PrismLauncher/libraries/iconfix/internal/qiconloader.cpp

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#include "qiconloader_p.h"

#include <QtGui/QIconEnginePlugin>
#include <QtGui/QPixmapCache>
#include <QtGui/QIconEngine>
#include <QtGui/QPalette>
#include <QtCore/QList>
#include <QtCore/QHash>
#include <QtCore/QDir>
#include <QtCore/QSettings>
#include <QtGui/QPainter>
#include <QApplication>
#include <QLatin1Literal>

#include "qhexstring_p.h"

namespace QtXdg
{

Q_GLOBAL_STATIC(QIconLoader, iconLoaderInstance)

/* Theme to use in last resort, if the theme does not have the icon, neither the parents  */

static QString fallbackTheme()
{
    return QString("hicolor");
}

QIconLoader::QIconLoader() : m_themeKey(1), m_supportsSvg(false), m_initialized(false)
{
}

// We lazily initialize the loader to make static icons
// work. Though we do not officially support this.

static inline QString systemThemeName()
{
    return QIcon::themeName();
}

static inline QStringList systemIconSearchPaths()
{
    auto paths = QIcon::themeSearchPaths();
    paths.push_front(":/icons");
    return paths;
}

void QIconLoader::ensureInitialized()
{
    if (!m_initialized)
    {
        m_initialized = true;

        Q_ASSERT(qApp);

        m_systemTheme = QIcon::themeName();

        if (m_systemTheme.isEmpty())
            m_systemTheme = fallbackTheme();
        m_supportsSvg = true;
    }
}

QIconLoader *QIconLoader::instance()
{
    iconLoaderInstance()->ensureInitialized();
    return iconLoaderInstance();
}

// Queries the system theme and invalidates existing
// icons if the theme has changed.
void QIconLoader::updateSystemTheme()
{
    // Only change if this is not explicitly set by the user
    if (m_userTheme.isEmpty())
    {
        QString theme = systemThemeName();
        if (theme.isEmpty())
            theme = fallbackTheme();
        if (theme != m_systemTheme)
        {
            m_systemTheme = theme;
            invalidateKey();
        }
    }
}

void QIconLoader::setThemeName(const QString &themeName)
{
    m_userTheme = themeName;
    invalidateKey();
}

void QIconLoader::setThemeSearchPath(const QStringList &searchPaths)
{
    m_iconDirs = searchPaths;
    themeList.clear();
    invalidateKey();
}

QStringList QIconLoader::themeSearchPaths() const
{
    if (m_iconDirs.isEmpty())
    {
        m_iconDirs = systemIconSearchPaths();
    }
    return m_iconDirs;
}

QIconTheme::QIconTheme(const QString &themeName) : m_valid(false)
{
    QFile themeIndex;

    QStringList iconDirs = systemIconSearchPaths();
    for (int i = 0; i < iconDirs.size(); ++i)
    {
        QDir iconDir(iconDirs[i]);
        QString themeDir = iconDir.path() + QLatin1Char('/') + themeName;
        themeIndex.setFileName(themeDir + QLatin1String("/index.theme"));
        if (themeIndex.exists())
        {
            m_contentDir = themeDir;
            m_valid = true;

            foreach (QString path, iconDirs)
            {
                if (QFileInfo(path).isDir())
                    m_contentDirs.append(path + QLatin1Char('/') + themeName);
            }

            break;
        }
    }

    // if there is no index file, abscond.
    if (!themeIndex.exists())
        return;

    // otherwise continue reading index file
    const QSettings indexReader(themeIndex.fileName(), QSettings::IniFormat);
    QStringListIterator keyIterator(indexReader.allKeys());
    while (keyIterator.hasNext())
    {
        const QString key = keyIterator.next();
        if (!key.endsWith(QLatin1String("/Size")))
            continue;

        // Note the QSettings ini-format does not accept
        // slashes in key names, hence we have to cheat
        int size = indexReader.value(key).toInt();
        if (!size)
            continue;

