qse/lib/http/httpd.c

/*
 * $Id$
 * 
    Copyright (c) 2006-2019 Chung, Hyung-Hwan. All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:
    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "httpd.h"
#include "../cmn/mem-prv.h"
#include <qse/cmn/chr.h>
#include <qse/cmn/str.h>
#include <qse/cmn/mbwc.h>
#include <qse/si/sio.h>

#if !defined(QSE_HTTPD_DEFAULT_MODPREFIX)
#	if defined(_WIN32)
#		define QSE_HTTPD_DEFAULT_MODPREFIX "qsehttpd-"
#	elif defined(__OS2__)
#		define QSE_HTTPD_DEFAULT_MODPREFIX "htd-"
#	elif defined(__DOS__)
#		define QSE_HTTPD_DEFAULT_MODPREFIX "htd-"
#	else
#		define QSE_HTTPD_DEFAULT_MODPREFIX "libqsehttpd-"
#	endif
#endif

#if !defined(QSE_HTTPD_DEFAULT_MODPOSTFIX)
#	define QSE_HTTPD_DEFAULT_MODPOSTFIX ""
#endif

typedef struct htrd_xtn_t htrd_xtn_t;
typedef struct tmr_xtn_t tmr_xtn_t;

struct htrd_xtn_t
{
	qse_httpd_t*        httpd;
	qse_httpd_client_t* client;
};

struct tmr_xtn_t
{
	qse_httpd_t* httpd;
};

static void free_server_list (qse_httpd_t* httpd);
static int perform_client_task (
	qse_httpd_t* httpd, void* mux, qse_httpd_hnd_t handle, int mask, void* cbarg);
static void unload_all_modules (qse_httpd_t* httpd);

qse_http_version_t qse_http_v11 = { 1, 1 };

qse_httpd_t* qse_httpd_open (qse_mmgr_t* mmgr, qse_size_t xtnsize, qse_httpd_errnum_t* errnum)
{
	qse_httpd_t* httpd;

	httpd = (qse_httpd_t*)QSE_MMGR_ALLOC(mmgr, QSE_SIZEOF(qse_httpd_t) + xtnsize);
	if (httpd)
	{
		if (qse_httpd_init (httpd, mmgr) <= -1)
		{
			if (errnum) *errnum = qse_httpd_geterrnum(httpd);
			QSE_MMGR_FREE (mmgr, httpd);
			return QSE_NULL;
		}
		else QSE_MEMSET (QSE_XTN(httpd), 0, xtnsize);
	}
	else if (errnum) *errnum = QSE_HTTPD_ENOMEM;

	return httpd;
}

void qse_httpd_close (qse_httpd_t* httpd)
{
	qse_httpd_fini (httpd);
	QSE_MMGR_FREE (httpd->_mmgr, httpd);
}

int qse_httpd_init (qse_httpd_t* httpd, qse_mmgr_t* mmgr)
{
	tmr_xtn_t* tmr_xtn;

	QSE_MEMSET (httpd, 0, QSE_SIZEOF(*httpd));

	httpd->_instsize = QSE_SIZEOF(*httpd);
	httpd->_mmgr = mmgr;

	httpd->tmr = qse_tmr_open (mmgr, QSE_SIZEOF(tmr_xtn_t), 2048);
	if (httpd->tmr == QSE_NULL) return -1;

	tmr_xtn = qse_tmr_getxtn (httpd->tmr);
	QSE_MEMSET (tmr_xtn, 0, QSE_SIZEOF(*tmr_xtn));
	tmr_xtn->httpd = httpd;

	qse_mbscpy (httpd->sname, QSE_MT("QSE-HTTPD " QSE_PACKAGE_VERSION));

	httpd->opt.tmout.sec = 3;
	httpd->opt.idle_limit.sec = 30;

	return 0;
}

void qse_httpd_fini (qse_httpd_t* httpd)
{
	qse_httpd_ecb_t* ecb;
	qse_size_t i;

	unload_all_modules (httpd);

	for (ecb = httpd->ecb; ecb; ecb = ecb->next)
		if (ecb->close) ecb->close (httpd);

	free_server_list (httpd);
	qse_tmr_close (httpd->tmr);

	for (i = 0; i < QSE_COUNTOF(httpd->opt.mod); i++)
	{
		if (httpd->opt.mod[i].ptr)
		{
			qse_httpd_freemem (httpd, httpd->opt.mod[i].ptr);
			httpd->opt.mod[i].ptr = QSE_NULL;
			httpd->opt.mod[i].len = 0;
		}
	}
}

void qse_httpd_stop (qse_httpd_t* httpd)
{
	httpd->stopreq = 1;
}

void qse_httpd_impede (qse_httpd_t* httpd)
{
	httpd->impedereq = 1;
}

qse_httpd_errnum_t qse_httpd_geterrnum (qse_httpd_t* httpd)
{
	return httpd->errnum;
}

void qse_httpd_seterrnum (qse_httpd_t* httpd, qse_httpd_errnum_t errnum)
{
	httpd->errnum = errnum;
}

static int dup_str_opt (qse_httpd_t* httpd, const void* value, qse_cstr_t* tmp)
{
	if (value)
	{
		tmp->ptr = qse_strdup(value, qse_httpd_getmmgr(httpd));
		if (tmp->ptr == QSE_NULL)
		{
			qse_httpd_seterrnum (httpd, QSE_HTTPD_ENOMEM);
			return -1;
		}
		tmp->len = qse_strlen (tmp->ptr);
	}
	else
	{
		tmp->ptr = QSE_NULL;
		tmp->len = 0;
	}

	return 0;
}

int qse_httpd_getopt (qse_httpd_t* httpd, qse_httpd_opt_t id, void* value)
{
	switch (id)
	{
		case QSE_HTTPD_TRAIT:
			*(int*)value = httpd->opt.trait;
			return 0;

		case QSE_HTTPD_TMOUT:
			*(qse_ntime_t*)value = httpd->opt.tmout;
			return 0;

		case QSE_HTTPD_IDLELIMIT:
			*(qse_ntime_t*)value = httpd->opt.idle_limit;
			return 0;

		case QSE_HTTPD_MODPREFIX:
		case QSE_HTTPD_MODPOSTFIX:
			*(const qse_char_t**)value = httpd->opt.mod[id - QSE_HTTPD_MODPREFIX].ptr;
			return 0;

		case QSE_HTTPD_SCB:
			*(qse_httpd_scb_t*)value = httpd->opt.scb;
			return 0;

		case QSE_HTTPD_RCB:
			*(qse_httpd_rcb_t*)value = httpd->opt.rcb;
			return 0;
	}

	httpd->errnum = QSE_HTTPD_EINVAL;
	return -1;
}

int qse_httpd_setopt (qse_httpd_t* httpd, qse_httpd_opt_t id, const void* value)
{
	switch (id)
	{
		case QSE_HTTPD_TRAIT:
			httpd->opt.trait = *(const int*)value;
			return 0;

		case QSE_HTTPD_TMOUT:
			httpd->opt.tmout = *(qse_ntime_t*)value;
			return 0;

		case QSE_HTTPD_IDLELIMIT:
			httpd->opt.idle_limit = *(qse_ntime_t*)value;
			return 0;

		case QSE_HTTPD_MODPREFIX:
		case QSE_HTTPD_MODPOSTFIX:
		{
			qse_cstr_t tmp;
			int idx;

			if (dup_str_opt(httpd, value, &tmp) <= -1) return -1;

			idx = id - QSE_HTTPD_MODPREFIX;
			if (httpd->opt.mod[idx].ptr) qse_httpd_freemem (httpd, httpd->opt.mod[idx].ptr);

			httpd->opt.mod[idx] = tmp;
			return 0;
		}

		case QSE_HTTPD_SCB:
			httpd->opt.scb = *(qse_httpd_scb_t*)value;
			return 0;

		case QSE_HTTPD_RCB:
			httpd->opt.rcb = *(qse_httpd_rcb_t*)value;
			return 0;

	}

	httpd->errnum = QSE_HTTPD_EINVAL;
	return -1;
}

/* ----------------------------------------------------------------------- */

qse_httpd_ecb_t* qse_httpd_popecb (qse_httpd_t* httpd)
{
	qse_httpd_ecb_t* top = httpd->ecb;
	if (top) httpd->ecb = top->next;
	return top;
}

void qse_httpd_pushecb (qse_httpd_t* httpd, qse_httpd_ecb_t* ecb)
{
	ecb->next = httpd->ecb;
	httpd->ecb = ecb;
}

/* ----------------------------------------------------------------------- */

void* qse_httpd_allocmem (qse_httpd_t* httpd, qse_size_t size)
{
	void* ptr = QSE_MMGR_ALLOC (qse_httpd_getmmgr(httpd), size);
	if (ptr == QSE_NULL) httpd->errnum = QSE_HTTPD_ENOMEM;
	return ptr;
}

void* qse_httpd_callocmem (qse_httpd_t* httpd, qse_size_t size)
{
	void* ptr = QSE_MMGR_ALLOC (qse_httpd_getmmgr(httpd), size);
	if (ptr == QSE_NULL) httpd->errnum = QSE_HTTPD_ENOMEM;
	else QSE_MEMSET (ptr, 0, size);
	return ptr;
}

void* qse_httpd_reallocmem (
	qse_httpd_t* httpd, void* ptr, qse_size_t size)
{
	void* nptr = QSE_MMGR_REALLOC (qse_httpd_getmmgr(httpd), ptr, size);
	if (nptr == QSE_NULL) httpd->errnum = QSE_HTTPD_ENOMEM;
	return nptr;
}

void qse_httpd_freemem (qse_httpd_t* httpd, void* ptr)
{
	QSE_MMGR_FREE (qse_httpd_getmmgr(httpd), ptr);
}

qse_mchar_t* qse_httpd_strtombsdup (qse_httpd_t* httpd, const qse_char_t* str)
{
	qse_mchar_t* mptr;

#if defined(QSE_CHAR_IS_MCHAR)
	mptr = qse_mbsdup (str, qse_httpd_getmmgr(httpd));
#else
	mptr = qse_wcstombsdup (str, QSE_NULL, qse_httpd_getmmgr(httpd));
#endif

	if (mptr == QSE_NULL) httpd->errnum = QSE_HTTPD_ENOMEM;
	return mptr;
}

qse_mchar_t* qse_httpd_strntombsdup (qse_httpd_t* httpd, const qse_char_t* str, qse_size_t len)
{
	qse_mchar_t* mptr;

