Move the pipe termination code to socket_base_t

So far, the pipe termination code was spread among socket type
classes, fair queuer, load balancer, etc. This patch moves
all the associated logic to a single place.

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

29 files changed, 190 insertions, 366 deletions

diff --git a/src/array.hpp b/src/array.hpp
index e7b5266..bb3c0ea 100644
--- a/src/array.hpp
+++ b/src/array.hpp
@@ -38,7 +38,8 @@ namespace zmq
 
         inline array_item_t () :
             array_index1 (-1),
-            array_index2 (-1)
+            array_index2 (-1),
+            array_index3 (-1)
         {
         }
 
@@ -68,10 +69,21 @@ namespace zmq
             return array_index2;
         }
 
+        inline void set_array_index3 (int index_)
+        {
+            array_index3 = index_;
+        }
+
+        inline int get_array_index3 ()
+        {
+            return array_index3;
+        }
+
     private:
 
         int array_index1;
         int array_index2;
+        int array_index3;
 
         array_item_t (const array_item_t&);
         const array_item_t &operator = (const array_item_t&);
@@ -117,8 +129,10 @@ namespace zmq
             if (item_) {
                 if (N == 1)
                     item_->set_array_index1 ((int) items.size ());
-                else
+                else if (N == 2)
                     item_->set_array_index2 ((int) items.size ());
+                else
+                    item_->set_array_index3 ((int) items.size ());
             }
             items.push_back (item_);
         }
@@ -127,16 +141,20 @@ namespace zmq
         {
             if (N == 1)
                 erase (item_->get_array_index1 ());
-            else
+            else if (N == 2)
                 erase (item_->get_array_index2 ());
+            else
+                erase (item_->get_array_index3 ());
         }
 
         inline void erase (size_type index_) {
             if (items.back ()) {
                 if (N == 1)
                     items.back ()->set_array_index1 ((int) index_);
-                else
+                else if (N == 2)
                     items.back ()->set_array_index2 ((int) index_);
+                else
+                    items.back ()->set_array_index3 ((int) index_);
             }
             items [index_] = items.back ();
             items.pop_back ();
@@ -150,12 +168,18 @@ namespace zmq
 		        if (items [index2_])
 		            items [index2_]->set_array_index1 ((int) index1_);
             }
-            else {
+            else if (N == 2) {
 		        if (items [index1_])
 		            items [index1_]->set_array_index2 ((int) index2_);
 		        if (items [index2_])
 		            items [index2_]->set_array_index2 ((int) index1_);
             }
+            else {
+		        if (items [index1_])
+		            items [index1_]->set_array_index3 ((int) index2_);
+		        if (items [index2_])
+		            items [index2_]->set_array_index3 ((int) index1_);
+            }
             std::swap (items [index1_], items [index2_]);
         }
 
@@ -168,8 +192,10 @@ namespace zmq
         {
             if (N == 1)
                 return (size_type) item_->get_array_index1 ();
-            else
+            else if (N == 2)
                 return (size_type) item_->get_array_index2 ();
+            else
+                return (size_type) item_->get_array_index3 ();
         }
 
     private:
diff --git a/src/dist.cpp b/src/dist.cpp
index 3afa196..f7f0488 100644
--- a/src/dist.cpp
+++ b/src/dist.cpp
@@ -21,16 +21,13 @@
 #include "dist.hpp"
 #include "pipe.hpp"
 #include "err.hpp"
-#include "own.hpp"
 #include "msg.hpp"
 #include "likely.hpp"
 
-zmq::dist_t::dist_t (own_t *sink_) :
+zmq::dist_t::dist_t () :
     active (0),
     eligible (0),
-    more (false),
-    sink (sink_),
-    terminating (false)
+    more (false)
 {
 }
 
@@ -55,21 +52,6 @@ void zmq::dist_t::attach (pipe_t *pipe_)
         active++;
         eligible++;
     }
-
-    if (unlikely (terminating)) {
-        sink->register_term_acks (1);
-        pipe_->terminate ();
-    }
-}
-
-void zmq::dist_t::terminate ()
-{
-    zmq_assert (!terminating);
-    terminating = true;
-
-    sink->register_term_acks ((int) pipes.size ());
-    for (pipes_t::size_type i = 0; i != pipes.size (); i++)
-        pipes [i]->terminate ();
 }
 
 void zmq::dist_t::terminated (pipe_t *pipe_)
@@ -81,9 +63,6 @@ void zmq::dist_t::terminated (pipe_t *pipe_)
     if (pipes.index (pipe_) < eligible)
         eligible--;
     pipes.erase (pipe_);
-
-    if (unlikely (terminating))
-        sink->unregister_term_ack ();
 }
 
 void zmq::dist_t::activated (pipe_t *pipe_)
diff --git a/src/dist.hpp b/src/dist.hpp
index c137332..10613c1 100644
--- a/src/dist.hpp
+++ b/src/dist.hpp
@@ -35,17 +35,16 @@ namespace zmq
     {
     public:
 
-        dist_t (class own_t *sink_);
+        dist_t ();
         ~dist_t ();
 
         void attach (class pipe_t *pipe_);
-        void terminate ();
-        int send (class msg_t *msg_, int flags_);
-        bool has_out ();
-
         void activated (class pipe_t *pipe_);
         void terminated (class pipe_t *pipe_);
 
+        int send (class msg_t *msg_, int flags_);
+        bool has_out ();
+
     private:
 
         //  Write the message to the pipe. Make the pipe inactive if writing
@@ -74,12 +73,6 @@ namespace zmq
         //  True if last we are in the middle of a multipart message.
         bool more;
 
