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/*!

    \class QNetworkProxy

    \since 4.1

    \brief The QNetworkProxy class provides a network layer proxy.

    \reentrant

    \ingroup network

    \inmodule QtNetwork

    QNetworkProxy provides the method for configuring network layer

    proxy support to the Qt network classes. The currently supported

    classes are QAbstractSocket, QTcpSocket, QUdpSocket, QTcpServer,

    QNetworkAccessManager and QFtp. The proxy support is designed to

    be as transparent as possible. This means that existing

    network-enabled applications that you have written should

    automatically support network proxy using the following code.

    \snippet doc/src/snippets/code/src_network_kernel_qnetworkproxy.cpp 0

    An alternative to setting an application wide proxy is to specify

    the proxy for individual sockets using QAbstractSocket::setProxy()

    and QTcpServer::setProxy(). In this way, it is possible to disable

    the use of a proxy for specific sockets using the following code:

    \snippet doc/src/snippets/code/src_network_kernel_qnetworkproxy.cpp 1

    Network proxy is not used if the address used in \l

    {QAbstractSocket::connectToHost()}{connectToHost()}, \l

    {QUdpSocket::bind()}{bind()} or \l

    {QTcpServer::listen()}{listen()} is equivalent to

    QHostAddress::LocalHost or QHostAddress::LocalHostIPv6.

    Each type of proxy support has certain restrictions associated with it.

    You should read the \l{ProxyType} documentation carefully before

    selecting a proxy type to use.

    \note Changes made to currently connected sockets do not take effect.

    If you need to change a connected socket, you should reconnect it.

    \section1 SOCKS5

    The SOCKS5 support in Qt 4 is based on \l{RFC 1928} and \l{RFC 1929}.

    The supported authentication methods are no authentication and

    username/password authentication.  Both IPv4 and IPv6 are

    supported. Domain names are resolved through the SOCKS5 server if

    the QNetworkProxy::HostNameLookupCapability is enabled, otherwise

    they are resolved locally and the IP address is sent to the

    server. There are several things to remember when using SOCKS5

    with QUdpSocket and QTcpServer:

    With QUdpSocket, a call to \l {QUdpSocket::bind()}{bind()} may fail

    with a timeout error. If a port number other than 0 is passed to

    \l {QUdpSocket::bind()}{bind()}, it is not guaranteed that it is the

    specified port that will be used.

    Use \l{QUdpSocket::localPort()}{localPort()} and

    \l{QUdpSocket::localAddress()}{localAddress()} to get the actual

    address and port number in use. Because proxied UDP goes through

    two UDP connections, it is more likely that packets will be dropped.

    With QTcpServer a call to \l{QTcpServer::listen()}{listen()} may

    fail with a timeout error. If a port number other than 0 is passed

    to \l{QTcpServer::listen()}{listen()}, then it is not guaranteed

    that it is the specified port that will be used.

    Use \l{QTcpServer::serverPort()}{serverPort()} and

    \l{QTcpServer::serverAddress()}{serverAddress()} to get the actual

    address and port used to listen for connections. SOCKS5 only supports

    one accepted connection per call to \l{QTcpServer::listen()}{listen()},

    and each call is likely to result in a different

    \l{QTcpServer::serverPort()}{serverPort()} being used.

    \sa QAbstractSocket, QTcpServer

*/

/*!

    \enum QNetworkProxy::ProxyType

    This enum describes the types of network proxying provided in Qt.

    There are two types of proxies that Qt understands:

    transparent proxies and caching proxies. The first group consists

    of proxies that can handle any arbitrary data transfer, while the

    second can only handle specific requests. The caching proxies only

    make sense for the specific classes where they can be used.

    \value NoProxy No proxying is used

    \value DefaultProxy Proxy is determined based on the application proxy set using setApplicationProxy()

    \value Socks5Proxy \l Socks5 proxying is used

    \value HttpProxy HTTP transparent proxying is used

    \value HttpCachingProxy Proxying for HTTP requests only

    \value FtpCachingProxy Proxying for FTP requests only

    The table below lists different proxy types and their

    capabilities. Since each proxy type has different capabilities, it

    is important to understand them before choosing a proxy type.

