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/*
Copyright (c) 2007-2009 FastMQ Inc.
This file is part of 0MQ.
0MQ is free software; you can redistribute it and/or modify it under
the terms of the Lesser GNU 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
Lesser GNU General Public License for more details.
You should have received a copy of the Lesser GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ZMQ_DISPATCHER_HPP_INCLUDED__
#define __ZMQ_DISPATCHER_HPP_INCLUDED__
#include <vector>
#include <set>
#include <map>
#include <string>
#include "i_signaler.hpp"
#include "ypipe.hpp"
#include "command.hpp"
#include "config.hpp"
#include "mutex.hpp"
#include "stdint.hpp"
namespace zmq
{
// Dispatcher implements bidirectional thread-safe passing of commands
// between N threads. It consists of a ypipes to pass commands and
// signalers to wake up the receiver thread when new commands are
// available. Note that dispatcher is inefficient for passing messages
// within a thread (sender thread = receiver thread). The optimisation is
// not part of the class and should be implemented by individual threads
// (presumably by calling the command handling function directly).
class dispatcher_t
{
public:
// Create the dispatcher object. Matrix of pipes to communicate between
// each socket and each I/O thread is created along with appropriate
// signalers.
dispatcher_t (int app_threads_, int io_threads_);
// To be called to terminate the whole infrastructure (zmq_term).
~dispatcher_t ();
// Create a socket.
class socket_base_t *create_socket (int type_);
// Returns number of thread slots in the dispatcher. To be used by
// individual threads to find out how many distinct signals can be
// received.
int thread_slot_count ();
// Send command from the source to the destination.
inline void write (int source_, int destination_,
const command_t &command_)
{
command_pipe_t &pipe =
command_pipes [source_ * signalers.size () + destination_];
pipe.write (command_);
if (!pipe.flush ())
signalers [destination_]->signal (source_);
}
// Receive command from the source. Returns false if there is no
// command available.
inline bool read (int source_, int destination_, command_t *command_)
{
return command_pipes [source_ * signalers.size () +
destination_].read (command_);
}
// Returns the I/O thread that is the least busy at the moment.
// Taskset specifies which I/O threads are eligible (0 = all).
class io_thread_t *choose_io_thread (uint64_t taskset_);
// All pipes are registered with the dispatcher so that even the
// orphaned pipes can be deallocated on the terminal shutdown.
void register_pipe (class pipe_t *pipe_);
void unregister_pipe (class pipe_t *pipe_);
private:
// Returns the app thread associated with the current thread.
// NULL if we are out of app thread slots.
class app_thread_t *choose_app_thread ();
// Application threads.
typedef std::vector <class app_thread_t*> app_threads_t;
app_threads_t app_threads;
// I/O threads.
typedef std::vector <class io_thread_t*> io_threads_t;
io_threads_t io_threads;
// Signalers for both application and I/O threads.
std::vector <i_signaler*> signalers;
// Pipe to hold the commands.
typedef ypipe_t <command_t, true,
command_pipe_granularity> command_pipe_t;
// NxN matrix of command pipes.
command_pipe_t *command_pipes;
// Synchronisation of accesses to shared thread data.
mutex_t threads_sync;
// As pipes may reside in orphaned state in particular moments
// of the pipe shutdown process, i.e. neither pipe reader nor
// pipe writer hold reference to the pipe, we have to hold references
// to all pipes in dispatcher so that we can deallocate them
// during terminal shutdown even though it conincides with the
// pipe being in the orphaned state.
typedef std::set <class pipe_t*> pipes_t;
pipes_t pipes;
// Synchronisation of access to the pipes repository.
mutex_t pipes_sync;
dispatcher_t (const dispatcher_t&);
void operator = (const dispatcher_t&);
};
}
#endif
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