fix to 3-thread synchronisation algorithm

src/io_object.cpp

@@ -19,10 +19,13 @@
 
 #include "io_object.hpp"
 #include "io_thread.hpp"
+#include "err.hpp"
 
 zmq::io_object_t::io_object_t (io_thread_t *parent_, object_t *owner_) :
     object_t (parent_),
-    owner (owner_)
+    owner (owner_),
+    plugged_in (false),
+    terminated (false)
 {
     //  Retrieve the poller from the thread we are running in.
     poller = parent_->get_poller ();
@@ -32,6 +35,23 @@ zmq::io_object_t::~io_object_t ()
 {
 }
 
+void zmq::io_object_t::process_plug ()
+{
+    zmq_assert (!plugged_in);
+
+    //  If termination of the object was already requested, destroy it and
+    //  send the termination acknowledgement.
+    if (terminated) {
+        send_term_ack (owner);
+        delete this;
+        return;
+    }
+
+    //  Notify the generic termination mechanism (io_object_t) that the object
+    //  is already plugged in.
+    plugged_in = true;
+}
+
 zmq::handle_t zmq::io_object_t::add_fd (fd_t fd_, i_poll_events *events_)
 {
     return poller->add_fd (fd_, events_);
@@ -72,6 +92,21 @@ void zmq::io_object_t::cancel_timer (i_poll_events *events_)
     poller->cancel_timer (events_);
 }
 
+void zmq::io_object_t::in_event ()
+{
+    zmq_assert (false);
+}
+
+void zmq::io_object_t::out_event ()
+{
+    zmq_assert (false);
+}
+
+void zmq::io_object_t::timer_event ()
+{
+    zmq_assert (false);
+}
+
 void zmq::io_object_t::term ()
 {
     send_term_req (owner, this);
@@ -79,6 +114,17 @@ void zmq::io_object_t::term ()
 
 void zmq::io_object_t::process_term ()
 {
+    zmq_assert (!terminated);
+
+    //  If termination request has occured even before the object was plugged in
+    //  wait till plugging in happens, then acknowledge the termination.
+    if (!plugged_in) {
+        terminated = true;
+        return;
+    }
+
+    //  Otherwise, destroy the object and acknowledge the termination
+    //  straight away.
     send_term_ack (owner);
     delete this;
 }

src/io_object.hpp

@@ -22,11 +22,12 @@
 
 #include "object.hpp"
 #include "i_poller.hpp"
+#include "i_poll_events.hpp"
 
 namespace zmq
 {
 
-    class io_object_t : public object_t
+    class io_object_t : public object_t, public i_poll_events
     {
     public:
 
@@ -45,6 +46,11 @@ namespace zmq
         //  of I/O object correctly.
         virtual ~io_object_t ();
 
+        //  Handlers for incoming commands. It vital that every I/O object
+        //  invokes io_object_t::process_plug at the end of it's own plug
+        //  handler.
+        void process_plug ();
+
         //  Methods to access underlying poller object.
         handle_t add_fd (fd_t fd_, struct i_poll_events *events_);
         void rm_fd (handle_t handle_);
@@ -55,12 +61,25 @@ namespace zmq
         void add_timer (struct i_poll_events *events_);
         void cancel_timer (struct i_poll_events *events_);
 
+        //  i_poll_events interface implementation.
+        void in_event ();
+        void out_event ();
+        void timer_event ();
+
         //  Socket owning this I/O object. It is responsible for destroying
         //  it when it's being closed.
         object_t *owner;
 
+        //  Set to true when object is plugged in. It's responsibility
+        //  of derived object to set the property after the feat.
+        bool plugged_in;
+
     private:
 
+        //  Set to true when object was terminated before it was plugged in.
+        //  In such case destruction is delayed till 'plug' command arrives.
+        bool terminated;
+
         struct i_poller *poller;
 
         //  Handlers for incoming commands.

src/socket_base.cpp

@@ -70,7 +70,11 @@ int zmq::socket_base_t::bind (const char *addr_)
 {
     //  TODO: The taskset should be taken from socket options.
     uint64_t taskset = 0;
-    object_t *listener = new zmq_listener_t (choose_io_thread (taskset), this);
+    zmq_listener_t *listener = new zmq_listener_t (choose_io_thread (taskset), this);
+    int rc = listener->set_address (addr_);
+    if (rc != 0)
+        return -1;
+
     send_plug (listener);
     send_own (this, listener);
     return 0;

src/tcp_listener.cpp

@@ -17,6 +17,8 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <string.h>
+
 #include "tcp_listener.hpp"
 #include "platform.hpp"
 #include "ip.hpp"
@@ -41,6 +43,7 @@
 zmq::tcp_listener_t::tcp_listener_t () :
     s (retired_fd)
 {
+    memset (&addr, 0, sizeof (addr));
 }
 
 zmq::tcp_listener_t::~tcp_listener_t ()
@@ -49,14 +52,14 @@ zmq::tcp_listener_t::~tcp_listener_t ()
         close ();
 }
 