        QString directoryKey = key.left(key.size() - 5);
        QIconDirInfo dirInfo(directoryKey);
        dirInfo.size = size;
        QString type =
            indexReader.value(directoryKey + QLatin1String("/Type")).toString();

        if (type == QLatin1String("Fixed"))
            dirInfo.type = QIconDirInfo::Fixed;
        else if (type == QLatin1String("Scalable"))
            dirInfo.type = QIconDirInfo::Scalable;
        else
            dirInfo.type = QIconDirInfo::Threshold;

        dirInfo.threshold =
            indexReader.value(directoryKey + QLatin1String("/Threshold"), 2)
                .toInt();

        dirInfo.minSize =
            indexReader.value(directoryKey + QLatin1String("/MinSize"), size)
                .toInt();

        dirInfo.maxSize =
            indexReader.value(directoryKey + QLatin1String("/MaxSize"), size)
                .toInt();
        m_keyList.append(dirInfo);
    }

    // Parent themes provide fallbacks for missing icons
    m_parents = indexReader.value(QLatin1String("Icon Theme/Inherits")).toStringList();
    m_parents.removeAll(QString());

    // Ensure a default platform fallback for all themes
    if (m_parents.isEmpty())
    {
        const QString fallback = fallbackTheme();
        if (!fallback.isEmpty())
            m_parents.append(fallback);
    }

    // Ensure that all themes fall back to hicolor
    if (!m_parents.contains(QLatin1String("hicolor")))
        m_parents.append(QLatin1String("hicolor"));
}

QThemeIconEntries QIconLoader::findIconHelper(const QString &themeName, const QString &iconName,
                                              QStringList &visited) const
{
    QThemeIconEntries entries;
    Q_ASSERT(!themeName.isEmpty());

    QPixmap pixmap;

    // Used to protect against potential recursions
    visited << themeName;

    QIconTheme theme = themeList.value(themeName);
    if (!theme.isValid())
    {
        theme = QIconTheme(themeName);
        if (!theme.isValid())
            theme = QIconTheme(fallbackTheme());

        themeList.insert(themeName, theme);
    }

    QStringList contentDirs = theme.contentDirs();
    const QVector<QIconDirInfo> subDirs = theme.keyList();

    const QString svgext(QLatin1String(".svg"));
    const QString pngext(QLatin1String(".png"));
    const QString xpmext(QLatin1String(".xpm"));

    // Add all relevant files
    for (int i = 0; i < subDirs.size(); ++i)
    {
        const QIconDirInfo &dirInfo = subDirs.at(i);
        QString subdir = dirInfo.path;

        foreach (QString contentDir, contentDirs)
        {
            QDir currentDir(contentDir + '/' + subdir);

            if (currentDir.exists(iconName + pngext))
            {
                PixmapEntry *iconEntry = new PixmapEntry;
                iconEntry->dir = dirInfo;
                iconEntry->filename = currentDir.filePath(iconName + pngext);
                // Notice we ensure that pixmap entries always come before
                // scalable to preserve search order afterwards
                entries.prepend(iconEntry);
            }
            else if (m_supportsSvg && currentDir.exists(iconName + svgext))
            {
                ScalableEntry *iconEntry = new ScalableEntry;
                iconEntry->dir = dirInfo;
                iconEntry->filename = currentDir.filePath(iconName + svgext);
                entries.append(iconEntry);
                break;
            }
            else if (currentDir.exists(iconName + xpmext))
            {
                PixmapEntry *iconEntry = new PixmapEntry;
                iconEntry->dir = dirInfo;
                iconEntry->filename = currentDir.filePath(iconName + xpmext);
                // Notice we ensure that pixmap entries always come before
                // scalable to preserve search order afterwards
                entries.append(iconEntry);
                break;
            }
        }
    }

