WebKit/qt/Api/qwebsettings.cpp

/*
    Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)

    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 "config.h"
#include "qwebsettings.h"

#include "qwebpage.h"
#include "qwebpage_p.h"

#include "Cache.h"
#include "CrossOriginPreflightResultCache.h"
#include "FontCache.h"
#include "Page.h"
#include "PageCache.h"
#include "Settings.h"
#include "KURL.h"
#include "PlatformString.h"
#include "IconDatabase.h"
#include "Image.h"
#include "IntSize.h"
#include "ApplicationCacheStorage.h"
#include "DatabaseTracker.h"

#include <QHash>
#include <QSharedData>
#include <QUrl>
#include <QFileInfo>

class QWebSettingsPrivate
{
public:
    QWebSettingsPrivate(WebCore::Settings *wcSettings = 0)
        : settings(wcSettings)
    {
    }

    QHash<int, QString> fontFamilies;
    QHash<int, int> fontSizes;
    QHash<int, bool> attributes;
    QUrl userStyleSheetLocation;
    QString defaultTextEncoding;
    QString localStorageDatabasePath;
    QString offlineWebApplicationCachePath;
    qint64 offlineStorageDefaultQuota;

    void apply();
    WebCore::Settings *settings;
};

typedef QHash<int, QPixmap> WebGraphicHash;
Q_GLOBAL_STATIC(WebGraphicHash, _graphics)

static WebGraphicHash* graphics()
{
    WebGraphicHash* hash = _graphics();

    if (hash->isEmpty()) {
        hash->insert(QWebSettings::MissingImageGraphic, QPixmap(QLatin1String(":webkit/resources/missingImage.png")));
        hash->insert(QWebSettings::MissingPluginGraphic, QPixmap(QLatin1String(":webkit/resources/nullPlugin.png")));
        hash->insert(QWebSettings::DefaultFrameIconGraphic, QPixmap(QLatin1String(":webkit/resources/urlIcon.png")));
        hash->insert(QWebSettings::TextAreaSizeGripCornerGraphic, QPixmap(QLatin1String(":webkit/resources/textAreaResizeCorner.png")));
    }

    return hash;
}

Q_GLOBAL_STATIC(QList<QWebSettingsPrivate *>, allSettings);

void QWebSettingsPrivate::apply()
{
    if (settings) {
        settings->setTextAreasAreResizable(true);

        QWebSettingsPrivate *global = QWebSettings::globalSettings()->d;

        QString family = fontFamilies.value(QWebSettings::StandardFont,
                                            global->fontFamilies.value(QWebSettings::StandardFont));
        settings->setStandardFontFamily(family);

        family = fontFamilies.value(QWebSettings::FixedFont,
                                    global->fontFamilies.value(QWebSettings::FixedFont));
        settings->setFixedFontFamily(family);

        family = fontFamilies.value(QWebSettings::SerifFont,
                                    global->fontFamilies.value(QWebSettings::SerifFont));
        settings->setSerifFontFamily(family);

        family = fontFamilies.value(QWebSettings::SansSerifFont,
                                    global->fontFamilies.value(QWebSettings::SansSerifFont));
        settings->setSansSerifFontFamily(family);

        family = fontFamilies.value(QWebSettings::CursiveFont,
                                    global->fontFamilies.value(QWebSettings::CursiveFont));
        settings->setCursiveFontFamily(family);

        family = fontFamilies.value(QWebSettings::FantasyFont,
                                    global->fontFamilies.value(QWebSettings::FantasyFont));
        settings->setFantasyFontFamily(family);

        int size = fontSizes.value(QWebSettings::MinimumFontSize,
                                   global->fontSizes.value(QWebSettings::MinimumFontSize));
        settings->setMinimumFontSize(size);

        size = fontSizes.value(QWebSettings::MinimumLogicalFontSize,
                                   global->fontSizes.value(QWebSettings::MinimumLogicalFontSize));
        settings->setMinimumLogicalFontSize(size);

        size = fontSizes.value(QWebSettings::DefaultFontSize,
                                   global->fontSizes.value(QWebSettings::DefaultFontSize));
        settings->setDefaultFontSize(size);