#if defined(QSE_CHAR_IS_MCHAR)
	mptr = qse_mbsxdup (str, len, qse_httpd_getmmgr(httpd));
#else
	mptr = qse_wcsntombsdup (str, len, QSE_NULL, qse_httpd_getmmgr(httpd));
#endif

	if (mptr == QSE_NULL) httpd->errnum = QSE_HTTPD_ENOMEM;
	return mptr;
}

qse_mchar_t* qse_httpd_mbsdup (qse_httpd_t* httpd, const qse_mchar_t* str)
{
	qse_mchar_t* mptr;

	mptr = qse_mbsdup (str, qse_httpd_getmmgr(httpd));
	if (mptr == QSE_NULL) httpd->errnum = QSE_HTTPD_ENOMEM;

	return mptr;
}

qse_mchar_t* qse_httpd_mbsxdup (qse_httpd_t* httpd, const qse_mchar_t* str, qse_size_t len)
{
	qse_mchar_t* mptr;

	mptr = qse_mbsxdup (str, len, qse_httpd_getmmgr(httpd));
	if (mptr == QSE_NULL) httpd->errnum = QSE_HTTPD_ENOMEM;

	return mptr;
}
/* ----------------------------------------------------------------------- */

static qse_httpd_real_task_t* enqueue_task (
	qse_httpd_t* httpd, qse_httpd_client_t* client, 
	qse_httpd_task_t* pred, const qse_httpd_task_t* task,
	qse_size_t xtnsize)
{
	qse_httpd_real_task_t* new_task;
	qse_httpd_real_task_t* real_pred;
	
/* TODO: limit check 
	if (client->task.count >= httpd->limit.client_task_queue)
	{
		httpd->errnum = QSE_HTTPD_ETASK;
		return -1;
	}
*/
	new_task = (qse_httpd_real_task_t*)
		qse_httpd_allocmem (httpd, QSE_SIZEOF(*new_task) + xtnsize);
	if (new_task == QSE_NULL) return QSE_NULL;

	QSE_MEMSET (new_task, 0, QSE_SIZEOF(*new_task) + xtnsize);
	new_task->core = *task;

	if (new_task->core.init)
	{
		httpd->errnum = QSE_HTTPD_ENOERR;
		if (new_task->core.init (httpd, client, (qse_httpd_task_t*)new_task) <= -1)
		{
			if (httpd->errnum == QSE_HTTPD_ENOERR) 
				httpd->errnum = QSE_HTTPD_ETASK;
			qse_httpd_freemem (httpd, new_task);
			return QSE_NULL;
		}
	}

	real_pred = (qse_httpd_real_task_t*)pred;
	if (pred)
	{
		new_task->next = real_pred->next;
		new_task->prev = real_pred;

		if (real_pred->next) real_pred->next->prev = new_task;
		else client->task.tail = (qse_httpd_task_t*)new_task;
		real_pred->next = new_task;
	}
	else
	{
		new_task->next = QSE_NULL;
		new_task->prev = (qse_httpd_real_task_t*)client->task.tail;

		if (client->task.tail) 
			((qse_httpd_real_task_t*)client->task.tail)->next = new_task;
		else 
			client->task.head = (qse_httpd_task_t*)new_task;
		client->task.tail = (qse_httpd_task_t*)new_task;
	}
	client->task.count++;

	return new_task;
}

static QSE_INLINE int dequeue_task (qse_httpd_t* httpd, qse_httpd_client_t* client)
{
	qse_httpd_real_task_t* task;
	qse_size_t i;

	if (client->task.count <= 0) return -1;

	task = (qse_httpd_real_task_t*)client->task.head;

	/* clear task triggers from mux if they are registered */
	for (i = 0; i < QSE_COUNTOF(task->core.trigger.v); i++)
	{
		if (client->status & QSE_HTTPD_CLIENT_TASK_TRIGGER_RW_IN_MUX(i))
		{
			QSE_ASSERT (task->core.trigger.v[i].handle != client->handle);
			httpd->opt.scb.mux.delhnd (httpd, httpd->mux, task->core.trigger.v[i].handle);
			client->status &= ~QSE_HTTPD_CLIENT_TASK_TRIGGER_RW_IN_MUX(i);
		}
	}

	/* --------------------------------------------------- */

	if (task == (qse_httpd_real_task_t*)client->task.tail)
	{
		client->task.head = QSE_NULL;
		client->task.tail = QSE_NULL;
	}
	else
	{
		task->next->prev = QSE_NULL;
		client->task.head = (qse_httpd_task_t*)task->next;
	}
	client->task.count--;

	if (task->core.fini) task->core.fini (httpd, client, (qse_httpd_task_t*)task);
	qse_httpd_freemem (httpd, task);

	return 0;
}

static QSE_INLINE void purge_tasks (qse_httpd_t* httpd, qse_httpd_client_t* client)
{
	while (dequeue_task (httpd, client) == 0);
}

/* ----------------------------------------------------------------------- */

static QSE_INLINE void unchain_cached_proxy_peer (qse_httpd_t* httpd, qse_httpd_client_t* client, qse_httpd_peer_t* peer)
{
	QSE_ASSERT (peer->flags & QSE_HTTPD_PEER_CACHED);

	if (peer->next) peer->next->prev = peer->prev;
	else client->peer.last = peer->prev;

	if (peer->prev) peer->prev->next = peer->next;
	else client->peer.first = peer->next;
}

static void purge_cached_proxy_peer (qse_httpd_t* httpd, qse_httpd_client_t* client, qse_httpd_peer_t* peer)
{
	unchain_cached_proxy_peer (httpd, client, peer);

#if defined(QSE_HTTPD_DEBUG)
	{
		qse_mchar_t tmp[128];

		qse_nwadtombs (&peer->nwad, tmp, QSE_COUNTOF(tmp), QSE_NWADTOMBS_ALL);
		HTTPD_DBGOUT2 ("Closing cached peer [%hs] - %zd\n", tmp, (qse_size_t)peer->handle);
	}
#endif

	httpd->opt.scb.peer.close (httpd, peer);
	qse_httpd_freemem (httpd, peer);
}

static void purge_cached_proxy_peers (qse_httpd_t* httpd, qse_httpd_client_t* client)
{
	while (client->peer.first)
	{
		purge_cached_proxy_peer (httpd, client, client->peer.first);
	}
}

qse_httpd_peer_t* qse_httpd_cacheproxypeer (qse_httpd_t* httpd, qse_httpd_client_t* client, qse_httpd_peer_t* tmpl)
{
	qse_httpd_peer_t* peer;

	if (tmpl->flags & QSE_HTTPD_PEER_CACHED)
	{
		/* If QSE_HTTPD_PEER_CACHED is set, tmpl points to a block allocated
		 * here previously. Link such a block to the cache list */
		peer = tmpl;
	}
	else
	{
		/* Clone the peer object if it's not previsouly allocated here */
		peer = qse_httpd_allocmem (httpd, QSE_SIZEOF(*peer));
		if (peer == QSE_NULL) goto oops;

		QSE_MEMCPY (peer, tmpl, QSE_SIZEOF(*peer));
		peer->flags |= QSE_HTTPD_PEER_CACHED;
	}

	/* place the peer at the back of the peer list of a client */
	if (client->peer.last)
	{
		peer->next = QSE_NULL;
		peer->prev = client->peer.last;
		client->peer.last->next = peer;
		client->peer.last = peer;
	}
	else
	{
		peer->next = QSE_NULL;
		peer->prev = QSE_NULL;
		client->peer.first = peer;
		client->peer.last = peer;
	}

	qse_gettime (&peer->timestamp);
	return peer;

oops:
	if (peer) qse_httpd_freemem (httpd, peer);
	return QSE_NULL;
}

qse_httpd_peer_t* qse_httpd_decacheproxypeer (
	qse_httpd_t* httpd, qse_httpd_client_t* client, 
	const qse_nwad_t* nwad, const qse_nwad_t* local, int secure)
{
	qse_httpd_peer_t* peer, * next;
	qse_ntime_t now, diff;
	static qse_ntime_t diff_limit = { 5, 0 }; /* TODO: make this configurable */

	qse_gettime (&now);

	peer = client->peer.first;
	while (peer)
	{
		next = peer->next;

		qse_sub_ntime (&diff, &now, &peer->timestamp);
		if (qse_cmp_ntime(&diff, &diff_limit) >= 0)
		{
			/* the entry is too old */
			purge_cached_proxy_peer (httpd, client, peer);
		}
		else if (qse_nwadequal(nwad, &peer->nwad) && qse_nwadequal (local, &peer->local))
		{
			if ((secure && (peer->flags & QSE_HTTPD_PEER_SECURE)) ||
			    (!secure && !(peer->flags & QSE_HTTPD_PEER_SECURE))) 
			{
				unchain_cached_proxy_peer (httpd, client, peer);
				peer->next = QSE_NULL;
				peer->prev = QSE_NULL;
				return peer;
			}
		}

		peer = next;
	}

	return QSE_NULL;
}


/* ----------------------------------------------------------------------- */
static int htrd_peek_request (qse_htrd_t* htrd, qse_htre_t* req)
{
	htrd_xtn_t* xtn = (htrd_xtn_t*)qse_htrd_getxtn(htrd);
	return xtn->httpd->opt.rcb.peekreq(xtn->httpd, xtn->client, req);
}

static int htrd_poke_request (qse_htrd_t* htrd, qse_htre_t* req)
{
	htrd_xtn_t* xtn = (htrd_xtn_t*)qse_htrd_getxtn(htrd);
	return xtn->httpd->opt.rcb.pokereq(xtn->httpd, xtn->client, req);
}

static qse_htrd_recbs_t htrd_recbs =
{
	QSE_STRUCT_FIELD (peek, htrd_peek_request),
	QSE_STRUCT_FIELD (poke, htrd_poke_request)
};

/* ----------------------------------------------------------------------- */
static void tmr_idle_update (qse_tmr_t* tmr, qse_tmr_index_t old_index, qse_tmr_index_t new_index, qse_tmr_event_t* evt);
static void tmr_idle_handle (qse_tmr_t* tmr, const qse_ntime_t* now, qse_tmr_event_t* evt);

static void mark_bad_client (qse_httpd_client_t* client)
{
	/* you can call this function multiple times */
	if (!(client->status & QSE_HTTPD_CLIENT_BAD))
	{
		client->status |= QSE_HTTPD_CLIENT_BAD;
		client->bad_next = client->server->httpd->client.bad;
		client->server->httpd->client.bad = client;
	}
}

static qse_httpd_client_t* new_client (qse_httpd_t* httpd, qse_httpd_client_t* tmpl)
{
	qse_httpd_client_t* client = QSE_NULL;
	qse_tmr_event_t idle_event;
	htrd_xtn_t* xtn;

	client = qse_httpd_allocmem(httpd, QSE_SIZEOF(*client));
	if (client == QSE_NULL) goto oops;

