privacore-open-source-search-engine/MsgC.h

// Matt Wells, copyright Nov 2004

/* When adding links/urls to spiderdb, Msg10.cpp, should lookup their IP
address if not already provided using a new Msg class. This is done by MsgC.
Msg class consults the local cache (g_dnsLocal) in Dns.cpp for the IP
address first, if not found it should then consult S_localDnsCache. If it 
is not found there, then send the dns lookup request to a host in
the cluster based on the hash of the hostname DIV'd with the number of hosts in
the cluster, g_hostdb.m_numHosts. The request should be looked up in 
g_dnsDistributed, not Dns.cpp's local cache, and delivered to
the responsible host. If not there, then the request should be sent to the
appropriate dns server. It is like an L1a/L1b/L2/L3 architecture, where L1 
is local, L2 is on a host in the network and L3 is on the dns server. The
returned result (the IP address) should be stored in all 4 caches.*/

#ifndef GB_MSGC_H
#define GB_MSGC_H

#include "Multicast.h"
#include "Url.h"

class Msge1;

class MsgC {

 public:

	MsgC();
	~MsgC();

	// Don't bother about dnsState, only Msg14 used to use it, and now 
	// since we are not using getIp in Msg16 anymore, it is useless.
	// returns false if blocked, true otherwise
	bool getIp(const char  *hostname    , int32_t   hostnameLen ,
		   int32_t  *ip ,
		   void  *state ,
		   void (* callback) ( void *state , int32_t ip ),
		   int32_t  niceness = 2);
	// register our request handle with g_udp server
	static bool registerHandler();

	int32_t gotReply();

	void (*m_callback) (void *state ,int32_t ip);

	// used by Msge1 to store a pointer to itself
	Msge1 *m_msge1;
	int32_t m_msge1State;

	// private:
	Multicast m_mcast;
	Url   m_u;	
	char  m_request[MAX_URL_LEN];
	int32_t *m_ipPtr;
};

#endif // GB_MSGC_H