/* filterindex.c - generate the list of candidate entries from a filter */
/* $OpenLDAP: pkg/ldap/servers/slapd/back-ldbm/filterindex.c,v 1.40.2.3 2003/02/09 16:31:38 kurt Exp $ */
/*
 * Copyright 1998-2003 The OpenLDAP Foundation, All Rights Reserved.
 * COPYING RESTRICTIONS APPLY, see COPYRIGHT file
 */

#include "portable.h"

#include <stdio.h>

#include <ac/socket.h>
#include <ac/string.h>

#include "slap.h"
#include "back-ldbm.h"

static ID_BLOCK	*presence_candidates(
	Backend *be,
	AttributeDescription *desc );
static ID_BLOCK	*equality_candidates(
	Backend *be, AttributeAssertion *ava );
static ID_BLOCK	*approx_candidates(
	Backend *be, AttributeAssertion *ava );
static ID_BLOCK	*substring_candidates(
	Backend *be,
	SubstringsAssertion *sub );
static ID_BLOCK	*list_candidates(
	Backend *be,
	Filter *flist,
	int ftype );

ID_BLOCK *
filter_candidates(
    Backend	*be,
    Filter	*f
)
{
	ID_BLOCK	*result;

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, "filter_candidates: enter\n", 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "=> filter_candidates\n", 0, 0, 0 );
#endif


	result = NULL;
	switch ( f->f_choice ) {
	case SLAPD_FILTER_DN_ONE:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, 
			   "filter_candidates:  DN ONE (%s)\n", f->f_dn, 0, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tDN ONE\n", 0, 0, 0 );
#endif

		/* an error is treated as an empty list */
		if ( dn2idl( be, f->f_dn, DN_ONE_PREFIX, &result ) != 0
				&& result != NULL ) {
			idl_free( result );
			result = NULL;
		}
		break;

	case SLAPD_FILTER_DN_SUBTREE:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, 
			   "filter_candidates:  DN SUBTREE (%s)\n", f->f_dn, 0, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tDN SUBTREE\n", 0, 0, 0 );
#endif

		/* an error is treated as an empty list */
		if ( dn2idl( be, f->f_dn, DN_SUBTREE_PREFIX, &result ) != 0
				&& result != NULL ) {
			idl_free( result );
			result = NULL;
		}
		break;

	case LDAP_FILTER_PRESENT:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, 
			"filter_candidates:  Present (%s)\n", 
			f->f_desc->ad_cname.bv_val, 0, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tPRESENT\n", 0, 0, 0 );
#endif

		result = presence_candidates( be, f->f_desc );
		break;

	case LDAP_FILTER_EQUALITY:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, 
			   "filter_candidates:  EQUALITY (%s),(%s)\n",
			   f->f_ava->aa_desc->ad_cname.bv_val,
			   f->f_ava->aa_value.bv_val, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tEQUALITY\n", 0, 0, 0 );
#endif

		result = equality_candidates( be, f->f_ava );
		break;

	case LDAP_FILTER_APPROX:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, 
			   "filter_candidates:  APPROX (%s), (%s)\n",
			   f->f_ava->aa_desc->ad_cname.bv_val,
			   f->f_ava->aa_value.bv_val, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tAPPROX\n", 0, 0, 0 );
#endif

		result = approx_candidates( be, f->f_ava );
		break;

	case LDAP_FILTER_SUBSTRINGS:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1,
			   "filter_candidates:  SUBSTRINGS\n", 0, 0, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tSUBSTRINGS\n", 0, 0, 0 );
#endif

		result = substring_candidates( be, f->f_sub );
		break;

	case LDAP_FILTER_GE:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, "filter_candidates:  GE\n", 0, 0, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tGE\n", 0, 0, 0 );
#endif

		result = presence_candidates( be, f->f_ava->aa_desc );
		break;

	case LDAP_FILTER_LE:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, "filter_candidates:  LE\n", 0, 0, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tLE\n", 0, 0, 0 );
#endif

		result = presence_candidates( be, f->f_ava->aa_desc );
		break;

	case LDAP_FILTER_AND:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, "filter_candidates:  AND\n", 0, 0, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tAND\n", 0, 0, 0 );
#endif

		result = list_candidates( be, f->f_and, LDAP_FILTER_AND );
		break;

	case LDAP_FILTER_OR:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, "filter_candidates:  OR\n", 0, 0, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tOR\n", 0, 0, 0 );
#endif

		result = list_candidates( be, f->f_or, LDAP_FILTER_OR );
		break;

	case LDAP_FILTER_NOT:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, "filter_candidates:  NOT\n", 0, 0, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tNOT\n", 0, 0, 0 );
#endif

