"Survey" pattern implemented

Survey pattern is "multicast with reply". There are two roles:
surveyor and respondent. Surveyor publishes a survey which gets
delivered to all connected respondents. Each repondent can send
a response to the survey. All the responses are delivered to
the original surveyor. Once the surveyor decides that the survey
is over (e.g. deadline was reached) it can send initiate survey.
Late responses from old surveys are automatically discarded by
the surveyor socket.

Socket types: SURVEYOR, XSURVEYOR, RESPONDENT, XRESPONDENT

Patch also includes a test program with surveoyr, two respondents
and an intermediary device.

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

1 files changed, 123 insertions, 0 deletions

diff --git a/src/xrespondent.hpp b/src/xrespondent.hpp
new file mode 100644
index 0000000..eb6ac9a
--- /dev/null
+++ b/src/xrespondent.hpp
@@ -0,0 +1,123 @@
+/*
+    Copyright (c) 2012 250bpm s.r.o.
+    Copyright (c) 2012 Other contributors as noted in the AUTHORS file
+
+    This file is part of Crossroads I/O project.
+
+    Crossroads I/O 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.
+
+    Crossroads 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/>.
+*/
+
+#ifndef __XS_XRESPONDENT_HPP_INCLUDED__
+#define __XS_XRESPONDENT_HPP_INCLUDED__
+
+#include <map>
+
+#include "socket_base.hpp"
+#include "session_base.hpp"
+#include "stdint.hpp"
+#include "blob.hpp"
+#include "msg.hpp"
+#include "fq.hpp"
+
+namespace xs
+{
+
+    class ctx_t;
+    class pipe_t;
+    class io_thread_t;
+
+    //  TODO: This class uses O(n) scheduling. Rewrite it to use O(1) algorithm.
+    class xrespondent_t :
+        public socket_base_t
+    {
+    public:
+
+        xrespondent_t (xs::ctx_t *parent_, uint32_t tid_, int sid_);
+        ~xrespondent_t ();
+
+        //  Overloads of functions from socket_base_t.
+        void xattach_pipe (xs::pipe_t *pipe_, bool icanhasall_);
+        int xsend (msg_t *msg_, int flags_);
+        int xrecv (msg_t *msg_, int flags_);
+        bool xhas_in ();
+        bool xhas_out ();
+        void xread_activated (xs::pipe_t *pipe_);
+        void xwrite_activated (xs::pipe_t *pipe_);
+        void xterminated (xs::pipe_t *pipe_);
+
+    protected:
+
+        //  Rollback any message parts that were sent but not yet flushed.
+        int rollback ();
+
+    private:
+
+        //  Fair queueing object for inbound pipes.
+        fq_t fq;
+
+        //  This value is either 0 (nothing is prefetched), 1 (only message body
+        //  is prefetched) or 2 (both identity and message body are prefetched).
+        int prefetched;
+
+        //  Holds the prefetched identity.
+        blob_t prefetched_id;
+
+        //  Holds the prefetched message.
+        msg_t prefetched_msg;
+
+        //  If true, more incoming message parts are expected.
+        bool more_in;
+
+        struct outpipe_t
+        {
+            xs::pipe_t *pipe;
+            bool active;
+        };
+
+        //  Outbound pipes indexed by the peer IDs.
+        typedef std::map <uint32_t, outpipe_t> outpipes_t;
+        outpipes_t outpipes;
+
+        //  The pipe we are currently writing to.
+        xs::pipe_t *current_out;
+
+        //  If true, more outgoing message parts are expected.
+        bool more_out;
+
+        //  Peer ID are generated. It's a simple increment and wrap-over
+        //  algorithm. This value is the next ID to use (if not used already).
+        uint32_t next_peer_id;
+
+        xrespondent_t (const xrespondent_t&);
+        const xrespondent_t &operator = (const xrespondent_t&);
+    };
+
+    class xrespondent_session_t : public session_base_t
+    {
+    public:
+
+        xrespondent_session_t (xs::io_thread_t *io_thread_, bool connect_,
+            socket_base_t *socket_, const options_t &options_,
+            const char *protocol_, const char *address_);
+        ~xrespondent_session_t ();
+
+    private:
+
+        xrespondent_session_t (const xrespondent_session_t&);
+        const xrespondent_session_t &operator = (const xrespondent_session_t&);
+    };
+
+}
+
+#endif