	QSE_MEMSET (client, 0, QSE_SIZEOF(*client));
	client->tmr_idle = QSE_TMR_INVALID_INDEX;

	client->_instsize = QSE_SIZEOF(*client);
	client->type = QSE_HTTPD_CLIENT;
	client->htrd = qse_htrd_open (qse_httpd_getmmgr(httpd), QSE_SIZEOF(*xtn));
	if (client->htrd == QSE_NULL) 
	{
		httpd->errnum = QSE_HTTPD_ENOMEM;
		goto oops;
	}

	if (httpd->opt.idle_limit.sec > 0 || 
	    (httpd->opt.idle_limit.sec == 0 && httpd->opt.idle_limit.nsec > 0))
	{
		/* idle limit is enabled when the limit is greater than 0.0 */
		QSE_MEMSET (&idle_event, 0, QSE_SIZEOF(idle_event));
		qse_gettime (&idle_event.when);
		qse_add_ntime (&idle_event.when, &httpd->opt.idle_limit, &idle_event.when);
		idle_event.ctx = client;
		idle_event.handler = tmr_idle_handle;
		idle_event.updater = tmr_idle_update;

		if (qse_httpd_insert_timer_event (httpd, &idle_event, &client->tmr_idle) <= -1) goto oops;
	}

	qse_htrd_setopt (client->htrd, QSE_HTRD_REQUEST | QSE_HTRD_TRAILERS | QSE_HTRD_CANONQPATH);

	/* copy the public fields, 
	 * keep the private fields initialized at 0 */
	client->status = tmpl->status;
	if (httpd->opt.scb.client.accepted == QSE_NULL) 
		client->status |= QSE_HTTPD_CLIENT_READY;
	client->handle = tmpl->handle;
	client->handle2 = tmpl->handle2;
	client->remote_addr = tmpl->remote_addr;
	client->local_addr = tmpl->local_addr;
	client->orgdst_addr = tmpl->orgdst_addr;
	client->server = tmpl->server;
	client->initial_ifindex = tmpl->initial_ifindex;

	xtn = (htrd_xtn_t*)qse_htrd_getxtn(client->htrd);
	xtn->httpd = httpd;
	xtn->client = client;

	qse_htrd_setrecbs (client->htrd, &htrd_recbs);

	return client;

oops:
	if (client) 
	{
		if (client->tmr_idle != QSE_TMR_INVALID_INDEX) 
		{
			qse_httpd_remove_timer_event (httpd, client->tmr_idle);
			client->tmr_idle = QSE_TMR_INVALID_INDEX;
		}
		if (client->htrd) qse_htrd_close (client->htrd);
		qse_httpd_freemem (httpd, client);
	}

	return QSE_NULL;
}

static void free_client (qse_httpd_t* httpd, qse_httpd_client_t* client)
{
	QSE_ASSERT (client->htrd != QSE_NULL);

	purge_tasks (httpd, client);
	purge_cached_proxy_peers (httpd, client);

	qse_htrd_close (client->htrd);

#if defined(QSE_HTTPD_DEBUG)
	{
		qse_mchar_t tmp[128];
		qse_nwadtombs (&client->remote_addr, tmp, QSE_COUNTOF(tmp), QSE_NWADTOMBS_ALL);
		HTTPD_DBGOUT2 ("Closing client [%hs] - %zd\n", tmp, (qse_size_t)client->handle);
	}
#endif

	if (client->status & QSE_HTTPD_CLIENT_HANDLE_RW_IN_MUX)
	{
		httpd->opt.scb.mux.delhnd (httpd, httpd->mux, client->handle);
		client->status &= ~QSE_HTTPD_CLIENT_HANDLE_RW_IN_MUX;
	}

	if (client->tmr_idle != QSE_TMR_INVALID_INDEX)
	{
		qse_httpd_remove_timer_event (httpd, client->tmr_idle);
		client->tmr_idle = QSE_TMR_INVALID_INDEX;
	}

	/* note that client.closed is not a counterpart to client.accepted. 
	 * so it is called even if client.close() failed. */
	if (httpd->opt.scb.client.closed)
		httpd->opt.scb.client.closed (httpd, client);
	
	httpd->opt.scb.client.close (httpd, client);

	qse_httpd_freemem (httpd, client);
}

static void purge_client (qse_httpd_t* httpd, qse_httpd_client_t* client)
{
	qse_httpd_client_t* prev;
	qse_httpd_client_t* next;

	prev = client->prev;
	next = client->next;

#if defined(QSE_HTTPD_DEBUG)
	{
		qse_mchar_t tmp[128];
		qse_nwadtombs (&client->remote_addr, tmp, QSE_COUNTOF(tmp), QSE_NWADTOMBS_ALL);
		HTTPD_DBGOUT2 ("Purging client [%hs] - %zd\n", tmp, (qse_size_t)client->handle);
	}
#endif

	free_client (httpd, client);

	if (prev) prev->next = next;
	else httpd->client.list.head = next;
	if (next) next->prev = prev;
	else httpd->client.list.tail = prev;

	httpd->client.list.count--;
}

static void purge_client_list (qse_httpd_t* httpd)
{
	while (httpd->client.list.tail)
		purge_client (httpd, httpd->client.list.tail);
}

static void move_client_to_tail (qse_httpd_t* httpd, qse_httpd_client_t* client)
{
	if (httpd->client.list.tail != client)
	{
		qse_httpd_client_t* prev;
		qse_httpd_client_t* next;

		prev = client->prev;
		next = client->next;

		if (prev) prev->next = next;
		else httpd->client.list.head = next;
		if (next) next->prev = prev;
		else httpd->client.list.tail = prev;

		client->next = QSE_NULL;
		client->prev = httpd->client.list.tail;
		httpd->client.list.tail->next = client;
		httpd->client.list.tail = client;
	}
}

#if 0
static int is_client_allowed (qse_httpd_t* httpd, qse_httpd_client_t* client)
{
	qse_httpd_mod_t* mod;

/* TODO: no sequential search. speed up */
	for (mod = httpd->modlist; mod;  mod = mod->next)
	{
		if (mod->new_client) mod->new_client (httpd, client);
	}

	return 0;
}
#endif

static int accept_client (
	qse_httpd_t* httpd, void* mux, qse_httpd_hnd_t handle, int mask, void* cbarg)
{
	qse_httpd_server_t* server;
	qse_httpd_client_t clibuf;
	qse_httpd_client_t* client;

	if (mask & QSE_HTTPD_MUX_READ)
	{
		server = (qse_httpd_server_t*)cbarg;

		/*QSE_ASSERT (handle == server->handle);*/

		QSE_MEMSET (&clibuf, 0, QSE_SIZEOF(clibuf));

		if (httpd->opt.scb.server.accept (httpd, server, &clibuf) <= -1) 
		{
		#if QSE_HTTPD_DEBUG
			qse_mchar_t tmp[128];
			qse_nwadtombs (&server->dope.nwad, tmp, QSE_COUNTOF(tmp), QSE_NWADTOMBS_ALL);
			HTTPD_DBGOUT2 ("Failed to accept from server [%hs] [%d]\n", tmp, (int)server->handle);
		#endif
			return -1;
		}

/* TODO: check maximum number of client. if exceed call client.close */

		if (server->dope.flags & QSE_HTTPD_SERVER_SECURE) 
			clibuf.status |= QSE_HTTPD_CLIENT_SECURE;

		clibuf.server = server;

#if 0
		if (is_client_allowed (httpd, &clibuf) <= -1)
		{
			httpd->opt.scb.client.close (httpd, &clibuf);
			return -1;
		}
#endif

		client = new_client (httpd, &clibuf);
		if (client == QSE_NULL)
		{
			httpd->opt.scb.client.close (httpd, &clibuf);
			return -1;
		}

		if (httpd->opt.scb.mux.addhnd (httpd, mux, client->handle, QSE_HTTPD_MUX_READ, client) <= -1)
		{
			free_client (httpd, client);
			return -1;
		}
		client->status |= QSE_HTTPD_CLIENT_HANDLE_READ_IN_MUX;

		qse_gettime (&client->last_active); /* TODO: error check */
		/* link the new client to the tail of the client list. */
		if (httpd->client.list.tail)
		{
			QSE_ASSERT (httpd->client.list.head);
			client->prev = httpd->client.list.tail;
			httpd->client.list.tail->next = client;
			httpd->client.list.tail = client;
		}
		else
		{
			httpd->client.list.head = client;
			httpd->client.list.tail = client;
		}
		httpd->client.list.count++;

	#if defined(QSE_HTTPD_DEBUG)
		{
			qse_mchar_t tmp1[128], tmp2[128], tmp3[128];
			qse_nwadtombs (&client->local_addr, tmp1, QSE_COUNTOF(tmp1), QSE_NWADTOMBS_ALL);
			qse_nwadtombs (&client->orgdst_addr, tmp2, QSE_COUNTOF(tmp2), QSE_NWADTOMBS_ALL);
			qse_nwadtombs (&client->remote_addr, tmp3, QSE_COUNTOF(tmp3), QSE_NWADTOMBS_ALL);
			HTTPD_DBGOUT5 ("Accepted client %hs(%hs) on %zd from %hs - %zd\n", 
				tmp1, tmp2, (qse_size_t)server->handle, tmp3, (qse_size_t)client->handle);
		}
	#endif
	}

	return 0;
}

static void tmr_idle_update (qse_tmr_t* tmr, qse_tmr_index_t old_index, qse_tmr_index_t new_index, qse_tmr_event_t* evt)
{
	qse_httpd_client_t* client = (qse_httpd_client_t*)evt->ctx;
	QSE_ASSERT (client->tmr_idle == old_index);
	client->tmr_idle = new_index;
}

static void tmr_idle_handle (qse_tmr_t* tmr, const qse_ntime_t* now, qse_tmr_event_t* evt)
{
	qse_httpd_client_t* client = (qse_httpd_client_t*)evt->ctx;

	if (qse_cmp_ntime(now, &client->last_active) >= 0)
	{
		qse_ntime_t diff;
		qse_sub_ntime (&diff, now, &client->last_active);
		if (qse_cmp_ntime(&diff, &client->server->httpd->opt.idle_limit) >= 0)
		{
			/* this client is idle */
			HTTPD_DBGOUT1 ("Purging idle client %zd\n", (qse_size_t)client->handle);
			purge_client (client->server->httpd, client);
		}
		else
		{
			qse_tmr_event_t idle_event;

