaximumRemoteSize", 0);

    if (bNeedCache) {
        if (width <= 128 && height <= 128) {
            cacheWidth = cacheHeight = 128;
        } else {
            cacheWidth = cacheHeight = 256;
        }
        thumbPath = thumbRoot + QLatin1String(cacheWidth == 128 ? "normal/" : "large/");
        if (!QDir(thumbPath).exists()) {
            if (QDir().mkpath(thumbPath)) { // Qt5 TODO: mkpath(dirPath, permissions)
                QFile f(thumbPath);
                f.setPermissions(QFile::ReadUser | QFile::WriteUser | QFile::ExeUser); // 0700
            }
        }
    } else {
        bSave = false;
    }

    initialItems.clear();
    determineNextFile();
}

void PreviewJob::removeItem(const QUrl &url)
{
    Q_D(PreviewJob);
    for (QLinkedList<PreviewItem>::Iterator it = d->items.begin(); it != d->items.end(); ++it)
        if ((*it).item.url() == url) {
            d->items.erase(it);
            break;
        }

    if (d->currentItem.item.url() == url) {
        KJob *job = subjobs().first();
        job->kill();
        removeSubjob(job);
        d->determineNextFile();
    }
}

void KIO::PreviewJob::setSequenceIndex(int index)
{
    d_func()->sequenceIndex = index;
}

int KIO::PreviewJob::sequenceIndex() const
{
    return d_func()->sequenceIndex;
}

void PreviewJob::setIgnoreMaximumSize(bool ignoreSize)
{
    d_func()->ignoreMaximumSize = ignoreSize;
}

void PreviewJobPrivate::cleanupTempFile()
{
    if (!tempName.isEmpty()) {
        Q_ASSERT((!QFileInfo(tempName).isDir() && QFileInfo(tempName).isFile()) || QFileInfo(tempName).isSymLink());
        QFile::remove(tempName);
        tempName.clear();
    }
}

void PreviewJobPrivate::determineNextFile()
{
    Q_Q(PreviewJob);
    if (!currentItem.item.isNull()) {
        if (!succeeded) {
            emit q->failed(currentItem.item);
        }
    }
    // No more items ?
    if (items.isEmpty()) {
        q->emitResult();
        return;
    } else {
        // First, stat the orig file
        state = PreviewJobPrivate::STATE_STATORIG;
        currentItem = items.first();
        succeeded = false;
        items.removeFirst();
        KIO::Job *job = KIO::stat(currentItem.item.url(), KIO::HideProgressInfo);
        job->addMetaData(QStringLiteral("thumbnail"), QStringLiteral("1"));
        job->addMetaData(QStringLiteral("no-auth-prompt"), QStringLiteral("true"));
        q->addSubjob(job);
    }
}

void PreviewJob::slotResult(KJob *job)
{
    Q_D(PreviewJob);

    removeSubjob(job);
    Q_ASSERT(!hasSubjobs());    // We should have only one job at a time ...
    switch (d->state) {
    case PreviewJobPrivate::STATE_STATORIG: {
        if (job->error()) { // that's no good news...
            // Drop this one and move on to the next one
            d->determineNextFile();
            return;
        }
        const KIO::UDSEntry entry = static_cast<KIO::StatJob *>(job)->statResult();
        d->tOrig = QDateTime::fromSecsSinceEpoch(entry.numberValue(KIO::UDSEntry::UDS_MODIFICATION_TIME, 0));

        bool skipCurrentItem = false;
        const KIO::filesize_t size = (KIO::filesize_t)entry.numberValue(KIO::UDSEntry::UDS_SIZE, 0);
        const QUrl itemUrl = d->currentItem.item.mostLocalUrl();

        if (itemUrl.isLocalFile() || KProtocolInfo::protocolClass(itemUrl.scheme()) == QLatin1String(":local")) {
            skipCurrentItem = !d->ignoreMaximumSize && size > d->maximumLocalSize
                              && !d->currentItem.plugin->property(QStringLiteral("IgnoreMaximumSize")).toBool();
        } else {
            // For remote items the "IgnoreMaximumSize" plugin property is not respected
            skipCurrentItem = !d->ignoreMaximumSize && size > d->maximumRemoteSize;

