SocketService and SocketPort

[Byrial Jensen]

[Note: I sent my first message to the list a week ago when I was not
yet subscribed to the list. I got a mesage back that it awaited
moderator approval because it was posted by a non-member. However the
moderator seems to be sleeping - at least I never saw my message at
the list.]

I have programmed a simple tcp proxy-server using Common C++ and
have some experience and suggestions with regard to SocketService
and SocketPort I would like to share:

  - There is currently no way to create SocketPorts for non-server
    connections. I would like a SocketPort constructor which creates
    an outgoing client tcp connection as I need a lot of such
    connections in a proxy server.

  - The virtual callback functions of the SocketPort class (expired,
    pending, output) may /not/ delete the current SocketPort object
    (*this) because SocketService::run will still use a pointer
    (SocketPort *port) to the object /after/ the return of these
    callback functions and thus use deallocated memory.

    This is not documented and it is disobeyed by the tcpservice.cpp
    demo program. So the demo program contains undefined behaviour!

    I would like that the callback functions are allowed to not only
    delete the current SocketPort object, but also to create new 
    SocketPorts attached to the same SocketService and to delete
    other SocketPorts than *this, as this is useful in a proxy
    server. I have done it this way in my code (here implemented
    only inside "#ifdef CCXX_USE_POLL"):

diff -udrpb commoncpp2-1.0.2-org/include/cc++/socket.h 
commoncpp2-1.0.2/include/cc++/socket.h
--- commoncpp2-1.0.2-org/include/cc++/socket.h  Tue Aug 27 04:11:07 2002
+++ commoncpp2-1.0.2/include/cc++/socket.h      Sun Oct  6 09:22:21 2002
@@ -1814,6 +1814,7 @@ private:
        bool detect_pending;
        bool detect_output;
        bool detect_disconnect;
+       volatile bool recent_changes;
        
        friend class SocketService;
 
diff -udrpb commoncpp2-1.0.2-org/src/port.cpp commoncpp2-1.0.2/src/port.cpp
--- commoncpp2-1.0.2-org/src/port.cpp   Thu Jul 18 16:52:25 2002
+++ commoncpp2-1.0.2/src/port.cpp       Sun Oct  6 09:34:06 2002
@@ -403,6 +403,7 @@ void SocketService::attach(SocketPort *p
 
        ++count;
        if(!first) first = port;
+       recent_changes = true;
        
        // start thread if necessary
        if (count == 1)
@@ -438,6 +439,7 @@ void SocketService::detach(SocketPort *p
        port->service = NULL;
        
        --count;
+       recent_changes = true;
        leaveMutex();
        update();
 }
@@ -533,6 +535,7 @@ void SocketService::run(void)
                
                MUTEX_START
                onEvent();
+               recent_changes = false;
                port = first;
                while(port)
                {
@@ -544,19 +547,22 @@ void SocketService::run(void)
                                        port->detect_disconnect = false;
                                        p_ufd->events &= ~POLLHUP;
 
-                                       SocketPort* p = port;
-                                       port = port->next;
-                                       detach(p);
-                                       reallocate = true;
-                                       p->disconnect();
-                                       continue;
+                                       port->disconnect();
+                                       if (recent_changes)
+                                               break;
                                }
        
-                               if ( ( POLLIN | POLLPRI ) & p_ufd->revents )
+                               if ( ( POLLIN | POLLPRI ) & p_ufd->revents ) {
                                        port->pending();
+                                       if (recent_changes)
+                                               break;
+                               }
        
-                               if ( POLLOUT & p_ufd->revents )
+                               if ( POLLOUT & p_ufd->revents ) {
                                        port->output();
+                                       if (recent_changes)
+                                               break;
+                               }
 
                        } else {
                                reallocate = true;
@@ -573,6 +579,8 @@ retry:
                        {
                                port->endTimer();
                                port->expired();
+                               if (recent_changes)
+                                       break;
                                goto retry;
                        }
 
  - It would be more effective if SocketService::Run used the return
    values from the poll/select system calls.

  - TCPSocket does not support onAccept as claimed in the
    documentation. Yes, the function exists but it is not called by
    the SocketPort(SocketService *svc, TCPSocket &tcp) constructor.

Best regards
Byrial