add proxy control flow and test

AUTHORS

@@ -53,6 +53,7 @@ Joe Thornber <[email protected]>
 Jon Dyte <[email protected]>
 Kamil Shakirov <[email protected]>
 Ken Steele <[email protected]>
+Laurent Alebarde <[email protected]>
 Marc Rossi <[email protected]>
 Martin Hurton <[email protected]>
 Martin Lucina <[email protected]>

include/zmq.h

@@ -395,7 +395,7 @@ ZMQ_EXPORT int zmq_poll (zmq_pollitem_t *items, int nitems, long timeout);
 
 /*  Built-in message proxy (3-way) */
 
-ZMQ_EXPORT int zmq_proxy (void *frontend, void *backend, void *capture);
+ZMQ_EXPORT int zmq_proxy (void *frontend, void *backend, void *capture, void *control);
 
 /*  Encode a binary key as printable text using ZMQ RFC 32  */
 ZMQ_EXPORT char *zmq_z85_encode (char *dest, uint8_t *data, size_t size);

src/proxy.cpp

@@ -57,7 +57,8 @@
 int zmq::proxy (
     class socket_base_t *frontend_,
     class socket_base_t *backend_,
-    class socket_base_t *capture_)
+    class socket_base_t *capture_,
+    class socket_base_t *control_)
 {
     msg_t msg;
     int rc = msg.init ();
@@ -71,16 +72,59 @@ int zmq::proxy (
     size_t moresz;
     zmq_pollitem_t items [] = {
         { frontend_, 0, ZMQ_POLLIN, 0 },
-        { backend_, 0, ZMQ_POLLIN, 0 }
+        { backend_, 0, ZMQ_POLLIN, 0 },
+        { control_, 0, ZMQ_POLLIN, 0 }
     };
-    while (true) {
+    int qt_poll_items = (control_ ? 3 : 2);
+    enum {suspend, resume, terminate} state = resume;
+    while (state != terminate) {
         //  Wait while there are either requests or replies to process.
-        rc = zmq_poll (&items [0], 2, -1);
+        rc = zmq_poll (&items [0], qt_poll_items, -1);
         if (unlikely (rc < 0))
             return -1;
 
+        //  Process a control command if any
+        if (control_ && items [2].revents & ZMQ_POLLIN) {
+			rc = control_->recv (&msg, 0);
+			if (unlikely (rc < 0))
+				return -1;
+
+			moresz = sizeof more;
+			rc = control_->getsockopt (ZMQ_RCVMORE, &more, &moresz);
+			if (unlikely (rc < 0) || more)
+				return -1;
+
+			//  Copy message to capture socket if any
+			if (capture_) {
+				msg_t ctrl;
+				rc = ctrl.init ();
+				if (unlikely (rc < 0))
+					return -1;
+				rc = ctrl.copy (msg);
+				if (unlikely (rc < 0))
+					return -1;
+				rc = capture_->send (&ctrl, 0);
+				if (unlikely (rc < 0))
+					return -1;
+			}
+
+			// process control command
+			int size = msg.size();
+			char* message = (char*) malloc(size + 1);
+			memcpy(message, msg.data(), size);
+			message[size] = '\0';
+			if (size == 8 && !memcmp(message, "SUSPEND", 8))
+				state = suspend;
+			else if (size == 7 && !memcmp(message, "RESUME", 7))
+				state = resume;
+			else if (size == 10 && !memcmp(message, "TERMINATE", 10))
+				state = terminate;
+			else
+				fprintf(stderr, "Warning : \"%s\" bad command received by proxy\n", message); // prefered compared to "return -1"
+			free (message);
+        }
         //  Process a request
-        if (items [0].revents & ZMQ_POLLIN) {
+        if (state == resume && items [0].revents & ZMQ_POLLIN) {
             while (true) {
                 rc = frontend_->recv (&msg, 0);
                 if (unlikely (rc < 0))
@@ -112,7 +156,7 @@ int zmq::proxy (
             }
         }
         //  Process a reply
-        if (items [1].revents & ZMQ_POLLIN) {
+        if (state == resume && items [1].revents & ZMQ_POLLIN) {
             while (true) {
                 rc = backend_->recv (&msg, 0);
                 if (unlikely (rc < 0))

src/proxy.hpp

@@ -25,7 +25,8 @@ namespace zmq
     int proxy (
         class socket_base_t *frontend_,
         class socket_base_t *backend_,
-        class socket_base_t *control_);
+        class socket_base_t *capture_,
+        class socket_base_t *control_ = NULL); // backward compatibility without this argument
 }
 
 #endif

src/zmq.cpp

@@ -1016,7 +1016,7 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
 
 //  The proxy functionality
 
-int zmq_proxy (void *frontend_, void *backend_, void *control_)
+int zmq_proxy (void *frontend_, void *backend_, void *capture_, void *control_)
 {
     if (!frontend_ || !backend_) {
         errno = EFAULT;
@@ -1025,6 +1025,7 @@ int zmq_proxy (void *frontend_, void *backend_, void *control_)
     return zmq::proxy (
         (zmq::socket_base_t*) frontend_,
         (zmq::socket_base_t*) backend_,
+        (zmq::socket_base_t*) capture_,
         (zmq::socket_base_t*) control_);
 }
 

tests/Makefile.am

@@ -39,6 +39,7 @@ noinst_PROGRAMS = test_system \
                   test_conflate \
                   test_inproc_connect \
                   test_issue_566 \
+                  test_proxy \
                   test_abstract_ipc
 
 if !ON_MINGW
@@ -85,6 +86,7 @@ test_req_relaxed_SOURCES = test_req_relaxed.cpp
 test_conflate_SOURCES = test_conflate.cpp
 test_inproc_connect_SOURCES = test_inproc_connect.cpp
 test_issue_566_SOURCES = test_issue_566.cpp
+test_proxy_SOURCES = test_proxy.cpp
 test_abstract_ipc_SOURCES = test_abstract_ipc.cpp
 if !ON_MINGW
 test_shutdown_stress_SOURCES = test_shutdown_stress.cpp