        size = fontSizes.value(QWebSettings::DefaultFixedFontSize,
                                   global->fontSizes.value(QWebSettings::DefaultFixedFontSize));
        settings->setDefaultFixedFontSize(size);

        bool value = attributes.value(QWebSettings::AutoLoadImages,
                                      global->attributes.value(QWebSettings::AutoLoadImages));
        settings->setLoadsImagesAutomatically(value);

        value = attributes.value(QWebSettings::JavascriptEnabled,
                                      global->attributes.value(QWebSettings::JavascriptEnabled));
        settings->setJavaScriptEnabled(value);

        value = attributes.value(QWebSettings::JavascriptCanOpenWindows,
                                      global->attributes.value(QWebSettings::JavascriptCanOpenWindows));
        settings->setJavaScriptCanOpenWindowsAutomatically(value);

        value = attributes.value(QWebSettings::JavaEnabled,
                                      global->attributes.value(QWebSettings::JavaEnabled));
        settings->setJavaEnabled(value);

        value = attributes.value(QWebSettings::PluginsEnabled,
                                      global->attributes.value(QWebSettings::PluginsEnabled));
        settings->setPluginsEnabled(value);

        value = attributes.value(QWebSettings::PrivateBrowsingEnabled,
                                      global->attributes.value(QWebSettings::PrivateBrowsingEnabled));
        settings->setPrivateBrowsingEnabled(value);

        value = attributes.value(QWebSettings::JavascriptCanAccessClipboard,
                                      global->attributes.value(QWebSettings::JavascriptCanAccessClipboard));
        settings->setDOMPasteAllowed(value);

        value = attributes.value(QWebSettings::DeveloperExtrasEnabled,
                                      global->attributes.value(QWebSettings::DeveloperExtrasEnabled));
        settings->setDeveloperExtrasEnabled(value);

        QUrl location = !userStyleSheetLocation.isEmpty() ? userStyleSheetLocation : global->userStyleSheetLocation;
        settings->setUserStyleSheetLocation(WebCore::KURL(location));

        QString encoding = !defaultTextEncoding.isEmpty() ? defaultTextEncoding: global->defaultTextEncoding;
        settings->setDefaultTextEncodingName(encoding);

        QString localStoragePath = !localStorageDatabasePath.isEmpty() ? localStorageDatabasePath : global->localStorageDatabasePath;
        settings->setLocalStorageDatabasePath(localStoragePath);

        value = attributes.value(QWebSettings::ZoomTextOnly,
                                 global->attributes.value(QWebSettings::ZoomTextOnly));
        settings->setZoomsTextOnly(value);

        value = attributes.value(QWebSettings::PrintElementBackgrounds,
                                      global->attributes.value(QWebSettings::PrintElementBackgrounds));
        settings->setShouldPrintBackgrounds(value);

        value = attributes.value(QWebSettings::OfflineStorageDatabaseEnabled,
                                      global->attributes.value(QWebSettings::OfflineStorageDatabaseEnabled));
        settings->setDatabasesEnabled(value);

        value = attributes.value(QWebSettings::OfflineWebApplicationCacheEnabled,
                                      global->attributes.value(QWebSettings::OfflineWebApplicationCacheEnabled));
        settings->setOfflineWebApplicationCacheEnabled(value);

        value = attributes.value(QWebSettings::LocalStorageDatabaseEnabled,
                                      global->attributes.value(QWebSettings::LocalStorageDatabaseEnabled));
        settings->setLocalStorageEnabled(value);

        value = attributes.value(QWebSettings::LocalContentCanAccessRemoteUrls,
                                      global->attributes.value(QWebSettings::LocalContentCanAccessRemoteUrls));
        settings->setAllowUniversalAccessFromFileURLs(value);
    } else {
        QList<QWebSettingsPrivate *> settings = *::allSettings();
        for (int i = 0; i < settings.count(); ++i)
            settings[i]->apply();
    }
}

/*!
    Returns the global settings object.