            // Remote directories are not supported, don't try to do a file_copy on them
            if (!skipCurrentItem) {
                // TODO update item.mimeType from the UDS entry, in case it wasn't set initially
                // But we don't use the mimetype anymore, we just use isDir().
                if (d->currentItem.item.isDir()) {
                    skipCurrentItem = true;
                }
            }
        }
        if (skipCurrentItem) {
            d->determineNextFile();
            return;
        }

        bool pluginHandlesSequences = d->currentItem.plugin->property(QStringLiteral("HandleSequences"), QVariant::Bool).toBool();
        if (!d->currentItem.plugin->property(QStringLiteral("CacheThumbnail")).toBool()  || (d->sequenceIndex && pluginHandlesSequences)) {
            // This preview will not be cached, no need to look for a saved thumbnail
            // Just create it, and be done
            d->getOrCreateThumbnail();
            return;
        }

        if (d->statResultThumbnail()) {
            return;
        }

        d->getOrCreateThumbnail();
        return;
    }
    case PreviewJobPrivate::STATE_GETORIG: {
        if (job->error()) {
            d->cleanupTempFile();
            d->determineNextFile();
            return;
        }

        d->createThumbnail(static_cast<KIO::FileCopyJob *>(job)->destUrl().toLocalFile());
        return;
    }
    case PreviewJobPrivate::STATE_CREATETHUMB: {
        d->cleanupTempFile();
        d->determineNextFile();
        return;
    }
    }
}

bool PreviewJobPrivate::statResultThumbnail()
{
    if (thumbPath.isEmpty()) {
        return false;
    }

    QUrl url = currentItem.item.mostLocalUrl();
    // Don't include the password if any
    url.setPassword(QString());
    origName = url.toEncoded();

    QCryptographicHash md5(QCryptographicHash::Md5);
    md5.addData(QFile::encodeName(QString::fromUtf8(origName)));
    thumbName = QString::fromUtf8(QFile::encodeName(QString::fromLatin1(md5.result().toHex()))) + QLatin1String(".png");

    QImage thumb;
    if (!thumb.load(thumbPath + thumbName)) {
        return false;
    }

    if (thumb.text(QStringLiteral("Thumb::URI")) != QString::fromUtf8(origName) ||
            thumb.text(QStringLiteral("Thumb::MTime")).toLongLong() != tOrig.toSecsSinceEpoch()) {
        return false;
    }

    QString thumbnailerVersion = currentItem.plugin->property(QStringLiteral("ThumbnailerVersion"), QVariant::String).toString();

    if (!thumbnailerVersion.isEmpty() && thumb.text(QStringLiteral("Software")).startsWith(QStringLiteral("KDE Thumbnail Generator"))) {
        //Check if the version matches
        //The software string should read "KDE Thumbnail Generator pluginName (vX)"
        QString softwareString = thumb.text(QStringLiteral("Software")).remove(QStringLiteral("KDE Thumbnail Generator")).trimmed();
        if (softwareString.isEmpty()) {
            // The thumbnail has been created with an older version, recreating
            return false;
        }
        int versionIndex = softwareString.lastIndexOf(QLatin1String("(v"));
        if (versionIndex < 0) {
            return false;
        }

        QString cachedVersion = softwareString.remove(0, versionIndex + 2);
        cachedVersion.chop(1);
        uint thumbnailerMajor = thumbnailerVersion.toInt();
        uint cachedMajor = cachedVersion.toInt();
        if (thumbnailerMajor > cachedMajor) {
            return false;
        }
    }

    // Found it, use it
    emitPreview(thumb);
    succeeded = true;
    determineNextFile();
    return true;
}

void PreviewJobPrivate::getOrCreateThumbnail()
{
    Q_Q(PreviewJob);
    // We still need to load the orig file ! (This is getting tedious) :)
    const KFileItem &item = currentItem.item;
    const QString localPath = item.localPath();
    if (!localPath.isEmpty()) {
        createThumbnail(localPath);
    } else {
        const QUrl fileUrl = item.url();
        // heuristics for remote URL support
        bool supportsProtocol = false;
        if (m_remoteProtocolPlugins.value(fileUrl.scheme()).contains(item.mimetype())) {
            // There's a plugin supporting this protocol and mimetype
            supportsProtocol = true;
        } else if (m_remoteProtocolPlugins.value(QStringLiteral("KIO")).contains(item.mimetype())) {
            // Assume KIO understands any URL, ThumbCreator slaves who have
            // X-KDE-Protocols=KIO will get fed the remote URL directly.
            supportsProtocol = true;
        }

