Merge pull request #122 from minrk/proxy-poll

backport fix for #1428

src/proxy.cpp

@@ -94,10 +94,14 @@ int zmq::proxy (
             return -1;
 
         //  Get the pollout separately because when combining this with pollin it maxes the CPU
-        //  because pollout shall most of the time return directly
+        //  because pollout shall most of the time return directly.
+        //  POLLOUT is only checked when frontend and backend sockets are not the same.
+        if (frontend_ != backend_) {
             rc = zmq_poll (&itemsout [0], 2, 0);
-        if (unlikely (rc < 0))
+            if (unlikely (rc < 0)) {
                 return -1;
+            }
+        }
 
         //  Process a control command if any
         if (control_ && items [2].revents & ZMQ_POLLIN) {
@@ -141,7 +145,7 @@ int zmq::proxy (
         //  Process a request
         if (state == active
         &&  items [0].revents & ZMQ_POLLIN
-        &&  itemsout [1].revents & ZMQ_POLLOUT) {
+        &&  (frontend_ == backend_ || itemsout [1].revents & ZMQ_POLLOUT)) {
             while (true) {
                 rc = frontend_->recv (&msg, 0);
                 if (unlikely (rc < 0))
@@ -174,6 +178,7 @@ int zmq::proxy (
         }
         //  Process a reply
         if (state == active
+        &&  frontend_ != backend_
         &&  items [1].revents & ZMQ_POLLIN
         &&  itemsout [0].revents & ZMQ_POLLOUT) {
             while (true) {

tests/Makefile.am

@@ -40,6 +40,7 @@ noinst_PROGRAMS = test_system \
                   test_inproc_connect \
                   test_issue_566 \
                   test_abstract_ipc \
+                  test_proxy_single_socket \
                   test_proxy_terminate \
                   test_many_sockets
 
@@ -89,6 +90,7 @@ test_inproc_connect_SOURCES = test_inproc_connect.cpp
 test_issue_566_SOURCES = test_issue_566.cpp
 test_abstract_ipc_SOURCES = test_abstract_ipc.cpp
 test_many_sockets_SOURCES = test_many_sockets.cpp
+test_proxy_single_socket_SOURCES = test_proxy_single_socket.cpp
 test_proxy_terminate_SOURCES = test_proxy_terminate.cpp
 if !ON_MINGW
 test_shutdown_stress_SOURCES = test_shutdown_stress.cpp

tests/test_proxy_single_socket.cpp

@@ -0,0 +1,113 @@
+/*
+    Copyright (c) 2007-2015 Contributors as noted in the AUTHORS file
+
+    This file is part of libzmq, the ZeroMQ core engine in C++.
+
+    libzmq is free software; you can redistribute it and/or modify it under
+    the terms of the GNU Lesser General Public License (LGPL) as published
+    by the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    As a special exception, the Contributors give you permission to link
+    this library with independent modules to produce an executable,
+    regardless of the license terms of these independent modules, and to
+    copy and distribute the resulting executable under terms of your choice,
+    provided that you also meet, for each linked independent module, the
+    terms and conditions of the license of that module. An independent
+    module is a module which is not derived from or based on this library.
+    If you modify this library, you must extend this exception to your
+    version of the library.
+
+    libzmq is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "testutil.hpp"
+#include "../include/zmq_utils.h"
+
+
+
+// This is our server task.
+// It runs a proxy with a single REP socket as both frontend and backend.
+
+void
+server_task (void *ctx)
+{
+    void *rep = zmq_socket (ctx, ZMQ_REP);
+    assert (rep);
+    int rc = zmq_bind (rep, "tcp://127.0.0.1:5563");
+    assert (rc == 0);
+
+    // Control socket receives terminate command from main over inproc
+    void *control = zmq_socket (ctx, ZMQ_SUB);
+    assert (control);
+    rc = zmq_setsockopt (control, ZMQ_SUBSCRIBE, "", 0);
+    assert (rc == 0);
+    rc = zmq_connect (control, "inproc://control");
+    assert (rc == 0);
+
+    // Use rep as both frontend and backend
+    zmq_proxy_steerable (rep, rep, NULL, control);
+
+    rc = zmq_close (rep);
+    assert (rc == 0);
+    rc = zmq_close (control);
+    assert (rc == 0);
+}
+
+
+// The main thread simply starts several clients and a server, and then
+// waits for the server to finish.
+
+int main (void)
+{
+    setup_test_environment ();
+
+    void *ctx = zmq_ctx_new ();
+    assert (ctx);
+    // client socket pings proxy over tcp
+    void *req = zmq_socket (ctx, ZMQ_REQ);
+    assert (req);
+    int rc = zmq_connect (req, "tcp://127.0.0.1:5563");
+    assert (rc == 0);
+
+    // Control socket receives terminate command from main over inproc
+    void *control = zmq_socket (ctx, ZMQ_PUB);
+    assert (control);
+    rc = zmq_bind (control, "inproc://control");
+    assert (rc == 0);
+
+    void *server_thread = zmq_threadstart(&server_task, ctx);
+
+    char buf[255];
+    rc = zmq_send(req, "msg1", 4, 0);
+    assert (rc == 4);
+    rc = zmq_recv(req, buf, 255, 0);
+    assert (rc == 4);
+    assert (memcmp (buf, "msg1", 4) == 0);
+
+    rc = zmq_send(req, "msg22", 5, 0);
+    assert (rc == 5);
+    rc = zmq_recv(req, buf, 255, 0);
+    assert (rc == 5);
+    assert (memcmp (buf, "msg22", 5) == 0);
+
+    rc = zmq_send (control, "TERMINATE", 9, 0);
+    assert (rc == 9);
+
+    rc = zmq_close (control);
+    assert (rc == 0);
+    rc = zmq_close (req);
+    assert (rc == 0);
+
+    zmq_threadclose (server_thread);
+
+    rc = zmq_ctx_term (ctx);
+    assert (rc == 0);
+    return 0;
+}