    Any setting changed on the default object is automatically applied to all
    QWebPage instances where the particular setting is not overriden already.
*/
QWebSettings *QWebSettings::globalSettings()
{
    static QWebSettings *global = 0;
    if (!global)
        global = new QWebSettings;
    return global;
}

/*!
    \class QWebSettings
    \since 4.4
    \brief The QWebSettings class provides an object to store the settings used
    by QWebPage and QWebFrame.

    Each QWebPage object has its own QWebSettings object, which configures the
    settings for that page. If a setting is not configured, then it is looked
    up in the global settings object, which can be accessed using
    globalSettings().

    QWebSettings allows configuration of browser properties, such as font sizes and
    families, the location of a custom style sheet, and generic attributes like
    JavaScript and plugins. Individual attributes are set using the setAttribute()
    function. The \l{QWebSettings::WebAttribute}{WebAttribute} enum further describes
    each attribute.

    QWebSettings also configures global properties such as the Web page memory
    cache and the Web page icon database, local database storage and offline
    applications storage.

    \section1 Enabling Plugins

    Support for browser plugins can enabled by setting the
    \l{QWebSettings::PluginsEnabled}{PluginsEnabled} attribute. For many applications,
    this attribute is enabled for all pages by setting it on the
    \l{globalSettings()}{global settings object}.

    \section1 Web Application Support

    WebKit provides support for features specified in \l{HTML 5} that improve the
    performance and capabilities of Web applications. These include client-side
    (offline) storage and the use of a Web application cache.

    Client-side (offline) storage is an improvement over the use of cookies to
    store persistent data in Web applications. Applications can configure and
    enable the use of an offline storage database by calling the
    setOfflineStoragePath() with an appropriate file path, and can limit the quota
    for each application by calling setOfflineStorageDefaultQuota().

    \sa QWebPage::settings(), QWebView::settings(), {Browser}
*/

/*!
    \enum QWebSettings::FontFamily

    This enum describes the generic font families defined by CSS 2.
    For more information see the
    \l{http://www.w3.org/TR/REC-CSS2/fonts.html#generic-font-families}{CSS standard}.

    \value StandardFont
    \value FixedFont
    \value SerifFont
    \value SansSerifFont
    \value CursiveFont
    \value FantasyFont
*/

/*!
    \enum QWebSettings::FontSize

    This enum describes the font sizes configurable through QWebSettings.

    \value MinimumFontSize The hard minimum font size.
    \value MinimumLogicalFontSize The minimum logical font size that is applied
        after zooming with QWebFrame's textSizeMultiplier().
    \value DefaultFontSize The default font size for regular text.
    \value DefaultFixedFontSize The default font size for fixed-pitch text.
*/

/*!
    \enum QWebSettings::WebGraphic

    This enums describes the standard graphical elements used in webpages.

    \value MissingImageGraphic The replacement graphic shown when an image could not be loaded.
    \value MissingPluginGraphic The replacement graphic shown when a plugin could not be loaded.
    \value DefaultFrameIconGraphic The default icon for QWebFrame::icon().
    \value TextAreaSizeGripCornerGraphic The graphic shown for the size grip of text areas.
*/

/*!
    \enum QWebSettings::WebAttribute

    This enum describes various attributes that are configurable through QWebSettings.

    \value AutoLoadImages Specifies whether images are automatically loaded in
        web pages.
    \value JavascriptEnabled Enables or disables the running of JavaScript
        programs.
    \value JavaEnabled Enables or disables Java applets.
        Currently Java applets are not supported.
    \value PluginsEnabled Enables or disables plugins in Web pages.
    \value PrivateBrowsingEnabled Private browsing prevents WebKit from
        recording visited pages in the history and storing web page icons.
    \value JavascriptCanOpenWindows Specifies whether JavaScript programs
        can open new windows.
    \value JavascriptCanAccessClipboard Specifies whether JavaScript programs
        can read or write to the clipboard.
    \value DeveloperExtrasEnabled Enables extra tools for Web developers.
        Currently this enables the "Inspect" element in the context menu,
    which shows the WebKit WebInspector for web site debugging.
    \value LinksIncludedInFocusChain Specifies whether hyperlinks should be
        included in the keyboard focus chain.
    \value ZoomTextOnly Specifies whether the zoom factor on a frame applies to
        only the text or all content.
    \value PrintElementBackgrounds Specifies whether the background color and images
        are also drawn when the page is printed.
    \value OfflineStorageDatabaseEnabled Specifies whether support for the HTML 5
        offline storage feature is enabled or not.
    \value OfflineWebApplicationCacheEnabled Specifies whether support for the HTML 5
        web application cache feature is enabled or not.
    \value LocalStorageDatabaseEnabled Specifies whether support for the HTML 5
        local storage feature is enabled or not.
    \value LocalContentCanAccessRemoteUrls Specifies whether locally loaded documents are allowed to access remote urls.
*/