    if (entries.isEmpty())
    {
        const QStringList parents = theme.parents();
        // Search recursively through inherited themes
        for (int i = 0; i < parents.size(); ++i)
        {

            const QString parentTheme = parents.at(i).trimmed();

            if (!visited.contains(parentTheme)) // guard against recursion
                entries = findIconHelper(parentTheme, iconName, visited);

            if (!entries.isEmpty()) // success
                break;
        }
    }

/*********************************************************************
Author: Kaitlin Rupert <kaitlin.rupert@intel.com>
Date: Aug 12, 2010
Description: Make it so that the QIcon loader honors /usr/share/pixmaps
             directory.  This is a valid directory per the Freedesktop.org
             icon theme specification.
Bug: https://bugreports.qt.nokia.com/browse/QTBUG-12874
 *********************************************************************/
#ifdef Q_OS_LINUX
    /* Freedesktop standard says to look in /usr/share/pixmaps last */
    if (entries.isEmpty())
    {
        const QString pixmaps(QLatin1String("/usr/share/pixmaps"));

        QDir currentDir(pixmaps);
        QIconDirInfo dirInfo(pixmaps);
        if (currentDir.exists(iconName + pngext))
        {
            PixmapEntry *iconEntry = new PixmapEntry;
            iconEntry->dir = dirInfo;
            iconEntry->filename = currentDir.filePath(iconName + pngext);
            // Notice we ensure that pixmap entries always come before
            // scalable to preserve search order afterwards
            entries.prepend(iconEntry);
        }
        else if (m_supportsSvg && currentDir.exists(iconName + svgext))
        {
            ScalableEntry *iconEntry = new ScalableEntry;
            iconEntry->dir = dirInfo;
            iconEntry->filename = currentDir.filePath(iconName + svgext);
            entries.append(iconEntry);
        }
        else if (currentDir.exists(iconName + xpmext))
        {
            PixmapEntry *iconEntry = new PixmapEntry;
            iconEntry->dir = dirInfo;
            iconEntry->filename = currentDir.filePath(iconName + xpmext);
            // Notice we ensure that pixmap entries always come before
            // scalable to preserve search order afterwards
            entries.append(iconEntry);
        }
    }
#endif

    if (entries.isEmpty())
    {
        // Search for unthemed icons in main dir of search paths
        QStringList themeSearchPaths = QIcon::themeSearchPaths();
        foreach (QString contentDir, themeSearchPaths)
        {
            QDir currentDir(contentDir);

            if (currentDir.exists(iconName + pngext))
            {
                PixmapEntry *iconEntry = new PixmapEntry;
                iconEntry->filename = currentDir.filePath(iconName + pngext);
                // Notice we ensure that pixmap entries always come before
                // scalable to preserve search order afterwards
                entries.prepend(iconEntry);
            }
            else if (m_supportsSvg && currentDir.exists(iconName + svgext))
            {
                ScalableEntry *iconEntry = new ScalableEntry;
                iconEntry->filename = currentDir.filePath(iconName + svgext);
                entries.append(iconEntry);
                break;
            }
            else if (currentDir.exists(iconName + xpmext))
            {
                PixmapEntry *iconEntry = new PixmapEntry;
                iconEntry->filename = currentDir.filePath(iconName + xpmext);
                // Notice we ensure that pixmap entries always come before
                // scalable to preserve search order afterwards
                entries.append(iconEntry);
                break;
            }
        }
    }
    return entries;
}

QThemeIconEntries QIconLoader::loadIcon(const QString &name) const
{
    if (!themeName().isEmpty())
    {
        QStringList visited;
        return findIconHelper(themeName(), name, visited);
    }

    return QThemeIconEntries();
}

// -------- Icon Loader Engine -------- //

QIconLoaderEngineFixed::QIconLoaderEngineFixed(const QString &iconName)
    : m_iconName(iconName), m_key(0)
{
}