			QSE_ASSERT (client->server->httpd->tmr == tmr);

			/*qse_gettime (&idle_event.when);*/
			QSE_MEMSET (&idle_event, 0, QSE_SIZEOF(idle_event));
			idle_event.when = *now;
			qse_add_ntime (&idle_event.when, &client->server->httpd->opt.idle_limit, &idle_event.when);
			idle_event.ctx = client;
			idle_event.handler = tmr_idle_handle;
			idle_event.updater = tmr_idle_update;

			/* the timer must have been deleted when this callback is called. */
			QSE_ASSERT (client->tmr_idle == QSE_TMR_INVALID_INDEX); 
			if (qse_httpd_insert_timer_event (client->server->httpd, &idle_event, &client->tmr_idle) <= -1)
			{
				HTTPD_DBGOUT1 ("Cannot update idle timer for client %d. Marking it bad", (int)client->handle);
				mark_bad_client (client);
			}
		}
	}
}

/* ----------------------------------------------------------------------- */

static void deactivate_servers (qse_httpd_t* httpd)
{
	qse_httpd_server_t* server;

	for (server = httpd->server.list.head; server; server = server->next)
	{
		if (server->dope.flags & QSE_HTTPD_SERVER_ACTIVE)
		{
		#if defined(QSE_HTTPD_DEBUG)
			{
				qse_mchar_t tmp[128];
				qse_nwadtombs (&server->dope.nwad, tmp, QSE_COUNTOF(tmp), QSE_NWADTOMBS_ALL);
				HTTPD_DBGOUT2 ("Closing server [%hs] %zd to mux\n", tmp, (qse_size_t)server->handle);
			}
		#endif

			httpd->opt.scb.mux.delhnd (httpd, httpd->mux, server->handle);
			httpd->opt.scb.server.close (httpd, server);
			server->dope.flags &= ~QSE_HTTPD_SERVER_ACTIVE;
			httpd->server.nactive--;
		}
	}
}

static int activate_servers (qse_httpd_t* httpd)
{
	qse_httpd_server_t* server;

	for (server = httpd->server.list.head; server; server = server->next)
	{
		QSE_ASSERT (server->httpd == httpd);

		if (httpd->opt.scb.server.open (httpd, server) <= -1)
		{
		#if defined(QSE_HTTPD_DEBUG)
			{
				qse_mchar_t tmp[128];
				qse_nwadtombs (&server->dope.nwad, tmp, QSE_COUNTOF(tmp), QSE_NWADTOMBS_ALL);
				HTTPD_DBGOUT1 ("Cannot open server [%hs]\n", tmp);
			}
		#endif

			continue;
		}
		else
		{
		#if defined(QSE_HTTPD_DEBUG)
			{
				qse_mchar_t tmp[128], tmp2[128];
				qse_nwadtombs (&server->dope.nwad, tmp, QSE_COUNTOF(tmp), QSE_NWADTOMBS_ALL);
				qse_nwadtombs (&server->nwad, tmp2, QSE_COUNTOF(tmp2), QSE_NWADTOMBS_ALL);
				HTTPD_DBGOUT3 ("Opened server [%hs] actual address [%hs] - %zd\n", tmp,  tmp2, (qse_size_t)server->handle);
			}
		#endif
		}

		if (httpd->opt.scb.mux.addhnd (
			httpd, httpd->mux, server->handle, QSE_HTTPD_MUX_READ, server) <= -1)
		{
		#if defined(QSE_HTTPD_DEBUG)
			{
				qse_mchar_t tmp[128];
				qse_nwadtombs (&server->dope.nwad, tmp, QSE_COUNTOF(tmp), QSE_NWADTOMBS_ALL);
				HTTPD_DBGOUT2 ("Cannot add server [%hs] %zd to mux. Closing\n", tmp, (qse_size_t)server->handle);
			}
		#endif

			httpd->opt.scb.server.close (httpd, server);
			continue;
		}

		server->dope.flags |= QSE_HTTPD_SERVER_ACTIVE;
		httpd->server.nactive++;
	}

	return 0;
}

static void free_server_list (qse_httpd_t* httpd)
{
	qse_httpd_server_t* server;

	server = httpd->server.list.head;

	while (server)
	{
		qse_httpd_server_t* next = server->next;
		qse_httpd_detachserver (httpd, server);
		server = next;
	}

	QSE_ASSERT (httpd->server.navail == 0);
	QSE_ASSERT (httpd->server.list.head == QSE_NULL);
	QSE_ASSERT (httpd->server.list.tail == QSE_NULL);
}

qse_httpd_server_t* qse_httpd_attachserver (
	qse_httpd_t* httpd, const qse_httpd_server_dope_t* dope, qse_size_t xtnsize)
{
	qse_httpd_server_t* server;

	server = qse_httpd_callocmem (httpd, QSE_SIZEOF(*server) + xtnsize);
	if (server == QSE_NULL) return QSE_NULL;

	server->_instsize = QSE_SIZEOF(*server);
	server->type = QSE_HTTPD_SERVER;
	/* copy the server dope */
	server->dope = *dope;
	/* and correct some fields in case the dope contains invalid stuffs */
	server->dope.flags &= ~QSE_HTTPD_SERVER_ACTIVE;

	server->httpd = httpd;
	/* chain the server to the tail of the list */
	server->prev = httpd->server.list.tail;
	server->next = QSE_NULL;
	if (httpd->server.list.tail)
		httpd->server.list.tail->next = server;
	else
		httpd->server.list.head = server;
	httpd->server.list.tail = server;
	httpd->server.navail++;
	
	return server;
}

void qse_httpd_detachserver (qse_httpd_t* httpd, qse_httpd_server_t* server)
{
	qse_httpd_server_t* prev, * next;

	prev = server->prev;
	next = server->next;

	QSE_ASSERT (!(server->dope.flags & QSE_HTTPD_SERVER_ACTIVE));

	if (server->dope.detach) server->dope.detach (httpd, server);

	qse_httpd_freemem (httpd, server);
	httpd->server.navail--;

	if (prev) prev->next = next;
	else httpd->server.list.head = next;
	if (next) next->prev = prev;
	else httpd->server.list.tail = prev;
}

qse_httpd_server_t* qse_httpd_getfirstserver (qse_httpd_t* httpd)
{
	return httpd->server.list.head;
}

qse_httpd_server_t* qse_httpd_getlastserver (qse_httpd_t* httpd)
{
	return httpd->server.list.tail;
}

qse_httpd_server_t* qse_httpd_getnextserver (qse_httpd_t* httpd, qse_httpd_server_t* server)
{
	return server->next;
}

qse_httpd_server_t* qse_httpd_getprevserver (qse_httpd_t* httpd, qse_httpd_server_t* server)
{
	return server->prev;
}


int qse_httpd_addhnd (qse_httpd_t* httpd, qse_httpd_hnd_t handle, int mask, qse_httpd_custom_t* mate)
{
	/* qse_httpd_loop() opens the multiplexer. you can call this function from 
	 * preloop/postloop hooks only. but calling it from postloop hooks is
	 * useless. */
	return httpd->opt.scb.mux.addhnd (httpd, httpd->mux, handle, mask, mate);
}

int qse_httpd_delhnd (qse_httpd_t* httpd, qse_httpd_hnd_t handle)
{
	return httpd->opt.scb.mux.delhnd (httpd, httpd->mux, handle);
}

/* ----------------------------------------------------------------------- */

static int activate_dns (qse_httpd_t* httpd)
{
	int i;

	QSE_MEMSET (&httpd->dns, 0, QSE_SIZEOF(httpd->dns));

	if (!httpd->opt.scb.dns.open) 
	{
		httpd->errnum = QSE_HTTPD_ENOIMPL;
		return -1;
	}

	if (httpd->opt.scb.dns.open (httpd, &httpd->dns) <= -1) return -1;

	httpd->dns.type = QSE_HTTPD_DNS;

	for (i = 0; i < httpd->dns.handle_count; i++)
	{
		if (httpd->dns.handle_mask & (1 << i))
		{
			if (httpd->opt.scb.mux.addhnd (httpd, httpd->mux, httpd->dns.handle[i], QSE_HTTPD_MUX_READ, &httpd->dns) <= -1) 
			{
				while (i > 0)
				{
					--i;
					if (httpd->dns.handle_mask & (1 << i))
						httpd->opt.scb.mux.delhnd (httpd, httpd->mux, httpd->dns.handle[i]);
				}
				httpd->opt.scb.dns.close (httpd, &httpd->dns);
				return -1;
			}
		}
	}

	return 0;
}

static void deactivate_dns (qse_httpd_t* httpd)
{
	int i;

	for (i = 0; i < httpd->dns.handle_count; i++)
	{
		if (httpd->dns.handle_mask & (1 << i))
			httpd->opt.scb.mux.delhnd (httpd, httpd->mux, httpd->dns.handle[i]);
	}

	httpd->opt.scb.dns.close (httpd, &httpd->dns);
}
/* ----------------------------------------------------------------------- */

static int activate_urs (qse_httpd_t* httpd)
{
	int i;

	QSE_MEMSET (&httpd->urs, 0, QSE_SIZEOF(httpd->urs));

	if (!httpd->opt.scb.urs.open) 
	{
		httpd->errnum = QSE_HTTPD_ENOIMPL;
		return -1;
	}

	if (httpd->opt.scb.urs.open (httpd, &httpd->urs) <= -1) return -1;

	httpd->urs.type = QSE_HTTPD_URS;

	for (i = 0; i < httpd->urs.handle_count; i++)
	{
		if (httpd->urs.handle_mask & (1 << i))
		{
			if (httpd->opt.scb.mux.addhnd (httpd, httpd->mux, httpd->urs.handle[i], QSE_HTTPD_MUX_READ, &httpd->urs) <= -1) 
			{
				while (i > 0) 
				{
					--i;
					if (httpd->urs.handle_mask & (1 << i))
						httpd->opt.scb.mux.delhnd (httpd, httpd->mux, httpd->urs.handle[i]);
				}
				httpd->opt.scb.urs.close (httpd, &httpd->urs);
				return -1;
			}
		}
	}

	return 0;
}

static void deactivate_urs (qse_httpd_t* httpd)
{
	int i;

	for (i = 0; i < httpd->urs.handle_count; i++)
	{
		if (httpd->urs.handle_mask & (1 << i))
			httpd->opt.scb.mux.delhnd (httpd, httpd->mux, httpd->urs.handle[i]);
	}

	httpd->opt.scb.urs.close (httpd, &httpd->urs);
}

/* ----------------------------------------------------------------------- */

static int read_from_client (qse_httpd_t* httpd, qse_httpd_client_t* client)
{
	qse_mchar_t buf[MAX_RECV_SIZE]; /* TODO: adjust this buffer size */
	qse_ssize_t m;
	