/*!
    \internal
*/
QWebSettings::QWebSettings()
    : d(new QWebSettingsPrivate)
{
    // Initialize our global defaults
    d->fontSizes.insert(QWebSettings::MinimumFontSize, 0);
    d->fontSizes.insert(QWebSettings::MinimumLogicalFontSize, 0);
    d->fontSizes.insert(QWebSettings::DefaultFontSize, 14);
    d->fontSizes.insert(QWebSettings::DefaultFixedFontSize, 14);
    d->fontFamilies.insert(QWebSettings::StandardFont, QLatin1String("Arial"));
    d->fontFamilies.insert(QWebSettings::FixedFont, QLatin1String("Courier New"));
    d->fontFamilies.insert(QWebSettings::SerifFont, QLatin1String("Times New Roman"));
    d->fontFamilies.insert(QWebSettings::SansSerifFont, QLatin1String("Arial"));
    d->fontFamilies.insert(QWebSettings::CursiveFont, QLatin1String("Arial"));
    d->fontFamilies.insert(QWebSettings::FantasyFont, QLatin1String("Arial"));

    d->attributes.insert(QWebSettings::AutoLoadImages, true);
    d->attributes.insert(QWebSettings::JavascriptEnabled, true);
    d->attributes.insert(QWebSettings::LinksIncludedInFocusChain, true);
    d->attributes.insert(QWebSettings::ZoomTextOnly, false);
    d->attributes.insert(QWebSettings::PrintElementBackgrounds, true);
    d->attributes.insert(QWebSettings::OfflineStorageDatabaseEnabled, true);
    d->attributes.insert(QWebSettings::OfflineWebApplicationCacheEnabled, true);
    d->attributes.insert(QWebSettings::LocalStorageDatabaseEnabled, true);
    d->attributes.insert(QWebSettings::LocalContentCanAccessRemoteUrls, true);
    d->offlineStorageDefaultQuota = 5 * 1024 * 1024;

}

/*!
    \internal
*/
QWebSettings::QWebSettings(WebCore::Settings *settings)
    : d(new QWebSettingsPrivate(settings))
{
    d->settings = settings;
    d->apply();
    allSettings()->append(d);
}

/*!
    \internal
*/
QWebSettings::~QWebSettings()
{
    if (d->settings)
        allSettings()->removeAll(d);

    delete d;
}

/*!
    Sets the font size for \a type to \a size.
*/
void QWebSettings::setFontSize(FontSize type, int size)
{
    d->fontSizes.insert(type, size);
    d->apply();
}

/*!
    Returns the default font size for \a type.
*/
int QWebSettings::fontSize(FontSize type) const
{
    int defaultValue = 0;
    if (d->settings) {
        QWebSettingsPrivate *global = QWebSettings::globalSettings()->d;
        defaultValue = global->fontSizes.value(type);
    }
    return d->fontSizes.value(type, defaultValue);
}

/*!
    Resets the font size for \a type to the size specified in the global
    settings object.

    This function has no effect on the global QWebSettings instance.
*/
void QWebSettings::resetFontSize(FontSize type)
{
    if (d->settings) {
        d->fontSizes.remove(type);
        d->apply();
    }
}

/*!
    Specifies the location of a user stylesheet to load with every web page.