-        //  Object to send events to.
-        class own_t *sink;
-
-        //  If true, termination process is already underway.
-        bool terminating;
-
         dist_t (const dist_t&);
         const dist_t &operator = (const dist_t&);
     };
diff --git a/src/fq.cpp b/src/fq.cpp
index b4ee641..7318822 100644
--- a/src/fq.cpp
+++ b/src/fq.cpp
@@ -21,15 +21,12 @@
 #include "fq.hpp"
 #include "pipe.hpp"
 #include "err.hpp"
-#include "own.hpp"
 #include "msg.hpp"
 
-zmq::fq_t::fq_t (own_t *sink_) :
+zmq::fq_t::fq_t () :
     active (0),
     current (0),
-    more (false),
-    sink (sink_),
-    terminating (false)
+    more (false)
 {
 }
 
@@ -43,20 +40,10 @@ void zmq::fq_t::attach (pipe_t *pipe_)
     pipes.push_back (pipe_);
     pipes.swap (active, pipes.size () - 1);
     active++;
-
-    //  If we are already terminating, ask the pipe to terminate straight away.
-    if (terminating) {
-        sink->register_term_acks (1);
-        pipe_->terminate ();
-    }
 }
 
 void zmq::fq_t::terminated (pipe_t *pipe_)
 {
-    //  Make sure that we are not closing current pipe while
-    //  message is half-read.
-    zmq_assert (terminating || (!more || pipes [current] != pipe_));
-
     //  Remove the pipe from the list; adjust number of active pipes
     //  accordingly.
     if (pipes.index (pipe_) < active) {
@@ -65,19 +52,6 @@ void zmq::fq_t::terminated (pipe_t *pipe_)
             current = 0;
     }
     pipes.erase (pipe_);
-
-    if (terminating)
-        sink->unregister_term_ack ();
-}
-
-void zmq::fq_t::terminate ()
-{
-    zmq_assert (!terminating);
-    terminating = true;
-
-    sink->register_term_acks ((int) pipes.size ());
-    for (pipes_t::size_type i = 0; i != pipes.size (); i++)
-        pipes [i]->terminate ();
 }
 
 void zmq::fq_t::activated (pipe_t *pipe_)
diff --git a/src/fq.hpp b/src/fq.hpp
index bbe1b59..106e978 100644
--- a/src/fq.hpp
+++ b/src/fq.hpp
@@ -35,18 +35,16 @@ namespace zmq
     {
     public:
 
-        fq_t (class own_t *sink_);
+        fq_t ();
         ~fq_t ();
 
         void attach (pipe_t *pipe_);
-        void terminate ();
+        void activated (pipe_t *pipe_);
+        void terminated (pipe_t *pipe_);
 
         int recv (msg_t *msg_, int flags_);
         bool has_in ();
 
-        void activated (pipe_t *pipe_);
-        void terminated (pipe_t *pipe_);
-
     private:
 
         //  Inbound pipes.
@@ -64,12 +62,6 @@ namespace zmq
         //  there are following parts still waiting in the current pipe.
         bool more;
 
-        //  Object to send events to.
-        class own_t *sink;
-
-        //  If true, termination process is already underway.
-        bool terminating;
-
         fq_t (const fq_t&);
         const fq_t &operator = (const fq_t&);
     };
diff --git a/src/lb.cpp b/src/lb.cpp
index 2ba902a..7aeef9e 100644
--- a/src/lb.cpp
+++ b/src/lb.cpp
@@ -21,16 +21,13 @@
 #include "lb.hpp"
 #include "pipe.hpp"
 #include "err.hpp"
-#include "own.hpp"
 #include "msg.hpp"
 
-zmq::lb_t::lb_t (own_t *sink_) :
+zmq::lb_t::lb_t () :
     active (0),
     current (0),
     more (false),
-    dropping (false),
-    sink (sink_),
-    terminating (false)
+    dropping (false)
 {
 }
 
@@ -44,21 +41,6 @@ void zmq::lb_t::attach (pipe_t *pipe_)
     pipes.push_back (pipe_);
     pipes.swap (active, pipes.size () - 1);
     active++;
-
-    if (terminating) {
-        sink->register_term_acks (1);
-        pipe_->terminate ();
-    }
-}
-
-void zmq::lb_t::terminate ()
-{
-    zmq_assert (!terminating);
-    terminating = true;
-
-    sink->register_term_acks ((int) pipes.size ());
-    for (pipes_t::size_type i = 0; i != pipes.size (); i++)
-        pipes [i]->terminate ();
 }
 
 void zmq::lb_t::terminated (pipe_t *pipe_)
@@ -78,9 +60,6 @@ void zmq::lb_t::terminated (pipe_t *pipe_)
             current = 0;
     }
     pipes.erase (pipe_);
-
-    if (terminating)
-        sink->unregister_term_ack ();
 }
 
 void zmq::lb_t::activated (pipe_t *pipe_)
diff --git a/src/lb.hpp b/src/lb.hpp
index d764f6d..0dfd25e 100644
--- a/src/lb.hpp
+++ b/src/lb.hpp
@@ -34,17 +34,16 @@ namespace zmq
     {
     public:
 
-        lb_t (class own_t *sink_);
+        lb_t ();
         ~lb_t ();
 
         void attach (pipe_t *pipe_);
-        void terminate ();
-        int send (msg_t *msg_, int flags_);
-        bool has_out ();
-
         void activated (pipe_t *pipe_);
         void terminated (pipe_t *pipe_);
 
+        int send (msg_t *msg_, int flags_);
+        bool has_out ();
+
     private:
 
         //  List of outbound pipes.
@@ -64,12 +63,6 @@ namespace zmq
         //  True if we are dropping current message.
         bool dropping;
 
