Move accept() to abstract socket class and implement in TCPSocket

Deprecate TCPServer in favor of just TCPSocket::accept()

Author: Seppo Takalo

features/netsocket/InternetSocket.cpp

@@ -20,9 +20,9 @@
 using namespace mbed;
 
 InternetSocket::InternetSocket()
-    : _stack(0)
-    , _socket(0)
-    , _timeout(osWaitForever)
+    : _stack(0), _socket(0), _timeout(osWaitForever),
+      _readers(0), _writers(0), _factory_allocated(false),
+      _pending(0)
 {
 }
 
@@ -68,7 +68,19 @@ nsapi_error_t InternetSocket::close()
     // on this socket
     event();
 
+    // Wait until all readers and writers are gone
+    while (_readers || _writers) {
+        _lock.unlock();
+        _event_flag.wait_any(FINISHED_FLAG, osWaitForever);
+        _lock.lock();
+    }
+
     _lock.unlock();
+
+    // When allocated by accept() call, will self desctruct on close();
+    if (_factory_allocated) {
+        delete this;
+    }
     return ret;
 }
 
@@ -172,6 +184,15 @@ nsapi_error_t InternetSocket::getsockopt(int level, int optname, void *optval, u
     return ret;
 
 }
+void InternetSocket::event()
+{
+    _event_flag.set(READ_FLAG|WRITE_FLAG);
+
+    _pending += 1;
+    if (_callback && _pending == 1) {
+        _callback();
+    }
+}
 
 void InternetSocket::sigio(Callback<void()> callback)
 {

features/netsocket/InternetSocket.h

@@ -23,6 +23,7 @@
 #include "netsocket/Socket.h"
 #include "netsocket/NetworkStack.h"
 #include "rtos/Mutex.h"
+#include "rtos/EventFlags.h"
 #include "Callback.h"
 #include "mbed_toolchain.h"
 
@@ -217,16 +218,26 @@ class InternetSocket : public Socket {
 protected:
     InternetSocket();
     virtual nsapi_protocol_t get_proto() = 0;
-    virtual void event() = 0;
+    virtual void event();
     int modify_multicast_group(const SocketAddress &address, nsapi_socket_option_t socketopt);
 
     NetworkStack *_stack;
     nsapi_socket_t _socket;
     uint32_t _timeout;
     mbed::Callback<void()> _event;
     mbed::Callback<void()> _callback;
+    rtos::EventFlags _event_flag;
     rtos::Mutex _lock;
     SocketAddress _remote_peer;
+    uint8_t _readers;
+    uint8_t _writers;
+    volatile unsigned _pending;
+    bool _factory_allocated;
+
+    // Event flags
+    static const int READ_FLAG     = 0x1u;
+    static const int WRITE_FLAG    = 0x2u;
+    static const int FINISHED_FLAG = 0x3u;
 };
 
 #endif // INTERNETSOCKET_H

features/netsocket/Socket.h

@@ -110,11 +110,10 @@ class Socket {
     /** Receive a data from a socket
      *
      *  Receives a data and stores the source address in address if address
-     *  is not NULL. Returns the number of bytes written into the buffer. If the
-     *  datagram is larger than the buffer, the excess data is silently discarded.
+     *  is not NULL. Returns the number of bytes written into the buffer.
      *
      *  By default, recvfrom blocks until a datagram is received. If socket is set to
-     *  non-blocking or times out with no datagram, NSAPI_ERROR_WOULD_BLOCK
+     *  non-blocking or times out with no data, NSAPI_ERROR_WOULD_BLOCK
      *  is returned.
      *
      *  @param address  Destination for the source address or NULL
@@ -213,6 +212,32 @@ class Socket {
      *  @return         0 on success, negative error code on failure
      */
     virtual nsapi_error_t getsockopt(int level, int optname, void *optval, unsigned *optlen) = 0;
+
+    /** Accepts a connection on a socket.
+     *
+     *  The server socket must be bound and set to listen for connections.
+     *  On a new connection, returns connected network socket which user is expected to call close()
+     *  and that deallocates the resources. Referencing a returned pointer after a close()
+     *  call is not allowed and leads to undefined behaviour.
+     *
+     *  By default, accept blocks until incomming connection occurs. If socket is set to
+     *  non-blocking or times out, error is set to NSAPI_ERROR_WOULD_BLOCK.
+     *
+     *  @param error      pointer to storage of the error value or NULL
+     *  @return           pointer to a socket
+     */
+    virtual Socket *accept(nsapi_error_t *error = NULL) = 0;
+
+    /** Listen for incoming connections.
+     *
+     *  Marks the socket as a passive socket that can be used to accept
+     *  incoming connections.
+     *
+     *  @param backlog  Number of pending connections that can be queued
+     *                  simultaneously, defaults to 1
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual nsapi_error_t listen(int backlog = 1) = 0;
 };
 