    The \a location can be a URL or a path on the local filesystem.

    \sa userStyleSheetUrl()
*/
void QWebSettings::setUserStyleSheetUrl(const QUrl &location)
{
    d->userStyleSheetLocation = location;
    d->apply();
}

/*!
    Returns the location of the user stylesheet.

    \sa setUserStyleSheetUrl()
*/
QUrl QWebSettings::userStyleSheetUrl() const
{
    return d->userStyleSheetLocation;
}

/*!
    \since 4.6
    Specifies the default text encoding system.

    The \a encoding, must be a string describing an encoding such as "utf-8",
    "iso-8859-1", etc. If left empty a default value will be used. For a more
    extensive list of encoding names see \l{QTextCodec}

    \sa defaultTextEncoding()
*/
void QWebSettings::setDefaultTextEncoding(const QString &encoding)
{
    d->defaultTextEncoding = encoding;
    d->apply();
}

/*!
    \since 4.6
    Returns the default text encoding.

    \sa setDefaultTextEncoding()
*/
QString QWebSettings::defaultTextEncoding() const
{
    return d->defaultTextEncoding;
}

/*!
    Sets the path of the icon database to \a path. The icon database is used
    to store "favicons" associated with web sites.

    \a path must point to an existing directory where the icons are stored.

    Setting an empty path disables the icon database.
*/
void QWebSettings::setIconDatabasePath(const QString &path)
{
    WebCore::iconDatabase()->delayDatabaseCleanup();

    if (!path.isEmpty()) {
        WebCore::iconDatabase()->setEnabled(true);
        QFileInfo info(path);
        if (info.isDir() && info.isWritable())
            WebCore::iconDatabase()->open(path);
    } else {
        WebCore::iconDatabase()->setEnabled(false);
        WebCore::iconDatabase()->close();
    }
}

/*!
    Returns the path of the icon database or an empty string if the icon
    database is disabled.

    \sa setIconDatabasePath(), clearIconDatabase()
*/
QString QWebSettings::iconDatabasePath()
{
    if (WebCore::iconDatabase()->isEnabled() && WebCore::iconDatabase()->isOpen()) {
        return WebCore::iconDatabase()->databasePath();
    } else {
        return QString();
    }
}

/*!
    Clears the icon database.
*/
void QWebSettings::clearIconDatabase()
{
    if (WebCore::iconDatabase()->isEnabled() && WebCore::iconDatabase()->isOpen())
        WebCore::iconDatabase()->removeAllIcons();
}

/*!
    Returns the web site's icon for \a url.

    If the web site does not specify an icon, or the icon is not in the
    database, a null QIcon is returned.

    \note The returned icon's size is arbitrary.

    \sa setIconDatabasePath()
*/
QIcon QWebSettings::iconForUrl(const QUrl &url)
{
    WebCore::Image* image = WebCore::iconDatabase()->iconForPageURL(WebCore::KURL(url).string(),
                                WebCore::IntSize(16, 16));
    if (!image) {
        return QPixmap();
    }
    QPixmap *icon = image->nativeImageForCurrentFrame();
    if (!icon) {
        return QPixmap();
    }
    return *icon;
}

/*!
    Sets \a graphic to be drawn when QtWebKit needs to draw an image of the
    given \a type.

    For example, when an image cannot be loaded the pixmap specified by
    \l{QWebSettings::WebGraphic}{MissingImageGraphic} is drawn instead.

    \sa webGraphic()
*/
void QWebSettings::setWebGraphic(WebGraphic type, const QPixmap &graphic)
{
    WebGraphicHash *h = graphics();
    if (graphic.isNull())
        h->remove(type);
    else
        h->insert(type, graphic);
}

/*!
    Returns a previously set pixmap used to draw replacement graphics of the
    specified \a type.

    For example, when an image cannot be loaded the pixmap specified by
    \l{QWebSettings::WebGraphic}{MissingImageGraphic} is drawn instead.

    \sa setWebGraphic()
*/
QPixmap QWebSettings::webGraphic(WebGraphic type)
{
    return graphics()->value(type);
}

/*!
    Frees up as much memory as possible by cleaning all memory caches such
    as page, object and font cache.

