pipe deallocation added

12 files changed, 290 insertions, 37 deletions

diff --git a/src/command.hpp b/src/command.hpp
index d3bad79..d16d4fa 100644
--- a/src/command.hpp
+++ b/src/command.hpp
@@ -40,6 +40,8 @@ namespace zmq
             attach,
             bind,
             revive,
+            pipe_term,
+            pipe_term_ack,
             term_req,
             term,
             term_ack
@@ -78,6 +80,15 @@ namespace zmq
             struct {
             } revive;
 
+            //  Sent by pipe reader to pipe writer to ask it to terminate
+            //  its end of the pipe.
+            struct {
+            } pipe_term;
+
+            //  Pipe writer acknowledges pipe_term command.
+            struct {
+            } pipe_term_ack;
+
             //  Sent by I/O object ot the socket to request the shutdown of
             //  the I/O object.
             struct {
diff --git a/src/dispatcher.cpp b/src/dispatcher.cpp
index c0f4541..71e20df 100644
--- a/src/dispatcher.cpp
+++ b/src/dispatcher.cpp
@@ -83,6 +83,10 @@ zmq::dispatcher_t::~dispatcher_t ()
     for (io_threads_t::size_type i = 0; i != io_threads.size (); i++)
         delete io_threads [i];
 
+    //  Deallocate all the orphaned pipes.
+    for (pipes_t::iterator it = pipes.begin (); it != pipes.end (); it++)
+        delete *it;
+
     delete [] command_pipes;
 
 #ifdef ZMQ_HAVE_WINDOWS
@@ -146,3 +150,19 @@ zmq::io_thread_t *zmq::dispatcher_t::choose_io_thread (uint64_t taskset_)
 
     return io_threads [result];
 }
+
+void zmq::dispatcher_t::register_pipe (class pipe_t *pipe_)
+{
+    pipes_sync.lock ();
+    bool inserted = pipes.insert (pipe_).second;
+    zmq_assert (inserted);
+    pipes_sync.unlock ();
+}
+
+void zmq::dispatcher_t::unregister_pipe (class pipe_t *pipe_)
+{
+    pipes_sync.lock ();
+    pipes_t::size_type erased = pipes.erase (pipe_);
+    zmq_assert (erased == 1);
+    pipes_sync.unlock ();
+}
diff --git a/src/dispatcher.hpp b/src/dispatcher.hpp
index 08596cb..cb445ef 100644
--- a/src/dispatcher.hpp
+++ b/src/dispatcher.hpp
@@ -21,6 +21,7 @@
 #define __ZMQ_DISPATCHER_HPP_INCLUDED__
 
 #include <vector>
+#include <set>
 #include <map>
 #include <string>
 
@@ -85,6 +86,11 @@ namespace zmq
         //  Taskset specifies which I/O threads are eligible (0 = all).
         class io_thread_t *choose_io_thread (uint64_t taskset_);
 
+        //  All pipes are registered with the dispatcher so that even the
+        //  orphaned pipes can be deallocated on the terminal shutdown.
+        void register_pipe (class pipe_t *pipe_);
+        void unregister_pipe (class pipe_t *pipe_);
+
     private:
 
         //  Returns the app thread associated with the current thread.
@@ -112,6 +118,18 @@ namespace zmq
         //  Synchronisation of accesses to shared thread data.
         mutex_t threads_sync;
 
+        //  As pipes may reside in orphaned state in particular moments
+        //  of the pipe shutdown process, i.e. neither pipe reader nor
+        //  pipe writer hold reference to the pipe, we have to hold references
+        //  to all pipes in dispatcher so that we can deallocate them
+        //  during terminal shutdown even though it conincides with the
+        //  pipe being in the orphaned state.
+        typedef std::set <class pipe_t*> pipes_t;
+        pipes_t pipes;
+
+        // Synchronisation of access to the pipes repository.
+        mutex_t pipes_sync;
+
         dispatcher_t (const dispatcher_t&);
         void operator = (const dispatcher_t&);
     };
diff --git a/src/i_endpoint.hpp b/src/i_endpoint.hpp
index bb7409e..14a479e 100644
--- a/src/i_endpoint.hpp
+++ b/src/i_endpoint.hpp
@@ -26,6 +26,8 @@ namespace zmq
     struct i_endpoint
     {
         virtual void revive (class reader_t *pipe_) = 0;
+        virtual void detach_inpipe (class reader_t *pipe_) = 0;
+        virtual void detach_outpipe (class writer_t *pipe_) = 0;
     };
 