-int zmq::tcp_listener_t::open (const char *addr_)
+int zmq::tcp_listener_t::set_address (const char *addr_)
 {
     //  Convert the interface into sockaddr_in structure.
-    sockaddr_in ip_address;
-    int rc = resolve_ip_interface (&ip_address, addr_);
-    if (rc != 0)
-        return -1;
-    
+    return resolve_ip_interface (&addr, addr_);
+}
+
+int zmq::tcp_listener_t::open ()
+{
     //  Create a listening socket.
     s = socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
     if (s == -1)
@@ -64,7 +67,7 @@ int zmq::tcp_listener_t::open (const char *addr_)
 
     //  Allow reusing of the address.
     int flag = 1;
-    rc = setsockopt (s, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof (int));
+    int rc = setsockopt (s, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof (int));
     errno_assert (rc == 0);
 
     //  Set the non-blocking flag.
@@ -75,7 +78,7 @@ int zmq::tcp_listener_t::open (const char *addr_)
     errno_assert (rc != -1);
 
     //  Bind the socket to the network interface and port.
-    rc = bind (s, (struct sockaddr*) &ip_address, sizeof (ip_address));
+    rc = bind (s, (struct sockaddr*) &addr, sizeof (addr));
     if (rc != 0) {
         close ();
         return -1;

src/tcp_listener.hpp

@@ -21,6 +21,7 @@
 #define __ZMQ_TCP_LISTENER_HPP_INCLUDED__
 
 #include "fd.hpp"
+#include "ip.hpp"
 
 namespace zmq
 {
@@ -34,10 +35,13 @@ namespace zmq
         tcp_listener_t ();
         ~tcp_listener_t ();
 
-        //  Open TCP listining socket. Address is in
+        //  Set up the address to listen on. Address is in
         //  <interface-name>:<port-number> format. Interface name may be '*'
         //  to bind to all the interfaces.
-        int open (const char *addr_);
+        int set_address (const char *addr_);
+
+        //  Open TCP listining socket. 
+        int open ();
 
         //  Close the listening socket.
         int close ();
@@ -53,6 +57,9 @@ namespace zmq
 
     private:
 
+        //  IP address/port to listen on.
+        sockaddr_in addr;
+
         //  Underlying socket.
         fd_t s;
 

src/zmq_listener.cpp

@@ -29,12 +29,46 @@ zmq::zmq_listener_t::zmq_listener_t (io_thread_t *parent_, object_t *owner_) :
 
 zmq::zmq_listener_t::~zmq_listener_t ()
 {
+    if (plugged_in)
+        rm_fd (handle);
+}
+
+int zmq::zmq_listener_t::set_address (const char *addr_)
+{
+     return tcp_listener.set_address (addr_);
 }
 
 void zmq::zmq_listener_t::process_plug ()
 {
-    //  TODO: Testing code follows...
+    //  Open the listening socket.
+    int rc = tcp_listener.open ();
+    zmq_assert (rc == 0);
+
+    //  Start polling for incoming connections.
+    handle = add_fd (tcp_listener.get_fd (), this);
+    set_pollin (handle);
+
+    io_object_t::process_plug ();
+}
+
+void zmq::zmq_listener_t::in_event ()
+{
+    fd_t fd = tcp_listener.accept ();
+
+    //  If connection was reset by the peer in the meantime, just ignore it.
+    //  TODO: Handle specific errors like ENFILE/EMFILE etc.
+    if (fd == retired_fd)
+        return;
+
+    //  TODO
+    zmq_assert (false);
+
+/*
     object_t *engine = new zmq_engine_t (choose_io_thread (0), owner);
     send_plug (engine);
     send_own (owner, engine);
+*/
 }
+
+
+

src/zmq_listener.hpp

@@ -20,7 +20,10 @@
 #ifndef __ZMQ_ZMQ_LISTENER_HPP_INCLUDED__
 #define __ZMQ_ZMQ_LISTENER_HPP_INCLUDED__
 
+#include <string>
+
 #include "io_object.hpp"
+#include "tcp_listener.hpp"
 
 namespace zmq
 {
@@ -31,6 +34,9 @@ namespace zmq
 
         zmq_listener_t (class io_thread_t *parent_, object_t *owner_);
 
+        //  Set IP address to listen on.
+        int set_address (const char *addr_);
+
     private:
 
         ~zmq_listener_t ();
@@ -38,6 +44,15 @@ namespace zmq
         //  Handlers for incoming commands.
         void process_plug ();
 
+        //  Handle I/O events.
+        void in_event ();
+
+        //  Actual listening socket.
+        tcp_listener_t tcp_listener;
+
+        //  Handle corresponding to the listening socket.
+        handle_t handle;
+
         zmq_listener_t (const zmq_listener_t&);
         void operator = (const zmq_listener_t&);
     };