Fixed ambiguity/protected access issue in Socket::open

NetworkStack/NetworkInterface overloads
 - Multiple inheritance results in ambiguity

NetworkStack with templated get_stack overload
 - get_stack hidden behind protected access prevents template match
 - explicit call to NetworkInterface::get_stack does not follow vtable

Solution is to use two overloaded function for
NetworkStack/NetworkInterface, and an overload for a templated type that
supports a static_cast to NetworkStack. This resolves the ambiguity
without being blocked by protected access.

Moved duplicated overloads out to overload of common nsapi_create_stack
function.

Author: geky

NetworkInterface.h

@@ -17,7 +17,8 @@
 #ifndef NETWORK_INTERFACE_H
 #define NETWORK_INTERFACE_H
 
-#include "NetworkSocketAPI/NetworkStack.h"
+// Predeclared class
+class NetworkStack;
 
 
 /** NetworkInterface class
@@ -41,6 +42,8 @@ class NetworkInterface {
     friend class TCPSocket;
     friend class TCPServer;
     friend class SocketAddress;
+    template <typename IF>
+    friend NetworkStack *nsapi_create_stack(IF *iface);
 
     /** Provide access to the NetworkStack object
      *

NetworkStack.cpp

@@ -249,3 +249,9 @@ NetworkStack *nsapi_create_stack(nsapi_stack_t *stack)
     MBED_ASSERT(sizeof stack->_stack_buffer >= sizeof(NetworkStackWrapper));
     return new (stack->_stack_buffer) NetworkStackWrapper;
 }
+
+NetworkStack *nsapi_create_stack(NetworkStack *stack)
+{
+    return stack;
+}
+

NetworkStack.h

@@ -19,6 +19,7 @@
 
 #include "nsapi_types.h"
 #include "NetworkSocketAPI/SocketAddress.h"
+#include "NetworkSocketAPI/NetworkInterface.h"
 
 
 /** NetworkStack class
@@ -280,10 +281,20 @@ class NetworkStack
 
 /** Convert a raw nsapi_stack_t object into a C++ NetworkStack object
  *
- *  @param stack    Reference to a raw nsapi_stack_t object
+ *  @param stack    Reference to an object that can be converted to a stack
+ *                  - A raw nsapi_stack_t object
+ *                  - A reference to a network stack
+ *                  - A reference to a network interface
  *  @return         Reference to the underlying network stack
  */
 NetworkStack *nsapi_create_stack(nsapi_stack_t *stack);
+NetworkStack *nsapi_create_stack(NetworkStack *stack);
+
+template <typename IF>
+NetworkStack *nsapi_create_stack(IF *iface)
+{
+    return nsapi_create_stack(static_cast<NetworkInterface *>(iface)->get_stack());
+}
 
 
 #endif

Socket.cpp

@@ -23,7 +23,7 @@ Socket::Socket()
 {
 }
 
-int Socket::open(NetworkStack *stack, nsapi_protocol_t proto)
+int Socket::open(NetworkStack *stack)
 {
     _lock.lock();
 
@@ -34,7 +34,7 @@ int Socket::open(NetworkStack *stack, nsapi_protocol_t proto)
     _stack = stack;
 
     nsapi_socket_t socket;
-    int err = _stack->socket_open(&socket, proto);
+    int err = _stack->socket_open(&socket, get_proto());
     if (err) {
         _lock.unlock();
         return err;

Socket.h

@@ -46,11 +46,11 @@ class Socket {
      *  @param stack    Network stack as target for socket
      *  @return         0 on success, negative error code on failure
      */
-    virtual int open(NetworkStack *stack) = 0;
+    int open(NetworkStack *stack);
 
-    template <typename IF>
-    int open(IF *iface) {
-        return open(iface->get_stack());
+    template <typename S>
+    int open(S *stack) {
+        return open(nsapi_create_stack(stack));
     }
 
     /** Close the socket
@@ -180,7 +180,7 @@ class Socket {
 
 protected:
     Socket();
-    int open(NetworkStack *stack, nsapi_protocol_t proto);
+    virtual nsapi_protocol_t get_proto() = 0;
     virtual void event() = 0;
 
     NetworkStack *_stack;

SocketAddress.cpp

@@ -143,11 +143,6 @@ static void ipv6_to_address(char *addr, const uint8_t *bytes)
 }
 
 
-SocketAddress::SocketAddress(NetworkStack *iface, const char *host, uint16_t port)
-{
-    _SocketAddress(iface, host, port);
-}
-
 SocketAddress::SocketAddress(nsapi_addr_t addr, uint16_t port)
 {
     _ip_address[0] = '\0';

SocketAddress.h

@@ -38,16 +38,14 @@ class SocketAddress {
      *
      *  On failure, the IP address and port will be set to zero
      *
-     *  @param iface    Network interface to use for DNS resolution
+     *  @param stack    Network stack to use for DNS resolution
      *  @param host     Hostname to resolve
      *  @param port     Optional 16-bit port
      */
-    SocketAddress(NetworkStack *iface, const char *host, uint16_t port = 0);
-
-    template <typename IF>
-    SocketAddress(IF *iface, const char *host, uint16_t port = 0)
+    template <typename S>
+    SocketAddress(S *stack, const char *host, uint16_t port = 0)
     {
-        _SocketAddress(iface->get_stack(), host, port);
+        _SocketAddress(nsapi_create_stack(stack), host, port);
     }
 
     /** Create a SocketAddress from a raw IP address and port

TCPServer.cpp

@@ -22,20 +22,14 @@ TCPServer::TCPServer()
 {
 }
 
-TCPServer::TCPServer(NetworkStack *stack)
-    : _pending(0), _accept_sem(0)
-{
-    open(stack);
-}
-
 TCPServer::~TCPServer()
 {
     close();
 }
 