	QSE_ASSERT (httpd->opt.scb.client.recv != QSE_NULL);

reread:
	httpd->errnum = QSE_HTTPD_ENOERR;
	m = httpd->opt.scb.client.recv (httpd, client, buf, QSE_SIZEOF(buf));
	if (m <= -1)
	{
		if (httpd->errnum == QSE_HTTPD_EAGAIN)
		{
			/* nothing to read yet. */
			return 0; /* return ok */
		}
		else if (httpd->errnum == QSE_HTTPD_EINTR)
		{
			goto reread;
		}
		else
		{
			/* TOOD: if (httpd->errnum == QSE_HTTPD_ENOERR) httpd->errnum = QSE_HTTPD_ECALLBACK; */
			if (httpd->opt.trait & QSE_HTTPD_LOGACT)
			{
				qse_httpd_act_t msg;
				msg.code = QSE_HTTPD_READERR_CLIENT;
				msg.u.client = client;
				httpd->opt.rcb.logact (httpd, &msg);
			}
			/* TODO: find a way to disconnect */
			return -1;
		}
	}
	else if (m == 0)
	{
#if 0
qse_printf (QSE_T("Debug: connection closed %d\n"), client->handle);
#endif
		/* reading from the client returned 0. this typically
		 * happens when the client closes the connection or
		 * shutdown the writing half of the socket. it's
		 * not really easy to determine one from the other.
		 * if QSE_HTTPD_MUTECLIENT is on, attempt to handle
		 * it as a half-close under a certain condition. */

		if (httpd->opt.trait & QSE_HTTPD_MUTECLIENT &&
		    client->task.head && client->htrd->clean)
		{
			/* there is still more tasks to finish and 
			 * http reader is not waiting for any more feeds.  */
			client->status |= QSE_HTTPD_CLIENT_MUTE;
#if 0
qse_printf (QSE_T(">>>>> Marking client %d as MUTE\n"), client->handle);
#endif
			return 0;
		}
		else
		{
#if 0
qse_printf (QSE_T(">>>>> Returning failure for client %d\n"), client->handle);
#endif
			httpd->errnum = QSE_HTTPD_EDISCON;
			return -1;
		}
	}
	
#if 0
qse_printf (QSE_T("!!!!!FEEDING %d from %d ["), (int)m, (int)client->handle);
#if !defined(__WATCOMC__)
{
int i;
for (i = 0; i < m; i++) qse_printf (QSE_T("%hc"), buf[i]);
}
#endif
qse_printf (QSE_T("]\n"));
#endif

	/* qse_htrd_feed() may call the request callback 
	 * multiple times. that's because we don't know 
	 * how many valid requests are included in 'buf'. */ 
	httpd->errnum = QSE_HTTPD_ENOERR;
	if (qse_htrd_feed (client->htrd, buf, m) <= -1)
	{
		if (httpd->errnum == QSE_HTTPD_ENOERR)
		{
			if (client->htrd->errnum == QSE_HTRD_EBADRE || 
				client->htrd->errnum == QSE_HTRD_EBADHDR)
				httpd->errnum = QSE_HTTPD_EBADREQ;
			else httpd->errnum = QSE_HTTPD_ENOMEM; /* TODO: better translate error code */
		}
	
#if 0
qse_printf (QSE_T("Error: http error while processing %d ["), (int)client->handle);
{
int i;
for (i = 0; i < m; i++) qse_printf (QSE_T("%hc"), buf[i]);
}
qse_printf (QSE_T("]\n"));
#endif
		return -1;
	}


#if 0
qse_printf (QSE_T("!!!!!FEEDING OK OK OK OK %d from %d\n"), (int)m, (int)client->handle);
#endif

	if (client->status & QSE_HTTPD_CLIENT_PENDING) 
	{
		/* this QSE_HTTPD_CLIENT_PENDING thing is a dirty hack for SSL.
		 * In SSL, data is transmitted in a record. a record can be
		 * as large as 16K bytes since its length field is 2 bytes.
		 * If SSL_read() has a record but it's given a smaller buffer
		 * than the actual record, the next call to select() won't return. 
		 * there is no data to read at the socket layer. SSL_pending() can 
		 * tell you the amount of data in the SSL buffer. I try to consume
		 * the pending data if the client.recv handler has set QSE_HTTPD_CLIENT_PENDING.
		 *
		 * TODO: Investigate if there is any starvation issues.
		 *       What if a single client never stops sending? 
		 */
		goto reread;
	}

	return 0;
}

static void clear_trigger_mask_result (qse_httpd_task_t* task)
{
	qse_size_t i;

	task->trigger.cmask &=  ~(QSE_HTTPD_TASK_TRIGGER_READABLE | 
	                          QSE_HTTPD_TASK_TRIGGER_WRITABLE);
	for (i = 0; i < QSE_COUNTOF(task->trigger.v); i++)
	{
		task->trigger.v[i].mask &= ~(QSE_HTTPD_TASK_TRIGGER_READABLE | 
		                             QSE_HTTPD_TASK_TRIGGER_WRITABLE);
	}
}

static int update_mux_for_current_task (qse_httpd_t* httpd, qse_httpd_client_t* client, qse_httpd_task_t* task)
{
	qse_size_t i;

	/* the code here is pretty fragile. there is a high chance
	 * that something can go wrong if the task handler plays
	 * with the trigger field in an unexpected manner. 
	 */

	clear_trigger_mask_result (task);

/*printf ("update_mux_for_current_task..............\n");*/
	if (QSE_MEMCMP (&client->trigger, &task->trigger, QSE_SIZEOF(client->trigger)) != 0 ||
	    ((client->status & QSE_HTTPD_CLIENT_MUTE) && !(client->status & QSE_HTTPD_CLIENT_MUTE_DELETED)))
	{
		/* manipulate muxtiplexer settings if there are trigger changes */

		int has_trigger = 0;
		int expected_client_handle_mux_mask;
		int expected_client_handle_mux_status;

		if ((client->trigger.flags & QSE_HTTPD_TASK_TRIGGER_INACTIVE) != 
		    (task->trigger.flags & QSE_HTTPD_TASK_TRIGGER_INACTIVE))
		{
			if (task->trigger.flags & QSE_HTTPD_TASK_TRIGGER_INACTIVE)
			{
				/* active to inactive */

/*printf ("ACTIVE TO INACTIVE....\n");*/
				for (i = 0; i < QSE_COUNTOF(task->trigger.v); i++)
				{
					if (client->status & QSE_HTTPD_CLIENT_TASK_TRIGGER_RW_IN_MUX(i))
					{
						httpd->opt.scb.mux.delhnd (httpd, httpd->mux, client->trigger.v[i].handle);
						client->status &= ~QSE_HTTPD_CLIENT_TASK_TRIGGER_RW_IN_MUX(i);
					}
				}

				if (client->status & QSE_HTTPD_CLIENT_HANDLE_RW_IN_MUX)
				{
					httpd->opt.scb.mux.delhnd (httpd, httpd->mux, client->handle);
					client->status &= ~QSE_HTTPD_CLIENT_HANDLE_RW_IN_MUX;
				}

				/* save the task trigger information */
				client->trigger = task->trigger;
				return 0;
			}

/*printf ("INACTIVE TO ACTIVE....\n");*/
			/* inactive to active . go on*/
		}
		else 
		{
			if (task->trigger.flags & QSE_HTTPD_TASK_TRIGGER_INACTIVE)
			{
/*printf ("INACTIVE TO INACTIVE....\n");*/
				/* inactive to inactive.
				 * save the trigger as the trigger handle and masks could change */
				client->trigger = task->trigger;
				return 0;
			}

/*printf ("ACTIVE TO ACTIVE....\n");*/
			/* active to active. go on */
		}

		/* delete previous trigger handles */
		for (i = 0; i < QSE_COUNTOF(task->trigger.v); i++)
		{
			if (client->status & QSE_HTTPD_CLIENT_TASK_TRIGGER_RW_IN_MUX(i))
			{
				httpd->opt.scb.mux.delhnd (httpd, httpd->mux, client->trigger.v[i].handle);
				client->status &= ~QSE_HTTPD_CLIENT_TASK_TRIGGER_RW_IN_MUX(i);
			}
		}

		/* add new trigger handles */
		for (i = 0; i < QSE_COUNTOF(task->trigger.v); i++)
		{
			int expected_trigger_mux_mask = 0;
			int expected_trigger_mux_status = 0;

			if (task->trigger.v[i].handle == client->handle) continue; 

			if (task->trigger.v[i].mask & QSE_HTTPD_TASK_TRIGGER_READ) 
			{
				expected_trigger_mux_mask |= QSE_HTTPD_MUX_READ;
				expected_trigger_mux_status |= QSE_HTTPD_CLIENT_TASK_TRIGGER_READ_IN_MUX(i);
			}
			if (task->trigger.v[i].mask & QSE_HTTPD_TASK_TRIGGER_WRITE) 
			{
				expected_trigger_mux_mask |= QSE_HTTPD_MUX_WRITE;
				expected_trigger_mux_status |= QSE_HTTPD_CLIENT_TASK_TRIGGER_WRITE_IN_MUX(i);
			}

			if (expected_trigger_mux_mask)
			{
				has_trigger = 1;
				if (httpd->opt.scb.mux.addhnd (httpd, httpd->mux, task->trigger.v[i].handle, expected_trigger_mux_mask, client) <= -1) return -1;
				client->status |= expected_trigger_mux_status;
			}
		}

