/* This file is part of the KDE libraries
   Copyright (C) 1999 Torben Weis <weis@kde.org>
   Copyright (C) 2000- Waldo Bastain <bastain@kde.org>
   Copyright (C) 2000- Dawit Alemayehu <adawit@kde.org>
   Copyright (C) 2008 Jarosław Staniek <staniek@kde.org>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License version 2 as published by the Free Software Foundation.

   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 "kprotocolmanager.h"
#include "kprotocolinfo_p.h"

#include "hostinfo.h"

#include <config-kiocore.h>

#include <string.h>
#include <qplatformdefs.h>
#ifdef Q_OS_WIN
#include <qt_windows.h>
#undef interface //windows.h defines this, breaks QtDBus since it has parameters named interface
#else
#include <sys/utsname.h>
#endif

#include <QtCore/QCoreApplication>
#include <QUrl>
#include <QtNetwork/QSslSocket>
#include <QtNetwork/QHostAddress>
#include <QtNetwork/QHostInfo>
#include <QDBusConnection>
#include <QDBusReply>
#include <QDBusInterface>
#include <QtCore/QCache>
#include <QLocale>
#include <qstandardpaths.h>
#include <qmimedatabase.h>

#if !defined(QT_NO_NETWORKPROXY) && (defined (Q_OS_WIN32) || defined(Q_OS_MAC))
#include <QtNetwork/QNetworkProxyFactory>
#include <QtNetwork/QNetworkProxyQuery>
#endif

#include <kio_version.h>
#include <kconfiggroup.h>
#include <ksharedconfig.h>

#include <kmimetypetrader.h>
#include <kprotocolinfofactory_p.h>

#include "slaveconfig.h"
#include "ioslave_defaults.h"
#include "http_slave_defaults.h"

#define QL1S(x)   QLatin1String(x)
#define QL1C(x)   QLatin1Char(x)

typedef QPair<QHostAddress, int> SubnetPair;

/*
    Domain suffix match. E.g. return true if host is "cuzco.inka.de" and
    nplist is "inka.de,hadiko.de" or if host is "localhost" and nplist is
    "localhost".
*/
static bool revmatch(const char *host, const char *nplist)
{
    if (host == 0) {
        return false;
    }

    const char *hptr = host + strlen(host) - 1;
    const char *nptr = nplist + strlen(nplist) - 1;
    const char *shptr = hptr;

    while (nptr >= nplist) {
        if (*hptr != *nptr) {
            hptr = shptr;

            // Try to find another domain or host in the list
            while (--nptr >= nplist && *nptr != ',' && *nptr != ' ');

            // Strip out multiple spaces and commas
            while (--nptr >= nplist && (*nptr == ',' || *nptr == ' '));
        } else {
            if (nptr == nplist || nptr[-1] == ',' || nptr[-1] == ' ') {
                return true;
            }
            if (nptr[-1] == '/' && hptr == host) { // "bugs.kde.org" vs "http://bugs.kde.org", the config UI says URLs are ok
                return true;
            }
            if (hptr == host) { // e.g. revmatch("bugs.kde.org","mybugs.kde.org")
                return false;
            }

            hptr--;
            nptr--;
        }
    }

    return false;
}

class KProxyData : public QObject
{
public:
    KProxyData(const QString &slaveProtocol, const QStringList &proxyAddresses)
        : protocol(slaveProtocol)
        , proxyList(proxyAddresses)
    {
    }

    void removeAddress(const QString &address)
    {
        proxyList.removeAll(address);
    }

    QString protocol;
    QStringList proxyList;
};

class KProtocolManagerPrivate
{
public:
    KProtocolManagerPrivate();
    ~KProtocolManagerPrivate();
    bool shouldIgnoreProxyFor(const QUrl &url);
    void sync();
    KProtocolManager::ProxyType proxyType();
    bool useReverseProxy();
    QString readNoProxyFor();
    QString proxyFor(const QString &protocol);
    QStringList getSystemProxyFor(const QUrl &url);

    QMutex mutex; // protects all member vars
    KSharedConfig::Ptr configPtr;
    KSharedConfig::Ptr http_config;
    QString modifiers;
    QString useragent;
    QString noProxyFor;
    QList<SubnetPair> noProxySubnets;
    QCache<QString, KProxyData> cachedProxyData;

    QMap<QString /*mimetype*/, QString /*protocol*/> protocolForArchiveMimetypes;
};

Q_GLOBAL_STATIC(KProtocolManagerPrivate, kProtocolManagerPrivate)

static void syncOnExit()
{
    if (kProtocolManagerPrivate.exists())
        kProtocolManagerPrivate()->sync();
}

KProtocolManagerPrivate::KProtocolManagerPrivate()
{
    // post routine since KConfig::sync() breaks if called too late
    qAddPostRoutine(syncOnExit);
    cachedProxyData.setMaxCost(200); // double the max cost.
}