QIconLoaderEngineFixed::~QIconLoaderEngineFixed()
{
    qDeleteAll(m_entries);
}

QIconLoaderEngineFixed::QIconLoaderEngineFixed(const QIconLoaderEngineFixed &other)
    : QIconEngine(other), m_iconName(other.m_iconName), m_key(0)
{
}

QIconEngine *QIconLoaderEngineFixed::clone() const
{
    return new QIconLoaderEngineFixed(*this);
}

bool QIconLoaderEngineFixed::read(QDataStream &in)
{
    in >> m_iconName;
    return true;
}

bool QIconLoaderEngineFixed::write(QDataStream &out) const
{
    out << m_iconName;
    return true;
}

bool QIconLoaderEngineFixed::hasIcon() const
{
    return !(m_entries.isEmpty());
}

// Lazily load the icon
void QIconLoaderEngineFixed::ensureLoaded()
{
    if (!(QIconLoader::instance()->themeKey() == m_key))
    {

        qDeleteAll(m_entries);

        m_entries = QIconLoader::instance()->loadIcon(m_iconName);
        m_key = QIconLoader::instance()->themeKey();
    }
}

void QIconLoaderEngineFixed::paint(QPainter *painter, const QRect &rect, QIcon::Mode mode,
                                   QIcon::State state)
{
    QSize pixmapSize = rect.size();
#if defined(Q_WS_MAC)
    pixmapSize *= qt_mac_get_scalefactor();
#endif
    painter->drawPixmap(rect, pixmap(pixmapSize, mode, state));
}

/*
 * This algorithm is defined by the freedesktop spec:
 * http://standards.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html
 */
static bool directoryMatchesSize(const QIconDirInfo &dir, int iconsize)
{
    if (dir.type == QIconDirInfo::Fixed)
    {
        return dir.size == iconsize;
    }
    else if (dir.type == QIconDirInfo::Scalable)
    {
        return dir.size <= dir.maxSize && iconsize >= dir.minSize;
    }
    else if (dir.type == QIconDirInfo::Threshold)
    {
        return iconsize >= dir.size - dir.threshold && iconsize <= dir.size + dir.threshold;
    }

    Q_ASSERT(1); // Not a valid value
    return false;
}

/*
 * This algorithm is defined by the freedesktop spec:
 * http://standards.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html
 */
static int directorySizeDistance(const QIconDirInfo &dir, int iconsize)
{
    if (dir.type == QIconDirInfo::Fixed)
    {
        return qAbs(dir.size - iconsize);
    }
    else if (dir.type == QIconDirInfo::Scalable)
    {
        if (iconsize < dir.minSize)
            return dir.minSize - iconsize;
        else if (iconsize > dir.maxSize)
            return iconsize - dir.maxSize;
        else
            return 0;
    }
    else if (dir.type == QIconDirInfo::Threshold)
    {
        if (iconsize < dir.size - dir.threshold)
            return dir.minSize - iconsize;
        else if (iconsize > dir.size + dir.threshold)
            return iconsize - dir.maxSize;
        else
            return 0;
    }

    Q_ASSERT(1); // Not a valid value
    return INT_MAX;
}

QIconLoaderEngineEntry *QIconLoaderEngineFixed::entryForSize(const QSize &size)
{
    int iconsize = qMin(size.width(), size.height());

    // Note that m_entries are sorted so that png-files
    // come first

    const int numEntries = m_entries.size();

    // Search for exact matches first
    for (int i = 0; i < numEntries; ++i)
    {
        QIconLoaderEngineEntry *entry = m_entries.at(i);
        if (directoryMatchesSize(entry->dir, iconsize))
        {
            return entry;
        }
    }

    // Find the minimum distance icon
    int minimalSize = INT_MAX;
    QIconLoaderEngineEntry *closestMatch = 0;
    for (int i = 0; i < numEntries; ++i)
    {
        QIconLoaderEngineEntry *entry = m_entries.at(i);
        int distance = directorySizeDistance(entry->dir, iconsize);
        if (distance < minimalSize)
        {
            minimalSize = distance;
            closestMatch = entry;
        }
    }
    return closestMatch;
}