 }
diff --git a/src/object.cpp b/src/object.cpp
index 4d54ebf..b3cf898 100644
--- a/src/object.cpp
+++ b/src/object.cpp
@@ -83,6 +83,14 @@ void zmq::object_t::process_command (command_t &cmd_)
             cmd_.args.bind.in_pipe, cmd_.args.bind.out_pipe);
         return;
 
+    case command_t::pipe_term:
+        process_pipe_term ();
+        return;
+
+    case command_t::pipe_term_ack:
+        process_pipe_term_ack ();
+        return;
+
     case command_t::term_req:
         process_term_req (cmd_.args.term_req.object);
         return;
@@ -100,6 +108,16 @@ void zmq::object_t::process_command (command_t &cmd_)
     }
 }
 
+void zmq::object_t::register_pipe (class pipe_t *pipe_)
+{
+    dispatcher->register_pipe (pipe_);
+}
+
+void zmq::object_t::unregister_pipe (class pipe_t *pipe_)
+{
+    dispatcher->unregister_pipe (pipe_);
+}
+
 zmq::io_thread_t *zmq::object_t::choose_io_thread (uint64_t taskset_)
 {
     return dispatcher->choose_io_thread (taskset_);
@@ -166,6 +184,22 @@ void zmq::object_t::send_revive (object_t *destination_)
     send_command (cmd);
 }
 
+void zmq::object_t::send_pipe_term (writer_t *destination_)
+{
+    command_t cmd;
+    cmd.destination = destination_;
+    cmd.type = command_t::pipe_term;
+    send_command (cmd);
+}
+
+void zmq::object_t::send_pipe_term_ack (reader_t *destination_)
+{
+    command_t cmd;
+    cmd.destination = destination_;
+    cmd.type = command_t::pipe_term_ack;
+    send_command (cmd);
+}
+
 void zmq::object_t::send_term_req (socket_base_t *destination_,
     owned_t *object_)
 {
@@ -223,6 +257,16 @@ void zmq::object_t::process_revive ()
     zmq_assert (false);
 }
 
+void zmq::object_t::process_pipe_term ()
+{
+    zmq_assert (false);
+}
+
+void zmq::object_t::process_pipe_term_ack ()
+{
+    zmq_assert (false);
+}
+
 void zmq::object_t::process_term_req (owned_t *object_)
 {
     zmq_assert (false);
diff --git a/src/object.hpp b/src/object.hpp
index 0dbac24..8ce569e 100644
--- a/src/object.hpp
+++ b/src/object.hpp
@@ -42,6 +42,10 @@ namespace zmq
         int get_thread_slot ();
         void process_command (struct command_t &cmd_);
 
+        //  Allow pipe to access corresponding dispatcher functions.
+        void register_pipe (class pipe_t *pipe_);
+        void unregister_pipe (class pipe_t *pipe_);
+
     protected:
 
         //  Derived object can use following functions to interact with
@@ -60,6 +64,8 @@ namespace zmq
         void send_bind (object_t *destination_, class owned_t *session_,
             class reader_t *in_pipe_, class writer_t *out_pipe_);
         void send_revive (class object_t *destination_);
+        void send_pipe_term (class writer_t *destination_);
+        void send_pipe_term_ack (class reader_t *destination_);
         void send_term_req (class socket_base_t *destination_,
             class owned_t *object_);
         void send_term (class owned_t *destination_);
@@ -74,6 +80,8 @@ namespace zmq
         virtual void process_bind (class owned_t *session_,
             class reader_t *in_pipe_, class writer_t *out_pipe_);
         virtual void process_revive ();
+        virtual void process_pipe_term ();
+        virtual void process_pipe_term_ack ();
         virtual void process_term_req (class owned_t *object_);
         virtual void process_term ();
         virtual void process_term_ack ();
diff --git a/src/pipe.cpp b/src/pipe.cpp
index 5016631..3748ae9 100644
--- a/src/pipe.cpp
+++ b/src/pipe.cpp
@@ -19,6 +19,8 @@
 