KProtocolManagerPrivate::~KProtocolManagerPrivate()
{
}

/*
 * Returns true if url is in the no proxy list.
 */
bool KProtocolManagerPrivate::shouldIgnoreProxyFor(const QUrl &url)
{
    bool isMatch = false;
    const KProtocolManager::ProxyType type = proxyType();
    const bool useRevProxy = ((type == KProtocolManager::ManualProxy) && useReverseProxy());
    const bool useNoProxyList = (type == KProtocolManager::ManualProxy || type == KProtocolManager::EnvVarProxy);

    // No proxy only applies to ManualProxy and EnvVarProxy types...
    if (useNoProxyList && noProxyFor.isEmpty()) {
        QStringList noProxyForList(readNoProxyFor().split(QL1C(',')));
        QMutableStringListIterator it(noProxyForList);
        while (it.hasNext()) {
            SubnetPair subnet = QHostAddress::parseSubnet(it.next());
            if (!subnet.first.isNull()) {
                noProxySubnets << subnet;
                it.remove();
            }
        }
        noProxyFor =  noProxyForList.join(QL1S(","));
    }

    if (!noProxyFor.isEmpty()) {
        QString qhost = url.host().toLower();
        QByteArray host = qhost.toLatin1();
        const QString qno_proxy = noProxyFor.trimmed().toLower();
        const QByteArray no_proxy = qno_proxy.toLatin1();
        isMatch = revmatch(host, no_proxy);

        // If no match is found and the request url has a port
        // number, try the combination of "host:port". This allows
        // users to enter host:port in the No-proxy-For list.
        if (!isMatch && url.port() > 0) {
            qhost += QL1C(':');
            qhost += QString::number(url.port());
            host = qhost.toLatin1();
            isMatch = revmatch(host, no_proxy);
        }

        // If the hostname does not contain a dot, check if
        // <local> is part of noProxy.
        if (!isMatch && !host.isEmpty() && (strchr(host, '.') == NULL)) {
            isMatch = revmatch("<local>", no_proxy);
        }
    }

    const QString host(url.host());

    if (!noProxySubnets.isEmpty() && !host.isEmpty()) {
        QHostAddress address(host);
        // If request url is not IP address, do a DNS lookup of the hostname.
        // TODO: Perhaps we should make configurable ?
        if (address.isNull()) {
            //qDebug() << "Performing DNS lookup for" << host;
            QHostInfo info = KIO::HostInfo::lookupHost(host, 2000);
            const QList<QHostAddress> addresses = info.addresses();
            if (!addresses.isEmpty()) {
                address = addresses.first();
            }
        }

        if (!address.isNull()) {
            Q_FOREACH (const SubnetPair &subnet, noProxySubnets) {
                if (address.isInSubnet(subnet)) {
                    isMatch = true;
                    break;
                }
            }
        }
    }

    return (useRevProxy != isMatch);
}

void KProtocolManagerPrivate::sync()
{
    QMutexLocker lock(&mutex);
    if (http_config) {
        http_config->sync();
    }
    if (configPtr) {
        configPtr->sync();
    }
}

#define PRIVATE_DATA \
    KProtocolManagerPrivate *d = kProtocolManagerPrivate()

void KProtocolManager::reparseConfiguration()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    if (d->http_config) {
        d->http_config->reparseConfiguration();
    }
    if (d->configPtr) {
        d->configPtr->reparseConfiguration();
    }
    d->cachedProxyData.clear();
    d->noProxyFor.clear();
    d->modifiers.clear();
    d->useragent.clear();
    lock.unlock();

    // Force the slave config to re-read its config...
    KIO::SlaveConfig::self()->reset();
}

static KSharedConfig::Ptr config()
{
    PRIVATE_DATA;
    Q_ASSERT(!d->mutex.tryLock()); // the caller must have locked the mutex
    if (!d->configPtr) {
        d->configPtr = KSharedConfig::openConfig("kioslaverc", KConfig::NoGlobals);
    }
    return d->configPtr;
}

KProtocolManager::ProxyType KProtocolManagerPrivate::proxyType()
{
    KConfigGroup cg(config(), "Proxy Settings");
    return static_cast<KProtocolManager::ProxyType>(cg.readEntry("ProxyType", 0));
}

bool KProtocolManagerPrivate::useReverseProxy()
{
    KConfigGroup cg(config(), "Proxy Settings");
    return cg.readEntry("ReversedException", false);
}

QString KProtocolManagerPrivate::readNoProxyFor()
{
    QString noProxy = config()->group("Proxy Settings").readEntry("NoProxyFor");
    if (proxyType() == KProtocolManager::EnvVarProxy) {
        noProxy = QString::fromLocal8Bit(qgetenv(noProxy.toLocal8Bit()));
    }
    return noProxy;
}