        if (supportsProtocol) {
            createThumbnail(fileUrl.toString());
            return;
        }
        if (item.isDir()) {
            // Skip remote dirs (bug 208625)
            cleanupTempFile();
            determineNextFile();
            return;
        }
        // No plugin support access to this remote content, copy the file
        // to the local machine, then create the thumbnail
        state = PreviewJobPrivate::STATE_GETORIG;
        QTemporaryFile localFile;
        localFile.setAutoRemove(false);
        localFile.open();
        tempName = localFile.fileName();
        const QUrl currentURL = item.mostLocalUrl();
        KIO::Job *job = KIO::file_copy(currentURL, QUrl::fromLocalFile(tempName), -1, KIO::Overwrite | KIO::HideProgressInfo /* No GUI */);
        job->addMetaData(QStringLiteral("thumbnail"), QStringLiteral("1"));
        q->addSubjob(job);
    }
}

void PreviewJobPrivate::createThumbnail(const QString &pixPath)
{
    Q_Q(PreviewJob);
    state = PreviewJobPrivate::STATE_CREATETHUMB;
    QUrl thumbURL;
    thumbURL.setScheme(QStringLiteral("thumbnail"));
    thumbURL.setPath(pixPath);
    KIO::TransferJob *job = KIO::get(thumbURL, NoReload, HideProgressInfo);
    q->addSubjob(job);
    q->connect(job, SIGNAL(data(KIO::Job*,QByteArray)), SLOT(slotThumbData(KIO::Job*,QByteArray)));
    bool save = bSave && currentItem.plugin->property(QStringLiteral("CacheThumbnail")).toBool() && !sequenceIndex;
    job->addMetaData(QStringLiteral("mimeType"), currentItem.item.mimetype());
    job->addMetaData(QStringLiteral("width"), QString().setNum(save ? cacheWidth : width));
    job->addMetaData(QStringLiteral("height"), QString().setNum(save ? cacheHeight : height));
    job->addMetaData(QStringLiteral("iconSize"), QString().setNum(save ? 64 : iconSize));
    job->addMetaData(QStringLiteral("iconAlpha"), QString().setNum(iconAlpha));
    job->addMetaData(QStringLiteral("plugin"), currentItem.plugin->library());
    job->addMetaData(QStringLiteral("enabledPlugins"), enabledPlugins.join(QLatin1Char(',')));
    if (sequenceIndex) {
        job->addMetaData(QStringLiteral("sequence-index"), QString().setNum(sequenceIndex));
    }

#if WITH_SHM
    if (shmid == -1) {
        if (shmaddr) {
            shmdt((char *)shmaddr);
            shmctl(shmid, IPC_RMID, nullptr);
        }
        shmid = shmget(IPC_PRIVATE, cacheWidth * cacheHeight * 4, IPC_CREAT | 0600);
        if (shmid != -1) {
            shmaddr = (uchar *)(shmat(shmid, nullptr, SHM_RDONLY));
            if (shmaddr == (uchar *) - 1) {
                shmctl(shmid, IPC_RMID, nullptr);
                shmaddr = nullptr;
                shmid = -1;
            }
        } else {
            shmaddr = nullptr;
        }
    }
    if (shmid != -1) {
        job->addMetaData(QStringLiteral("shmid"), QString().setNum(shmid));
    }
#endif
}

void PreviewJobPrivate::slotThumbData(KIO::Job *, const QByteArray &data)
{
    bool save = bSave &&
                currentItem.plugin->property(QStringLiteral("CacheThumbnail")).toBool() &&
                (!currentItem.item.url().isLocalFile() ||
                 !currentItem.item.url().adjusted(QUrl::RemoveFilename).toLocalFile().startsWith(thumbRoot))
                && !sequenceIndex;
    QImage thumb;
#if WITH_SHM
    if (shmaddr) {
        // Keep this in sync with kdebase/kioslave/thumbnail.cpp
        QDataStream str(data);
        int width, height;
        quint8 iFormat;
        str >> width >> height >> iFormat;
        QImage::Format format = static_cast<QImage::Format>(iFormat);
        thumb = QImage(shmaddr, width, height, format).copy();
    } else
#endif
        thumb.loadFromData(data);