-        //  Object to send events to.
-        class own_t *sink;
-
-        //  If true, termination process is already underway.
-        bool terminating;
-
         lb_t (const lb_t&);
         const lb_t &operator = (const lb_t&);
     };
diff --git a/src/own.cpp b/src/own.cpp
index cdf20a4..f2ca4b2 100644
--- a/src/own.cpp
+++ b/src/own.cpp
@@ -153,6 +153,11 @@ void zmq::own_t::terminate ()
     send_term_req (owner, this);
 }
 
+bool zmq::own_t::is_terminating ()
+{
+    return terminating;
+}
+
 void zmq::own_t::process_term (int linger_)
 {
     //  Double termination should never happen.
@@ -173,7 +178,6 @@ void zmq::own_t::process_term (int linger_)
 void zmq::own_t::register_term_acks (int count_)
 {
     term_acks += count_;
-    printf ("reg %d acks (%p, %d)\n", count_, (void*) this, term_acks);
 }
 
 void zmq::own_t::unregister_term_ack ()
@@ -181,8 +185,6 @@ void zmq::own_t::unregister_term_ack ()
     zmq_assert (term_acks > 0);
     term_acks--;
 
-    printf ("unreg 1 acks (%p, %d)\n", (void*) this, term_acks);
-
     //  This may be a last ack we are waiting for before termination...
     check_term_acks (); 
 }
diff --git a/src/own.hpp b/src/own.hpp
index 5023a30..0902f73 100644
--- a/src/own.hpp
+++ b/src/own.hpp
@@ -76,6 +76,9 @@ namespace zmq
         //  called more than once.
         void terminate ();
 
+        //  Returns true if the object is in process of termination.
+        bool is_terminating ();
+
         //  Derived object destroys own_t. There's no point in allowing
         //  others to invoke the destructor. At the same time, it has to be
         //  virtual so that generic own_t deallocation mechanism destroys
diff --git a/src/pair.cpp b/src/pair.cpp
index 93a4327..30b56e6 100644
--- a/src/pair.cpp
+++ b/src/pair.cpp
@@ -25,8 +25,7 @@
 
 zmq::pair_t::pair_t (class ctx_t *parent_, uint32_t tid_) :
     socket_base_t (parent_, tid_),
-    pipe (NULL),
-    terminating (false)
+    pipe (NULL)
 {
     options.type = ZMQ_PAIR;
 }
@@ -39,44 +38,22 @@ zmq::pair_t::~pair_t ()
 void zmq::pair_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
 {
     zmq_assert (!pipe);
-
     pipe = pipe_;
-    pipe->set_event_sink (this);
-
-    if (terminating) {
-        register_term_acks (1);
-        pipe_->terminate ();
-    }
 }
 
-void zmq::pair_t::terminated (pipe_t *pipe_)
+void zmq::pair_t::xterminated (pipe_t *pipe_)
 {
     zmq_assert (pipe_ == pipe);
     pipe = NULL;
-
-    if (terminating)
-        unregister_term_ack ();
-}
-
-void zmq::pair_t::process_term (int linger_)
-{
-    terminating = true;
-
-    if (pipe) {
-        register_term_acks (1);
-        pipe->terminate ();
-    }
-
-    socket_base_t::process_term (linger_);
 }
 
-void zmq::pair_t::read_activated (pipe_t *pipe_)
+void zmq::pair_t::xread_activated (pipe_t *pipe_)
 {
     //  There's just one pipe. No lists of active and inactive pipes.
     //  There's nothing to do here.
 }
 
-void zmq::pair_t::write_activated (pipe_t *pipe_)
+void zmq::pair_t::xwrite_activated (pipe_t *pipe_)
 {
     //  There's just one pipe. No lists of active and inactive pipes.
     //  There's nothing to do here.
diff --git a/src/pair.hpp b/src/pair.hpp
index 2cb050a..1ddf50e 100644
--- a/src/pair.hpp
+++ b/src/pair.hpp
@@ -22,14 +22,12 @@
 #define __ZMQ_PAIR_HPP_INCLUDED__
 
 #include "socket_base.hpp"
-#include "pipe.hpp"
 
 namespace zmq
 {
 
     class pair_t :
-        public socket_base_t,
-        public i_pipe_events
+        public socket_base_t
     {
     public:
 
@@ -42,21 +40,14 @@ namespace zmq
         int xrecv (class msg_t *msg_, int flags_);
         bool xhas_in ();
         bool xhas_out ();
-
-        //  i_pipe_events interface implementation.
-        void read_activated (class pipe_t *pipe_);
-        void write_activated (class pipe_t *pipe_);
-        void terminated (class pipe_t *pipe_);
+        void xread_activated (class pipe_t *pipe_);
+        void xwrite_activated (class pipe_t *pipe_);
+        void xterminated (class pipe_t *pipe_);
 
     private:
 
-        //  Hook into termination process.
-        void process_term (int linger_);
-
         class pipe_t *pipe;
 
-        bool terminating;
-
         pair_t (const pair_t&);
         const pair_t &operator = (const pair_t&);
     };
diff --git a/src/pipe.cpp b/src/pipe.cpp
index fb03042..3d0c0a6 100644
--- a/src/pipe.cpp
+++ b/src/pipe.cpp
@@ -108,7 +108,7 @@ bool zmq::pipe_t::check_read ()
 
         //  If pipe_term was already received but wasn't processed because
         //  of pending messages, we can ack it now.
-        if (terminating)
+        if (term_recvd)
             send_pipe_term_ack (peer);
 
         return false;
@@ -133,7 +133,7 @@ bool zmq::pipe_t::read (msg_t *msg_)
 