		/* client-side handle is registered for both reading and 
		 * writing when the task is executed for the first time.
		 * see update_mux_for_next_task() for this.
		 *
		 * starting from the second call, the client-side handle
		 * is registered for writing if it's explicitly requested.
		 * it's always registered for reading if not for QSE_HTTPD_CLIENT_MUTE.
		 *
		 * this means that QSE_HTTP_TASK_TRIGGER_READ set or clear
		 * in task->trigger.cmask is not honored.
		 */

		expected_client_handle_mux_mask = 0;
		expected_client_handle_mux_status = 0;
		if (task->trigger.cmask & QSE_HTTPD_TASK_TRIGGER_WRITE) 
		{
			expected_client_handle_mux_mask |= QSE_HTTPD_MUX_WRITE;
			expected_client_handle_mux_status |= QSE_HTTPD_CLIENT_HANDLE_WRITE_IN_MUX;
		}

		if (client->status & QSE_HTTPD_CLIENT_MUTE)
		{
			/* reading should be excluded from mux if the client-side has 
			 * been closed */
			client->status |= QSE_HTTPD_CLIENT_MUTE_DELETED;
		}
		else
		{
			if (task->trigger.cmask & QSE_HTTPD_TASK_TRIGGER_READ)
			{
				expected_client_handle_mux_mask |= QSE_HTTPD_MUX_READ;
				expected_client_handle_mux_status |= QSE_HTTPD_CLIENT_HANDLE_READ_IN_MUX; 
			}
		}

		if (!expected_client_handle_mux_mask && !has_trigger)
		{
			/* if there is no trigger and the client handle is to be excluded
			 * from reading and writing, writing should be enabled. */
			expected_client_handle_mux_mask |= QSE_HTTPD_MUX_WRITE;
			expected_client_handle_mux_status |= QSE_HTTPD_CLIENT_HANDLE_WRITE_IN_MUX;
		}

		if ((client->status & QSE_HTTPD_CLIENT_HANDLE_RW_IN_MUX) != expected_client_handle_mux_status)
		{
			httpd->opt.scb.mux.delhnd (httpd, httpd->mux, client->handle);
			client->status &= ~QSE_HTTPD_CLIENT_HANDLE_RW_IN_MUX;

			if (expected_client_handle_mux_mask)
			{
				if (httpd->opt.scb.mux.addhnd (httpd, httpd->mux, client->handle, expected_client_handle_mux_mask, client) <= -1) return -1;
				client->status |= expected_client_handle_mux_status;
			}
		}

		/* save the task trigger information */
		client->trigger = task->trigger;
	}

	return 0;
}

static int update_mux_for_next_task (qse_httpd_t* httpd, qse_httpd_client_t* client)
{
	/* A new task should be invoked at least once regardless of the
	 * data availablility(read) on the client side. Arrange to invoke
	 * this task so long as the client-side handle is readable or writable. */

	qse_httpd_task_t* task;
	int expected_mux_mask;
	int expected_mux_status;
	int expected_trigger_cmask;

/*printf ("update_mux_for_next_task\n");*/
	expected_mux_mask = QSE_HTTPD_MUX_READ;
	expected_mux_status = QSE_HTTPD_CLIENT_HANDLE_READ_IN_MUX;
	expected_trigger_cmask = QSE_HTTPD_TASK_TRIGGER_READ;

	task = client->task.head;
	if (task)
	{
		/* there is a pending task. arrange to trigger it as if it is 
		 * just entasked. */
		expected_mux_mask |= QSE_HTTPD_MUX_WRITE;
		expected_mux_status |= QSE_HTTPD_CLIENT_HANDLE_WRITE_IN_MUX;
		expected_trigger_cmask |= QSE_HTTPD_TASK_TRIGGER_WRITE;

		if (client->status & QSE_HTTPD_CLIENT_MUTE)
		{
			/* when client-side has been disconnected, it can't read
			 * from the side any more. so exclude reading */
			expected_mux_mask &= ~QSE_HTTPD_MUX_READ;
			expected_mux_status &= ~QSE_HTTPD_CLIENT_HANDLE_READ_IN_MUX;
			expected_trigger_cmask &= ~QSE_HTTPD_TASK_TRIGGER_READ;
		}
	}
	else 
	{
		/* there is no pending task to invoke. */

		if (client->status & QSE_HTTPD_CLIENT_MUTE)
		{
			/* and this client has closed connection previously.
			 * if not, reading would be the only clue to mux for
			 * invocation. return failure as reading from the client-side
			 * is not possible */
			return -1;
		}
	}

	if ((client->status & QSE_HTTPD_CLIENT_HANDLE_RW_IN_MUX) != expected_mux_status)
	{
		httpd->opt.scb.mux.delhnd (httpd, httpd->mux, client->handle);
		client->status &= ~QSE_HTTPD_CLIENT_HANDLE_RW_IN_MUX;

		QSE_ASSERT (expected_mux_status & QSE_HTTPD_CLIENT_HANDLE_RW_IN_MUX);
		if (httpd->opt.scb.mux.addhnd (httpd, httpd->mux, client->handle, expected_mux_mask, client) <= -1) return -1;
		client->status |= expected_mux_status;
	}

	if (task) task->trigger.cmask = expected_trigger_cmask;
	return 0;
}

static int invoke_client_task (
	qse_httpd_t* httpd, qse_httpd_client_t* client, 
	qse_httpd_hnd_t handle, int mask)
{
	qse_httpd_task_t* task;
	qse_size_t i;
	int n, trigger_fired;

	if (handle == client->handle && (mask & QSE_HTTPD_MUX_READ)) 
	{
		/* keep reading from the client-side as long as
		 * it's readable. */
		if (!(client->status & QSE_HTTPD_CLIENT_MUTE) && 
		    read_from_client (httpd, client) <= -1) 
		{
			/* return failure on disconnection also in order to
			 * purge the client in perform_client_task().
			 * thus the following line isn't necessary.
			 *if (httpd->errnum == QSE_HTTPD_EDISCON) return 0;*/
			return -1;
		}
	}

	task = client->task.head;
	if (task == QSE_NULL) 
	{
		/* this client doesn't have any task */
		if (client->status & QSE_HTTPD_CLIENT_MUTE)
		{
			/* handle the delayed client disconnection */
			return -1;
		}
		return 0;
	}

	trigger_fired = 0;

	clear_trigger_mask_result (task);
	if (handle == client->handle)
	{
		if (mask & QSE_HTTPD_MUX_READ)
		{
			/*QSE_ASSERT (task->trigger.cmask & QSE_HTTPD_TASK_TRIGGER_READ);*/
			task->trigger.cmask |= QSE_HTTPD_TASK_TRIGGER_READABLE;
			trigger_fired = 1;
		}
		if (mask & QSE_HTTPD_MUX_WRITE)
		{
			/*QSE_ASSERT (task->trigger.cmask & QSE_HTTPD_TASK_TRIGGER_WRITE);*/
			task->trigger.cmask |= QSE_HTTPD_TASK_TRIGGER_WRITABLE;
			trigger_fired = 1;
		}
	}
	else
	{
		for (i = 0; i < QSE_COUNTOF(task->trigger.v); i++)
		{
			if (task->trigger.v[i].handle == handle)
			{
				if (mask & QSE_HTTPD_MUX_READ)
				{
					/*QSE_ASSERT (task->trigger.v[i].mask & QSE_HTTPD_TASK_TRIGGER_READ);*/
					/* the assertion above may be false if a task for the same 
					 * trigger set was called earlier by a qse_mux_poll() call.
					 * and the task has changed some masks.
					 *
					 * for instance, you put handle A and B in to a trigger.
					 * if the task is triggered for A but the task may change
					 * the mask for B. the task may get executed for B by 
					 * the same qse_mux_poll() call. 
					 */

					task->trigger.v[i].mask |= QSE_HTTPD_TASK_TRIGGER_READABLE;
					trigger_fired = 1;
				}
				if (mask & QSE_HTTPD_MUX_WRITE)
				{
					/*QSE_ASSERT (task->trigger.v[i].mask & QSE_HTTPD_TASK_TRIGGER_WRITE);*/
					task->trigger.v[i].mask |= QSE_HTTPD_TASK_TRIGGER_WRITABLE;
					trigger_fired = 1;
				}
			}
		}
	}

	if (trigger_fired && !(task->trigger.cmask & QSE_HTTPD_TASK_TRIGGER_WRITABLE))
	{
		/* the task is invoked for triggers. 
		 * check if the client handle is writable */
		qse_ntime_t tmout;
		tmout.sec = 0;
		tmout.nsec = 0;

		if (httpd->opt.scb.mux.writable (httpd, client->handle, &tmout) <= 0) 
		{
			/* it is not writable yet. so just skip 
			 * performing the actual task */
			return 0;
		}

		/* WRITABLE can be set without WRITE as this is the result of 
		 * the additional writability check. */
		task->trigger.cmask |= QSE_HTTPD_TASK_TRIGGER_WRITABLE;
	}

	n = task->main (httpd, client, task);
	if (n == 0)
	{
		/* the current task is over. remove the task 
		 * from the queue. dequeue_task() clears task triggers
		 * from the mux. so i don't clear them explicitly here */
		dequeue_task (httpd, client); 

		/* update the multiplexer settings */
		n = update_mux_for_next_task (httpd, client);

		/* reset the task trigger remembered */
		QSE_MEMSET (&client->trigger, 0, QSE_SIZEOF(client->trigger));
	}
	else if (n > 0)
	{
		n = update_mux_for_current_task (httpd, client, task);
	}

	return n;
}

static int perform_client_task (
	qse_httpd_t* httpd, void* mux, qse_httpd_hnd_t handle, int mask, void* cbarg)
{
	qse_httpd_client_t* client;

	client = (qse_httpd_client_t*)cbarg;

	if (client->status & QSE_HTTPD_CLIENT_BAD) return 0;

	if (!(client->status & QSE_HTTPD_CLIENT_READY))
	{
		int x;
		x = httpd->opt.scb.client.accepted (httpd, client);
		if (x <= -1) goto oops;
		if (x >= 1) 
		{
			client->status |= QSE_HTTPD_CLIENT_READY;

			qse_gettime (&client->last_active);
			move_client_to_tail (httpd, client);
		}
	}
	else
	{
		/* locate an active client to the tail of the client list */
		qse_gettime (&client->last_active); /* TODO: error check??? */
		move_client_to_tail (httpd, client);

		if (invoke_client_task (httpd, client, handle, mask) <= -1) goto oops;
	}

	return 0;

oops:
	/*purge_client (httpd, client);*/
	mark_bad_client (client);
	return -1;
}

static int perform_dns (qse_httpd_t* httpd, void* mux, qse_httpd_hnd_t handle, int mask, void* cbarg)
{
	qse_httpd_dns_t* dns = (qse_httpd_dns_t*)cbarg;

	QSE_ASSERT (mask & QSE_HTTPD_MUX_READ);
	QSE_ASSERT (&httpd->dns == dns);

	return httpd->opt.scb.dns.recv (httpd, dns, handle);
}

static int perform_urs (qse_httpd_t* httpd, void* mux, qse_httpd_hnd_t handle, int mask, void* cbarg)
{
	qse_httpd_urs_t* urs = (qse_httpd_urs_t*)cbarg;