    if (thumb.isNull()) {
        QDataStream s(data);
        s >> thumb;
    }

    if (save) {
        thumb.setText(QStringLiteral("Thumb::URI"), QString::fromUtf8(origName));
        thumb.setText(QStringLiteral("Thumb::MTime"), QString::number(tOrig.toSecsSinceEpoch()));
        thumb.setText(QStringLiteral("Thumb::Size"), number(currentItem.item.size()));
        thumb.setText(QStringLiteral("Thumb::Mimetype"), currentItem.item.mimetype());
        QString thumbnailerVersion = currentItem.plugin->property(QStringLiteral("ThumbnailerVersion"), QVariant::String).toString();
        QString signature = QLatin1String("KDE Thumbnail Generator ") + currentItem.plugin->name();
        if (!thumbnailerVersion.isEmpty()) {
            signature.append(QLatin1String(" (v") + thumbnailerVersion + QLatin1Char(')'));
        }
        thumb.setText(QStringLiteral("Software"), signature);
        QSaveFile saveFile(thumbPath + thumbName);
        if (saveFile.open(QIODevice::WriteOnly)) {
            if (thumb.save(&saveFile, "PNG")) {
                saveFile.commit();
            }
        }
    }
    emitPreview(thumb);
    succeeded = true;
}

void PreviewJobPrivate::emitPreview(const QImage &thumb)
{
    Q_Q(PreviewJob);
    QPixmap pix;
    if (thumb.width() > width || thumb.height() > height) {
        pix = QPixmap::fromImage(thumb.scaled(QSize(width, height), Qt::KeepAspectRatio, Qt::SmoothTransformation));
    } else {
        pix = QPixmap::fromImage(thumb);
    }
    emit q->gotPreview(currentItem.item, pix);
}

QStringList PreviewJob::availablePlugins()
{
    QStringList result;
    const KService::List plugins = KServiceTypeTrader::self()->query(QStringLiteral("ThumbCreator"));
    for (KService::List::ConstIterator it = plugins.begin(); it != plugins.end(); ++it)
        if (!result.contains((*it)->desktopEntryName())) {
            result.append((*it)->desktopEntryName());
        }
    return result;
}

QStringList PreviewJob::defaultPlugins()
{
    const QStringList blacklist = QStringList()
                            << QStringLiteral("textthumbnail");

    QStringList defaultPlugins = availablePlugins();
    for (const QString plugin : blacklist) {
        defaultPlugins.removeAll(plugin);
    }

    return defaultPlugins;
}

QStringList PreviewJob::supportedMimeTypes()
{
    QStringList result;
    const KService::List plugins = KServiceTypeTrader::self()->query(QStringLiteral("ThumbCreator"));
    for (KService::List::ConstIterator it = plugins.begin(); it != plugins.end(); ++it) {
        result += (*it)->mimeTypes();
    }
    return result;
}

#ifndef KIOWIDGETS_NO_DEPRECATED
PreviewJob *KIO::filePreview(const KFileItemList &items, int width, int height,
                             int iconSize, int iconAlpha, bool scale, bool save,
                             const QStringList *enabledPlugins)
{
    return new PreviewJob(items, width, height, iconSize, iconAlpha,
                          scale, save, enabledPlugins);
}

PreviewJob *KIO::filePreview(const QList<QUrl> &items, int width, int height,
                             int iconSize, int iconAlpha, bool scale, bool save,
                             const QStringList *enabledPlugins)
{
    KFileItemList fileItems;
    fileItems.reserve(items.size());
    for (QList<QUrl>::const_iterator it = items.begin(); it != items.end(); ++it) {
        Q_ASSERT((*it).isValid());   // please call us with valid urls only
        fileItems.append(KFileItem(*it));
    }
    return new PreviewJob(fileItems, width, height, iconSize, iconAlpha,
                          scale, save, enabledPlugins);
}
#endif

PreviewJob *KIO::filePreview(const KFileItemList &items, const QSize &size, const QStringList *enabledPlugins)
{
    return new PreviewJob(items, size, enabledPlugins);
}

#ifndef KIOWIDGETS_NO_DEPRECATED
KIO::filesize_t PreviewJob::maximumFileSize()
{
    KConfigGroup cg(KSharedConfig::openConfig(), "PreviewSettings");
    return cg.readEntry("MaximumSize", 5 * 1024 * 1024LL /* 5MB */);
}
#endif

#include "moc_previewjob.cpp"