         //  If pipe_term was already received but wasn't processed because
         //  of pending messages, we can ack it now.
-        if (terminating)
+        if (term_recvd)
             send_pipe_term_ack (peer);
 
         return false;
diff --git a/src/pull.cpp b/src/pull.cpp
index 66457b8..5e48777 100644
--- a/src/pull.cpp
+++ b/src/pull.cpp
@@ -21,10 +21,10 @@
 #include "pull.hpp"
 #include "err.hpp"
 #include "msg.hpp"
+#include "pipe.hpp"
 
 zmq::pull_t::pull_t (class ctx_t *parent_, uint32_t tid_) :
-    socket_base_t (parent_, tid_),
-    fq (this)
+    socket_base_t (parent_, tid_)
 {
     options.type = ZMQ_PULL;
 }
@@ -36,32 +36,19 @@ zmq::pull_t::~pull_t ()
 void zmq::pull_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
 {
     zmq_assert (pipe_);
-    pipe_->set_event_sink (this);
     fq.attach (pipe_);
 }
 
-void zmq::pull_t::read_activated (pipe_t *pipe_)
+void zmq::pull_t::xread_activated (pipe_t *pipe_)
 {
     fq.activated (pipe_);
 }
 
-void zmq::pull_t::write_activated (pipe_t *pipe_)
-{
-    //  There are no outbound messages in pull socket. This should never happen.
-    zmq_assert (false);
-}
-
-void zmq::pull_t::terminated (pipe_t *pipe_)
+void zmq::pull_t::xterminated (pipe_t *pipe_)
 {
     fq.terminated (pipe_);
 }
 
-void zmq::pull_t::process_term (int linger_)
-{
-    fq.terminate ();
-    socket_base_t::process_term (linger_);
-}
-
 int zmq::pull_t::xrecv (msg_t *msg_, int flags_)
 {
     return fq.recv (msg_, flags_);
diff --git a/src/pull.hpp b/src/pull.hpp
index af59724..cbcf05a 100644
--- a/src/pull.hpp
+++ b/src/pull.hpp
@@ -22,15 +22,13 @@
 #define __ZMQ_PULL_HPP_INCLUDED__
 
 #include "socket_base.hpp"
-#include "pipe.hpp"
 #include "fq.hpp"
 
 namespace zmq
 {
 
     class pull_t :
-        public socket_base_t,
-        public i_pipe_events
+        public socket_base_t
     {
     public:
 
@@ -43,17 +41,11 @@ namespace zmq
         void xattach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_);
         int xrecv (class msg_t *msg_, int flags_);
         bool xhas_in ();
+        void xread_activated (class pipe_t *pipe_);
+        void xterminated (class pipe_t *pipe_);
 
     private:
 
-        //  i_pipe_events interface implementation.
-        void read_activated (pipe_t *pipe_);
-        void write_activated (pipe_t *pipe_);
-        void terminated (pipe_t *pipe_);
-
-        //  Hook into the termination process.
-        void process_term (int linger_);
-
         //  Fair queueing object for inbound pipes.
         fq_t fq;
 
diff --git a/src/push.cpp b/src/push.cpp
index 12fc8d2..44ebc07 100644
--- a/src/push.cpp
+++ b/src/push.cpp
@@ -24,8 +24,7 @@
 #include "msg.hpp"
 
 zmq::push_t::push_t (class ctx_t *parent_, uint32_t tid_) :
-    socket_base_t (parent_, tid_),
-    lb (this)
+    socket_base_t (parent_, tid_)
 {
     options.type = ZMQ_PUSH;
 }
@@ -37,32 +36,19 @@ zmq::push_t::~push_t ()
 void zmq::push_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
 {
     zmq_assert (pipe_);
-    pipe_->set_event_sink (this);
     lb.attach (pipe_);
 }
 
-void zmq::push_t::read_activated (pipe_t *pipe_)
-{
-    //  There are no inbound messages in push socket. This should never happen.
-    zmq_assert (false);
-}
-
-void zmq::push_t::write_activated (pipe_t *pipe_)
+void zmq::push_t::xwrite_activated (pipe_t *pipe_)
 {
     lb.activated (pipe_);
 }
 
-void zmq::push_t::terminated (pipe_t *pipe_)
+void zmq::push_t::xterminated (pipe_t *pipe_)
 {
     lb.terminated (pipe_);
 }
 
-void zmq::push_t::process_term (int linger_)
-{
-    lb.terminate ();
-    socket_base_t::process_term (linger_);
-}
-
 int zmq::push_t::xsend (msg_t *msg_, int flags_)
 {
     return lb.send (msg_, flags_);
diff --git a/src/push.hpp b/src/push.hpp
index 67763eb..5dabe14 100644
--- a/src/push.hpp
+++ b/src/push.hpp
@@ -22,15 +22,13 @@
 #define __ZMQ_PUSH_HPP_INCLUDED__
 
 #include "socket_base.hpp"
-#include "pipe.hpp"
 #include "lb.hpp"
 
 namespace zmq
 {
 
     class push_t :
-        public socket_base_t,
-        public i_pipe_events
+        public socket_base_t
     {
     public:
 
@@ -43,17 +41,11 @@ namespace zmq
         void xattach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_);
         int xsend (class msg_t *msg_, int flags_);
         bool xhas_out ();
+        void xwrite_activated (class pipe_t *pipe_);
+        void xterminated (class pipe_t *pipe_);
 
     private:
 
-        //  i_pipe_events interface implementation.
-        void read_activated (pipe_t *pipe_);
-        void write_activated (pipe_t *pipe_);
-        void terminated (pipe_t *pipe_);
-
-        //  Hook into the termination process.
-        void process_term (int linger_);
-
         //  Load balancer managing the outbound pipes.
         lb_t lb;
 
diff --git a/src/reaper.cpp b/src/reaper.cpp
index d3ebbba..0295137 100644
--- a/src/reaper.cpp
+++ b/src/reaper.cpp
@@ -87,7 +87,7 @@ void zmq::reaper_t::process_stop ()
 {
     terminating = true;
 