QMap<QString, QString> KProtocolManager::entryMap(const QString &group)
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return config()->entryMap(group);
}

static KConfigGroup http_config()
{
    PRIVATE_DATA;
    Q_ASSERT(!d->mutex.tryLock()); // the caller must have locked the mutex
    if (!d->http_config) {
        d->http_config = KSharedConfig::openConfig("kio_httprc", KConfig::NoGlobals);
    }
    return KConfigGroup(d->http_config, QString());
}

/*=============================== TIMEOUT SETTINGS ==========================*/

int KProtocolManager::readTimeout()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    KConfigGroup cg(config(), QString());
    int val = cg.readEntry("ReadTimeout", DEFAULT_READ_TIMEOUT);
    return qMax(MIN_TIMEOUT_VALUE, val);
}

int KProtocolManager::connectTimeout()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    KConfigGroup cg(config(), QString());
    int val = cg.readEntry("ConnectTimeout", DEFAULT_CONNECT_TIMEOUT);
    return qMax(MIN_TIMEOUT_VALUE, val);
}

int KProtocolManager::proxyConnectTimeout()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    KConfigGroup cg(config(), QString());
    int val = cg.readEntry("ProxyConnectTimeout", DEFAULT_PROXY_CONNECT_TIMEOUT);
    return qMax(MIN_TIMEOUT_VALUE, val);
}

int KProtocolManager::responseTimeout()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    KConfigGroup cg(config(), QString());
    int val = cg.readEntry("ResponseTimeout", DEFAULT_RESPONSE_TIMEOUT);
    return qMax(MIN_TIMEOUT_VALUE, val);
}

/*========================== PROXY SETTINGS =================================*/

bool KProtocolManager::useProxy()
{
    return proxyType() != NoProxy;
}

bool KProtocolManager::useReverseProxy()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return d->useReverseProxy();
}

KProtocolManager::ProxyType KProtocolManager::proxyType()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return d->proxyType();
}

KProtocolManager::ProxyAuthMode KProtocolManager::proxyAuthMode()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    KConfigGroup cg(config(), "Proxy Settings");
    return static_cast<ProxyAuthMode>(cg.readEntry("AuthMode", 0));
}

/*========================== CACHING =====================================*/

bool KProtocolManager::useCache()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return http_config().readEntry("UseCache", true);
}

KIO::CacheControl KProtocolManager::cacheControl()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    QString tmp = http_config().readEntry("cache");
    if (tmp.isEmpty()) {
        return DEFAULT_CACHE_CONTROL;
    }
    return KIO::parseCacheControl(tmp);
}

QString KProtocolManager::cacheDir()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return http_config().readPathEntry("CacheDir", QStandardPaths::writableLocation(QStandardPaths::CacheLocation) + '/' + "http");
}

int KProtocolManager::maxCacheAge()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return http_config().readEntry("MaxCacheAge", DEFAULT_MAX_CACHE_AGE);   // 14 days
}

int KProtocolManager::maxCacheSize()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return http_config().readEntry("MaxCacheSize", DEFAULT_MAX_CACHE_SIZE);   // 5 MB
}

QString KProtocolManager::noProxyFor()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return d->readNoProxyFor();
}

static QString adjustProtocol(const QString &scheme)
{
    if (scheme.compare(QL1S("webdav"), Qt::CaseInsensitive) == 0) {
        return QL1S("http");
    }

    if (scheme.compare(QL1S("webdavs"), Qt::CaseInsensitive) == 0) {
        return QL1S("https");
    }

    return scheme.toLower();
}

QString KProtocolManager::proxyFor(const QString &protocol)
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return d->proxyFor(protocol);
}

QString KProtocolManagerPrivate::proxyFor(const QString &protocol)
{
    const QString key = adjustProtocol(protocol) + QL1S("Proxy");
    QString proxyStr(config()->group("Proxy Settings").readEntry(key));
    const int index = proxyStr.lastIndexOf(QL1C(' '));

    if (index > -1)  {
        bool ok = false;
        const QString portStr(proxyStr.right(proxyStr.length() - index - 1));
        portStr.toInt(&ok);
        if (ok) {
            proxyStr = proxyStr.left(index) + QL1C(':') + portStr;
        } else {
            proxyStr.clear();
        }
    }

    return proxyStr;
}

QString KProtocolManager::proxyForUrl(const QUrl &url)
{
    const QStringList proxies = proxiesForUrl(url);

    if (proxies.isEmpty()) {
        return QString();
    }

    return proxies.first();
}

QStringList KProtocolManagerPrivate::getSystemProxyFor(const QUrl &url)
{
    QStringList proxies;