    \since 4.6
 */
void QWebSettings::clearMemoryCaches()
{
    // Turn the cache on and off.  Disabling the object cache will remove all
    // resources from the cache.  They may still live on if they are referenced
    // by some Web page though.
    if (!WebCore::cache()->disabled()) {
        WebCore::cache()->setDisabled(true);
        WebCore::cache()->setDisabled(false);
    }

    int pageCapacity = WebCore::pageCache()->capacity();
    // Setting size to 0, makes all pages be released.
    WebCore::pageCache()->setCapacity(0);
    WebCore::pageCache()->releaseAutoreleasedPagesNow();
    WebCore::pageCache()->setCapacity(pageCapacity);

    // Invalidating the font cache and freeing all inactive font data.
    WebCore::fontCache()->invalidate();

#if ENABLE(OFFLINE_WEB_APPLICATIONS)
    // Empty the application cache.
    WebCore::cacheStorage().empty();
#endif

    // Empty the Cross-Origin Preflight cache
    WebCore::CrossOriginPreflightResultCache::shared().empty();
}

/*!
    Sets the maximum number of pages to hold in the memory cache to \a pages.
*/
void QWebSettings::setMaximumPagesInCache(int pages)
{
    WebCore::pageCache()->setCapacity(qMax(0, pages));
}

/*!
    Returns the maximum number of web pages that are kept in the memory cache.
*/
int QWebSettings::maximumPagesInCache()
{
    return WebCore::pageCache()->capacity();
}

/*!
   Specifies the capacities for the memory cache for dead objects such as
   stylesheets or scripts.

   The \a cacheMinDeadCapacity specifies the \e minimum number of bytes that
   dead objects should consume when the cache is under pressure.
   
   \a cacheMaxDead is the \e maximum number of bytes that dead objects should
   consume when the cache is \bold not under pressure.

   \a totalCapacity specifies the \e maximum number of bytes that the cache
   should consume \bold overall.

   The cache is enabled by default. Calling setObjectCacheCapacities(0, 0, 0)
   will disable the cache. Calling it with one non-zero enables it again.
*/
void QWebSettings::setObjectCacheCapacities(int cacheMinDeadCapacity, int cacheMaxDead, int totalCapacity)
{
    bool disableCache = cacheMinDeadCapacity == 0 && cacheMaxDead == 0 && totalCapacity == 0;
    WebCore::cache()->setDisabled(disableCache);

    WebCore::cache()->setCapacities(qMax(0, cacheMinDeadCapacity),
                                    qMax(0, cacheMaxDead),
                                    qMax(0, totalCapacity));
}

/*!
    Sets the actual font family to \a family for the specified generic family,
    \a which.
*/
void QWebSettings::setFontFamily(FontFamily which, const QString &family)
{
    d->fontFamilies.insert(which, family);
    d->apply();
}

/*!
    Returns the actual font family for the specified generic font family,
    \a which.
*/
QString QWebSettings::fontFamily(FontFamily which) const
{
    QString defaultValue;
    if (d->settings) {
        QWebSettingsPrivate *global = QWebSettings::globalSettings()->d;
        defaultValue = global->fontFamilies.value(which);
    }
    return d->fontFamilies.value(which, defaultValue);
}

/*!
    Resets the actual font family to the default font family, specified by
    \a which.

    This function has no effect on the global QWebSettings instance.
*/
void QWebSettings::resetFontFamily(FontFamily which)
{
    if (d->settings) {
        d->fontFamilies.remove(which);
        d->apply();
    }
}

/*!
    \fn void QWebSettings::setAttribute(WebAttribute attribute, bool on)
    
    Enables or disables the specified \a attribute feature depending on the
    value of \a on.
*/
void QWebSettings::setAttribute(WebAttribute attr, bool on)
{
    d->attributes.insert(attr, on);
    d->apply();
}

/*!
    \fn bool QWebSettings::testAttribute(WebAttribute attribute) const

    Returns true if \a attribute is enabled; otherwise returns false.
*/
bool QWebSettings::testAttribute(WebAttribute attr) const
{
    bool defaultValue = false;
    if (d->settings) {
        QWebSettingsPrivate *global = QWebSettings::globalSettings()->d;
        defaultValue = global->attributes.value(attr);
    }
    return d->attributes.value(attr, defaultValue);
}

/*!
    \fn void QWebSettings::resetAttribute(WebAttribute attribute)

    Resets the setting of \a attribute.
    This function has no effect on the global QWebSettings instance.

