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REQ socket implementation is layered on top of XREQ

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This commit is contained in:
Martin Sustrik 2010-08-07 09:52:34 +02:00
parent f77edfce26
commit 3e97c0fef4
4 changed files with 47 additions and 263 deletions
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7
src/fq.cpp
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@ -46,6 +46,9 @@ void zmq::fq_t::attach (reader_t *pipe_)
void zmq::fq_t::terminated (reader_t *pipe_)
{
// TODO: This is a problem with session-initiated termination. It breaks
// message atomicity. However, for socket initiated termination it's
// just fine.
zmq_assert (!more || pipes [current] != pipe_);
// Remove the pipe from the list; adjust number of active pipes
@ -87,6 +90,10 @@ int zmq::fq_t::recv (zmq_msg_t *msg_, int flags_)
// Try to fetch new message. If we've already read part of the message
// subsequent part should be immediately available.
bool fetched = pipes [current]->read (msg_);
// Check the atomicity of the message. If we've already received the
// first part of the message we should get the remaining parts
// without blocking.
zmq_assert (!(more && !fetched));
// Note that when message is not fetched, current pipe is killed and

6
src/pipe.cpp
View File

@ -269,9 +269,6 @@ void zmq::writer_t::terminate ()
if (terminating)
return;
// Rollback any unfinished messages.
rollback ();
if (msg_store == NULL || (msg_store->empty () && !extra_msg_flag))
write_delimiter ();
else
@ -280,6 +277,9 @@ void zmq::writer_t::terminate ()
void zmq::writer_t::write_delimiter ()
{
// Rollback any unfinished messages.
rollback ();
// Push delimiter into the pipe.
// Trick the compiler to belive that the tag is a valid pointer.
zmq_msg_t msg;