-    //  If there are no sockets beig reaped finish immediately.
+    //  If there are no sockets being reaped finish immediately.
     if (!sockets) {
         send_done ();
         poller->rm_fd (mailbox_handle);
@@ -100,10 +100,6 @@ void zmq::reaper_t::process_reap (socket_base_t *socket_)
     //  Add the socket to the poller.
     socket_->start_reaping (poller);
 
-    //  Start termination of associated I/O object hierarchy.
-    socket_->terminate ();
-    socket_->check_destroy ();
-
     ++sockets;
 }
 
diff --git a/src/socket_base.cpp b/src/socket_base.cpp
index baa4bd2..fae55f2 100644
--- a/src/socket_base.cpp
+++ b/src/socket_base.cpp
@@ -211,10 +211,15 @@ int zmq::socket_base_t::check_protocol (const std::string &protocol_)
     return 0;
 }
 
-void zmq::socket_base_t::attach_pipe (class pipe_t *pipe_,
+void zmq::socket_base_t::attach_pipe (pipe_t *pipe_,
     const blob_t &peer_identity_)
 {
-    // If the peer haven't specified it's identity, let's generate one.
+    //  First, register the pipe so that we can terminate it later on.
+    pipe_->set_event_sink (this);
+    pipes.push_back (pipe_);
+    
+    //  Then, pass the pipe to the specific socket type.
+    //  If the peer haven't specified it's identity, let's generate one.
     if (peer_identity_.size ()) {
         xattach_pipe (pipe_, peer_identity_);
     }
@@ -223,6 +228,13 @@ void zmq::socket_base_t::attach_pipe (class pipe_t *pipe_,
         generate_uuid ((unsigned char*) identity.data () + 1);
         xattach_pipe (pipe_, identity);
     }
+
+    //  If the socket is already being closed, ask any new pipes to terminate
+    //  straight away.
+    if (is_terminating ()) {
+        register_term_acks (1);
+        pipe_->terminate ();
+    }
 }
 
 int zmq::socket_base_t::setsockopt (int option_, const void *optval_,
@@ -635,9 +647,15 @@ zmq::session_t *zmq::socket_base_t::find_session (const blob_t &name_)
 
 void zmq::socket_base_t::start_reaping (poller_t *poller_)
 {
+    //  Plug the socket to the reaper thread.
     poller = poller_;
     handle = poller->add_fd (mailbox.get_fd (), this);
     poller->set_pollin (handle);
+
+    //  Initialise the termination and check whether it can be deallocated
+    //  immediately.
+    terminate ();
+    check_destroy ();
 }
 
 int zmq::socket_base_t::process_commands (bool block_, bool throttle_)
@@ -720,6 +738,11 @@ void zmq::socket_base_t::process_term (int linger_)
     //  will be initiated.
     unregister_endpoints (this);
 
+    //  Ask all attached pipes to terminate.
+    for (pipes_t::size_type i = 0; i != pipes.size (); ++i)
+        pipes [i]->terminate ();
+    register_term_acks (pipes.size ());
+
     //  Continue the termination process immediately.
     own_t::process_term (linger_);
 }
@@ -758,6 +781,15 @@ int zmq::socket_base_t::xrecv (msg_t *msg_, int options_)
     return -1;
 }
 
+void zmq::socket_base_t::xread_activated (pipe_t *pipe_)
+{
+    zmq_assert (false);
+}
+void zmq::socket_base_t::xwrite_activated (pipe_t *pipe_)
+{
+    zmq_assert (false);
+}
+
 void zmq::socket_base_t::in_event ()
 {
     //  Process any commands from other threads/sockets that may be available
@@ -794,3 +826,26 @@ void zmq::socket_base_t::check_destroy ()
         own_t::process_destroy ();
     }
 }
+
+void zmq::socket_base_t::read_activated (pipe_t *pipe_)
+{
+    xread_activated (pipe_);
+}
+
+void zmq::socket_base_t::write_activated (pipe_t *pipe_)
+{
+    xwrite_activated (pipe_);
+}
+
+void zmq::socket_base_t::terminated (pipe_t *pipe_)
+{
+    //  Notify the specific socket type about the pipe termination.
+    xterminated (pipe_);
+
+    //  Remove the pipe from the list of attached pipes and confirm its
+    //  termination if we are already shutting down.
+    pipes.erase (pipe_);
+    if (is_terminating ())
+        unregister_term_ack ();
+}
+
diff --git a/src/socket_base.hpp b/src/socket_base.hpp
index 531751b..7126733 100644
--- a/src/socket_base.hpp
+++ b/src/socket_base.hpp
@@ -34,6 +34,7 @@
 #include "mailbox.hpp"
 #include "stdint.hpp"
 #include "blob.hpp"
+#include "pipe.hpp"
 #include "own.hpp"
 
 namespace zmq
@@ -42,7 +43,8 @@ namespace zmq
     class socket_base_t :
         public own_t,
         public array_item_t,
-        public i_poll_events
+        public i_poll_events,
+        public i_pipe_events
     {
         friend class reaper_t;
 
@@ -81,14 +83,6 @@ namespace zmq
         void unregister_session (const blob_t &name_);
         class session_t *find_session (const blob_t &name_);
 
-        //  i_reader_events interface implementation.
-        void activated (class reader_t *pipe_);
-        void terminated (class reader_t *pipe_);
-
-        //  i_writer_events interface implementation.
-        void activated (class writer_t *pipe_);
-        void terminated (class writer_t *pipe_);
-
         //  Using this function reaper thread ask the socket to regiter with
         //  its poller.
         void start_reaping (poller_t *poller_);
@@ -99,9 +93,10 @@ namespace zmq
         void out_event ();
         void timer_event (int id_);
 