#if !defined(QT_NO_NETWORKPROXY) && (defined(Q_OS_WIN32) || defined(Q_OS_MAC))
    QNetworkProxyQuery query(url);
    const QList<QNetworkProxy> proxyList = QNetworkProxyFactory::systemProxyForQuery(query);
    Q_FOREACH (const QNetworkProxy &proxy, proxyList) {
        QUrl url;
        const QNetworkProxy::ProxyType type = proxy.type();
        if (type == QNetworkProxy::NoProxy || type == QNetworkProxy::DefaultProxy) {
            proxies << QL1S("DIRECT");
            continue;
        }

        if (type == QNetworkProxy::HttpProxy || type == QNetworkProxy::HttpCachingProxy) {
            url.setScheme(QL1S("http"));
        } else if (type == QNetworkProxy::Socks5Proxy) {
            url.setScheme(QL1S("socks"));
        } else if (type == QNetworkProxy::FtpCachingProxy) {
            url.setScheme(QL1S("ftp"));
        }

        url.setHost(proxy.hostName());
        url.setPort(proxy.port());
        url.setUserName(proxy.user());
        proxies << url.url();
    }
#else
    // On Unix/Linux use system environment variables if any are set.
    QString proxyVar(proxyFor(url.scheme()));
    // Check for SOCKS proxy, if not proxy is found for given url.
    if (!proxyVar.isEmpty()) {
        const QString proxy(QString::fromLocal8Bit(qgetenv(proxyVar.toLocal8Bit())).trimmed());
        if (!proxy.isEmpty()) {
            proxies << proxy;
        }
    }
    // Add the socks proxy as an alternate proxy if it exists,
    proxyVar = proxyFor(QL1S("socks"));
    if (!proxyVar.isEmpty()) {
        QString proxy = QString::fromLocal8Bit(qgetenv(proxyVar.toLocal8Bit())).trimmed();
        // Make sure the scheme of SOCKS proxy is always set to "socks://".
        const int index = proxy.indexOf(QL1S("://"));
        proxy = QL1S("socks://") + (index == -1 ? proxy : proxy.mid(index + 3));
        if (!proxy.isEmpty()) {
            proxies << proxy;
        }
    }
#endif
    return proxies;
}

QStringList KProtocolManager::proxiesForUrl(const QUrl &url)
{
    QStringList proxyList;

    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    if (!d->shouldIgnoreProxyFor(url)) {
        switch (d->proxyType()) {
        case PACProxy:
        case WPADProxy: {
            QUrl u(url);
            const QString protocol = adjustProtocol(u.scheme());
            u.setScheme(protocol);

            if (protocol.startsWith(QL1S("http")) || protocol.startsWith(QL1S("ftp"))) {
                QDBusReply<QStringList> reply = QDBusInterface(QL1S("org.kde.kded5"),
                                                QL1S("/modules/proxyscout"),
                                                QL1S("org.kde.KPAC.ProxyScout"))
                                                .call(QL1S("proxiesForUrl"), u.toString());
                proxyList = reply;
            }
            break;
        }
        case EnvVarProxy:
            proxyList = d->getSystemProxyFor(url);
            break;
        case ManualProxy: {
            QString proxy(d->proxyFor(url.scheme()));
            if (!proxy.isEmpty()) {
                proxyList << proxy;
            }
            // Add the socks proxy as an alternate proxy if it exists,
            proxy = d->proxyFor(QL1S("socks"));
            if (!proxy.isEmpty()) {
                // Make sure the scheme of SOCKS proxy is always set to "socks://".
                const int index = proxy.indexOf(QL1S("://"));
                proxy = QL1S("socks://") + (index == -1 ? proxy : proxy.mid(index + 3));
                proxyList << proxy;
            }
        }
        break;
        case NoProxy:
        default:
            break;
        }
    }

    if (proxyList.isEmpty()) {
        proxyList << QL1S("DIRECT");
    }

    return proxyList;
}

void KProtocolManager::badProxy(const QString &proxy)
{
    QDBusInterface(QL1S("org.kde.kded5"), QL1S("/modules/proxyscout"))
    .asyncCall(QL1S("blackListProxy"), proxy);

    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    const QStringList keys(d->cachedProxyData.keys());
    Q_FOREACH (const QString &key, keys) {
        d->cachedProxyData[key]->removeAddress(proxy);
    }
}

QString KProtocolManager::slaveProtocol(const QUrl &url, QString &proxy)
{
    QStringList proxyList;
    const QString protocol = KProtocolManager::slaveProtocol(url, proxyList);
    if (!proxyList.isEmpty()) {
        proxy = proxyList.first();
    }
    return protocol;
}

// Generates proxy cache key from request given url.
static void extractProxyCacheKeyFromUrl(const QUrl &u, QString *key)
{
    if (!key) {
        return;
    }