    \table

    \header

        \o Proxy type

        \o Description

        \o Default capabilities

    \row

        \o SOCKS 5

        \o Generic proxy for any kind of connection. Supports TCP,

           UDP, binding to a port (incoming connections) and

           authentication.

        \o TunnelingCapability, ListeningCapability,

           UdpTunnelingCapability, HostNameLookupCapability

    \row

        \o HTTP

        \o Implemented using the "CONNECT" command, supports only

           outgoing TCP connections; supports authentication.

        \o TunnelingCapability, CachingCapability, HostNameLookupCapability

    \row

        \o Caching-only HTTP

        \o Implemented using normal HTTP commands, it is useful only

           in the context of HTTP requests (see QNetworkAccessManager)

        \o CachingCapability, HostNameLookupCapability

    \row

        \o Caching FTP

        \o Implemented using an FTP proxy, it is useful only in the

           context of FTP requests (see QFtp,

           QNetworkAccessManager)

        \o CachingCapability, HostNameLookupCapability

    \endtable

    Also note that you shouldn't set the application default proxy

    (setApplicationProxy()) to a proxy that doesn't have the

    TunnelingCapability capability. If you do, QTcpSocket will not

    know how to open connections.

    \sa setType(), type(), capabilities(), setCapabilities()

*/

/*!

    \enum QNetworkProxy::Capability

    \since 4.5

    These flags indicate the capabilities that a given proxy server

    supports.

    QNetworkProxy sets different capabilities by default when the

    object is created (see QNetworkProxy::ProxyType for a list of the

    defaults). However, it is possible to change the capabitilies

    after the object has been created with setCapabilities().

    The capabilities that QNetworkProxy supports are:

    \value TunnelingCapability Ability to open transparent, tunneled

    TCP connections to a remote host. The proxy server relays the

    transmission verbatim from one side to the other and does no

    caching.

    \value ListeningCapability Ability to create a listening socket

    and wait for an incoming TCP connection from a remote host.

    \value UdpTunnelingCapability Ability to relay UDP datagrams via

    the proxy server to and from a remote host.

    \value CachingCapability Ability to cache the contents of the

    transfer. This capability is specific to each protocol and proxy

    type. For example, HTTP proxies can cache the contents of web data

    transferred with "GET" commands.

    \value HostNameLookupCapability Ability to connect to perform the

    lookup on a remote host name and connect to it, as opposed to

    requiring the application to perform the name lookup and request

    connection to IP addresses only.

*/

#include "qnetworkproxy.h"

#ifndef QT_NO_NETWORKPROXY

#include "private/qnetworkproxy_p.h"

#include "private/qsocks5socketengine_p.h"

#include "private/qhttpsocketengine_p.h"

#include "qauthenticator.h"

#include "qhash.h"

#include "qmutex.h"

#include "qurl.h"

QT_BEGIN_NAMESPACE

class QSocks5SocketEngineHandler;

class QHttpSocketEngineHandler;

class QGlobalNetworkProxy

{

public:

    QGlobalNetworkProxy()

        : mutex(QMutex::Recursive)

        , applicationLevelProxy(0)

        , applicationLevelProxyFactory(0)

        , socks5SocketEngineHandler(0)

        , httpSocketEngineHandler(0)

    {

    }

    ~QGlobalNetworkProxy()

    {

        delete applicationLevelProxy;

        delete applicationLevelProxyFactory;

        delete socks5SocketEngineHandler;

        delete httpSocketEngineHandler;

    }

    void init()

    {

        QMutexLocker lock(&mutex);

#ifndef QT_NO_SOCKS5

        if (!socks5SocketEngineHandler)

            socks5SocketEngineHandler = new QSocks5SocketEngineHandler();

#endif

#ifndef QT_NO_HTTP

        if (!httpSocketEngineHandler)

            httpSocketEngineHandler = new QHttpSocketEngineHandler();

#endif

    }

    void setApplicationProxy(const QNetworkProxy &proxy)

    {

        QMutexLocker lock(&mutex);

        if (!applicationLevelProxy)

            applicationLevelProxy = new QNetworkProxy;