-int TCPServer::open(NetworkStack *stack)
+nsapi_protocol_t TCPServer::get_proto()
 {
-    return Socket::open(stack, NSAPI_TCP);
+    return NSAPI_TCP;
 }
 
 int TCPServer::listen(int backlog)

TCPServer.h

@@ -56,22 +56,6 @@ class TCPServer : public Socket {
      */
     virtual ~TCPServer();
 
-    /** Opens a socket
-     *
-     *  Creates a network socket on the network stack of the given
-     *  network interface. Not needed if stack is passed to the
-     *  socket's constructor.
-     *
-     *  @param stack    Network stack as target for socket
-     *  @return         0 on success, negative error code on failure
-     */
-    virtual int open(NetworkStack *stack);
-
-    template <typename IF>
-    int open(IF *iface) {
-        return open(iface->get_stack());
-    }
-
     /** Listen for connections on a TCP socket
      *
      *  Marks the socket as a passive socket that can be used to accept
@@ -97,7 +81,9 @@ class TCPServer : public Socket {
      *  @return         0 on success, negative error code on failure
      */
     int accept(TCPSocket *connection);
+
 protected:
+    virtual nsapi_protocol_t get_proto();
     virtual void event();
 
     volatile unsigned _pending;

TCPSocket.cpp

@@ -24,20 +24,14 @@ TCPSocket::TCPSocket()
 {
 }
 
-TCPSocket::TCPSocket(NetworkStack *stack)
-    : _pending(0)
-{
-    open(stack);
-}
-
 TCPSocket::~TCPSocket()
 {
     close();
 }
 
-int TCPSocket::open(NetworkStack *stack)
+nsapi_protocol_t TCPSocket::get_proto()
 {
-    return Socket::open(stack, NSAPI_TCP);
+    return NSAPI_TCP;
 }
 
 int TCPSocket::connect(const SocketAddress &address)

TCPSocket.h

@@ -40,14 +40,12 @@ class TCPSocket : public Socket {
      *
      *  @param stack    Network stack as target for socket
      */
-    TCPSocket(NetworkStack *stack);
-
-    template <typename IF>
-    TCPSocket(IF *iface)
+    template <typename S>
+    TCPSocket(S *stack)
         : _pending(0), _read_sem(0), _write_sem(0),
           _read_in_progress(false), _write_in_progress(false)
     {
-        open(iface->get_stack());
+        open(stack);
     }
 
     /** Destroy a socket
@@ -56,22 +54,6 @@ class TCPSocket : public Socket {
      */
     virtual ~TCPSocket();
 
-    /** Opens a socket
-     *
-     *  Creates a network socket on the network stack of the given
-     *  network interface. Not needed if stack is passed to the
-     *  socket's constructor.
-     *
-     *  @param stack    Network stack as target for socket
-     *  @return         0 on success, negative error code on failure
-     */
-    virtual int open(NetworkStack *stack);
-
-    template <typename IF>
-    int open(IF *iface) {
-        return open(iface->get_stack());
-    }
-
     /** Connects TCP socket to a remote host
      *
      *  Initiates a connection to a remote server specified by either
@@ -128,6 +110,7 @@ class TCPSocket : public Socket {
 protected:
     friend class TCPServer;
 
+    virtual nsapi_protocol_t get_proto();
     virtual void event();
 
     volatile unsigned _pending;

UDPSocket.cpp

@@ -24,21 +24,14 @@ UDPSocket::UDPSocket()
 {
 }
 
-UDPSocket::UDPSocket(NetworkStack *stack)
-    : _pending(0), _read_sem(0), _write_sem(0),
-      _read_in_progress(false), _write_in_progress(false)
-{
-    open(stack);
-}
-
 UDPSocket::~UDPSocket()
 {
     close();
 }
 
-int UDPSocket::open(NetworkStack *stack)
+nsapi_protocol_t UDPSocket::get_proto()
 {
-    return Socket::open(stack, NSAPI_UDP);
+    return NSAPI_UDP;
 }
 
 int UDPSocket::sendto(const char *host, uint16_t port, const void *data, unsigned size)

UDPSocket.h

@@ -40,14 +40,12 @@ class UDPSocket : public Socket {
      *
      *  @param stack    Network stack as target for socket
      */
-    UDPSocket(NetworkStack *stack);
-
-    template <typename IF>
-    UDPSocket(IF *iface)
+    template <typename S>
+    UDPSocket(S *stack)
         : _pending(0), _read_sem(0), _write_sem(0),
           _read_in_progress(false), _write_in_progress(false)
     {
-        open(iface->get_stack());
+        open(stack);
     }
 
     /** Destroy a socket
@@ -56,22 +54,6 @@ class UDPSocket : public Socket {
      */
     virtual ~UDPSocket();
 
-    /** Opens a socket
-     *
-     *  Creates a network socket on the network stack of the given
-     *  network interface. Not needed if stack is passed to the
-     *  socket's constructor.
-     *
-     *  @param stack    Network stack as target for socket
-     *  @return         0 on success, negative error code on failure
-     */
-    virtual int open(NetworkStack *stack);
-
-    template <typename IF>
-    int open(IF *iface) {
-        return open(iface->get_stack());
-    }
-
     /** Send a packet over a UDP socket
      *
      *  Sends data to the specified address specified by either a domain name
@@ -126,6 +108,7 @@ class UDPSocket : public Socket {
     int recvfrom(SocketAddress *address, void *data, unsigned size);
 
 protected:
+    virtual nsapi_protocol_t get_proto();
     virtual void event();
 
     volatile unsigned _pending;