-        //  To be called after processing commands or invoking any command
-        //  handlers explicitly. If required, it will deallocate the socket.
-        void check_destroy ();
+        //  i_pipe_events interface implementation.
+        void read_activated (pipe_t *pipe_);
+        void write_activated (pipe_t *pipe_);
+        void terminated (pipe_t *pipe_);
 
     protected:
 
@@ -127,16 +122,20 @@ namespace zmq
         virtual bool xhas_in ();
         virtual int xrecv (class msg_t *msg_, int options_);
 
-        //  We are declaring termination handler as protected so that
-        //  individual socket types can hook into the termination process
-        //  by overloading it.
-        void process_term (int linger_);
+        //  i_pipe_events will be forwarded to these functions.
+        virtual void xread_activated (pipe_t *pipe_);
+        virtual void xwrite_activated (pipe_t *pipe_);
+        virtual void xterminated (pipe_t *pipe_) = 0;
 
         //  Delay actual destruction of the socket.
         void process_destroy ();
 
     private:
 
+        //  To be called after processing commands or invoking any command
+        //  handlers explicitly. If required, it will deallocate the socket.
+        void check_destroy ();
+
         //  Used to check whether the object is a socket.
         uint32_t tag;
 
@@ -156,7 +155,7 @@ namespace zmq
         //  bind, is available and compatible with the socket type.
         int check_protocol (const std::string &protocol_);
 
-        //  If no identity is set, generate one and call xattach_pipe ().
+        //  Register the pipe with this socket.
         void attach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_);
 
         //  Processes commands sent to this socket (if any). If 'block' is
@@ -169,10 +168,15 @@ namespace zmq
         void process_stop ();
         void process_bind (class pipe_t *pipe_, const blob_t &peer_identity_);
         void process_unplug ();
+        void process_term (int linger_);
 
         //  Socket's mailbox object.
         mailbox_t mailbox;
 
+        //  List of attached pipes.
+        typedef array_t <pipe_t, 3> pipes_t;
+        pipes_t pipes;
+
         //  Reaper's poller and handle of this socket within it.
         poller_t *poller;
         poller_t::handle_t handle;
diff --git a/src/sub.hpp b/src/sub.hpp
index 8575961..8ba8987 100644
--- a/src/sub.hpp
+++ b/src/sub.hpp
@@ -37,7 +37,7 @@ namespace zmq
 
         int xsetsockopt (int option_, const void *optval_, size_t optvallen_);
         int xsend (class msg_t *msg_, int options_);
-	bool xhas_out ();
+        bool xhas_out ();
 
     private:
 
diff --git a/src/xpub.cpp b/src/xpub.cpp
index 888b42d..d5dba9f 100644
--- a/src/xpub.cpp
+++ b/src/xpub.cpp
@@ -24,8 +24,7 @@
 #include "msg.hpp"
 
 zmq::xpub_t::xpub_t (class ctx_t *parent_, uint32_t tid_) :
-    socket_base_t (parent_, tid_),
-    dist (this)
+    socket_base_t (parent_, tid_)
 {
     options.type = ZMQ_XPUB;
 }
@@ -37,35 +36,19 @@ zmq::xpub_t::~xpub_t ()
 void zmq::xpub_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
 {
     zmq_assert (pipe_);
-    pipe_->set_event_sink (this);
     dist.attach (pipe_);
 }
 
-void zmq::xpub_t::read_activated (pipe_t *pipe_)
-{
-    //  PUB socket never receives messages. This should never happen.
-    zmq_assert (false);
-}
-
-void zmq::xpub_t::write_activated (pipe_t *pipe_)
+void zmq::xpub_t::xwrite_activated (pipe_t *pipe_)
 {
     dist.activated (pipe_);
 }
 
-void zmq::xpub_t::terminated (pipe_t *pipe_)
+void zmq::xpub_t::xterminated (pipe_t *pipe_)
 {
     dist.terminated (pipe_);
 }
 
-void zmq::xpub_t::process_term (int linger_)
-{
-    //  Terminate the outbound pipes.
-    dist.terminate ();
-
-    //  Continue with the termination immediately.
-    socket_base_t::process_term (linger_);
-}
-
 int zmq::xpub_t::xsend (msg_t *msg_, int flags_)
 {
     return dist.send (msg_, flags_);
diff --git a/src/xpub.hpp b/src/xpub.hpp
index 48efd17..8a6ff73 100644
--- a/src/xpub.hpp
+++ b/src/xpub.hpp
@@ -23,15 +23,13 @@
 
 #include "socket_base.hpp"
 #include "array.hpp"
-#include "pipe.hpp"
 #include "dist.hpp"
 
 namespace zmq
 {
 
     class xpub_t :
-        public socket_base_t,
-        public i_pipe_events
+        public socket_base_t
     {
     public:
 
@@ -44,17 +42,11 @@ namespace zmq
         bool xhas_out ();
         int xrecv (class msg_t *msg_, int flags_);
         bool xhas_in ();
+        void xwrite_activated (class pipe_t *pipe_);
+        void xterminated (class pipe_t *pipe_);
 
     private:
 
-        //  i_pipe_events interface implementation.
-        void read_activated (pipe_t *pipe_);
-        void write_activated (pipe_t *pipe_);
-        void terminated (pipe_t *pipe_);
-
-        //  Hook into the termination process.
-        void process_term (int linger_);
-
         //  Distributor of messages holding the list of outbound pipes.
         dist_t dist;
 
diff --git a/src/xrep.cpp b/src/xrep.cpp
index d82890d..920be8d 100644
--- a/src/xrep.cpp
+++ b/src/xrep.cpp
@@ -28,8 +28,7 @@ zmq::xrep_t::xrep_t (class ctx_t *parent_, uint32_t tid_) :
     prefetched (false),
     more_in (false),
     current_out (NULL),
-    more_out (false),
-    terminating (false)
+    more_out (false)
 {
     options.type = ZMQ_XREP;
 