 #include <pthread.h>
 
+#include <../include/zmq.h>
+
 #include "pipe.hpp"
 
 zmq::reader_t::reader_t (object_t *parent_, pipe_t *pipe_,
@@ -39,9 +41,21 @@ zmq::reader_t::~reader_t ()
 
 bool zmq::reader_t::read (zmq_msg_t *msg_)
 {
-    return pipe->read (msg_);
+    if (!pipe->read (msg_))
+        return false;
+
+    //  If delimiter was read, start termination process of the pipe.
+    unsigned char *offset = 0;
+    if (msg_->content == (void*) (offset + ZMQ_DELIMITER)) {
+        if (endpoint)
+            endpoint->detach_inpipe (this);
+        term ();
+        return false;
+    }
 
     //  TODO: Adjust the size of the pipe.
+
+    return true;
 }
 
 void zmq::reader_t::set_endpoint (i_endpoint *endpoint_)
@@ -59,19 +73,48 @@ int zmq::reader_t::get_index ()
     return index;
 }
 
+void zmq::reader_t::term ()
+{
+    endpoint = NULL;
+    send_pipe_term (peer);
+}
+
 void zmq::reader_t::process_revive ()
 {
     endpoint->revive (this);
 }
 
+void zmq::reader_t::process_pipe_term_ack ()
+{
+    peer = NULL;
+    delete pipe;
+}
+
 zmq::writer_t::writer_t (object_t *parent_, pipe_t *pipe_,
       uint64_t hwm_, uint64_t lwm_) :
     object_t (parent_),
     pipe (pipe_),
     peer (&pipe_->reader),
     hwm (hwm_),
-    lwm (lwm_)
+    lwm (lwm_),
+    index (-1),
+    endpoint (NULL)
+{
+}
+
+void zmq::writer_t::set_endpoint (i_endpoint *endpoint_)
+{
+    endpoint = endpoint_;
+}
+
+void zmq::writer_t::set_index (int index_)
+{
+    index = index_;
+}
+
+int zmq::writer_t::get_index ()
 {
+    return index;
 }
 
 zmq::writer_t::~writer_t ()
@@ -99,14 +142,46 @@ void zmq::writer_t::flush ()
         send_revive (peer);
 }
 
+void zmq::writer_t::term ()
+{
+    endpoint = NULL;
+
+    //  Push delimiter into the pipe.
+    //  Trick the compiler to belive that the tag is a valid pointer.
+    zmq_msg_t msg;
+    const unsigned char *offset = 0;
+    msg.content = (void*) (offset + ZMQ_DELIMITER);
+    msg.shared = false;
+    pipe->write (msg);
+    pipe->flush ();
+}
+
+void zmq::writer_t::process_pipe_term ()
+{
+    if (endpoint)
+        endpoint->detach_outpipe (this);
+
+    reader_t *p = peer;
+    peer = NULL;
+    send_pipe_term_ack (p);
+}
+
 zmq::pipe_t::pipe_t (object_t *reader_parent_, object_t *writer_parent_,
       uint64_t hwm_, uint64_t lwm_) :
     reader (reader_parent_, this, hwm_, lwm_),
     writer (writer_parent_, this, hwm_, lwm_)
 {
+    reader.register_pipe (this);
 }
 
 zmq::pipe_t::~pipe_t ()
 {
+    //  Deallocate all the unread messages in the pipe. We have to do it by
+    //  hand because zmq_msg_t is a POD, not a class, so there's no associated
+    //  destructor.
+    zmq_msg_t msg;
+    while (read (&msg))
+       zmq_msg_close (&msg);
+
+    reader.unregister_pipe (this);
 }
-
diff --git a/src/pipe.hpp b/src/pipe.hpp
index b7593c7..b4e592a 100644
--- a/src/pipe.hpp
+++ b/src/pipe.hpp
@@ -39,25 +39,29 @@ namespace zmq
             uint64_t hwm_, uint64_t lwm_);
         ~reader_t ();
 
+        void set_endpoint (i_endpoint *endpoint_);
+
         //  Reads a message to the underlying pipe.
         bool read (struct zmq_msg_t *msg_);
 
-        void set_endpoint (i_endpoint *endpoint_);
-
         //  Mnaipulation of index of the pipe.
         void set_index (int index_);
         int get_index ();
 
+        //  Ask pipe to terminate.
+        void term ();
+
     private:
 
         //  Command handlers.
         void process_revive ();
+        void process_pipe_term_ack ();
 
         //  The underlying pipe.
         class pipe_t *pipe;
 
         //  Pipe writer associated with the other side of the pipe.
-        class object_t *peer;
+        class writer_t *peer;
 
