/* $Id: asyncns.h 23 2007-02-16 12:49:17Z lennart $ */

/***

  This file is part of libasyncns.

  Copyright (C) 2006 Collabora Ltd.

 * 

  libasyncns 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 2 of the

  License, or (at your option) any later version.

  libasyncns 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

  General Public License for more details.

  You should have received a copy of the GNU Lesser General Public

  License along with libasyncns; if not, write to the Free Software

  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307

  USA.

***/

#ifndef fooasyncnshfoo

#define fooasyncnshfoo

#include <sys/types.h>

#include <sys/socket.h>

#include <netdb.h>

/** /mainpage

 *

 * /section moo Method of operation

 *

 * To use libasyncns allocate an asyncns_t object with

 * asyncns_new(). This will spawn a number of worker threads (or processes, depending on what is available) which

 * are subsequently used to process the queries the controlling

 * program issues via asyncns_getaddrinfo() and

 * asyncns_getnameinfo(). Use asyncns_free() to shut down the worker

 * threads/processes.

 *

 * Since libasyncns may fork off new processes you have to make sure that

 * your program is not irritated by spurious SIGCHLD signals.

 */

/** /example asyncns-test.c

 * An example program */

#ifdef  __cplusplus

extern "C" {

#endif

/** An opaque libasyncns session structure */

typedef struct asyncns asyncns_t;

/** An opaque libasyncns query structure */

typedef struct asyncns_query asyncns_query_t;

/** Allocate a new libasyncns session with n_proc worker processes */

asyncns_t* asyncns_new(unsigned n_proc);

/** Free a libasyncns session. This destroys all attached

 * asyncns_query_t objects automatically */

void asyncns_free(asyncns_t *asyncns);

/** Return the UNIX file descriptor to select() for readability

 * on. Use this function to integrate libasyncns with your custom main

 * loop. */

int asyncns_fd(asyncns_t *asyncns);

/** Process pending responses. After this function is called you can

 * get the next completed query object(s) using asyncns_getnext(). If

 * block is non-zero wait until at least one response has been

 * processed. If block is zero, process all pending responses and

 * return. */

int asyncns_wait(asyncns_t *asyncns, int block);

/** Issue a name to address query on the specified session. The

 * arguments are compatible with the ones of libc's

 * getaddrinfo(3). The function returns a new query object. When the

 * query is completed you may retrieve the results using

 * asyncns_getaddrinfo_done().*/

asyncns_query_t* asyncns_getaddrinfo(asyncns_t *asyncns, const char *node, const char *service, const struct addrinfo *hints);

/** Retrieve the results of a preceding asyncns_getaddrinfo()

 * call. Returns a addrinfo structure and a return value compatible

 * with libc's getaddrinfo(3). The query object q is destroyed by this

 * call and may not be used any further. Make sure to free the

 * returned addrinfo structure with asyncns_freeaddrinfo() and not

 * libc's freeaddrinfo(3)! If the query is not completed yet EAI_AGAIN

 * is returned.*/

int asyncns_getaddrinfo_done(asyncns_t *asyncns, asyncns_query_t* q, struct addrinfo **ret_res);

/** Issue an address to name query on the specified session. The

arguments are compatible with the ones of libc's getnameinfo(3). The

function returns a new query object. When the query is completed you

may retrieve the results using asyncns_getnameinfo_done(). Set gethost

(resp. getserv) to non-zero if you want to query the hostname

(resp. the service name). */

asyncns_query_t* asyncns_getnameinfo(asyncns_t *asyncns, const struct sockaddr *sa, socklen_t salen, int flags, int gethost, int getserv);

/** Retrieve the results of a preceding asyncns_getnameinfo)(

 * call. Returns the hostname and the service name in ret_host and

 * ret_serv. The query object q is destroyed by this call and may not

 * be used any further. If the query is not completed yet EAI_AGAIN is

 * returned. */

int asyncns_getnameinfo_done(asyncns_t *asyncns, asyncns_query_t* q, char *ret_host, size_t hostlen, char *ret_serv, size_t servlen);

/** Issue an resolver query on the specified session. The arguments are

 * compatible with the ones of libc's res_query(3). The function returns a new

 * query object. When the query is completed you may retrieve the results using

 * asyncns_res_done().  */

asyncns_query_t* asyncns_res_query(asyncns_t *asyncns, const char *dname, int class, int type);

/** Issue an resolver query on the specified session. The arguments are

 * compatible with the ones of libc's res_search(3). The function returns a new

 * query object. When the query is completed you may retrieve the results using

 * asyncns_res_done().  */

asyncns_query_t* asyncns_res_search(asyncns_t *asyncns, const char *dname, int class, int type);

/** Retrieve the results of a preceding asyncns_res_query)( or

 * asyncns_res_search call.  The query object q is destroyed by this call and

 * may not be used any further. Returns a pointer to the answer of the

 * res_query call. If the query is not completed yet -EAGAIN is returned, on

 * failure -errno is returned otherwise the length of answer is returned. */

int asyncns_res_done(asyncns_t *asyncns, asyncns_query_t* q, unsigned char

**answer);

/** Return the next completed query object. If no query has been

 * completed yet, return NULL. Please note that you need to run

 * asyncns_wait() before this function will return sensible data.  */

asyncns_query_t* asyncns_getnext(asyncns_t *asyncns);

/** Return the number of query objects (completed or not) attached to

 * this session */

int asyncns_getnqueries(asyncns_t *asyncns);

/** Cancel a currently running query. q is is destroyed by this call

 * and may not be used any futher. */

void asyncns_cancel(asyncns_t *asyncns, asyncns_query_t* q);

/** Free the addrinfo structure as returned by

asyncns_getaddrinfo_done(). Make sure to use this functions instead of

the libc's freeaddrinfo()! */

void asyncns_freeaddrinfo(struct addrinfo *ai);

/** Returns non-zero when the query operation specified by q has been completed */

int asyncns_isdone(asyncns_t *asyncns, asyncns_query_t*q);

/** Assign some opaque userdata with a query object */

void asyncns_setuserdata(asyncns_t *asyncns, asyncns_query_t *q, void *userdata);

/** Return userdata assigned to a query object. Use

 * asyncns_setuserdata() to set this data. If no data has been set

 * prior to this call it returns NULL. */

void* asyncns_getuserdata(asyncns_t *asyncns, asyncns_query_t *q);

#ifdef  __cplusplus

}

#endif

#endif