        *applicationLevelProxy = proxy;

        delete applicationLevelProxyFactory;

        applicationLevelProxyFactory = 0;

    }

    void setApplicationProxyFactory(QNetworkProxyFactory *factory)

    {

        QMutexLocker lock(&mutex);

        if (applicationLevelProxy)

            *applicationLevelProxy = QNetworkProxy();

        delete applicationLevelProxyFactory;

        applicationLevelProxyFactory = factory;

    }

    QNetworkProxy applicationProxy()

    {

        return proxyForQuery(QNetworkProxyQuery()).first();

    }

    QList<QNetworkProxy> proxyForQuery(const QNetworkProxyQuery &query);

private:

    QMutex mutex;

    QNetworkProxy *applicationLevelProxy;

    QNetworkProxyFactory *applicationLevelProxyFactory;

    QSocks5SocketEngineHandler *socks5SocketEngineHandler;

    QHttpSocketEngineHandler *httpSocketEngineHandler;

};

QList<QNetworkProxy> QGlobalNetworkProxy::proxyForQuery(const QNetworkProxyQuery &query)

{

    QMutexLocker locker(&mutex);

    QList<QNetworkProxy> result;

    if (!applicationLevelProxyFactory) {

        if (applicationLevelProxy

            && applicationLevelProxy->type() != QNetworkProxy::DefaultProxy)

            result << *applicationLevelProxy;

        else

            result << QNetworkProxy(QNetworkProxy::NoProxy);

        return result;

    }

    // we have a factory

    result = applicationLevelProxyFactory->queryProxy(query);

    if (result.isEmpty()) {

        qWarning("QNetworkProxyFactory: factory %p has returned an empty result set",

                 applicationLevelProxyFactory);

        result << QNetworkProxy(QNetworkProxy::NoProxy);

    }

    return result;

}

Q_GLOBAL_STATIC(QGlobalNetworkProxy, globalNetworkProxy)

namespace {

    template<bool> struct StaticAssertTest;

    template<> struct StaticAssertTest<true> { enum { Value = 1 }; };

}

static inline void qt_noop_with_arg(int) {}

#define q_static_assert(expr)   qt_noop_with_arg(sizeof(StaticAssertTest< expr >::Value))

static QNetworkProxy::Capabilities defaultCapabilitiesForType(QNetworkProxy::ProxyType type)

{

    q_static_assert(int(QNetworkProxy::DefaultProxy) == 0);

    q_static_assert(int(QNetworkProxy::FtpCachingProxy) == 5);

    static const int defaults[] =

    {

        /* [QNetworkProxy::DefaultProxy] = */

        (int(QNetworkProxy::ListeningCapability) |

         int(QNetworkProxy::TunnelingCapability) |

         int(QNetworkProxy::UdpTunnelingCapability)),

        /* [QNetworkProxy::Socks5Proxy] = */

        (int(QNetworkProxy::TunnelingCapability) |

         int(QNetworkProxy::ListeningCapability) |

         int(QNetworkProxy::UdpTunnelingCapability) |

         int(QNetworkProxy::HostNameLookupCapability)),

        // it's weird to talk about the proxy capabilities of a "not proxy"...

        /* [QNetworkProxy::NoProxy] = */

        (int(QNetworkProxy::ListeningCapability) |

         int(QNetworkProxy::TunnelingCapability) |

         int(QNetworkProxy::UdpTunnelingCapability)),

        /* [QNetworkProxy::HttpProxy] = */

        (int(QNetworkProxy::TunnelingCapability) |

         int(QNetworkProxy::CachingCapability) |

         int(QNetworkProxy::HostNameLookupCapability)),

        /* [QNetworkProxy::HttpCachingProxy] = */

        (int(QNetworkProxy::CachingCapability) |

         int(QNetworkProxy::HostNameLookupCapability)),

        /* [QNetworkProxy::FtpCachingProxy] = */

        (int(QNetworkProxy::CachingCapability) |

         int(QNetworkProxy::HostNameLookupCapability)),

    };

    if (int(type) < 0 || int(type) > int(QNetworkProxy::FtpCachingProxy))

        type = QNetworkProxy::DefaultProxy;

    return QNetworkProxy::Capabilities(defaults[int(type)]);

