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/*
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/>.
*/
#include <algorithm>
#include "surveyor.hpp"
#include "err.hpp"
#include "msg.hpp"
#include "wire.hpp"
#include "likely.hpp"
#include "random.hpp"
xs::surveyor_t::surveyor_t (class ctx_t *parent_, uint32_t tid_, int sid_) :
xsurveyor_t (parent_, tid_, sid_),
receiving_responses (false),
survey_id (generate_random ()),
timeout (0),
has_prefetched (false)
{
options.type = XS_SURVEYOR;
prefetched.init ();
}
xs::surveyor_t::~surveyor_t ()
{
prefetched.close ();
}
int xs::surveyor_t::xsend (msg_t *msg_, int flags_)
{
int rc;
// Survey pattern works only with sigle-part messages.
if (flags_ & XS_SNDMORE || msg_->flags () & msg_t::more) {
errno = EINVAL;
return -1;
}
// Start the new survey. First, generate new survey ID.
++survey_id;
msg_t id;
rc = id.init_size (4);
errno_assert (rc == 0);
put_uint32 ((unsigned char*) id.data (), survey_id);
id.set_flags (msg_t::more);
rc = xsurveyor_t::xsend (&id, 0);
if (rc != 0) {
id.close ();
return -1;
}
id.close ();
// Now send the body of the survey.
rc = xsurveyor_t::xsend (msg_, flags_);
errno_assert (rc == 0);
// Start waiting for responses from the peers.
receiving_responses = true;
// Set up the timeout for the survey (-1 means infinite).
if (!options.survey_timeout)
timeout = -1;
else
timeout = now_ms () + options.survey_timeout;
return 0;
}
int xs::surveyor_t::xrecv (msg_t *msg_, int flags_)
{
int rc;
// If there's no survey underway, it's an error.
if (!receiving_responses) {
errno = EFSM;
return -1;
}
// If we have a message prefetched we can return it straight away.
if (has_prefetched) {
msg_->move (prefetched);
has_prefetched = false;
return 0;
}
// Get the first part of the response -- the survey ID.
rc = xsurveyor_t::xrecv (msg_, flags_);
if (rc != 0) {
if (errno != EAGAIN)
return -1;
// In case of AGAIN we should check whether the survey timeout expired.
// If so, we should return ETIMEDOUT so that user is able to
// distinguish survey timeout from RCVTIMEO-caused timeout.
errno = now_ms () >= timeout ? ETIMEDOUT : EAGAIN;
return -1;
}
// Check whether this is response for the onging survey. If not, we can
// drop the response.
if (unlikely (!(msg_->flags () & msg_t::more) || msg_->size () != 4 ||
get_uint32 ((unsigned char*) msg_->data ()) != survey_id)) {
while (true) {
rc = xsurveyor_t::xrecv (msg_, flags_);
errno_assert (rc == 0);
if (!(msg_->flags () & msg_t::more))
break;
}
msg_->close ();
msg_->init ();
errno = EAGAIN;
return -1;
}
// Get the body of the response.
rc = xsurveyor_t::xrecv (msg_, flags_);
errno_assert (rc == 0);
return 0;
}
bool xs::surveyor_t::xhas_in ()
{
// When no survey is underway, POLLIN is never signaled.
if (!receiving_responses)
return false;
// If there's already a message prefetches signal POLLIN.
if (has_prefetched)
return true;
// Try to prefetch a message.
int rc = xrecv (&prefetched, XS_DONTWAIT);
// No message available.
if (rc != 0 && errno == EAGAIN)
return false;
errno_assert (rc == 0);
// We have a message prefetched. We can signal POLLIN now.
has_prefetched = true;
return true;
}
bool xs::surveyor_t::xhas_out ()
{
return xsurveyor_t::xhas_out ();
}
int xs::surveyor_t::rcvtimeo ()
{
int t = (int) (timeout - now_ms ());
if (t < 0)
return options.rcvtimeo;
if (options.rcvtimeo < 0)
return t;
return std::min (t, options.rcvtimeo);
}
xs::surveyor_session_t::surveyor_session_t (io_thread_t *io_thread_,
bool connect_, socket_base_t *socket_, const options_t &options_,
const char *protocol_, const char *address_) :
xsurveyor_session_t (io_thread_, connect_, socket_, options_, protocol_,
address_)
{
}
xs::surveyor_session_t::~surveyor_session_t ()
{
}
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