XSUB socket has a subscription distributor

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

src/xsub.cpp

@@ -27,12 +27,13 @@
 zmq::xsub_t::xsub_t (class ctx_t *parent_, uint32_t tid_) :
     socket_base_t (parent_, tid_),
     fq (this),
+    dist (this),
     has_message (false),
     more (false)
 {
     options.type = ZMQ_XSUB;
     options.requires_in = true;
-    options.requires_out = false;
+    options.requires_out = true;
     zmq_msg_init (&message);
 }
 
@@ -44,13 +45,15 @@ zmq::xsub_t::~xsub_t ()
 void zmq::xsub_t::xattach_pipes (class reader_t *inpipe_,
     class writer_t *outpipe_, const blob_t &peer_identity_)
 {
-    zmq_assert (inpipe_ && !outpipe_);
+    zmq_assert (inpipe_ && outpipe_);
     fq.attach (inpipe_);
+    dist.attach (outpipe_);
 }
 
 void zmq::xsub_t::process_term (int linger_)
 {
     fq.terminate ();
+    dist.terminate ();
     socket_base_t::process_term (linger_);
 }
 

src/xsub.hpp

@@ -24,6 +24,7 @@
 
 #include "trie.hpp"
 #include "socket_base.hpp"
+#include "dist.hpp"
 #include "fq.hpp"
 
 namespace zmq
@@ -57,6 +58,9 @@ namespace zmq
         //  Fair queueing object for inbound pipes.
         fq_t fq;
 
+        //  Distributor mechanism for outbound messages (subscriptions).
+        dist_t dist;
+
         //  The repository of subscriptions.
         trie_t subscriptions;