243
src/req.cpp
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@ -21,129 +21,16 @@
#include "req.hpp"
#include "err.hpp"
#include "pipe.hpp"
zmq::req_t::req_t (class ctx_t *parent_, uint32_t slot_) :
socket_base_t (parent_, slot_),
active (0),
current (0),
xreq_t (parent_, slot_),
receiving_reply (false),
reply_pipe_active (false),
more (false),
reply_pipe (NULL)
message_begins (true)
{
options.requires_in = true;
options.requires_out = true;
}
zmq::req_t::~req_t ()
{
zmq_assert (in_pipes.empty ());
zmq_assert (out_pipes.empty ());
}
void zmq::req_t::xattach_pipes (reader_t *inpipe_, writer_t *outpipe_,
const blob_t &peer_identity_)
{
zmq_assert (inpipe_ && outpipe_);
zmq_assert (in_pipes.size () == out_pipes.size ());
inpipe_->set_event_sink (this);
in_pipes.push_back (inpipe_);
in_pipes.swap (active, in_pipes.size () - 1);
outpipe_->set_event_sink (this);
out_pipes.push_back (outpipe_);
out_pipes.swap (active, out_pipes.size () - 1);
active++;
}
void zmq::req_t::xterm_pipes ()
{
for (in_pipes_t::size_type i = 0; i != in_pipes.size (); i++)
in_pipes [i]->terminate ();
for (out_pipes_t::size_type i = 0; i != out_pipes.size (); i++)
out_pipes [i]->terminate ();
}
void zmq::req_t::terminated (reader_t *pipe_)
{
zmq_assert (!receiving_reply || !more || reply_pipe != pipe_);
zmq_assert (pipe_);
zmq_assert (in_pipes.size () == out_pipes.size ());
// TODO: The pipe we are awaiting the reply from is detached. What now?
if (receiving_reply && pipe_ == reply_pipe) {
zmq_assert (false);
}
in_pipes_t::size_type index = in_pipes.index (pipe_);
// ???
if (!zombie) {
if (out_pipes [index])
out_pipes [index]->terminate ();
out_pipes.erase (index);
}
in_pipes.erase (index);
if (index < active) {
active--;
if (current == active)
current = 0;
}
}
void zmq::req_t::terminated (writer_t *pipe_)
{
zmq_assert (receiving_reply || !more || out_pipes [current] != pipe_);
zmq_assert (pipe_);
zmq_assert (in_pipes.size () == out_pipes.size ());
out_pipes_t::size_type index = out_pipes.index (pipe_);
// ???
if (!zombie) {
if (in_pipes [index])
in_pipes [index]->terminate ();
in_pipes.erase (index);
}
out_pipes.erase (index);
if (index < active) {
active--;
if (current == active)
current = 0;
}
}
bool zmq::req_t::xhas_pipes ()
{
return !in_pipes.empty () || !out_pipes.empty ();
}
void zmq::req_t::activated (reader_t *pipe_)
{
// TODO: Actually, misbehaving peer can cause this kind of thing.
// Handle it decently, presumably kill the offending connection.
zmq_assert (pipe_ == reply_pipe);
reply_pipe_active = true;
}
void zmq::req_t::activated (writer_t *pipe_)
{
out_pipes_t::size_type index = out_pipes.index (pipe_);
zmq_assert (index >= active);
if (in_pipes [index] != NULL) {
in_pipes.swap (index, active);
out_pipes.swap (index, active);
active++;
}
}
int zmq::req_t::xsend (zmq_msg_t *msg_, int flags_)
@ -155,99 +42,58 @@ int zmq::req_t::xsend (zmq_msg_t *msg_, int flags_)
return -1;
}
while (active > 0) {
if (out_pipes [current]->check_write ())
break;
zmq_assert (!more);
active--;
if (current < active) {
in_pipes.swap (current, active);
out_pipes.swap (current, active);
}
else
current = 0;
}
if (active == 0) {
errno = EAGAIN;
return -1;
}
// If we are starting to send the request, generate a prefix.
if (!more) {
// First part of the request is empty message part (stack bottom).
if (message_begins) {
zmq_msg_t prefix;
int rc = zmq_msg_init (&prefix);
zmq_assert (rc == 0);
prefix.flags |= ZMQ_MSG_MORE;
bool written = out_pipes [current]->write (&prefix);
zmq_assert (written);
prefix.flags = ZMQ_MSG_MORE;
rc = xreq_t::xsend (&prefix, flags_);
if (rc != 0)
return rc;
message_begins = false;
}
// Push the message to the selected pipe.
bool written = out_pipes [current]->write (msg_);
zmq_assert (written);
more = msg_->flags & ZMQ_MSG_MORE;
bool more = msg_->flags & ZMQ_MSG_MORE;
int rc = xreq_t::xsend (msg_, flags_);
if (rc != 0)
return rc;
// If the request was fully sent, flip the FSM into reply-receiving state.
if (!more) {
out_pipes [current]->flush ();
receiving_reply = true;
reply_pipe = in_pipes [current];
// We can safely assume that the reply pipe is active as the last time
// we've used it we've read the reply and haven't tried to read from it
// anymore.
reply_pipe_active = true;
// Move to the next pipe (load-balancing).
current = (current + 1) % active;
message_begins = true;
}
// Detach the message from the data buffer.
int rc = zmq_msg_init (msg_);
zmq_assert (rc == 0);
return 0;
}
int zmq::req_t::xrecv (zmq_msg_t *msg_, int flags_)
{
// Deallocate old content of the message.
int rc = zmq_msg_close (msg_);
zmq_assert (rc == 0);
// If request wasn't send, we can't wait for reply.
if (!receiving_reply) {
zmq_msg_init (msg_);
errno = EFSM;
return -1;
}
// Get the reply from the reply pipe.
if (!reply_pipe_active || !reply_pipe->read (msg_)) {
reply_pipe_active = false;
zmq_msg_init (msg_);
errno = EAGAIN;
return -1;
}
// If we are starting to receive new reply, check whether prefix
// is well-formed and drop it.
if (!more) {
// First part of the reply should be empty message part (stack bottom).
if (message_begins) {
int rc = xreq_t::xrecv (msg_, flags_);
if (rc != 0)
return rc;
zmq_assert (msg_->flags & ZMQ_MSG_MORE);
zmq_assert (zmq_msg_size (msg_) == 0);
rc = zmq_msg_close (msg_);
zmq_assert (rc == 0);
// Get the actual reply.
bool recvd = reply_pipe->read (msg_);
zmq_assert (recvd);
}
// If this was last part of the reply, switch to request phase.
more = msg_->flags & ZMQ_MSG_MORE;
if (!more) {
int rc = xreq_t::xrecv (msg_, flags_);
if (rc != 0)
return rc;
// If the reply is fully received, flip the FSM into request-sending state.
if (!(msg_->flags & ZMQ_MSG_MORE)) {
receiving_reply = false;
reply_pipe = NULL;
message_begins = true;
}
return 0;
@ -255,43 +101,18 @@ int zmq::req_t::xrecv (zmq_msg_t *msg_, int flags_)
bool zmq::req_t::xhas_in ()
{
if (receiving_reply && more)
return true;
if (!receiving_reply || !reply_pipe_active)
if (!receiving_reply)
return false;
zmq_assert (reply_pipe);
if (!reply_pipe->check_read ()) {
reply_pipe_active = false;
return false;
}
return true;
return xreq_t::xhas_in ();
}
bool zmq::req_t::xhas_out ()
{
if (!receiving_reply && more)
return true;
if (receiving_reply)
return false;
while (active > 0) {
if (out_pipes [current]->check_write ())
return true;;
active--;
if (current < active) {
in_pipes.swap (current, active);
out_pipes.swap (current, active);
}
else
current = 0;
}
return false;
return xreq_t::xhas_out ();
}

