Session class separated into socket-type-specific sessions

This is a preliminary patch allowing for socket-type-specific
functionality in the I/O thread. For example, message format
can be checked asynchronously and misbehaved connections dropped
straight away.

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

1 files changed, 457 insertions, 0 deletions

diff --git a/src/session_base.cpp b/src/session_base.cpp
new file mode 100644
index 0000000..7d4c5ab
--- /dev/null
+++ b/src/session_base.cpp
@@ -0,0 +1,457 @@
+/*
+    Copyright (c) 2007-2011 iMatix Corporation
+    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
+
+    This file is part of 0MQ.
+
+    0MQ is free software; you can redistribute it and/or modify it under
+    the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    0MQ 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 "session_base.hpp"
+#include "socket_base.hpp"
+#include "i_engine.hpp"
+#include "err.hpp"
+#include "pipe.hpp"
+#include "likely.hpp"
+#include "tcp_connecter.hpp"
+#include "ipc_connecter.hpp"
+#include "vtcp_connecter.hpp"
+#include "pgm_sender.hpp"
+#include "pgm_receiver.hpp"
+
+#include "req.hpp"
+#include "xreq.hpp"
+#include "rep.hpp"
+#include "xrep.hpp"
+#include "pub.hpp"
+#include "xpub.hpp"
+#include "sub.hpp"
+#include "xsub.hpp"
+#include "push.hpp"
+#include "pull.hpp"
+#include "router.hpp"
+#include "pair.hpp"
+
+zmq::session_base_t *zmq::session_base_t::create (class io_thread_t *io_thread_,
+    bool connect_, class socket_base_t *socket_, const options_t &options_,
+    const char *protocol_, const char *address_)
+{
+    session_base_t *s = NULL;
+    switch (options_.type) {
+    case ZMQ_REQ:
+        s = new (std::nothrow) req_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    case ZMQ_XREQ:
+        s = new (std::nothrow) xreq_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+    case ZMQ_REP:
+        s = new (std::nothrow) rep_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    case ZMQ_XREP:
+        s = new (std::nothrow) xrep_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    case ZMQ_PUB:
+        s = new (std::nothrow) pub_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    case ZMQ_XPUB:
+        s = new (std::nothrow) xpub_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    case ZMQ_SUB:
+        s = new (std::nothrow) sub_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    case ZMQ_XSUB:
+        s = new (std::nothrow) xsub_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    case ZMQ_PUSH:
+        s = new (std::nothrow) push_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    case ZMQ_PULL:
+        s = new (std::nothrow) pull_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    case ZMQ_ROUTER:
+        s = new (std::nothrow) router_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    case ZMQ_PAIR:
+        s = new (std::nothrow) pair_session_t (io_thread_, connect_,
+            socket_, options_, protocol_, address_);
+        break;
+    default:
+        errno = EINVAL;
+        return NULL;
+    }
+    alloc_assert (s);
+    return s;
+}
+
+zmq::session_base_t::session_base_t (class io_thread_t *io_thread_,
+      bool connect_, class socket_base_t *socket_, const options_t &options_,
+      const char *protocol_, const char *address_) :
+    own_t (io_thread_, options_),
+    io_object_t (io_thread_),
+    connect (connect_),
+    pipe (NULL),
+    incomplete_in (false),
+    pending (false),
+    engine (NULL),
+    socket (socket_),
+    io_thread (io_thread_),
+    has_linger_timer (false)
+{
+    if (protocol_)
+        protocol = protocol_;
+    if (address_)
+        address = address_;
+}
+
+zmq::session_base_t::~session_base_t ()
+{
+    zmq_assert (!pipe);
+
+    //  If there's still a pending linger timer, remove it.
+    if (has_linger_timer) {
+        cancel_timer (linger_timer_id);
+        has_linger_timer = false;
+    }
+
+    //  Close the engine.
+    if (engine)
+        engine->terminate ();
+}
+
+void zmq::session_base_t::attach_pipe (pipe_t *pipe_)
+{
+    zmq_assert (!is_terminating ());
+    zmq_assert (!pipe);
+    zmq_assert (pipe_);
+    pipe = pipe_;
+    pipe->set_event_sink (this);
+}
+
+bool zmq::session_base_t::read (msg_t *msg_)
+{
+    if (!pipe)
+        return false;
+
+    if (!pipe->read (msg_))
+        return false;
+
+    incomplete_in =
+        msg_->flags () & (msg_t::more | msg_t::label) ? true : false;
+    return true;
+}
+
+bool zmq::session_base_t::write (msg_t *msg_)
+{
+    if (pipe && pipe->write (msg_)) {
+        int rc = msg_->init ();
+        errno_assert (rc == 0);
+        return true;
+    }
+
+    return false;
+}
+
+void zmq::session_base_t::flush ()
+{
+    if (pipe)
+        pipe->flush ();
+}
+
+void zmq::session_base_t::clean_pipes ()
+{
+    if (pipe) {
+
+        //  Get rid of half-processed messages in the out pipe. Flush any
+        //  unflushed messages upstream.