	QSE_ASSERT (mask & QSE_HTTPD_MUX_READ);
	QSE_ASSERT (&httpd->urs == urs);

	return httpd->opt.scb.urs.recv (httpd, urs, handle);
}

static void purge_bad_clients (qse_httpd_t* httpd)
{
	qse_httpd_client_t* client;

	while (httpd->client.bad)
	{
		client = httpd->client.bad;
		httpd->client.bad = client->bad_next;
		purge_client (httpd, client);
	}
}

void* qse_httpd_gettaskxtn (qse_httpd_t* httpd, qse_httpd_task_t* task)
{
	return (void*)((qse_httpd_real_task_t*)task + 1);
}

qse_httpd_task_t* qse_httpd_entask (
	qse_httpd_t* httpd, qse_httpd_client_t* client, 
	qse_httpd_task_t* pred, const qse_httpd_task_t* task,
	qse_size_t xtnsize)
{
	qse_httpd_real_task_t* new_task;

	if (client->status & QSE_HTTPD_CLIENT_BAD) return QSE_NULL;

	new_task = enqueue_task (httpd, client, pred, task, xtnsize);
	if (new_task == QSE_NULL) 
	{
		/*purge_client (httpd, client);*/
		mark_bad_client (client);
	}
	else if (new_task->prev == QSE_NULL)
	{
		/* this task is the first task to activate. */

		if (update_mux_for_next_task (httpd, client) <= -1)
		{
			/*purge_client (httpd, client);*/
			mark_bad_client (client);

			/* call dequeue_task() to get new_task removed. this works
			 * because it is the only task. the task finalizer is also 
			 * called when it's dequeued. */
			dequeue_task (httpd, client);
 
			new_task = QSE_NULL;
		}
	}

	return (qse_httpd_task_t*)new_task;
}

static int dispatch_mux (qse_httpd_t* httpd, void* mux, qse_httpd_hnd_t handle, int mask, void* cbarg)
{
	switch (((qse_httpd_mate_t*)cbarg)->type)
	{
		case QSE_HTTPD_SERVER:
			return accept_client (httpd, mux, handle, mask, cbarg);

		case QSE_HTTPD_CLIENT:
			return perform_client_task (httpd, mux, handle, mask, cbarg);

		case QSE_HTTPD_DNS:
			return perform_dns (httpd, mux, handle, mask, cbarg);

		case QSE_HTTPD_URS:
			return perform_urs (httpd, mux, handle, mask, cbarg);

		case QSE_HTTPD_CUSTOM:
			return ((qse_httpd_custom_t*)cbarg)->dispatch (httpd, mux, handle, mask);
	}

	httpd->errnum = QSE_HTTPD_EINTERN;
	return -1;
}

int qse_httpd_loop (qse_httpd_t* httpd)
{
	int xret, count;
	qse_ntime_t tmout;
	qse_httpd_ecb_t* ecb;

	QSE_ASSERTX (httpd->server.list.head != QSE_NULL,
		"Add listeners before calling qse_httpd_loop()");

	QSE_ASSERTX (httpd->client.list.head == QSE_NULL,
		"No client should exist when this loop is started");

	QSE_ASSERT (QSE_TMR_SIZE(httpd->tmr) == 0);

	if (httpd->server.list.head == QSE_NULL) 
	{
		httpd->errnum = QSE_HTTPD_ENOSVR;
		return -1;
	}

	httpd->stopreq = 0;
	httpd->impedereq = 0;
	httpd->dnsactive = 0;

	/* system callbacks and request callbacks must be set before the call to this function */
	QSE_ASSERT (httpd->opt.scb.mux.open && httpd->opt.scb.mux.close && httpd->opt.scb.mux.poll);
	QSE_ASSERT (httpd->opt.rcb.peekreq && httpd->opt.rcb.pokereq);

	/* a server must be attached before the call to this function */
	QSE_ASSERT (httpd->server.navail > 0);

	httpd->mux = httpd->opt.scb.mux.open (httpd, dispatch_mux);
	if (httpd->mux == QSE_NULL) return -1;

	if (activate_dns (httpd) <= -1)
	{
		if (httpd->opt.trait & QSE_HTTPD_LOGACT)
		{
			qse_httpd_act_t msg;
			msg.code = QSE_HTTPD_CATCH_MWARNMSG;
			qse_mbscpy (msg.u.mwarnmsg, QSE_MT("cannot activate dns"));
			httpd->opt.rcb.logact (httpd, &msg);
		}

		HTTPD_DBGOUT0 ("Failed to activate DNS\n");
	}
	else httpd->dnsactive = 1;

	if (activate_urs (httpd) <= -1)
	{
		if (httpd->opt.trait & QSE_HTTPD_LOGACT)
		{
			qse_httpd_act_t msg;
			msg.code = QSE_HTTPD_CATCH_MWARNMSG;
			qse_mbscpy (msg.u.mwarnmsg, QSE_MT("cannot activate urs"));
			httpd->opt.rcb.logact (httpd, &msg);
		}
		HTTPD_DBGOUT0 ("Failed to activate URS\n");
	}
	else httpd->ursactive = 1;

	if (activate_servers (httpd) <= -1) 
	{
		if (httpd->dnsactive) deactivate_dns (httpd);
		if (httpd->ursactive) deactivate_urs (httpd);
		httpd->opt.scb.mux.close (httpd, httpd->mux);
		return -1;
	}
	if (httpd->server.nactive <= 0)
	{
		HTTPD_DBGOUT0 ("No servers are active. aborting\n");

		if (httpd->dnsactive) deactivate_dns (httpd);
		if (httpd->ursactive) deactivate_urs (httpd);
		httpd->opt.scb.mux.close (httpd, httpd->mux);

		httpd->errnum = QSE_HTTPD_ENOSVR;
		return -1;
	}

	/* call preloop hooks */
	for (ecb = httpd->ecb; ecb; ecb = ecb->next)
	{
		if (ecb->preloop) ecb->preloop (httpd);
	}

	xret = 0;
	while (!httpd->stopreq)
	{
		if (qse_tmr_gettmout (httpd->tmr, QSE_NULL, &tmout) <= -1) tmout = httpd->opt.tmout;
		count = httpd->opt.scb.mux.poll (httpd, httpd->mux, &tmout);
		/*HTTPD_DBGOUT4 ("Multiplexer returned %d client count = %d  tmout = %d.%d\n", (int)count, (int)httpd->client.list.count, (int)tmout.sec, (int)tmout.nsec);*/
		if (count <= -1) 
		{
			if (httpd->errnum != QSE_HTTPD_EINTR)
			{
				xret = -1; 
				break;
			}
		}

		qse_tmr_fire (httpd->tmr, QSE_NULL, QSE_NULL);
		purge_bad_clients (httpd);

		if (httpd->impedereq)
		{
			httpd->impedereq = 0;
			httpd->opt.rcb.impede (httpd);
		}
	}

	for (ecb = httpd->ecb; ecb; ecb = ecb->next)
	{
		if (ecb->postloop) ecb->postloop (httpd);
	}

	purge_client_list (httpd);
	deactivate_servers (httpd);

	if (httpd->ursactive) deactivate_urs (httpd);
	if (httpd->dnsactive) deactivate_dns (httpd);

	httpd->opt.scb.mux.close (httpd, httpd->mux);

	QSE_ASSERT (QSE_TMR_SIZE(httpd->tmr) == 0);
	return xret;
}

/* ----------------------------------------------------------------------- */

void qse_httpd_discardcontent (qse_httpd_t* httpd, qse_htre_t* req)
{
	qse_htre_discardcontent (req);
}

void qse_httpd_completecontent (qse_httpd_t* httpd, qse_htre_t* req)
{
	qse_htre_completecontent (req);
}

/* ----------------------------------------------------------------------- */
void qse_httpd_setname (qse_httpd_t* httpd, const qse_mchar_t* name)
{
	qse_mbsxcpy (httpd->sname, QSE_COUNTOF(httpd->sname), name);
}

const qse_mchar_t* qse_httpd_getname (qse_httpd_t* httpd)
{
	return httpd->sname;
}

const qse_mchar_t* qse_httpd_fmtgmtimetobb (
	qse_httpd_t* httpd, const qse_ntime_t* nt, int idx)
{
	qse_ntime_t now;

	QSE_ASSERT (idx >= 0 && idx < QSE_COUNTOF(httpd->gtbuf));

	if (nt == QSE_NULL) 
	{
		if (qse_gettime(&now) <= -1) 
		{
			now.sec = 0;
			now.nsec = 0;
		}
		nt = &now;
	}

	qse_fmthttptime (nt, httpd->gtbuf[idx], QSE_COUNTOF(httpd->gtbuf[idx]));
	return httpd->gtbuf[idx];
}

/* ----------------------------------------------------------------------- */

qse_mchar_t* qse_httpd_escapehtml (qse_httpd_t* httpd, const qse_mchar_t* str)
{
	qse_mchar_t* ptr, * buf;
	qse_size_t reqlen = 0;

	for (ptr = (qse_mchar_t*)str; *ptr != QSE_MT('\0'); ptr++) 
	{
		switch (*ptr)
		{
			case QSE_MT('<'):
			case QSE_MT('>'):
				reqlen += 4;
				break;

			case QSE_MT('&'):
				reqlen += 5;
				break;

			default: 
				reqlen++;
				break;
		}
	}

	if (ptr - str == reqlen) return (qse_mchar_t*)str; /* no escaping is needed */

	buf = qse_httpd_allocmem (httpd, QSE_SIZEOF(*buf) * (reqlen + 1));
	if (buf == QSE_NULL) return QSE_NULL;

	ptr = buf;
	while (*str != QSE_MT('\0'))
	{
		switch (*str)
		{
			case QSE_MT('<'):
				*ptr++ = QSE_MT('&');
				*ptr++ = QSE_MT('l');
				*ptr++ = QSE_MT('t');
				*ptr++ = QSE_MT(';');
				break;

			case QSE_MT('>'):
				*ptr++ = QSE_MT('&');
				*ptr++ = QSE_MT('g');
				*ptr++ = QSE_MT('t');
				*ptr++ = QSE_MT(';');
				break;

			case QSE_MT('&'):
				*ptr++ = QSE_MT('&');
				*ptr++ = QSE_MT('a');
				*ptr++ = QSE_MT('m');
				*ptr++ = QSE_MT('p');
				*ptr++ = QSE_MT(';');
				break;

			default: 
				*ptr++ = *str;
				break;
		}
		str++;
	}
	*ptr = QSE_MT('\0');
	return buf;
}

