Implement new message encoder/decoder

This is supposed to become part of the ZMTP/1.1.

The main differences from the ZMTP/1.0 framing protocol are:
- flags field comes first, followed by the length field
- long messages are signaled using a flag rather then 0xff escape
- length field does not include the flags field, 0 is a valid value

src/Makefile.am

@@ -133,6 +133,8 @@ libzmq_la_SOURCES = \
     xpub.cpp \
     router.cpp \
     dealer.cpp \
+    v1_decoder.cpp \
+    v1_encoder.cpp \
     xsub.cpp \
     zmq.cpp \
     zmq_utils.cpp

src/stream_engine.cpp

@@ -40,6 +40,8 @@
 #include "session_base.hpp"
 #include "encoder.hpp"
 #include "decoder.hpp"
+#include "v1_encoder.hpp"
+#include "v1_decoder.hpp"
 #include "config.hpp"
 #include "err.hpp"
 #include "ip.hpp"
@@ -390,19 +392,23 @@ bool zmq::stream_engine_t::handshake ()
 
     //  We have received either a header of identity message
     //  or the whole greeting.
-
-    encoder = new (std::nothrow) encoder_t (out_batch_size);
-    decoder = new (std::nothrow) decoder_t (in_batch_size, options.maxmsgsize);
-
-    encoder->set_msg_source (session);
-    decoder->set_msg_sink (session);
-
     zmq_assert (greeting [0] != 0xff || greeting_bytes_read >= 10);
 
+    //  POsition of the version field in the greeting.
+    const size_t version_pos = 10;
+
     //  Is the peer using the unversioned protocol?
     //  If so, we send and receive rests of identity
     //  messages.
     if (greeting [0] != 0xff || !(greeting [9] & 0x01)) {
+        encoder = new (std::nothrow) encoder_t (out_batch_size);
+        alloc_assert (encoder);
+        encoder->set_msg_source (session);
+
+        decoder = new (std::nothrow) decoder_t (in_batch_size, options.maxmsgsize);
+        alloc_assert (decoder);
+        decoder->set_msg_sink (session);
+
         //  We have already sent the message header.
         //  Since there is no way to tell the encoder to
         //  skip the message header, we simply throw that
@@ -425,6 +431,26 @@ bool zmq::stream_engine_t::handshake ()
         if (options.type == ZMQ_PUB || options.type == ZMQ_XPUB)
             decoder->set_msg_sink (this);
     }
+    else
+    if (greeting [version_pos] == 0) {
+        //  ZMTP/1.0 framing.
+        encoder = new (std::nothrow) encoder_t (out_batch_size);
+        alloc_assert (encoder);
+        encoder->set_msg_source (session);
+
+        decoder = new (std::nothrow) decoder_t (in_batch_size, options.maxmsgsize);
+        alloc_assert (decoder);
+        decoder->set_msg_sink (session);
+    }
+    else {
+        //  v1 framing protocol.
+        encoder = new (std::nothrow) v1_encoder_t (out_batch_size, session);
+        alloc_assert (encoder);
+
+        decoder = new (std::nothrow)
+            v1_decoder_t (in_batch_size, options.maxmsgsize, session);
+        alloc_assert (decoder);
+    }
 
     // Start polling for output if necessary.
     if (outsize == 0)