+        pipe->rollback ();
+        pipe->flush ();
+
+        //  Remove any half-read message from the in pipe.
+        while (incomplete_in) {
+            msg_t msg;
+            int rc = msg.init ();
+            errno_assert (rc == 0);
+            if (!read (&msg)) {
+                zmq_assert (!incomplete_in);
+                break;
+            }
+            rc = msg.close ();
+            errno_assert (rc == 0);
+        }
+    }
+}
+
+void zmq::session_base_t::terminated (pipe_t *pipe_)
+{
+    //  Drop the reference to the deallocated pipe.
+    zmq_assert (pipe == pipe_);
+    pipe = NULL;
+
+    //  If we are waiting for pending messages to be sent, at this point
+    //  we are sure that there will be no more messages and we can proceed
+    //  with termination safely.
+    if (pending)
+        proceed_with_term ();
+}
+
+void zmq::session_base_t::read_activated (pipe_t *pipe_)
+{
+    zmq_assert (pipe == pipe_);
+
+    if (likely (engine != NULL))
+        engine->activate_out ();
+    else
+        pipe->check_read ();
+}
+
+void zmq::session_base_t::write_activated (pipe_t *pipe_)
+{
+    zmq_assert (pipe == pipe_);
+
+    if (engine)
+        engine->activate_in ();
+}
+
+void zmq::session_base_t::hiccuped (pipe_t *pipe_)
+{
+    //  Hiccups are always sent from session to socket, not the other
+    //  way round.
+    zmq_assert (false);
+}
+
+void zmq::session_base_t::process_plug ()
+{
+    if (connect)
+        start_connecting (false);
+}
+
+void zmq::session_base_t::process_attach (i_engine *engine_)
+{
+    //  If some other object (e.g. init) notifies us that the connection failed
+    //  without creating an engine we need to start the reconnection process.
+    if (!engine_) {
+        zmq_assert (!engine);
+        detached ();
+        return;
+    }
+
+    //  Create the pipe if it does not exist yet.
+    if (!pipe && !is_terminating ()) {
+        object_t *parents [2] = {this, socket};
+        pipe_t *pipes [2] = {NULL, NULL};
+        int hwms [2] = {options.rcvhwm, options.sndhwm};
+        bool delays [2] = {options.delay_on_close, options.delay_on_disconnect};
+        int rc = pipepair (parents, pipes, hwms, delays);
+        errno_assert (rc == 0);
+
+        //  Plug the local end of the pipe.
+        pipes [0]->set_event_sink (this);
+
+        //  Remember the local end of the pipe.
+        zmq_assert (!pipe);
+        pipe = pipes [0];
+
+        //  Ask socket to plug into the remote end of the pipe.
+        send_bind (socket, pipes [1]);
+    }
+
+    //  Plug in the engine.
+    zmq_assert (!engine);
+    engine = engine_;
+    engine->plug (io_thread, this);
+}
+
+void zmq::session_base_t::detach ()
+{
+    //  Engine is dead. Let's forget about it.
+    engine = NULL;
+
+    //  Remove any half-done messages from the pipes.
+    clean_pipes ();
+
+    //  Send the event to the derived class.
+    detached ();
+
+    //  Just in case there's only a delimiter in the pipe.
+    if (pipe)
+        pipe->check_read ();
+}
+
+void zmq::session_base_t::process_term (int linger_)
+{
+    zmq_assert (!pending);
+
+    //  If the termination of the pipe happens before the term command is
+    //  delivered there's nothing much to do. We can proceed with the
+    //  stadard termination immediately.
+    if (!pipe) {
+        proceed_with_term ();
+        return;
+    }
+
+    pending = true;
+
+    //  If there's finite linger value, delay the termination.
+    //  If linger is infinite (negative) we don't even have to set
+    //  the timer.
+    if (linger_ > 0) {
+        zmq_assert (!has_linger_timer);
+        add_timer (linger_, linger_timer_id);
+        has_linger_timer = true;
+    }
+
+    //  Start pipe termination process. Delay the termination till all messages
+    //  are processed in case the linger time is non-zero.