/* ----------------------------------------------------------------------- */

int qse_httpd_resolvename (qse_httpd_t* httpd, const qse_mchar_t* name, qse_httpd_resolve_t resol, const qse_httpd_dns_server_t* dns_server, void* ctx)
{
	if (!httpd->dnsactive) 
	{
		qse_httpd_seterrnum (httpd, QSE_HTTPD_ENODNS);
		return -1;
	}

#if defined(QSE_HTTPD_DEBUG)
	{
		qse_mchar_t tmp[128];
		if (dns_server)
			qse_nwadtombs (&dns_server->nwad, tmp, QSE_COUNTOF(tmp), QSE_NWADTOMBS_ALL);
		else
			qse_mbscpy (tmp, QSE_MT("default server"));

		HTTPD_DBGOUT2 ("Sending DNS request [%hs] to [%hs]\n", name, tmp);
	}
#endif

	return httpd->opt.scb.dns.send (httpd, &httpd->dns, name, resol, dns_server, ctx);
}

int qse_httpd_rewriteurl (qse_httpd_t* httpd, const qse_mchar_t* url, qse_httpd_rewrite_t rewrite, const qse_httpd_urs_server_t* urs_server, void* ctx)
{
	if (!httpd->ursactive)
	{
		qse_httpd_seterrnum (httpd, QSE_HTTPD_ENOURS);
		return -1;
	}

	HTTPD_DBGOUT1 ("Sending URS request [%hs]\n", url);
	return httpd->opt.scb.urs.send (httpd, &httpd->urs, url, rewrite, urs_server, ctx);
}

int qse_httpd_activatetasktrigger (qse_httpd_t* httpd, qse_httpd_client_t* client, qse_httpd_task_t* task)
{
	int x, org_cmask;

	/* don't do anything if it's active */
	if (!(task->trigger.flags & QSE_HTTPD_TASK_TRIGGER_INACTIVE)) return 0;

	/* when task trigger is inactive, no handle are registered
	 * into mux. update_mux_for_current_task adds the client handle
	 * to mux for reading only if writing is not requested explicitly.
	 * if no data is available for reading, the task can never be
	 * called after activation. so let's request writing here.
	 */
	QSE_ASSERT (!(client->status & QSE_HTTPD_CLIENT_HANDLE_RW_IN_MUX));
	org_cmask = task->trigger.cmask;
	task->trigger.cmask |= QSE_HTTPD_TASK_TRIGGER_WRITE;

	task->trigger.flags &= ~QSE_HTTPD_TASK_TRIGGER_INACTIVE;

	x = update_mux_for_current_task (httpd, client, task);

	task->trigger.cmask = org_cmask;
	return x;
}

int qse_httpd_inactivatetasktrigger (qse_httpd_t* httpd, qse_httpd_client_t* client, qse_httpd_task_t* task)
{
	if (task->trigger.flags & QSE_HTTPD_TASK_TRIGGER_INACTIVE) return 0;

	task->trigger.flags |= QSE_HTTPD_TASK_TRIGGER_INACTIVE;
	return update_mux_for_current_task (httpd, client, task);
}


/* ------------------------------------------------------------------- */


static void update_timer_event (qse_tmr_t* tmr, qse_tmr_index_t old_index, qse_tmr_index_t new_index, qse_tmr_event_t* evt)
{
	tmr_xtn_t* tmr_xtn;
	qse_httpd_t* httpd;
	qse_httpd_timer_updater_t updater;

	tmr_xtn = qse_tmr_getxtn (tmr);
	httpd = tmr_xtn->httpd;
	updater = evt->ctx2;
	updater (httpd, old_index, new_index, evt->ctx);
}

static void handle_timer_event (qse_tmr_t* tmr, const qse_ntime_t* now, qse_tmr_event_t* evt)
{
	tmr_xtn_t* tmr_xtn;
	qse_httpd_t* httpd;
	qse_httpd_timer_handler_t handler;

	tmr_xtn = qse_tmr_getxtn (tmr);
	httpd = tmr_xtn->httpd;
	handler = evt->ctx3;
	handler (httpd, now, evt->ctx);
}

int qse_httpd_inserttimerevent (qse_httpd_t* httpd, const qse_httpd_timer_event_t* event, qse_httpd_timer_index_t* index)
{
	qse_tmr_event_t timer_event;
	qse_tmr_index_t timer_index;

	QSE_MEMSET (&timer_event, 0, QSE_SIZEOF(timer_event));
	timer_event.ctx     = event->ctx;
	timer_event.ctx2    = event->updater;
	timer_event.ctx3    = event->handler;
	timer_event.when    = event->when;
	timer_event.updater = update_timer_event;
	timer_event.handler = handle_timer_event;

	timer_index = qse_tmr_insert (httpd->tmr, &timer_event);
	if (timer_index == QSE_TMR_INVALID_INDEX)
	{
		qse_httpd_seterrnum (httpd, QSE_HTTPD_ENOMEM);
		return -1;
	}

	*index = timer_index;
	return 0;
}

void qse_httpd_removetimerevent (qse_httpd_t* httpd, qse_httpd_timer_index_t index)
{
	qse_tmr_delete (httpd->tmr, index);
}

/* qse_httpd_insert_timer_event() is a lighter-weight version of 
 * qse_httpd_inserttimerevent() and intended for internal use only */

int qse_httpd_insert_timer_event (qse_httpd_t* httpd, const qse_tmr_event_t* event, qse_tmr_index_t* index)
{
	qse_tmr_index_t tmp = qse_tmr_insert (httpd->tmr, event);
	if (tmp == QSE_TMR_INVALID_INDEX)
	{
		qse_httpd_seterrnum (httpd, QSE_HTTPD_ENOMEM);
		return -1;
	}

	*index = tmp;
	return 0;
}
void qse_httpd_remove_timer_event (qse_httpd_t* httpd, qse_tmr_index_t index)
{
	qse_tmr_delete (httpd->tmr, index);
}

/* ----------------------------------------------------------------------- */

static void unload_all_modules (qse_httpd_t* httpd)
{
	qse_httpd_mod_t* mod;

	while (httpd->modlist)
	{
		mod = httpd->modlist;
		httpd->modlist = mod->next;

		if (mod->unload) mod->unload (mod);
		httpd->opt.scb.mod.close (httpd, mod->handle  );
		qse_httpd_freemem (httpd, mod);
	}
}

qse_httpd_mod_t* qse_httpd_loadmod (qse_httpd_t* httpd, const qse_char_t* name)
{
	qse_httpd_mod_t* mod;
	qse_size_t name_len, prefix_len, postfix_len, fullname_len;
	const qse_char_t* prefix, * postfix;
	qse_char_t* entry_point_name;
	qse_httpd_mod_load_t load;

/* TODO: no singly linked list speed up */

	name_len = qse_strlen(name);

	if (httpd->opt.mod[0].len > 0)
	{
		prefix = httpd->opt.mod[0].ptr;
		prefix_len = httpd->opt.mod[0].len;
	}
	else
	{
		prefix = QSE_T(QSE_HTTPD_DEFAULT_MODPREFIX);
		prefix_len = qse_strlen(prefix);
	}

	if (httpd->opt.mod[1].len > 0)
	{
		postfix = httpd->opt.mod[1].ptr;
		postfix_len = httpd->opt.mod[1].len;
	}
	else
	{
		postfix = QSE_T(QSE_HTTPD_DEFAULT_MODPOSTFIX);
		postfix_len = qse_strlen(postfix);
	}

	/* 
	 * +15: length of _qse_httpd_mod_
	 * +2: _\0
	 */
	fullname_len = prefix_len + name_len + postfix_len;
	mod = qse_httpd_callocmem (httpd, QSE_SIZEOF(*mod) + (name_len + 1 + fullname_len + 1 + 15 + name_len + 2) * QSE_SIZEOF(qse_char_t));
	if (mod == QSE_NULL) return QSE_NULL;

	mod->httpd = httpd;
	mod->name = (qse_char_t*)(mod + 1);
	mod->fullname = mod->name + name_len + 1;
	entry_point_name = mod->fullname + fullname_len + 1;
	qse_strcpy (mod->name, name);
	qse_strjoin (mod->fullname, prefix, name, postfix, QSE_NULL);
	qse_strjoin (entry_point_name, QSE_T("_qse_httpd_mod_"), name, QSE_NULL);

	mod->handle = httpd->opt.scb.mod.open (httpd, mod->fullname);
	if (!mod->handle)
	{
		qse_httpd_freemem (httpd, mod);
		return QSE_NULL;
	}

	/* attempt qse_httpd_mod_xxx */
	load = httpd->opt.scb.mod.symbol (httpd, mod->handle, &entry_point_name[1]);
	if (!load)
	{
		/* attempt _qse_awk_mod_xxx */
		load = httpd->opt.scb.mod.symbol (httpd, mod->handle, &entry_point_name[0]);
		if (!load)
		{
			/* attempt qse_awk_mod_xxx_ */
			entry_point_name[15 + name_len] = QSE_T('_');
			entry_point_name[15 + name_len + 1] = QSE_T('\0');
			load = httpd->opt.scb.mod.symbol (httpd, mod->handle, &entry_point_name[1]);
		}
	}

	if (!load || load (mod) <= -1)
	{
		httpd->opt.scb.mod.close (httpd, mod->handle);
		qse_httpd_freemem (httpd, mod);
		return QSE_NULL;
	}

	/* link the loaded module to the module list */
	mod->next = httpd->modlist;
	httpd->modlist = mod;

	return mod;
}

int qse_httpd_configmod (qse_httpd_t* httpd, qse_httpd_mod_t* mod, const qse_char_t* key, const qse_char_t* value)
{
	QSE_ASSERT (httpd == mod->httpd);

	if (mod->config)
	{
		return mod->config (mod, key, value);
	}
	else
	{
		/* not allowed to set the module configuration 
		 * without the 'config' handler */
		httpd->errnum = QSE_HTTPD_EACCES; 
		return -1;
	}
}

qse_httpd_mod_t* qse_httpd_findmod (qse_httpd_t* httpd, const qse_char_t* name)
{
	qse_httpd_mod_t* mod;

/* TODO: no sequential search. speed up */
	for (mod = httpd->modlist; mod;  mod = mod->next)
	{
		if (qse_strcmp (mod->name, name) == 0) return mod;
	}

	return QSE_NULL;
}