         //  High and low watermarks for in-memory storage (in bytes).
         uint64_t hwm;
@@ -86,6 +90,8 @@ namespace zmq
             uint64_t hwm_, uint64_t lwm_);
         ~writer_t ();
 
+        void set_endpoint (i_endpoint *endpoint_);
+
         //  Checks whether message with specified size can be written to the
         //  pipe. If writing the message would cause high watermark to be
         //  exceeded, the function returns false.
@@ -98,13 +104,23 @@ namespace zmq
         //  Flush the messages downsteam.
         void flush ();
 
+        //  Mnaipulation of index of the pipe.
+        void set_index (int index_);
+        int get_index ();
+
+        //  Ask pipe to terminate.
+        void term ();
+
     private:
 
+        //  Command handlers.
+        void process_pipe_term ();
+
         //  The underlying pipe.
         class pipe_t *pipe;
 
         //  Pipe reader associated with the other side of the pipe.
-        class object_t *peer;
+        class reader_t *peer;
 
         //  High and low watermarks for in-memory storage (in bytes).
         uint64_t hwm;
@@ -114,6 +130,12 @@ namespace zmq
         uint64_t head;
         uint64_t tail;
 
+        //  Index of the pipe in the socket's list of outbound pipes.
+        int index;
+
+        //  Endpoint (either session or socket) the pipe is attached to.
+        i_endpoint *endpoint;
+
         writer_t (const writer_t&);
         void operator = (const writer_t&);
     };
diff --git a/src/session.cpp b/src/session.cpp
index 0b1b947..d667851 100644
--- a/src/session.cpp
+++ b/src/session.cpp
@@ -36,6 +36,11 @@ zmq::session_t::session_t (object_t *parent_, socket_base_t *owner_,
 
 zmq::session_t::~session_t ()
 {
+    //  Ask associated pipes to terminate.
+    if (in_pipe)
+        in_pipe->term ();
+    if (out_pipe)
+        out_pipe->term ();
 }
 
 void zmq::session_t::set_inbound_pipe (reader_t *pipe_)
@@ -49,6 +54,7 @@ void zmq::session_t::set_outbound_pipe (writer_t *pipe_)
 {
     zmq_assert (!out_pipe);
     out_pipe = pipe_;
+    out_pipe->set_endpoint (this);
 }
 
 
@@ -92,6 +98,17 @@ void zmq::session_t::revive (reader_t *pipe_)
         engine->revive ();
 }
 
+void zmq::session_t::detach_inpipe (reader_t *pipe_)
+{
+    active = false;
+    in_pipe = NULL;
+}
+
+void zmq::session_t::detach_outpipe (writer_t *pipe_)
+{
+    out_pipe = NULL;
+}
+
 void zmq::session_t::process_plug ()
 {
     //  Register the session with the socket.
@@ -112,6 +129,7 @@ void zmq::session_t::process_plug ()
         pipe_t *outbound = new pipe_t (owner, this, options.hwm, options.lwm);
         zmq_assert (outbound);
         out_pipe = &outbound->writer;
+        out_pipe->set_endpoint (this);
         send_bind (owner, this, &outbound->reader, &inbound->writer);
     }
 
diff --git a/src/session.hpp b/src/session.hpp
index 4a0882b..ba5bcdd 100644
--- a/src/session.hpp
+++ b/src/session.hpp
@@ -52,6 +52,8 @@ namespace zmq
 
         //  i_endpoint interface implementation.
         void revive (class reader_t *pipe_);
+        void detach_inpipe (class reader_t *pipe_);
+        void detach_outpipe (class writer_t *pipe_);
 
         //  Handlers for incoming commands.
         void process_plug ();
diff --git a/src/socket_base.cpp b/src/socket_base.cpp
index 68fc82b..e14065b 100644
--- a/src/socket_base.cpp
+++ b/src/socket_base.cpp
@@ -50,6 +50,16 @@ zmq::socket_base_t::~socket_base_t ()
 {
     shutting_down = true;
 
+    //  Ask all pipes to terminate.
+    for (in_pipes_t::iterator it = in_pipes.begin ();
+          it != in_pipes.end (); it++)
+        (*it)->term ();
+    in_pipes.clear ();
+    for (out_pipes_t::iterator it = out_pipes.begin ();
+          it != out_pipes.end (); it++)
+        (*it)->term ();
+    out_pipes.clear ();
+
     while (true) {
 