    *key = u.scheme();
    *key += u.host();

    if (u.port() > 0) {
        *key += QString::number(u.port());
    }
}

QString KProtocolManager::slaveProtocol(const QUrl &url, QStringList &proxyList)
{
#if 0
    if (url.hasSubUrl()) { // We don't want the suburl's protocol
        const QUrl::List list = QUrl::split(url);
        return slaveProtocol(list.last(), proxyList);
    }
#endif

    proxyList.clear();

    // Do not perform a proxy lookup for any url classified as a ":local" url or
    // one that does not have a host component or if proxy is disabled.
    QString protocol(url.scheme());
    if (url.host().isEmpty()
            || KProtocolInfo::protocolClass(protocol) == QL1S(":local")
            || KProtocolManager::proxyType() == KProtocolManager::NoProxy) {
        return protocol;
    }

    QString proxyCacheKey;
    extractProxyCacheKeyFromUrl(url, &proxyCacheKey);

    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    // Look for cached proxy information to avoid more work.
    if (d->cachedProxyData.contains(proxyCacheKey)) {
        KProxyData *data = d->cachedProxyData.object(proxyCacheKey);
        proxyList = data->proxyList;
        return data->protocol;
    }
    lock.unlock();

    const QStringList proxies = proxiesForUrl(url);
    const int count = proxies.count();

    if (count > 0 && !(count == 1 && proxies.first() == QL1S("DIRECT"))) {
        Q_FOREACH (const QString &proxy, proxies) {
            if (proxy == QL1S("DIRECT")) {
                proxyList << proxy;
            } else {
                QUrl u(proxy);
                if (!u.isEmpty() && u.isValid() && !u.scheme().isEmpty()) {
                    proxyList << proxy;
                }
            }
        }
    }

    // The idea behind slave protocols is not applicable to http
    // and webdav protocols as well as protocols unknown to KDE.
    if (!proxyList.isEmpty()
            && !protocol.startsWith(QL1S("http"))
            && !protocol.startsWith(QL1S("webdav"))
            && KProtocolInfo::isKnownProtocol(protocol)) {
        Q_FOREACH (const QString &proxy, proxyList) {
            QUrl u(proxy);
            if (u.isValid() && KProtocolInfo::isKnownProtocol(u.scheme())) {
                protocol = u.scheme();
                break;
            }
        }
    }

    lock.relock();
    // cache the proxy information...
    d->cachedProxyData.insert(proxyCacheKey, new KProxyData(protocol, proxyList));
    return protocol;
}

/*================================= USER-AGENT SETTINGS =====================*/

QString KProtocolManager::userAgentForHost(const QString &hostname)
{
    const QString sendUserAgent = KIO::SlaveConfig::self()->configData("http", hostname.toLower(), "SendUserAgent").toLower();
    if (sendUserAgent == QL1S("false")) {
        return QString();
    }

    const QString useragent = KIO::SlaveConfig::self()->configData("http", hostname.toLower(), "UserAgent");

    // Return the default user-agent if none is specified
    // for the requested host.
    if (useragent.isEmpty()) {
        return defaultUserAgent();
    }

    return useragent;
}

QString KProtocolManager::defaultUserAgent()
{
    const QString modifiers = KIO::SlaveConfig::self()->configData("http", QString(), "UserAgentKeys");
    return defaultUserAgent(modifiers);
}

static QString defaultUserAgentFromPreferredService()
{
    QString agentStr;

    // Check if the default COMPONENT contains a custom default UA string...
    KService::Ptr service = KMimeTypeTrader::self()->preferredService(QL1S("text/html"),
                            QL1S("KParts/ReadOnlyPart"));
    if (service && service->showInCurrentDesktop())
        agentStr = service->property(QL1S("X-KDE-Default-UserAgent"),
                                     QVariant::String).toString();
    return agentStr;
}

// This is not the OS, but the windowing system, e.g. X11 on Unix/Linux.
static QString platform()
{
#if defined(Q_OS_UNIX) && !defined(Q_OS_DARWIN)
    return QL1S("X11");
#elif defined(Q_OS_MAC)
    return QL1S("Macintosh");
#elif defined(Q_OS_WIN)
    return QL1S("Windows");
#else
    return QL1S("Unknown");
#endif
}

QString KProtocolManager::defaultUserAgent(const QString &_modifiers)
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    QString modifiers = _modifiers.toLower();
    if (modifiers.isEmpty()) {
        modifiers = DEFAULT_USER_AGENT_KEYS;
    }

    if (d->modifiers == modifiers && !d->useragent.isEmpty()) {
        return d->useragent;
    }

    d->modifiers = modifiers;