+    pipe->terminate (linger_ != 0);
+
+    //  TODO: Should this go into pipe_t::terminate ?
+    //  In case there's no engine and there's only delimiter in the
+    //  pipe it wouldn't be ever read. Thus we check for it explicitly.
+    pipe->check_read ();
+}
+
+void zmq::session_base_t::proceed_with_term ()
+{
+    //  The pending phase have just ended.
+    pending = false;
+
+    //  Continue with standard termination.
+    own_t::process_term (0);
+}
+
+void zmq::session_base_t::timer_event (int id_)
+{
+    //  Linger period expired. We can proceed with termination even though
+    //  there are still pending messages to be sent.
+    zmq_assert (id_ == linger_timer_id);
+    has_linger_timer = false;
+
+    //  Ask pipe to terminate even though there may be pending messages in it.
+    zmq_assert (pipe);
+    pipe->terminate (false);
+}
+
+void zmq::session_base_t::detached ()
+{
+    //  Transient session self-destructs after peer disconnects.
+    if (!connect) {
+        terminate ();
+        return;
+    }
+
+    //  Reconnect.
+    start_connecting (true);
+
+    //  For subscriber sockets we hiccup the inbound pipe, which will cause
+    //  the socket object to resend all the subscriptions.
+    if (pipe && (options.type == ZMQ_SUB || options.type == ZMQ_XSUB))
+        pipe->hiccup ();  
+}
+
+void zmq::session_base_t::start_connecting (bool wait_)
+{
+    zmq_assert (connect);
+
+    //  Choose I/O thread to run connecter in. Given that we are already
+    //  running in an I/O thread, there must be at least one available.
+    io_thread_t *io_thread = choose_io_thread (options.affinity);
+    zmq_assert (io_thread);
+
+    //  Create the connecter object.
+
+    if (protocol == "tcp") {
+        tcp_connecter_t *connecter = new (std::nothrow) tcp_connecter_t (
+            io_thread, this, options, address.c_str (), wait_);
+        alloc_assert (connecter);
+        launch_child (connecter);
+        return;
+    }
+
+#if !defined ZMQ_HAVE_WINDOWS && !defined ZMQ_HAVE_OPENVMS
+    if (protocol == "ipc") {
+        ipc_connecter_t *connecter = new (std::nothrow) ipc_connecter_t (
+            io_thread, this, options, address.c_str (), wait_);
+        alloc_assert (connecter);
+        launch_child (connecter);
+        return;
+    }
+#endif
+
+#if defined ZMQ_HAVE_VTCP
+    if (protocol == "vtcp") {
+
+        vtcp_connecter_t *connecter = new (std::nothrow) vtcp_connecter_t (
+            io_thread, this, options, address.c_str (),
+            wait_);
+        alloc_assert (connecter);
+        launch_child (connecter);
+        return;
+    }
+#endif
+
+#if defined ZMQ_HAVE_OPENPGM
+
+    //  Both PGM and EPGM transports are using the same infrastructure.
+    if (protocol == "pgm" || protocol == "epgm") {
+
+        //  For EPGM transport with UDP encapsulation of PGM is used.
+        bool udp_encapsulation = (protocol == "epgm");
+
+        //  At this point we'll create message pipes to the session straight
+        //  away. There's no point in delaying it as no concept of 'connect'
+        //  exists with PGM anyway.
+        if (options.type == ZMQ_PUB || options.type == ZMQ_XPUB) {
+
+            //  PGM sender.
+            pgm_sender_t *pgm_sender =  new (std::nothrow) pgm_sender_t (
+                io_thread, options);
+            alloc_assert (pgm_sender);
+
+            int rc = pgm_sender->init (udp_encapsulation, address.c_str ());
+            zmq_assert (rc == 0);
+
+            send_attach (this, pgm_sender);
+        }
+        else if (options.type == ZMQ_SUB || options.type == ZMQ_XSUB) {
+
+            //  PGM receiver.
+            pgm_receiver_t *pgm_receiver =  new (std::nothrow) pgm_receiver_t (
+                io_thread, options);
+            alloc_assert (pgm_receiver);
+
+            int rc = pgm_receiver->init (udp_encapsulation, address.c_str ());
+            zmq_assert (rc == 0);
+
+            send_attach (this, pgm_receiver);
+        }
+        else
+            zmq_assert (false);
+
+        return;
+    }
+#endif
+
+    zmq_assert (false);
+}
+