src/v1_decoder.cpp

@@ -0,0 +1,167 @@
+/*
+    Copyright (c) 2009-2011 250bpm s.r.o.
+    Copyright (c) 2007-2009 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 <stdlib.h>
+#include <string.h>
+
+#include "platform.hpp"
+#ifdef ZMQ_HAVE_WINDOWS
+#include "windows.hpp"
+#endif
+
+#include "v1_protocol.hpp"
+#include "v1_decoder.hpp"
+#include "likely.hpp"
+#include "wire.hpp"
+#include "err.hpp"
+
+zmq::v1_decoder_t::v1_decoder_t (size_t bufsize_,
+      int64_t maxmsgsize_, i_msg_sink *msg_sink_) :
+    decoder_base_t <v1_decoder_t> (bufsize_),
+    msg_sink (msg_sink_),
+    msg_flags (0),
+    maxmsgsize (maxmsgsize_)
+{
+    int rc = in_progress.init ();
+    errno_assert (rc == 0);
+
+    //  At the beginning, read one byte and go to flags_ready state.
+    next_step (tmpbuf, 1, &v1_decoder_t::flags_ready);
+}
+
+zmq::v1_decoder_t::~v1_decoder_t ()
+{
+    int rc = in_progress.close ();
+    errno_assert (rc == 0);
+}
+
+void zmq::v1_decoder_t::set_msg_sink (i_msg_sink *msg_sink_)
+{
+    msg_sink = msg_sink_;
+}
+
+bool zmq::v1_decoder_t::stalled () const
+{
+    return next == &v1_decoder_t::message_ready;
+}
+
+bool zmq::v1_decoder_t::flags_ready ()
+{
+    msg_flags = 0;
+    if (tmpbuf [0] & v1_protocol_t::more_flag)
+        msg_flags |= msg_t::more;
+
+    //  The payload length is either one or eight bytes,
+    //  depending on whether the 'large' bit is set.
+    if (tmpbuf [0] & v1_protocol_t::large_flag)
+        next_step (tmpbuf, 8, &v1_decoder_t::eight_byte_size_ready);
+    else
+        next_step (tmpbuf, 1, &v1_decoder_t::one_byte_size_ready);
+
+    return true;
+}
+
+bool zmq::v1_decoder_t::one_byte_size_ready ()
+{
+    int rc = 0;
+
+    //  Message size must not exceed the maximum allowed size.
+    if (maxmsgsize >= 0)
+        if (unlikely (tmpbuf [0] > static_cast <uint64_t> (maxmsgsize)))
+            goto error;
+
+    //  in_progress is initialised at this point so in theory we should
+    //  close it before calling zmq_msg_init_size, however, it's a 0-byte
+    //  message and thus we can treat it as uninitialised...
+    rc = in_progress.init_size (tmpbuf [0]);
+    if (unlikely (rc)) {
+        errno_assert (errno == ENOMEM);
+        int rc = in_progress.init ();
+        errno_assert (rc == 0);
+        goto error;
+    }
+
+    in_progress.set_flags (msg_flags);
+    next_step (in_progress.data (), in_progress.size (),
+        &v1_decoder_t::message_ready);
+
+    return true;
+
+error:
+    decoding_error ();
+    return false;
+}
+
+bool zmq::v1_decoder_t::eight_byte_size_ready ()
+{
+    int rc = 0;
+
+    //  The payload size is encoded as 64-bit unsigned integer.
+    //  The most significant byte comes first.
+    const uint64_t msg_size = get_uint64 (tmpbuf);
+
+    //  Message size must not exceed the maximum allowed size.
+    if (maxmsgsize >= 0)
+        if (unlikely (msg_size > static_cast <uint64_t> (maxmsgsize)))
+            goto error;
+
+    //  Message size must fit into size_t data type.
+    if (unlikely (msg_size != static_cast <size_t> (msg_size)))
+        goto error;
+
+    //  in_progress is initialised at this point so in theory we should
+    //  close it before calling init_size, however, it's a 0-byte
+    //  message and thus we can treat it as uninitialised.
+    rc = in_progress.init_size (static_cast <size_t> (msg_size));
+    if (unlikely (rc)) {
+        errno_assert (errno == ENOMEM);
+        int rc = in_progress.init ();
+        errno_assert (rc == 0);
+        goto error;
+    }
+
+    in_progress.set_flags (msg_flags);
+    next_step (in_progress.data (), in_progress.size (),
+        &v1_decoder_t::message_ready);
+
+    return true;
+
+error:
+    decoding_error ();
+    return false;
+}
+
+bool zmq::v1_decoder_t::message_ready ()
+{
+    //  Message is completely read. Push it further and start reading
+    //  new message. (in_progress is a 0-byte message after this point.)
+    if (unlikely (!msg_sink))
+        return false;
+    int rc = msg_sink->push_msg (&in_progress);
+    if (unlikely (rc != 0)) {
+        if (errno != EAGAIN)
+            decoding_error ();
+        return false;
+    }
+
+    next_step (tmpbuf, 1, &v1_decoder_t::flags_ready);
+    return true;
+}

src/v1_decoder.hpp

@@ -0,0 +1,70 @@
+/*
+    Copyright (c) 2009-2011 250bpm s.r.o.
+    Copyright (c) 2007-2012 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/>.
+*/
+
+#ifndef __ZMQ_V1_DECODER_HPP_INCLUDED__
+#define __ZMQ_V1_DECODER_HPP_INCLUDED__
+
+#include "err.hpp"
+#include "msg.hpp"
+#include "decoder.hpp"
+#include "i_msg_sink.hpp"
+#include "stdint.hpp"
+
+namespace zmq
+{
+
+    //  Decoder for 0MQ v1 framing protocol. Converts data stream into messages.
+
+    class v1_decoder_t : public decoder_base_t <v1_decoder_t>
+    {
+    public:
+
+        v1_decoder_t (size_t bufsize_,
+            int64_t maxmsgsize_, i_msg_sink *msg_sink_);
+        virtual ~v1_decoder_t ();
+
+        //  i_decoder interface.
+        virtual void set_msg_sink (i_msg_sink *msg_sink_);
+
+        virtual bool stalled () const;
+
+    private:
+
+        bool flags_ready ();
+        bool one_byte_size_ready ();
+        bool eight_byte_size_ready ();
+        bool message_ready ();
+
+        i_msg_sink *msg_sink;
+        unsigned char tmpbuf [8];
+        unsigned char msg_flags;
+        msg_t in_progress;
+
+        const int64_t maxmsgsize;
+
+        v1_decoder_t (const v1_decoder_t&);
+        void operator = (const v1_decoder_t&);
+    };
+
+}
+
+#endif
+

