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/* -*- C++ -*- */
// $Id$
// ============================================================================
//
// = LIBRARY
// gateway
//
// = FILENAME
// Peer.h
//
// = DESCRIPTION
// These classes process Supplier/Consumer events sent from the
// gateway (gatewayd) to its various peers (peerd). The general
// collaboration works as follows:
//
// 1. <Peer_Acceptor> creates a listener endpoint and waits
// passively for gatewayd to connect with it.
//
// 2. When a gatewayd connects, <Peer_Acceptor> creates an
// <Peer_Handler> object that sends/receives events from
// gatewayd on that connection.
//
// 3. The <Peer_Handler> waits for gatewayd to inform it of its
// connection ID, which is prepended to all subsequent outgoing
// events sent from peerd.
//
// 4. Once the connection ID is set, peerd periodically sends events
// to gatewayd. Peerd also receives and "processes" events
// forwarded to it from gatewayd. In this program, peerd
// "processes" the events sent to it by writing them to stdout.
//
// Note that in the current peerd implementation, one Peer process
// cannot serve as both a Consumer and Supplier of Events. This is
// because the gatewayd establishes a separate connection for
// Suppliers and Consumers and the peerd only maintains a single
// <Peer_Handler> object to handle this one connection. Enhancing
// this implementation to be both a Consumer and Supplier
// simultaneously is straightforward, however. In addition,
// multiple peerd processes can already work together to play these
// different roles.
//
// = AUTHOR
// Douglas C. Schmidt
//
// ============================================================================
#if !defined (PEER_H)
#define PEER_H
#include "ace/Service_Config.h"
#include "ace/Acceptor.h"
#include "ace/Connector.h"
#include "ace/SOCK_Acceptor.h"
#include "ace/SOCK_Connector.h"
#include "Options.h"
ACE_SVC_FACTORY_DECLARE (Peer_Factory)
class ACE_Svc_Export Peer_Handler : public ACE_Svc_Handler<ACE_SOCK_STREAM, ACE_NULL_SYNCH>
{
// = TITLE
// Handle Peer events arriving from a Gateway.
public:
// = Initialization and termination methods.
Peer_Handler (void);
// Initialize the peer.
~Peer_Handler (void);
// Shutdown the Peer.
virtual int open (void * = 0);
// Initialize the handler when called by
// <ACE_Acceptor::handle_input>.
virtual int handle_input (ACE_HANDLE);
// Receive and process peer events.
virtual int put (ACE_Message_Block *, ACE_Time_Value *tv = 0);
// Send a event to a gateway (may be queued if necessary due to flow
// control).
virtual int handle_output (ACE_HANDLE);
// Finish sending a event when flow control conditions abate.
virtual int handle_timeout (const ACE_Time_Value &,
const void *arg);
// Periodically send events via <ACE_Reactor> timer mechanism.
virtual int handle_close (ACE_HANDLE = ACE_INVALID_HANDLE,
ACE_Reactor_Mask = ACE_Event_Handler::ALL_EVENTS_MASK);
// Perform object termination.
protected:
typedef ACE_Svc_Handler<ACE_SOCK_STREAM, ACE_NULL_SYNCH> inherited;
int transmit (ACE_Message_Block *mb,
size_t n,
int event_type);
// Transmit <mb> to the gatewayd.
virtual int recv (ACE_Message_Block *&mb);
// Receive an Peer event from gatewayd.
virtual int send (ACE_Message_Block *mb);
// Send an Peer event to gatewayd, using <nonblk_put>.
virtual int nonblk_put (ACE_Message_Block *mb);
// Perform a non-blocking <put>, which tries to send an event to the
// gatewayd, but only if it isn't flow controlled.
int subscribe (void);
// Register Consumer subscriptions with the gateway.
// = Event/state/action handlers.
int transmit_stdin (void);
// Receive a event from stdin and send it to the gateway.
int await_connection_id (void);
// Action that receives the route id.
int await_events (void);
// Action that receives events.
int (Peer_Handler::*do_action_)(void);
// Pointer-to-member-function for the current action to run in this
// state. This points to one of the preceding 3 methods.
CONNECTION_ID connection_id_;
// Connection ID of the peer, which is obtained from the gatewayd.
ACE_Message_Block *msg_frag_;
// Keep track of event fragments that arrive in non-blocking recv's
// from the gatewayd.
size_t total_bytes_;
// The total number of bytes sent/received to the gatewayd thus far.
};
class ACE_Svc_Export Peer_Acceptor : public ACE_Acceptor<Peer_Handler, ACE_SOCK_ACCEPTOR>
{
// = TITLE
// Passively accept connections from gatewayd and dynamically
// create a new <Peer_Handler> object to communicate with the
// gatewayd.
public:
// = Initialization and termination methods.
Peer_Acceptor (void);
// Default initialization.
int open (u_short);
// the <Peer_Acceptor>.
int close (void);
// Terminate the <Peer_Acceptor>.
virtual int make_svc_handler (Peer_Handler *&);
// Factory method that creates a <Peer_Handler> just once.
private:
int open_acceptor (u_short port);
// Factor out common code for initializing the <Peer_Acceptor>.
Peer_Handler *peer_handler_;
// Pointer to <Peer_Handler> allocated just once.
ACE_INET_Addr addr_;
// Our acceptor addr.
typedef ACE_Acceptor<Peer_Handler, ACE_SOCK_ACCEPTOR> inherited;
};
class ACE_Svc_Export Peer_Connector : public ACE_Connector<Peer_Handler, ACE_SOCK_CONNECTOR>
{
// = TITLE
// Actively establish connections with gatewayd and dynamically
// create a new <Peer_Handler> object to communicate with the
// gatewayd.
public:
// = Initialization method.
int open (ACE_Reactor * = 0, int = 0);
// Initialize the <Peer_Connector>. NOTE: the arguments are
// ignored. They are only provided to avoid a compiler warning
// about hiding the virtual function ACE_Connector<Peer_Handler,
// ACE_SOCK_CONNECTOR>::open(ACE_Reactor*, int).
private:
int open_connector (Peer_Handler *&ph, u_short port);
// Factor out common code for initializing the <Peer_Connector>.
Peer_Handler *consumer_peer_handler_;
// Consumer <Peer_Handler> that is connected to a gatewayd.
Peer_Handler *supplier_peer_handler_;
// Supplier <Peer_Handler> that is connected to a gatewayd.
};
class ACE_Svc_Export Peer_Factory : public ACE_Service_Object
{
// = TITLE
// A factory class that actively and/or passively establishes
// connections with the gatewayd.
public:
// = Dynamic initialization and termination hooks from <ACE_Service_Object>.
virtual int init (int argc, char *argv[]);
// Initialize the acceptor and connector.
virtual int fini (void);
// Perform termination activities.
virtual int info (char **, size_t) const;
// Return info about this service.
virtual int handle_signal (int signum, siginfo_t *, ucontext_t *);
// Handle various signals (e.g., SIGPIPE, SIGINT, and SIGQUIT).
private:
Peer_Acceptor consumer_acceptor_;
// Pointer to an instance of our <Peer_Acceptor> that's used to
// accept connections and create Consumers.
Peer_Acceptor supplier_acceptor_;
// Pointer to an instance of our <Peer_Acceptor> that's used to
// accept connections and create Suppliers.
Peer_Connector connector_;
// An instance of our <Peer_Connector>. Note that one
// <Peer_Connector> is used to establish <Peer_Handler>s for both
// Consumers and Suppliers.
};
#endif /* PEER_H */
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