    \sa globalSettings()
*/
void QWebSettings::resetAttribute(WebAttribute attr)
{
    if (d->settings) {
        d->attributes.remove(attr);
        d->apply();
    }
}

/*!
    \since 4.5

    Sets the path for HTML5 offline storage to \a path.

    \a path must point to an existing directory where the databases are stored.

    Setting an empty path disables the feature.

    \sa offlineStoragePath()
*/
void QWebSettings::setOfflineStoragePath(const QString& path)
{
#if ENABLE(DATABASE)
    WebCore::DatabaseTracker::tracker().setDatabaseDirectoryPath(path);
#endif
}

/*!
    \since 4.5

    Returns the path of the HTML5 offline storage or an empty string if the
    feature is disabled.

    \sa setOfflineStoragePath()
*/
QString QWebSettings::offlineStoragePath()
{
#if ENABLE(DATABASE)
    return WebCore::DatabaseTracker::tracker().databaseDirectoryPath();
#else
    return QString();
#endif
}

/*!
    \since 4.5

    Sets the value of the default quota for new offline storage databases
    to \a maximumSize.
*/
void QWebSettings::setOfflineStorageDefaultQuota(qint64 maximumSize)
{
    QWebSettings::globalSettings()->d->offlineStorageDefaultQuota = maximumSize;
}

/*!
    \since 4.5

    Returns the value of the default quota for new offline storage databases.
*/
qint64 QWebSettings::offlineStorageDefaultQuota()
{
    return QWebSettings::globalSettings()->d->offlineStorageDefaultQuota;
}

/*
    \internal
    \relates QWebSettings
    
    Sets the path for HTML5 offline web application cache storage to \a path.

    \a path must point to an existing directory where the cache is stored.

    Setting an empty path disables the feature.

    \sa offlineWebApplicationCachePath()
*/
void QWEBKIT_EXPORT qt_websettings_setOfflineWebApplicationCachePath(const QString& path)
{
#if ENABLE(OFFLINE_WEB_APPLICATIONS)
    WebCore::cacheStorage().setCacheDirectory(path);
#endif
}

/*
    \internal
    \relates QWebSettings
    
    Returns the path of the HTML5 offline web application cache storage
    or an empty string if the feature is disabled.

    \sa setOfflineWebApplicationCachePath()
*/
QString QWEBKIT_EXPORT qt_websettings_offlineWebApplicationCachePath()
{
#if ENABLE(OFFLINE_WEB_APPLICATIONS)
    return WebCore::cacheStorage().cacheDirectory();
#else
    return QString();
#endif
}

/*
    \since 4.5
    \relates QWebSettings

    Sets the path for HTML5 local storage databases to \a path.

    \a path must point to an existing directory where the cache is stored.

    Setting an empty path disables the feature.

    \sa localStorageDatabasePath()
*/
void QWEBKIT_EXPORT qt_websettings_setLocalStorageDatabasePath(QWebSettings* settings, const QString& path)
{
    QWebSettingsPrivate *d = settings->handle();
    d->localStorageDatabasePath = path;
    d->apply();
}

/*
    \since 4.5
    \relates QWebSettings

    Returns the path for HTML5 local storage databases
    or an empty string if the feature is disabled.

    \sa setLocalStorageDatabasePath()
*/
QString QWEBKIT_EXPORT qt_websettings_localStorageDatabasePath(QWebSettings* settings)
{
    return settings->handle()->localStorageDatabasePath;
}

/*!
    \fn QWebSettingsPrivate* QWebSettings::handle() const
    \internal
*/