@@ -47,7 +46,6 @@ zmq::xrep_t::~xrep_t ()
 void zmq::xrep_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
 {
     zmq_assert (pipe_);
-    pipe_->set_event_sink (this);
 
     //  Add the pipe to the map out outbound pipes.
     //  TODO: What if new connection has same peer identity as the old one?
@@ -59,27 +57,9 @@ void zmq::xrep_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
     //  Add the pipe to the list of inbound pipes.
     inpipe_t inpipe = {pipe_, peer_identity_, true};
     inpipes.push_back (inpipe);
-
-    //  In case we are already terminating, ask this pipe to terminate as well.
-    if (terminating) {
-        register_term_acks (1);
-        pipe_->terminate ();
-    }
 }
 
-void zmq::xrep_t::process_term (int linger_)
-{
-    terminating = true;
-
-    register_term_acks ((int) (inpipes.size () + outpipes.size ()));
-
-    for (inpipes_t::iterator it = inpipes.begin (); it != inpipes.end (); ++it)
-        it->pipe->terminate ();
-
-    socket_base_t::process_term (linger_);
-}
-
-void zmq::xrep_t::terminated (pipe_t *pipe_)
+void zmq::xrep_t::xterminated (pipe_t *pipe_)
 {
     for (inpipes_t::iterator it = inpipes.begin (); it != inpipes.end ();
           ++it) {
@@ -89,8 +69,6 @@ void zmq::xrep_t::terminated (pipe_t *pipe_)
             inpipes.erase (it);
             if (current_in >= inpipes.size ())
                 current_in = 0;
-            if (terminating)
-                unregister_term_ack ();
             goto clean_outpipes;
         }
     }
@@ -103,15 +81,13 @@ clean_outpipes:
             outpipes.erase (it);
             if (pipe_ == current_out)
                 current_out = NULL;
-            if (terminating)
-                unregister_term_ack ();
             return;
         }
     }
     zmq_assert (false);
 }
 
-void zmq::xrep_t::read_activated (pipe_t *pipe_)
+void zmq::xrep_t::xread_activated (pipe_t *pipe_)
 {
     for (inpipes_t::iterator it = inpipes.begin (); it != inpipes.end ();
           ++it) {
@@ -124,7 +100,7 @@ void zmq::xrep_t::read_activated (pipe_t *pipe_)
     zmq_assert (false);
 }
 
-void zmq::xrep_t::write_activated (pipe_t *pipe_)
+void zmq::xrep_t::xwrite_activated (pipe_t *pipe_)
 {
     for (outpipes_t::iterator it = outpipes.begin ();
           it != outpipes.end (); ++it) {
@@ -312,3 +288,4 @@ bool zmq::xrep_t::xhas_out ()
 }
 
 
+
diff --git a/src/xrep.hpp b/src/xrep.hpp
index d0378c2..fbc7385 100644
--- a/src/xrep.hpp
+++ b/src/xrep.hpp
@@ -26,7 +26,6 @@
 
 #include "socket_base.hpp"
 #include "blob.hpp"
-#include "pipe.hpp"
 #include "msg.hpp"
 
 namespace zmq
@@ -34,8 +33,7 @@ namespace zmq
 
     //  TODO: This class uses O(n) scheduling. Rewrite it to use O(1) algorithm.
     class xrep_t :
-        public socket_base_t,
-        public i_pipe_events
+        public socket_base_t
     {
     public:
 
@@ -48,6 +46,9 @@ namespace zmq
         int xrecv (class msg_t *msg_, int flags_);
         bool xhas_in ();
         bool xhas_out ();
+        void xread_activated (class pipe_t *pipe_);
+        void xwrite_activated (class pipe_t *pipe_);
+        void xterminated (class pipe_t *pipe_);
 
     protected:
 
@@ -56,14 +57,6 @@ namespace zmq
 
     private:
 
-        //  Hook into the termination process.
-        void process_term (int linger_);
-
-        //  i_pipe_events interface implementation.
-        void read_activated (pipe_t *pipe_);
-        void write_activated (pipe_t *pipe_);
-        void terminated (pipe_t *pipe_);
-
         struct inpipe_t
         {
             class pipe_t *pipe;
@@ -103,9 +96,6 @@ namespace zmq
         //  If true, more outgoing message parts are expected.
         bool more_out;
 
-        //  If true, termination process is already underway.
-        bool terminating;
-
         xrep_t (const xrep_t&);
         const xrep_t &operator = (const xrep_t&);
     };
diff --git a/src/xreq.cpp b/src/xreq.cpp
index 4a6e67e..2371a34 100644
--- a/src/xreq.cpp
+++ b/src/xreq.cpp
@@ -23,9 +23,7 @@
 #include "msg.hpp"
 
 zmq::xreq_t::xreq_t (class ctx_t *parent_, uint32_t tid_) :
-    socket_base_t (parent_, tid_),
-    fq (this),
-    lb (this)
+    socket_base_t (parent_, tid_)
 {
     options.type = ZMQ_XREQ;
 }
@@ -34,21 +32,13 @@ zmq::xreq_t::~xreq_t ()
 {
 }
 
-void zmq::xreq_t::xattach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_)
+void zmq::xreq_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
 {
     zmq_assert (pipe_);
-    pipe_->set_event_sink (this);
     fq.attach (pipe_);
     lb.attach (pipe_);
 }
 