         //  On third pass of the loop there should be no more I/O objects
@@ -164,17 +174,18 @@ int zmq::socket_base_t::connect (const char *addr_)
     zmq_assert (in_pipe);
     in_pipe->reader.set_endpoint (this);
     session->set_outbound_pipe (&in_pipe->writer);
-    in_pipes.push_back (std::make_pair (&in_pipe->reader, session));
-    in_pipes.back ().first->set_index (active);
-    in_pipes [active].first->set_index (in_pipes.size () - 1);
+    in_pipes.push_back (&in_pipe->reader);
+    in_pipes.back ()->set_index (active);
+    in_pipes [active]->set_index (in_pipes.size () - 1);
     std::swap (in_pipes.back (), in_pipes [active]);
     active++;
 
     //  Create outbound pipe.
     pipe_t *out_pipe = new pipe_t (session, this, options.hwm, options.lwm);
     zmq_assert (out_pipe);
+    out_pipe->writer.set_endpoint (this);
     session->set_inbound_pipe (&out_pipe->reader);
-    out_pipes.push_back (std::make_pair (&out_pipe->writer, session));
+    out_pipes.push_back (&out_pipe->writer);
 
     //  Activate the session.
     send_plug (session);
@@ -225,7 +236,7 @@ int zmq::socket_base_t::flush ()
 {
     for (out_pipes_t::iterator it = out_pipes.begin (); it != out_pipes.end ();
           it++)
-        it->first->flush ();
+        (*it)->flush ();
 
     return 0;
 }
@@ -320,12 +331,38 @@ void zmq::socket_base_t::revive (reader_t *pipe_)
 {
     //  Move the pipe to the list of active pipes.
     in_pipes_t::size_type index = (in_pipes_t::size_type) pipe_->get_index ();
-    in_pipes [index].first->set_index (active);
-    in_pipes [active].first->set_index (index);    
+    in_pipes [index]->set_index (active);
+    in_pipes [active]->set_index (index);    
     std::swap (in_pipes [index], in_pipes [active]);
     active++;
 }
 
+void zmq::socket_base_t::detach_inpipe (class reader_t *pipe_)
+{
+    //  Remove the pipe from the list of inbound pipes.
+    in_pipes_t::size_type index = (in_pipes_t::size_type) pipe_->get_index ();
+    if (index < active) {
+        in_pipes [index]->set_index (active - 1);
+        in_pipes [active - 1]->set_index (index);
+        std::swap (in_pipes [index], in_pipes [active - 1]);
+        active--;
+        index = active;
+    }
+    in_pipes [index]->set_index (in_pipes.size () - 1);
+    in_pipes [in_pipes.size () - 1]->set_index (index);
+    std::swap (in_pipes [index], in_pipes [in_pipes.size () - 1]);
+    in_pipes.pop_back ();
+}
+
+void zmq::socket_base_t::detach_outpipe (class writer_t *pipe_)
+{
+    out_pipes_t::size_type index = (out_pipes_t::size_type) pipe_->get_index ();
+    out_pipes [index]->set_index (out_pipes.size () - 1);
+    out_pipes [out_pipes.size () - 1]->set_index (index);
+    std::swap (out_pipes [index], out_pipes [out_pipes.size () - 1]);
+    out_pipes.pop_back ();
+}
+
 void zmq::socket_base_t::process_own (owned_t *object_)
 {
     io_objects.insert (object_);
@@ -336,13 +373,14 @@ void zmq::socket_base_t::process_bind (owned_t *session_,
 {
     zmq_assert (in_pipe_);
     in_pipe_->set_endpoint (this);
-    in_pipes.push_back (std::make_pair (in_pipe_, session_));
-    in_pipes.back ().first->set_index (active);
-    in_pipes [active].first->set_index (in_pipes.size () - 1);
+    in_pipes.push_back (in_pipe_);
+    in_pipes.back ()->set_index (active);
+    in_pipes [active]->set_index (in_pipes.size () - 1);
     std::swap (in_pipes.back (), in_pipes [active]);
     active++;
     zmq_assert (out_pipe_);
-    out_pipes.push_back (std::make_pair (out_pipe_, session_));
+    out_pipe_->set_endpoint (this);
+    out_pipes.push_back (out_pipe_);
 }
 