src/v1_encoder.cpp

@@ -0,0 +1,103 @@
+/*
+    Copyright (c) 2007-2012 iMatix Corporation
+    Copyright (c) 2009-2011 250bpm s.r.o.
+    Copyright (c) 2011 VMware, Inc.
+    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 "v1_protocol.hpp"
+#include "v1_encoder.hpp"
+#include "likely.hpp"
+#include "wire.hpp"
+
+zmq::v1_encoder_t::v1_encoder_t (size_t bufsize_, i_msg_source *msg_source_) :
+    encoder_base_t <v1_encoder_t> (bufsize_),
+    msg_source (msg_source_)
+{
+    int rc = in_progress.init ();
+    errno_assert (rc == 0);
+
+    //  Write 0 bytes to the batch and go to message_ready state.
+    next_step (NULL, 0, &v1_encoder_t::message_ready, true);
+}
+
+zmq::v1_encoder_t::~v1_encoder_t ()
+{
+    int rc = in_progress.close ();
+    errno_assert (rc == 0);
+}
+
+void zmq::v1_encoder_t::set_msg_source (i_msg_source *msg_source_)
+{
+    msg_source = msg_source_;
+}
+
+bool zmq::v1_encoder_t::message_ready ()
+{
+    //  Release the content of the old message.
+    int rc = in_progress.close ();
+    errno_assert (rc == 0);
+
+    //  Read new message. If there is none, return false.
+    //  Note that new state is set only if write is successful. That way
+    //  unsuccessful write will cause retry on the next state machine
+    //  invocation.
+    if (unlikely (!msg_source)) {
+        rc = in_progress.init ();
+        errno_assert (rc == 0);
+        return false;
+    }
+
+    rc = msg_source->pull_msg (&in_progress);
+    if (unlikely (rc)) {
+        errno_assert (errno == EAGAIN);
+        rc = in_progress.init ();
+        errno_assert (rc == 0);
+        return false;
+    }
+
+    //  Encode flags.
+    unsigned char &protocol_flags = tmpbuf [0];
+    protocol_flags = 0;
+    if (in_progress.flags () & msg_t::more)
+        protocol_flags |= v1_protocol_t::more_flag;
+    if (in_progress.size () > 255)
+        protocol_flags |= v1_protocol_t::large_flag;
+
+    //  Encode the message length. For messages less then 256 bytes,
+    //  the length is encoded as 8-bit unsigned integer. For larger
+    //  messages, 64-bit unsigned integer in network byte order is used.
+    const size_t size = in_progress.size ();
+    if (unlikely (size > 255)) {
+        put_uint64 (tmpbuf + 1, size);
+        next_step (tmpbuf, 9, &v1_encoder_t::size_ready, false);
+    }
+    else {
+        tmpbuf [1] = static_cast <uint8_t> (size);
+        next_step (tmpbuf, 2, &v1_encoder_t::size_ready, false);
+    }
+    return true;
+}
+
+bool zmq::v1_encoder_t::size_ready ()
+{
+    //  Write message body into the buffer.
+    next_step (in_progress.data (), in_progress.size (),
+        &v1_encoder_t::message_ready, !(in_progress.flags () & msg_t::more));
+    return true;
+}

src/v1_encoder.hpp

@@ -0,0 +1,60 @@
+/*
+    Copyright (c) 2009-2011 250bpm s.r.o.
+    Copyright (c) 2007-2012 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/>.
+*/
+
+#ifndef __ZMQ_V1_ENCODER_HPP_INCLUDED__
+#define __ZMQ_V1_ENCODER_HPP_INCLUDED__
+
+#include "msg.hpp"
+#include "i_msg_source.hpp"
+#include "encoder.hpp"
+
+namespace zmq
+{
+
+    class i_msg_source;
+
+    //  Encoder for 0MQ framing protocol. Converts messages into data stream.
+
+    class v1_encoder_t : public encoder_base_t <v1_encoder_t>
+    {
+    public:
+
+        v1_encoder_t (size_t bufsize_, i_msg_source *msg_source_);
+        virtual ~v1_encoder_t ();
+
+        virtual void set_msg_source (i_msg_source *msg_source_);
+
+    private:
+
+        bool size_ready ();
+        bool message_ready ();
+
+        i_msg_source *msg_source;
+        msg_t in_progress;
+        unsigned char tmpbuf [9];
+
+        v1_encoder_t (const v1_encoder_t&);
+        const v1_encoder_t &operator = (const v1_encoder_t&);
+    };
+}
+
+#endif
+

src/v1_protocol.hpp

@@ -0,0 +1,43 @@
+/*
+    Copyright (c) 2007-2012 iMatix Corporation
+    Copyright (c) 2007-2012 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/>.
+*/
+
+#ifndef __ZMQ_V1_PROTOCOL_HPP_INCLUDED__
+#define __ZMQ_V1_PROTOCOL_HPP_INCLUDED__
+
+namespace zmq
+{
+
+    //  Definition of constans for v1 transport protocol.
+    class v1_protocol_t
+    {
+    public:
+        //  Message flags.
+        enum
+        {
+            more_flag = 1,
+            large_flag = 2
+        };
+
+    };
+
+}
+
+#endif
+