-void zmq::xreq_t::process_term (int linger_)
-{
-    fq.terminate ();
-    lb.terminate ();
-    socket_base_t::process_term (linger_);
-}
-
 int zmq::xreq_t::xsend (msg_t *msg_, int flags_)
 {
     return lb.send (msg_, flags_);
@@ -69,17 +59,17 @@ bool zmq::xreq_t::xhas_out ()
     return lb.has_out ();
 }
 
-void zmq::xreq_t::read_activated (pipe_t *pipe_)
+void zmq::xreq_t::xread_activated (pipe_t *pipe_)
 {
     fq.activated (pipe_);
 }
 
-void zmq::xreq_t::write_activated (pipe_t *pipe_)
+void zmq::xreq_t::xwrite_activated (pipe_t *pipe_)
 {
     lb.activated (pipe_);
 }
 
-void zmq::xreq_t::terminated (pipe_t *pipe_)
+void zmq::xreq_t::xterminated (pipe_t *pipe_)
 {
     fq.terminated (pipe_);
     lb.terminated (pipe_);
diff --git a/src/xreq.hpp b/src/xreq.hpp
index a75e5c8..5bf1a03 100644
--- a/src/xreq.hpp
+++ b/src/xreq.hpp
@@ -23,7 +23,6 @@
 #define __ZMQ_XREQ_HPP_INCLUDED__
 
 #include "socket_base.hpp"
-#include "pipe.hpp"
 #include "fq.hpp"
 #include "lb.hpp"
 
@@ -31,8 +30,7 @@ namespace zmq
 {
 
     class xreq_t :
-        public socket_base_t,
-        public i_pipe_events
+        public socket_base_t
     {
     public:
 
@@ -47,17 +45,12 @@ namespace zmq
         int xrecv (class msg_t *msg_, int flags_);
         bool xhas_in ();
         bool xhas_out ();
+        void xread_activated (class pipe_t *pipe_);
+        void xwrite_activated (class pipe_t *pipe_);
+        void xterminated (class pipe_t *pipe_);
 
     private:
 
-        //  i_pipe_events interface implementation.
-        void read_activated (pipe_t *pipe_);
-        void write_activated (pipe_t *pipe_);
-        void terminated (pipe_t *pipe_);
-
-        //  Hook into the termination process.
-        void process_term (int linger_);
-
         //  Messages are fair-queued from inbound pipes. And load-balanced to
         //  the outbound pipes.
         fq_t fq;
diff --git a/src/xsub.cpp b/src/xsub.cpp
index dc30d71..c5f610f 100644
--- a/src/xsub.cpp
+++ b/src/xsub.cpp
@@ -25,7 +25,6 @@
 
 zmq::xsub_t::xsub_t (class ctx_t *parent_, uint32_t tid_) :
     socket_base_t (parent_, tid_),
-    fq (this),
     has_message (false),
     more (false)
 {
@@ -43,32 +42,19 @@ zmq::xsub_t::~xsub_t ()
 void zmq::xsub_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
 {
     zmq_assert (pipe_);
-    pipe_->set_event_sink (this);
     fq.attach (pipe_);
 }
 
-void zmq::xsub_t::read_activated (pipe_t *pipe_)
+void zmq::xsub_t::xread_activated (pipe_t *pipe_)
 {
     fq.activated (pipe_);
 }
 
-void zmq::xsub_t::write_activated (pipe_t *pipe_)
-{
-    //  SUB socket never sends messages. This should never happen.
-    zmq_assert (false);
-}
-
-void zmq::xsub_t::terminated (pipe_t *pipe_)
+void zmq::xsub_t::xterminated (pipe_t *pipe_)
 {
     fq.terminated (pipe_);
 }
 
-void zmq::xsub_t::process_term (int linger_)
-{
-    fq.terminate ();
-    socket_base_t::process_term (linger_);
-}
-
 int zmq::xsub_t::xsend (msg_t *msg_, int options_)
 {
     size_t size = msg_->size ();
diff --git a/src/xsub.hpp b/src/xsub.hpp
index ed9c462..58ddae5 100644
--- a/src/xsub.hpp
+++ b/src/xsub.hpp
@@ -23,7 +23,6 @@
 
 #include "trie.hpp"
 #include "socket_base.hpp"
-#include "pipe.hpp"
 #include "msg.hpp"
 #include "fq.hpp"
 
@@ -31,8 +30,7 @@ namespace zmq
 {
 
     class xsub_t :
-        public socket_base_t,
-        public i_pipe_events
+        public socket_base_t
     {
     public:
 
@@ -47,17 +45,11 @@ namespace zmq
         bool xhas_out ();
         int xrecv (class msg_t *msg_, int flags_);
         bool xhas_in ();
+        void xread_activated (class pipe_t *pipe_);
+        void xterminated (class pipe_t *pipe_);
 
     private:
 
-        //  i_pipe_events interface implementation.
-        void read_activated (pipe_t *pipe_);
-        void write_activated (pipe_t *pipe_);
-        void terminated (pipe_t *pipe_);
-
-        //  Hook into the termination process.
-        void process_term (int linger_);
-
         //  Check whether the message matches at least one subscription.
         bool match (class msg_t *msg_);
 
diff --git a/tests/test_shutdown_stress.cpp b/tests/test_shutdown_stress.cpp
index dccf91f..ef81758 100644
--- a/tests/test_shutdown_stress.cpp
+++ b/tests/test_shutdown_stress.cpp
@@ -58,7 +58,7 @@ int main (int argc, char *argv [])
         ctx = zmq_init (7);
         assert (ctx);
 
-        s1 = zmq_socket (ctx, ZMQ_REP);
+        s1 = zmq_socket (ctx, ZMQ_PUB);
         assert (s1);
 
         rc = zmq_bind (s1, "tcp://127.0.0.1:5560");