 

features/netsocket/TCPServer.cpp

@@ -18,7 +18,6 @@
 #include "mbed.h"
 
 TCPServer::TCPServer()
-    : _pending(0), _accept_sem(0)
 {
 }
 
@@ -27,29 +26,9 @@ TCPServer::~TCPServer()
     close();
 }
 
-nsapi_protocol_t TCPServer::get_proto()
-{
-    return NSAPI_TCP;
-}
-
-nsapi_error_t TCPServer::listen(int backlog)
-{
-    _lock.lock();
-    nsapi_error_t ret;
-
-    if (!_socket) {
-        ret = NSAPI_ERROR_NO_SOCKET;
-    } else {
-        ret = _stack->socket_listen(_socket, backlog);
-    }
-
-    _lock.unlock();
-    return ret;
-}
-
 nsapi_error_t TCPServer::accept(TCPSocket *connection, SocketAddress *address)
 {
-    _lock.lock();
+    //TODO!!!!
     nsapi_error_t ret;
 
     while (true) {
@@ -76,19 +55,19 @@ nsapi_error_t TCPServer::accept(TCPSocket *connection, SocketAddress *address)
 
             connection->_lock.unlock();
             break;
-        } else if (NSAPI_ERROR_WOULD_BLOCK != ret) {
+        } else if ((_timeout == 0) || (ret != NSAPI_ERROR_WOULD_BLOCK)) {
             break;
         } else {
-            int32_t count;
+            uint32_t flag;
 
             // Release lock before blocking so other threads
             // accessing this object aren't blocked
             _lock.unlock();
-            count = _accept_sem.wait(_timeout);
+            flag = _event_flag.wait_any(READ_FLAG, _timeout);
             _lock.lock();
 
-            if (count < 1) {
-                // Semaphore wait timed out so break out and return
+            if (flag & osFlagsError) {
+                // Timeout break
                 ret = NSAPI_ERROR_WOULD_BLOCK;
                 break;
             }
@@ -98,41 +77,3 @@ nsapi_error_t TCPServer::accept(TCPSocket *connection, SocketAddress *address)
     _lock.unlock();
     return ret;
 }
-
-void TCPServer::event()
-{
-    int32_t acount = _accept_sem.wait(0);
-    if (acount <= 1) {
-        _accept_sem.release();
-    }
-
-    _pending += 1;
-    if (_callback && _pending == 1) {
-        _callback();
-    }
-}
-
-nsapi_error_t TCPServer::connect(const SocketAddress)
-{
-    return NSAPI_ERROR_UNSUPPORTED;
-}
-
-nsapi_size_or_error_t TCPServer::send(const void *, nsapi_size_t)
-{
-    return NSAPI_ERROR_UNSUPPORTED;
-}
-
-nsapi_size_or_error_t TCPServer::recv(void *, nsapi_size_t)
-{
-    return NSAPI_ERROR_UNSUPPORTED;
-}
-
-nsapi_size_or_error_t TCPServer::sendto(const SocketAddress&, const void *, nsapi_size_t)
-{
-    return NSAPI_ERROR_UNSUPPORTED;
-}
-
-nsapi_size_or_error_t TCPServer::recvfrom(SocketAddress*, void *, nsapi_size_t)
-{
-    return NSAPI_ERROR_UNSUPPORTED;
-}