}

class QNetworkProxyPrivate: public QSharedData

{

public:

    QString hostName;

    QString user;

    QString password;

    QNetworkProxy::Capabilities capabilities;

    quint16 port;

    QNetworkProxy::ProxyType type;

    bool capabilitiesSet;

    inline QNetworkProxyPrivate(QNetworkProxy::ProxyType t = QNetworkProxy::DefaultProxy,

                                const QString &h = QString(), quint16 p = 0,

                                const QString &u = QString(), const QString &pw = QString())

        : hostName(h),

          user(u),

          password(pw),

          capabilities(defaultCapabilitiesForType(t)),

          port(p),

          type(t),

          capabilitiesSet(false)

    { }

    inline bool operator==(const QNetworkProxyPrivate &other) const

    {

        return type == other.type &&

            port == other.port &&

            hostName == other.hostName &&

            user == other.user &&

            password == other.password &&

            capabilities == other.capabilities;

    }

};

template<> void QSharedDataPointer<QNetworkProxyPrivate>::detach()

{

    if (d && d->ref == 1)

        return;

    QNetworkProxyPrivate *x = (d ? new QNetworkProxyPrivate(*d)

                               : new QNetworkProxyPrivate);

    x->ref.ref();

    if (d && !d->ref.deref())

        delete d;

    d = x;

}

/*!

    Constructs a QNetworkProxy with DefaultProxy type; the proxy type is

    determined by applicationProxy(), which defaults to NoProxy.

    \sa setType(), setApplicationProxy()

*/

QNetworkProxy::QNetworkProxy()

    : d(0)

{

    globalNetworkProxy()->init();

}

/*!

    Constructs a QNetworkProxy with \a type, \a hostName, \a port,

    \a user and \a password.

    The default capabilities for proxy type \a type are set automatically.

    \sa capabilities()

*/

QNetworkProxy::QNetworkProxy(ProxyType type, const QString &hostName, quint16 port,

                  const QString &user, const QString &password)

    : d(new QNetworkProxyPrivate(type, hostName, port, user, password))

{

    globalNetworkProxy()->init();

}

/*!

    Constructs a copy of \a other.

*/

QNetworkProxy::QNetworkProxy(const QNetworkProxy &other)

    : d(other.d)

{

}

/*!

    Destroys the QNetworkProxy object.

*/

QNetworkProxy::~QNetworkProxy()

{

    // QSharedDataPointer takes care of deleting for us

}

/*!

    \since 4.4

    Compares the value of this network proxy to \a other and returns true

    if they are equal (same proxy type, server as well as username and password)

*/

bool QNetworkProxy::operator==(const QNetworkProxy &other) const

{

    return d == other.d || (d && other.d && *d == *other.d);

}

/*!

    \fn bool QNetworkProxy::operator!=(const QNetworkProxy &other) const

    \since 4.4

    Compares the value of this network proxy to \a other and returns true

    if they differ.

\*/

/*!

    \since 4.2

    Assigns the value of the network proxy \a other to this network proxy.

*/

QNetworkProxy &QNetworkProxy::operator=(const QNetworkProxy &other)

{

    d = other.d;

    return *this;

}

/*!

    Sets the proxy type for this instance to be \a type.

    Note that changing the type of a proxy does not change

    the set of capabilities this QNetworkProxy object holds if any

    capabilities have been set with setCapabilities().

    \sa type(), setCapabilities()

*/

void QNetworkProxy::setType(QNetworkProxy::ProxyType type)

{

    d->type = type;

    if (!d->capabilitiesSet)

        d->capabilities = defaultCapabilitiesForType(type);

}

/*!

    Returns the proxy type for this instance.

    \sa setType()

*/

QNetworkProxy::ProxyType QNetworkProxy::type() const

{

    return d ? d->type : DefaultProxy;

}

/*!

    \since 4.5

    Sets the capabilities of this proxy to \a capabilities.

    \sa setType(), capabilities()

*/

void QNetworkProxy::setCapabilities(Capabilities capabilities)

{

    d->capabilities = capabilities;