    /*
       The following code attempts to determine the default user agent string
       from the 'X-KDE-UA-DEFAULT-STRING' property of the desktop file
       for the preferred service that was configured to handle the 'text/html'
       mime type. If the preferred service's desktop file does not specify this
       property, the long standing default user agent string will be used.
       The following keyword placeholders are automatically converted when the
       user agent string is read from the property:

       %SECURITY%      Expands to"N" when SSL is not supported, otherwise it is ignored.
       %OSNAME%        Expands to operating system name, e.g. Linux.
       %OSVERSION%     Expands to operating system version, e.g. 2.6.32
       %SYSTYPE%       Expands to machine or system type, e.g. i386
       %PLATFORM%      Expands to windowing system, e.g. X11 on Unix/Linux.
       %LANGUAGE%      Expands to default language in use, e.g. en-US.
       %APPVERSION%    Expands to QCoreApplication applicationName()/applicationVerison(),
                       e.g. Konqueror/4.5.0. If application name and/or application version
                       number are not set, then "KDE" and the runtime KDE version numbers
                       are used respectively.

       All of the keywords are handled case-insensitively.
    */

    QString systemName, systemVersion, machine, supp;
    const bool sysInfoFound = getSystemNameVersionAndMachine(systemName, systemVersion, machine);
    QString agentStr = defaultUserAgentFromPreferredService();

    if (agentStr.isEmpty()) {
        supp += platform();

        if (sysInfoFound) {
            if (modifiers.contains('o')) {
                supp += QL1S("; ");
                supp += systemName;
                if (modifiers.contains('v')) {
                    supp += QL1C(' ');
                    supp += systemVersion;
                }

                if (modifiers.contains('m')) {
                    supp += QL1C(' ');
                    supp += machine;
                }
            }

            if (modifiers.contains('l')) {
                supp += QL1S("; ");
                supp += QLocale::languageToString(QLocale().language());
            }
        }

        // Full format: Mozilla/5.0 (Linux
        d->useragent = QL1S("Mozilla/5.0 (");
        d->useragent += supp;
        d->useragent += QL1S(") KHTML/");
        d->useragent += QString::number(KIO_VERSION_MAJOR);
        d->useragent += QL1C('.');
        d->useragent += QString::number(KIO_VERSION_MINOR);
        d->useragent += QL1C('.');
        d->useragent += QString::number(KIO_VERSION_PATCH);
        d->useragent += QL1S(" (like Gecko) Konqueror/");
        d->useragent += QString::number(KIO_VERSION_MAJOR);
        d->useragent += QL1C('.');
        d->useragent += QString::number(KIO_VERSION_MINOR);
    } else {
        QString appName = QCoreApplication::applicationName();
        if (appName.isEmpty() || appName.startsWith(QL1S("kcmshell"), Qt::CaseInsensitive)) {
            appName = QL1S("KDE");
        }

        QString appVersion = QCoreApplication::applicationVersion();
        if (appVersion.isEmpty()) {
            appVersion += QString::number(KIO_VERSION_MAJOR);
            appVersion += QL1C('.');
            appVersion += QString::number(KIO_VERSION_MINOR);
            appVersion += QL1C('.');
            appVersion += QString::number(KIO_VERSION_PATCH);
        }

        appName += QL1C('/');
        appName += appVersion;

        agentStr.replace(QL1S("%appversion%"), appName, Qt::CaseInsensitive);

        if (!QSslSocket::supportsSsl()) {
            agentStr.replace(QL1S("%security%"), QL1S("N"), Qt::CaseInsensitive);
        } else {
            agentStr.remove(QL1S("%security%"), Qt::CaseInsensitive);
        }

        if (sysInfoFound) {
            // Platform (e.g. X11). It is no longer configurable from UI.
            agentStr.replace(QL1S("%platform%"), platform(), Qt::CaseInsensitive);

            // Operating system (e.g. Linux)
            if (modifiers.contains('o')) {
                agentStr.replace(QL1S("%osname%"), systemName, Qt::CaseInsensitive);

                // OS version (e.g. 2.6.36)
                if (modifiers.contains('v')) {
                    agentStr.replace(QL1S("%osversion%"), systemVersion, Qt::CaseInsensitive);
                } else {
                    agentStr.remove(QL1S("%osversion%"), Qt::CaseInsensitive);
                }

                // Machine type (i686, x86-64, etc.)
                if (modifiers.contains('m')) {
                    agentStr.replace(QL1S("%systype%"), machine, Qt::CaseInsensitive);
                } else {
                    agentStr.remove(QL1S("%systype%"), Qt::CaseInsensitive);
                }
            } else {
                agentStr.remove(QL1S("%osname%"), Qt::CaseInsensitive);
                agentStr.remove(QL1S("%osversion%"), Qt::CaseInsensitive);
                agentStr.remove(QL1S("%systype%"), Qt::CaseInsensitive);
            }