/*
 * Returns the actual icon size. For scalable svg's this is equivalent
 * to the requested size. Otherwise the closest match is returned but
 * we can never return a bigger size than the requested size.
 *
 */
QSize QIconLoaderEngineFixed::actualSize(const QSize &size, QIcon::Mode mode,
                                         QIcon::State state)
{
    ensureLoaded();

    QIconLoaderEngineEntry *entry = entryForSize(size);
    if (entry)
    {
        const QIconDirInfo &dir = entry->dir;
        if (dir.type == QIconDirInfo::Scalable)
            return size;
        else
        {
            int result = qMin<int>(dir.size, qMin(size.width(), size.height()));
            return QSize(result, result);
        }
    }
    return QIconEngine::actualSize(size, mode, state);
}

QPixmap PixmapEntry::pixmap(const QSize &size, QIcon::Mode mode, QIcon::State state)
{
    Q_UNUSED(state);

    // Ensure that basePixmap is lazily initialized before generating the
    // key, otherwise the cache key is not unique
    if (basePixmap.isNull())
        basePixmap.load(filename);

    QSize actualSize = basePixmap.size();
    if (!actualSize.isNull() &&
        (actualSize.width() > size.width() || actualSize.height() > size.height()))
        actualSize.scale(size, Qt::KeepAspectRatio);

    QString key = QLatin1String("$qt_theme_") % HexString<qint64>(basePixmap.cacheKey()) %
                  HexString<int>(mode) %
                  HexString<qint64>(QGuiApplication::palette().cacheKey()) %
                  HexString<int>(actualSize.width()) % HexString<int>(actualSize.height());

    QPixmap cachedPixmap;
    if (QPixmapCache::find(key, &cachedPixmap))
    {
        return cachedPixmap;
    }
    else
    {
        if (basePixmap.size() != actualSize)
        {
            cachedPixmap = basePixmap.scaled(actualSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
        }
        else
        {
            cachedPixmap = basePixmap;
        }
        QPixmapCache::insert(key, cachedPixmap);
    }
    return cachedPixmap;
}

QPixmap ScalableEntry::pixmap(const QSize &size, QIcon::Mode mode, QIcon::State state)
{
    if (svgIcon.isNull())
    {
        svgIcon = QIcon(filename);
    }

    // Simply reuse svg icon engine
    return svgIcon.pixmap(size, mode, state);
}

QPixmap QIconLoaderEngineFixed::pixmap(const QSize &size, QIcon::Mode mode, QIcon::State state)
{
    ensureLoaded();

    QIconLoaderEngineEntry *entry = entryForSize(size);
    if (entry)
    {
        return entry->pixmap(size, mode, state);
    }

    return QPixmap();
}

QString QIconLoaderEngineFixed::key() const
{
    return QLatin1String("QIconLoaderEngineFixed");
}

void QIconLoaderEngineFixed::virtual_hook(int id, void *data)
{
    ensureLoaded();

    switch (id)
    {
    case QIconEngine::AvailableSizesHook:
    {
        QIconEngine::AvailableSizesArgument &arg =
            *reinterpret_cast<QIconEngine::AvailableSizesArgument *>(data);
        const int N = m_entries.size();
        QList<QSize> sizes;
        sizes.reserve(N);

        // Gets all sizes from the DirectoryInfo entries
        for (int i = 0; i < N; ++i)
        {
            int size = m_entries.at(i)->dir.size;
            sizes.append(QSize(size, size));
        }
        arg.sizes.swap(sizes); // commit
    }
    break;
    case QIconEngine::IconNameHook:
    {
        QString &name = *reinterpret_cast<QString *>(data);
        name = m_iconName;
    }
    break;
    default:
        QIconEngine::virtual_hook(id, data);
    }
}

} // QtXdg