54
src/req.hpp
View File

@ -20,17 +20,12 @@
#ifndef __ZMQ_REQ_HPP_INCLUDED__
#define __ZMQ_REQ_HPP_INCLUDED__
#include "socket_base.hpp"
#include "yarray.hpp"
#include "pipe.hpp"
#include "xreq.hpp"
namespace zmq
{
class req_t :
public socket_base_t,
public i_reader_events,
public i_writer_events
class req_t : public xreq_t
{
public:
@ -38,59 +33,20 @@ namespace zmq
~req_t ();
// Overloads of functions from socket_base_t.
void xattach_pipes (reader_t *inpipe_, writer_t *outpipe_,
const blob_t &peer_identity_);
void xterm_pipes ();
bool xhas_pipes ();
int xsend (zmq_msg_t *msg_, int flags_);
int xrecv (zmq_msg_t *msg_, int flags_);
bool xhas_in ();
bool xhas_out ();
// i_reader_events interface implementation.
void activated (reader_t *pipe_);
void terminated (reader_t *pipe_);
// i_writer_events interface implementation.
void activated (writer_t *pipe_);
void terminated (writer_t *pipe_);
private:
// List in outbound and inbound pipes. Note that the two lists are
// always in sync. I.e. outpipe with index N communicates with the
// same session as inpipe with index N.
//
// TODO: Once we have queue limits in place, list of active outpipes
// is to be held (presumably by stacking active outpipes at
// the beginning of the array). We don't have to do the same thing for
// inpipes, because we know which pipe we want to read the
// reply from.
typedef yarray_t <writer_t> out_pipes_t;
out_pipes_t out_pipes;
typedef yarray_t <reader_t> in_pipes_t;
in_pipes_t in_pipes;
// Number of active pipes.
size_t active;
// Req_t load-balances the requests - 'current' points to the session
// that's processing the request at the moment.
out_pipes_t::size_type current;
// If true, request was already sent and reply wasn't received yet or
// was raceived partially.
bool receiving_reply;
// True, if read can be attempted from the reply pipe.
bool reply_pipe_active;
// True, if message processed at the moment (either sent or received)
// is processed only partially.
bool more;
// Pipe we are awaiting the reply from.
reader_t *reply_pipe;
// If true, we are starting to send/recv a message. The first part
// of the message must be empty message part (backtrace stack bottom).
bool message_begins;
req_t (const req_t&);
void operator = (const req_t&);