/*
Copyright (c) 2007-2011 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_PIPE_HPP_INCLUDED__
#define __ZMQ_PIPE_HPP_INCLUDED__
#include "../include/zmq.h"
#include "stdint.hpp"
#include "array.hpp"
#include "ypipe.hpp"
#include "swap.hpp"
#include "config.hpp"
#include "object.hpp"
namespace zmq
{
// Creates a pipe. Returns pointer to reader and writer objects.
void create_pipe (object_t *reader_parent_, object_t *writer_parent_,
uint64_t hwm_, int64_t swap_size_, class reader_t **reader_,
class writer_t **writer_);
// The shutdown mechanism for pipe works as follows: Either endpoint
// (or even both of them) can ask pipe to terminate by calling 'terminate'
// method. Pipe then terminates in asynchronous manner. When the part of
// the shutdown tied to the endpoint is done it triggers 'terminated'
// event. When endpoint processes the event and returns, associated
// reader/writer object is deallocated.
typedef ypipe_t <zmq_msg_t, message_pipe_granularity> pipe_t;
struct i_reader_events
{
virtual ~i_reader_events () {}
virtual void terminated (class reader_t *pipe_) = 0;
virtual void activated (class reader_t *pipe_) = 0;
virtual void delimited (class reader_t *pipe_) = 0;
};
class reader_t : public object_t, public array_item_t
{
friend void create_pipe (object_t*, object_t*, uint64_t,
int64_t, reader_t**, writer_t**);
friend class writer_t;
public:
// Specifies the object to get events from the reader.
void set_event_sink (i_reader_events *endpoint_);
// Returns true if there is at least one message to read in the pipe.
bool check_read ();
// Reads a message to the underlying pipe.
bool read (zmq_msg_t *msg_);
// Ask pipe to terminate.
void terminate ();
private:
reader_t (class object_t *parent_, pipe_t *pipe_, uint64_t lwm_);
~reader_t ();
// To be called only by writer itself!
void set_writer (class writer_t *writer_);
// Command handlers.
void process_activate_reader ();
void process_pipe_term_ack ();
// Returns true if the message is delimiter; false otherwise.
static bool is_delimiter (zmq_msg_t &msg_);
// True, if pipe can be read from.
bool active;
// The underlying pipe.
pipe_t *pipe;
// Pipe writer associated with the other side of the pipe.
class writer_t *writer;
// Low watermark for in-memory storage (in bytes).
uint64_t lwm;
// Number of messages read so far.
uint64_t msgs_read;
// Sink for the events (either the socket of the session).
i_reader_events *sink;
// True is 'terminate' method was called or delimiter
// was read from the pipe.
bool terminating;
reader_t (const reader_t&);
const reader_t &operator = (const reader_t&);
};
struct i_writer_events
{
virtual ~i_writer_events () {}
virtual void terminated (class writer_t *pipe_) = 0;
virtual void activated (class writer_t *pipe_) = 0;
};
class writer_t : public object_t, public array_item_t
{
friend void create_pipe (object_t*, object_t*, uint64_t,
int64_t, reader_t**, writer_t**);
public:
// Specifies the object to get events from the writer.
void set_event_sink (i_writer_events *endpoint_);
// Checks whether messages can be written to the pipe.
// If writing the message would cause high watermark and (optionally)
// if the swap is full, the function returns false.
bool check_write (zmq_msg_t *msg_);
// Writes a message to the underlying pipe. Returns false if the
// message cannot be written because high watermark was reached.
bool write (zmq_msg_t *msg_);
// Remove unfinished part of a message from the pipe.
void rollback ();
// Flush the messages downsteam.
void flush ();
// Ask pipe to terminate.
void terminate ();
private:
writer_t (class object_t *parent_, pipe_t *pipe_, reader_t *reader_,
uint64_t hwm_, int64_t swap_size_);
~writer_t ();
// Command handlers.
void process_activate_writer (uint64_t msgs_read_);
void process_pipe_term ();
// Tests whether underlying pipe is already full. The swap is not
// taken into account.
bool pipe_full ();
// True, if this object can be written to. Undelying ypipe may be full
// but as long as there's swap space available, this flag is true.
bool active;
// The underlying pipe.
pipe_t *pipe;
// Pipe reader associated with the other side of the pipe.
reader_t *reader;
// High watermark for in-memory storage (in bytes).
uint64_t hwm;
// Last confirmed number of messages read from the pipe.
// The actual number can be higher.
uint64_t msgs_read;
// Number of messages we have written so far.
uint64_t msgs_written;
// Pointer to the message swap. If NULL, messages are always
// kept in main memory.
swap_t *swap;
// Sink for the events (either the socket or the session).
i_writer_events *sink;
// If true, swap is active. New messages are to be written to the swap.
bool swapping;
// If true, there's a delimiter to be written to the pipe after the
// swap is empied.
bool pending_delimiter;
// True is 'terminate' method was called of 'pipe_term' command
// arrived from the reader.
bool terminating;
writer_t (const writer_t&);
const writer_t &operator = (const writer_t&);
};
}
#endif