            // Language (e.g. en_US)
            if (modifiers.contains('l')) {
                agentStr.replace(QL1S("%language%"), QLocale::languageToString(QLocale().language()), Qt::CaseInsensitive);
            } else {
                agentStr.remove(QL1S("%language%"), Qt::CaseInsensitive);
            }

            // Clean up unnecessary separators that could be left over from the
            // possible keyword removal above...
            agentStr.replace(QRegExp("[(]\\s*[;]\\s*"), QL1S("("));
            agentStr.replace(QRegExp("[;]\\s*[;]\\s*"), QL1S("; "));
            agentStr.replace(QRegExp("\\s*[;]\\s*[)]"), QL1S(")"));
        } else {
            agentStr.remove(QL1S("%osname%"));
            agentStr.remove(QL1S("%osversion%"));
            agentStr.remove(QL1S("%platform%"));
            agentStr.remove(QL1S("%systype%"));
            agentStr.remove(QL1S("%language%"));
        }

        d->useragent = agentStr.simplified();
    }

    //qDebug() << "USERAGENT STRING:" << d->useragent;
    return d->useragent;
}

QString KProtocolManager::userAgentForApplication(const QString &appName, const QString &appVersion,
        const QStringList &extraInfo)
{
    QString systemName, systemVersion, machine, info;

    if (getSystemNameVersionAndMachine(systemName, systemVersion, machine)) {
        info +=  systemName;
        info += QL1C('/');
        info += systemVersion;
        info += QL1S("; ");
    }

    info += QL1S("KDE/");
    info += QString::number(KIO_VERSION_MAJOR);
    info += QL1C('.');
    info += QString::number(KIO_VERSION_MINOR);
    info += QL1C('.');
    info += QString::number(KIO_VERSION_PATCH);

    if (!machine.isEmpty()) {
        info += QL1S("; ");
        info += machine;
    }

    info += QL1S("; ");
    info += extraInfo.join(QL1S("; "));

    return (appName + QL1C('/') + appVersion + QL1S(" (") + info + QL1C(')'));
}

bool KProtocolManager::getSystemNameVersionAndMachine(
    QString &systemName, QString &systemVersion, QString &machine)
{
#if defined(Q_OS_WIN) && !defined(_WIN32_WCE)
    // we do not use unameBuf.sysname information constructed in kdewin32
    // because we want to get separate name and version
    systemName = QL1S("Windows");
    OSVERSIONINFOEX versioninfo;
    ZeroMemory(&versioninfo, sizeof(OSVERSIONINFOEX));
    // try calling GetVersionEx using the OSVERSIONINFOEX, if that fails, try using the OSVERSIONINFO
    versioninfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
    bool ok = GetVersionEx((OSVERSIONINFO *) &versioninfo);
    if (!ok) {
        versioninfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
        ok = GetVersionEx((OSVERSIONINFO *) &versioninfo);
    }
    if (ok) {
        systemVersion = QString::number(versioninfo.dwMajorVersion);
        systemVersion +=  QL1C('.');
        systemVersion += QString::number(versioninfo.dwMinorVersion);
    }
#else
    struct utsname unameBuf;
    if (0 != uname(&unameBuf)) {
        return false;
    }
    systemName = unameBuf.sysname;
    systemVersion = unameBuf.release;
    machine = unameBuf.machine;
#endif
    return true;
}

QString KProtocolManager::acceptLanguagesHeader()
{
    const QLatin1String english("en");

    // User's desktop language preference.
    QStringList languageList = QLocale().uiLanguages();

    // Replace possible "C" in the language list with "en", unless "en" is
    // already pressent. This is to keep user's priorities in order.
    // If afterwards "en" is still not present, append it.
    int idx = languageList.indexOf(QString::fromLatin1("C"));
    if (idx != -1) {
        if (languageList.contains(english)) {
            languageList.removeAt(idx);
        } else {
            languageList[idx] = english;
        }
    }
    if (!languageList.contains(english)) {
        languageList += english;
    }

    // Some languages may have web codes different from locale codes,
    // read them from the config and insert in proper order.
    KConfig acclangConf("accept-languages.codes", KConfig::NoGlobals);
    KConfigGroup replacementCodes(&acclangConf, "ReplacementCodes");
    QStringList languageListFinal;
    Q_FOREACH (const QString &lang, languageList) {
        const QStringList langs = replacementCodes.readEntry(lang, QStringList());
        if (langs.isEmpty()) {
            languageListFinal += lang;
        } else {
            languageListFinal += langs;
        }
    }

    // The header is composed of comma separated languages, with an optional
    // associated priority estimate (q=1..0) defaulting to 1.
    // As our language tags are already sorted by priority, we'll just decrease
    // the value evenly
    int prio = 10;
    QString header;
    Q_FOREACH (const QString &lang, languageListFinal) {
        header += lang;
        if (prio < 10) {
            header += QL1S(";q=0.");
            header += QString::number(prio);
        }
        // do not add cosmetic whitespace in here : it is less compatible (#220677)
        header += QL1S(",");
        if (prio > 1) {
            --prio;
        }
    }
    header.chop(1);

