/*?async.c?--?state?management?for?asynchronous?messages
?*
?*?Copyright?（C）?20102011?Olaf?Bergmann?
?*
?*?This?file?is?part?of?the?CoAP?library?libcoap.?Please?see
?*?README?for?terms?of?use.?
?*/

/**?
?*?@file?async.c
?*?@brief?state?management?for?asynchronous?messages
?*/

#ifndef?WITHOUT_ASYNC

#include?“config.h“

#include?“utlist.h“

#include?“mem.h“
#include?“debug.h“
#include?“async.h“

coap_async_state_t?*
coap_register_async（coap_context_t?*context?coap_address_t?*peer
		????coap_pdu_t?*request?unsigned?char?flags?void?*data）?{
??coap_async_state_t?*s;
??coap_tid_t?id;

??coap_transaction_id（peer?request?&id）;
??LL_SEARCH_SCALAR（context->async_statesidid）;

??if?（s?!=?NULL）?{
????/*?We?must?return?NULL?here?as?the?caller?must?know?that?he?is
?????*?responsible?for?releasing?@p?data.?*/
????debug（“asynchronous?state?for?transaction?%d?already?registered\n“?id）;
????return?NULL;
??}

??/*?store?information?for?handling?the?asynchronous?task?*/
??s?=?（coap_async_state_t?*）coap_malloc（sizeof（coap_async_state_t）?+?
					request->hdr->token_length）;
??if?（!s）?{
????coap_log（LOG_CRIT?“coap_register_async:?insufficient?memory\n“）;
????return?NULL;
??}

??memset（s?0?sizeof（coap_async_state_t）?+?request->hdr->token_length）;

??/*?set?COAP_ASYNC_CONFIRM?according?to?request‘s?type?*/
??s->flags?=?flags?&?~COAP_ASYNC_CONFIRM;
??if?（request->hdr->type?==?COAP_MESSAGE_CON）
????s->flags?|=?COAP_ASYNC_CONFIRM;

??s->appdata?=?data;

??memcpy（&s->peer?peer?sizeof（coap_address_t））;

??if?（request->hdr->token_length）?{
????s->tokenlen?=?request->hdr->token_length;
????memcpy（s->token?request->hdr->token?request->hdr->token_length）;
??}
????
??memcpy（&s->id?&id?sizeof（coap_tid_t））;

??coap_touch_async（s）;

??LL_PREPEND（context->async_state?s）;

??return?s;
}

coap_async_state_t?*
coap_find_async（coap_context_t?*context?coap_tid_t?id）?{
??coap_async_state_t?*tmp;
??LL_SEARCH_SCALAR（context->async_statetmpidid）;??
??return?tmp;
}

int
coap_remove_async（coap_context_t?*context?coap_tid_t?id?
		??coap_async_state_t?**s）?{
??coap_async_state_t?*tmp?=?coap_find_async（context?id）;

??if?（tmp）
????LL_DELETE（context->async_statetmp）;

??*s?=?tmp;
??return?tmp?!=?NULL;
}

void?
coap_free_async（coap_async_state_t?*s）?{
??if?（s?&&?（s->flags?&?COAP_ASYNC_RELEASE_DATA）?!=?0）
????coap_free（s->appdata）;
??coap_free（s）;?
}

#else
void?does_not_exist（）;	/*?make?some?compilers?happy?*/
#endif?/*?WITHOUT_ASYNC?*/