features/netsocket/TCPServer.h

@@ -28,12 +28,14 @@
 /** TCP socket server
  *  @addtogroup netsocket
  */
-class TCPServer : public InternetSocket {
+class TCPServer : public TCPSocket {
 public:
     /** Create an uninitialized socket
      *
      *  Must call open to initialize the socket on a network stack.
      */
+    MBED_DEPRECATED_SINCE("mbed-os-5.10",
+        "TCPServer is deprecated, use TCPSocket")
     TCPServer();
 
     /** Create a socket on a network interface
@@ -44,8 +46,9 @@ class TCPServer : public InternetSocket {
      *  @param stack    Network stack as target for socket
      */
     template <typename S>
+    MBED_DEPRECATED_SINCE("mbed-os-5.10",
+        "TCPServer is deprecated, use TCPSocket")
     TCPServer(S *stack)
-        : _pending(0), _accept_sem(0)
     {
         open(stack);
     }
@@ -56,17 +59,6 @@ class TCPServer : public InternetSocket {
      */
     virtual ~TCPServer();
 
-    /** Listen for connections on a TCP socket
-     *
-     *  Marks the socket as a passive socket that can be used to accept
-     *  incoming connections.
-     *
-     *  @param backlog  Number of pending connections that can be queued
-     *                  simultaneously, defaults to 1
-     *  @return         0 on success, negative error code on failure
-     */
-    nsapi_error_t listen(int backlog = 1);
-
     /** Accepts a connection on a TCP socket
      *
      *  The server socket must be bound and set to listen for connections.
@@ -81,51 +73,9 @@ class TCPServer : public InternetSocket {
      *  @param address    Destination for the remote address or NULL
      *  @return           0 on success, negative error code on failure
      */
+    MBED_DEPRECATED_SINCE("mbed-os-5.10",
+        "TCPServer::accept() is deprecated, use Socket *Socket::accept() instead")
     nsapi_error_t accept(TCPSocket *connection, SocketAddress *address = NULL);
-
-    /** Not supported on TCPServer.
-     * @param address unused
-     * @return NSAPI_ERROR_UNSUPPORTED
-     */
-    virtual nsapi_error_t connect(const SocketAddress &address);
-
-    /** Not supported on TCPServer.
-     * @param data unused
-     * @param size unused
-     * @return NSAPI_ERROR_UNSUPPORTED
-     */
-    virtual nsapi_size_or_error_t send(const void *data, nsapi_size_t size);
-
-    /** Not supported on TCPServer.
-     * @param data unused
-     * @param size unused
-     * @return NSAPI_ERROR_UNSUPPORTED
-     */
-    virtual nsapi_size_or_error_t recv(void *data, nsapi_size_t size);
-
-    /** Not supported on TCPServer.
-     * @param address unused
-     * @param data unused
-     * @param size unused
-     * @return NSAPI_ERROR_UNSUPPORTED
-     */
-    virtual nsapi_size_or_error_t sendto(const SocketAddress& address, const void *data, nsapi_size_t size);
-
-    /** Not supported on TCPServer.
-     * @param address unused
-     * @param data unused
-     * @param size unused
-     * @return NSAPI_ERROR_UNSUPPORTED
-     */
-    virtual nsapi_size_or_error_t recvfrom(SocketAddress* address, void *data, nsapi_size_t size);
-
-protected:
-    virtual nsapi_protocol_t get_proto();
-    virtual void event();
-
-    volatile unsigned _pending;
-    rtos::Semaphore _accept_sem;
 };
 
-
 #endif