    // Some of the languages may have country specifier delimited by
    // underscore, or modifier delimited by at-sign.
    // The header should use dashes instead.
    header.replace('_', '-');
    header.replace('@', '-');

    return header;
}

/*==================================== OTHERS ===============================*/

bool KProtocolManager::markPartial()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return config()->group(QByteArray()).readEntry("MarkPartial", true);
}

int KProtocolManager::minimumKeepSize()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return config()->group(QByteArray()).readEntry("MinimumKeepSize",
            DEFAULT_MINIMUM_KEEP_SIZE);  // 5000 byte
}

bool KProtocolManager::autoResume()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return config()->group(QByteArray()).readEntry("AutoResume", false);
}

bool KProtocolManager::persistentConnections()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return config()->group(QByteArray()).readEntry("PersistentConnections", true);
}

bool KProtocolManager::persistentProxyConnection()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return config()->group(QByteArray()).readEntry("PersistentProxyConnection", false);
}

QString KProtocolManager::proxyConfigScript()
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    return config()->group("Proxy Settings").readEntry("Proxy Config Script");
}

/* =========================== PROTOCOL CAPABILITIES ============== */

static KProtocolInfoPrivate *findProtocol(const QUrl &url)
{
    QString protocol = url.scheme();
    if (!KProtocolInfo::proxiedBy(protocol).isEmpty()) {
        QString dummy;
        protocol = KProtocolManager::slaveProtocol(url, dummy);
    }

    return KProtocolInfoFactory::self()->findProtocol(protocol);
}

KProtocolInfo::Type KProtocolManager::inputType(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return KProtocolInfo::T_NONE;
    }

    return prot->m_inputType;
}

KProtocolInfo::Type KProtocolManager::outputType(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return KProtocolInfo::T_NONE;
    }

    return prot->m_outputType;
}

bool KProtocolManager::isSourceProtocol(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_isSourceProtocol;
}

bool KProtocolManager::supportsListing(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_supportsListing;
}

QStringList KProtocolManager::listing(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return QStringList();
    }

    return prot->m_listing;
}

bool KProtocolManager::supportsReading(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_supportsReading;
}

bool KProtocolManager::supportsWriting(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_supportsWriting;
}

bool KProtocolManager::supportsMakeDir(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_supportsMakeDir;
}

bool KProtocolManager::supportsDeleting(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_supportsDeleting;
}

bool KProtocolManager::supportsLinking(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_supportsLinking;
}

bool KProtocolManager::supportsMoving(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_supportsMoving;
}

bool KProtocolManager::supportsOpening(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_supportsOpening;
}

bool KProtocolManager::canCopyFromFile(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_canCopyFromFile;
}

bool KProtocolManager::canCopyToFile(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_canCopyToFile;
}

bool KProtocolManager::canRenameFromFile(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_canRenameFromFile;
}

bool KProtocolManager::canRenameToFile(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_canRenameToFile;
}

bool KProtocolManager::canDeleteRecursive(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return false;
    }

    return prot->m_canDeleteRecursive;
}

KProtocolInfo::FileNameUsedForCopying KProtocolManager::fileNameUsedForCopying(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return KProtocolInfo::FromUrl;
    }

    return prot->m_fileNameUsedForCopying;
}

QString KProtocolManager::defaultMimetype(const QUrl &url)
{
    KProtocolInfoPrivate *prot = findProtocol(url);
    if (!prot) {
        return QString();
    }

    return prot->m_defaultMimetype;
}

QString KProtocolManager::protocolForArchiveMimetype(const QString &mimeType)
{
    PRIVATE_DATA;
    QMutexLocker lock(&d->mutex);
    if (d->protocolForArchiveMimetypes.isEmpty()) {
        const QList<KProtocolInfoPrivate *> allProtocols = KProtocolInfoFactory::self()->allProtocols();
        for (QList<KProtocolInfoPrivate *>::const_iterator it = allProtocols.begin();
                it != allProtocols.end(); ++it) {
            const QStringList archiveMimetypes = (*it)->m_archiveMimeTypes;
            Q_FOREACH (const QString &mime, archiveMimetypes) {
                d->protocolForArchiveMimetypes.insert(mime, (*it)->m_name);
            }
        }
    }
    return d->protocolForArchiveMimetypes.value(mimeType);
}

QString KProtocolManager::charsetFor(const QUrl &url)
{
    return KIO::SlaveConfig::self()->configData(url.scheme(), url.host(), QLatin1String("Charset"));
}

#undef PRIVATE_DATA