 void zmq::socket_base_t::process_term_req (owned_t *object_)
@@ -388,7 +426,7 @@ bool zmq::socket_base_t::distribute (zmq_msg_t *msg_, bool flush_)
     //  First check whether all pipes are available for writing.
     for (out_pipes_t::iterator it = out_pipes.begin (); it != out_pipes.end ();
           it++)
-        if (!it->first->check_write (zmq_msg_size (msg_)))
+        if (!(*it)->check_write (zmq_msg_size (msg_)))
             return false;
 
     msg_content_t *content = (msg_content_t*) msg_->content;
@@ -397,9 +435,9 @@ bool zmq::socket_base_t::distribute (zmq_msg_t *msg_, bool flush_)
     if (content == (msg_content_t*) ZMQ_VSM) {
         for (out_pipes_t::iterator it = out_pipes.begin ();
               it != out_pipes.end (); it++) {
-            it->first->write (msg_);
+            (*it)->write (msg_);
             if (flush_)
-                it->first->flush ();
+                (*it)->flush ();
         }
         int rc = zmq_msg_init (msg_);
         zmq_assert (rc == 0);
@@ -410,9 +448,9 @@ bool zmq::socket_base_t::distribute (zmq_msg_t *msg_, bool flush_)
     //  to send the message to - no refcount adjustment i.e. no atomic
     //  operations are needed.
     if (pipes_count == 1) {
-        out_pipes.begin ()->first->write (msg_);
+        (*out_pipes.begin ())->write (msg_);
         if (flush_)
-            out_pipes.begin ()->first->flush ();
+            (*out_pipes.begin ())->flush ();
         int rc = zmq_msg_init (msg_);
         zmq_assert (rc == 0);
         return true;
@@ -431,9 +469,9 @@ bool zmq::socket_base_t::distribute (zmq_msg_t *msg_, bool flush_)
     //  Push the message to all destinations.
     for (out_pipes_t::iterator it = out_pipes.begin (); it != out_pipes.end ();
           it++) {
-        it->first->write (msg_);
+        (*it)->write (msg_);
         if (flush_)
-            it->first->flush ();
+            (*it)->flush ();
     }
 
     //  Detach the original message from the data buffer.
@@ -451,13 +489,13 @@ bool zmq::socket_base_t::fetch (zmq_msg_t *msg_)
     //  Round-robin over the pipes to get next message.
     for (int count = active; count != 0; count--) {
 
-        bool fetched = in_pipes [current].first->read (msg_);
+        bool fetched = in_pipes [current]->read (msg_);
 
         //  If there's no message in the pipe, move it to the list of
         //  non-active pipes.
         if (!fetched) {
-            in_pipes [current].first->set_index (active - 1);
-            in_pipes [active - 1].first->set_index (current);
+            in_pipes [current]->set_index (active - 1);
+            in_pipes [active - 1]->set_index (current);
             std::swap (in_pipes [current], in_pipes [active - 1]);
             active--;
         }
diff --git a/src/socket_base.hpp b/src/socket_base.hpp
index 1f04bda..490c09a 100644
--- a/src/socket_base.hpp
+++ b/src/socket_base.hpp
@@ -24,7 +24,6 @@
 #include <map>
 #include <vector>
 #include <string>
-#include <utility>
 
 #include "i_endpoint.hpp"
 #include "object.hpp"
@@ -62,6 +61,8 @@ namespace zmq
 
         //  i_endpoint interface implementation.
         void revive (class reader_t *pipe_);
+        void detach_inpipe (class reader_t *pipe_);
+        void detach_outpipe (class writer_t *pipe_);
 
     private:
 
@@ -86,10 +87,7 @@ namespace zmq
         io_objects_t io_objects;
 
         //  Inbound pipes, i.e. those the socket is getting messages from.
-        //  The second member in the pair indicates the object on the other
-        //  side of the pipe.
-        typedef std::vector <std::pair <class reader_t*, owned_t*> >
-            in_pipes_t;
+        typedef std::vector <class reader_t*> in_pipes_t;
         in_pipes_t in_pipes;
 
         //  Index of the next inbound pipe to read messages from.
@@ -100,10 +98,7 @@ namespace zmq
         in_pipes_t::size_type active;
 
         //  Outbound pipes, i.e. those the socket is sending messages to.
-        //  The second member in the pair indicates the object on the other
-        //  side of the pipe.
-        typedef std::vector <std::pair <class writer_t*, owned_t*> >
-            out_pipes_t;
+        typedef std::vector <class writer_t*> out_pipes_t;
         out_pipes_t out_pipes;
 
         //  Number of I/O objects that were already asked to terminate