QAbstractSocket: fake a bind(QHostAddress::SpecialAddress)

Because this is misleading:

  socket.bind(QHostAddress::AnyIPv4);

The conversion of enum to int has preference over the construction of
QHostAddress from enum, so that ends up calling bind(6), which attempts
to bind to privileged port 6 and just returns with error. Meanwhile,

  socket.bind(QHostAddress::AnyIPv4, 0);

does construct the QHostAddress because that is preferred to converting
the int to the BindMode enum.

Ideally we'd simply add the overload to QAbstractSocket but we can't do
that because QHostAddress depends on QAbstractSocket. So I've added a
Qt7 task to invert that dependency.

Change-Id: I26b8286f61534f88b649fffd166b683266597796
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

src/network/kernel/qhostaddress.h

@@ -115,6 +115,8 @@ public:
     bool setAddress(const QString &address);
     void setAddress(SpecialAddress address);
 
+    // ### Qt7: consider moving NetworkLayerProtocol to QHostAddress so we
+    // don't depend on QAbstractSocket
     QAbstractSocket::NetworkLayerProtocol protocol() const;
     quint32 toIPv4Address(bool *ok = nullptr) const;
     Q_IPV6ADDR toIPv6Address() const;

src/network/socket/qabstractsocket.cpp

@@ -1604,6 +1604,19 @@ bool QAbstractSocketPrivate::bind(const QHostAddress &address, quint16 port, QAb
 }
 
 /*!
+    \fn bool QAbstractSocket::bind(QHostAddress::SpecialAddress addr, quint16 port, BindMode mode)
+    \since 6.2
+    \overload
+
+    Binds to the special address \a addr on port \a port, using the BindMode \a
+    mode.
+
+    By default, the socket is bound using the DefaultForPlatform BindMode.
+    If a port is not specified, a random port is chosen.
+*/
+
+/*!
+    \fn bool QAbstractSocket::bind(quint16 port, BindMode mode)
     \since 5.0
     \overload
 
@@ -1612,10 +1625,12 @@ bool QAbstractSocketPrivate::bind(const QHostAddress &address, quint16 port, QAb
     By default, the socket is bound using the DefaultForPlatform BindMode.
     If a port is not specified, a random port is chosen.
 */
+#if QT_VERSION < QT_VERSION_CHECK(7, 0, 0)
 bool QAbstractSocket::bind(quint16 port, BindMode mode)
 {
     return bind(QHostAddress::Any, port, mode);
 }
+#endif
 
 /*!
     Returns \c true if the socket is valid and ready for use; otherwise

src/network/socket/qabstractsocket.h

@@ -148,7 +148,15 @@ public:
 
     virtual bool bind(const QHostAddress &address, quint16 port = 0,
                       BindMode mode = DefaultForPlatform);
+#if QT_VERSION >= QT_VERSION_CHECK(7,0,0) || defined(Q_CLANG_QDOC)
+    // ### Qt7: this requires that QHostAddress stop depending on QAbstractSocket::NetworkLayerProtocol
+    bool bind(QHostAddress::SpecialAddress addr, quint16 port = 0, BindMode mode = DefaultForPlatform)
+    { return bind(QHostAddress(addr), port, mode); }
+    bool bind(quint16 port = 0, BindMode mode = DefaultForPlatform)
+    { retrurn bind(QHostAddress::Any, port, mode); }
+#else
     bool bind(quint16 port = 0, BindMode mode = DefaultForPlatform);
+#endif
 
     virtual void connectToHost(const QString &hostName, quint16 port, OpenMode mode = ReadWrite, NetworkLayerProtocol protocol = AnyIPProtocol);
     void connectToHost(const QHostAddress &address, quint16 port, OpenMode mode = ReadWrite);

src/network/socket/qtcpsocket.h

@@ -42,6 +42,7 @@
 
 #include <QtNetwork/qtnetworkglobal.h>
 #include <QtNetwork/qabstractsocket.h>
+#include <QtNetwork/qhostaddress.h>
 #include <QtCore/qvariant.h>
 
 QT_BEGIN_NAMESPACE
@@ -56,6 +57,13 @@ public:
     explicit QTcpSocket(QObject *parent = nullptr);
     virtual ~QTcpSocket();
 
+#if QT_VERSION < QT_VERSION_CHECK(7,0,0) && !defined(Q_CLANG_QDOC)
+    // ### Qt7: move into QAbstractSocket
+    using QAbstractSocket::bind;
+    bool bind(QHostAddress::SpecialAddress addr, quint16 port = 0, BindMode mode = DefaultForPlatform)
+    { return bind(QHostAddress(addr), port, mode); }
+#endif
+
 protected:
     QTcpSocket(QTcpSocketPrivate &dd, QObject *parent = nullptr);
     QTcpSocket(QAbstractSocket::SocketType socketType, QTcpSocketPrivate &dd,

src/network/socket/qudpsocket.h

@@ -60,6 +60,13 @@ public:
     explicit QUdpSocket(QObject *parent = nullptr);
     virtual ~QUdpSocket();
 
+#if QT_VERSION < QT_VERSION_CHECK(7,0,0) && !defined(Q_CLANG_QDOC)
+    // ### Qt7: move into QAbstractSocket
+    using QAbstractSocket::bind;
+    bool bind(QHostAddress::SpecialAddress addr, quint16 port = 0, BindMode mode = DefaultForPlatform)
+    { return bind(QHostAddress(addr), port, mode); }
+#endif
+
 #ifndef QT_NO_NETWORKINTERFACE
     bool joinMulticastGroup(const QHostAddress &groupAddress);
     bool joinMulticastGroup(const QHostAddress &groupAddress,