		/*
		 * As candidates lists may contain entries which do
		 * not match the assertion, negation of the inner candidate
		 * list could result in matching entries be excluded from
		 * the returned candidate list.
		 */
		result = idl_allids( be );
		break;
	default:
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, DETAIL1, "filter_candidates:  UNKNOWN\n", 0, 0, 0 );
#else
		Debug( LDAP_DEBUG_FILTER, "\tUNKNOWN\n", 0, 0, 0 );
#endif
		/* unknown filters must not return NULL, to allow
		 * extended filter processing to be done later.
		 */
		result = idl_allids( be );
		break;
	}

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, 
		"filter_candidates: return %ld\n", 
		result ? ID_BLOCK_NIDS(result) : 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "<= filter_candidates %ld\n",
	    result ? ID_BLOCK_NIDS(result) : 0, 0, 0 );
#endif

	return( result );
}

static ID_BLOCK *
presence_candidates(
    Backend	*be,
	AttributeDescription *desc
)
{
	ID_BLOCK	*idl;
	DBCache	*db;
	int rc;
	char *dbname;
	slap_mask_t mask;
	struct berval prefix = {0, NULL};

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, "presence_candidates: enter\n", 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "=> presence_candidates\n", 0, 0, 0 );
#endif

	idl = idl_allids( be );

	if( desc == slap_schema.si_ad_objectClass ) {
		return idl;
	}

	rc = index_param( be, desc, LDAP_FILTER_PRESENT,
		&dbname, &mask, &prefix );

	if( rc != LDAP_SUCCESS ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, INFO, 
			   "presence_candidates: index_param returned %d\n", rc, 0, 0 );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= presence_candidates: index_param returned=%d\n",
			rc, 0, 0 );
#endif

		return idl;
	}

	if( dbname == NULL ) {
		/* not indexed */
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, INFO, "presence_candidates: not indexed\n", 0, 0, 0 );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= presense_candidates: not indexed\n",
			0, 0, 0 );
#endif

		return idl;
	}

	db = ldbm_cache_open( be, dbname, LDBM_SUFFIX, LDBM_WRCREAT );
	
	if ( db == NULL ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, INFO, 
			   "presence_candidates: db open failed (%s%s)\n",
			   dbname, LDBM_SUFFIX, 0 );
#else
		Debug( LDAP_DEBUG_ANY,
		    "<= presense_candidates db open failed (%s%s)\n",
			dbname, LDBM_SUFFIX, 0 );
#endif

		return idl;
	}

	if( prefix.bv_val != NULL ) {
		idl_free( idl );
		idl = NULL;

		rc = key_read( be, db, &prefix, &idl );

		if( rc != LDAP_SUCCESS ) {
#ifdef NEW_LOGGING
			LDAP_LOG( FILTER, ERR, 
				   "presence_candidates: key read failed (%d)\n", rc, 0, 0 );
#else
			Debug( LDAP_DEBUG_TRACE,
				"<= presense_candidates key read failed (%d)\n",
			    rc, 0, 0 );
#endif


		} else if( idl == NULL ) {
#ifdef NEW_LOGGING
			LDAP_LOG( FILTER, DETAIL1, "presence_candidates: NULL\n", 0, 0, 0 );
#else
			Debug( LDAP_DEBUG_TRACE,
				"<= presense_candidates NULL\n",
			    0, 0, 0 );
#endif

		}
	}

	ldbm_cache_close( be, db );

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, 
		"presence_candidates:  return %ld\n", 
		idl ? ID_BLOCK_NIDS(idl) : 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "<= presence_candidates %ld\n",
	    idl ? ID_BLOCK_NIDS(idl) : 0, 0, 0 );
#endif

	return( idl );
}

static ID_BLOCK *
equality_candidates(
    Backend	*be,
	AttributeAssertion *ava
)
{
	ID_BLOCK	*idl;
	DBCache	*db;
	int i;
	int rc;
	char *dbname;
	slap_mask_t mask;
	struct berval prefix = {0, NULL};
	struct berval *keys = NULL;
	MatchingRule *mr;

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, "equality_candidates: enter\n", 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "=> equality_candidates\n", 0, 0, 0 );
#endif


	idl = idl_allids( be );

	rc = index_param( be, ava->aa_desc, LDAP_FILTER_EQUALITY,
		&dbname, &mask, &prefix );

	if( rc != LDAP_SUCCESS ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, 
			   "equality_candidates:  index_param returned %d\n", rc, 0, 0 );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= equality_candidates: index_param returned=%d\n",
			rc, 0, 0 );
#endif

		return idl;
	}

	if( dbname == NULL ) {
		/* not indexed */
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, "equality_candidates: not indexed\n", 0, 0, 0 );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= equality_candidates: not indexed\n",
			0, 0, 0 );
#endif

		return idl;
	}

	mr = ava->aa_desc->ad_type->sat_equality;
	if( !mr ) {
		return idl;
	}

	if( !mr->smr_filter ) {
		return idl;
	}

	rc = (mr->smr_filter)(
		LDAP_FILTER_EQUALITY,
		mask,
		ava->aa_desc->ad_type->sat_syntax,
		mr,
		&prefix,
		&ava->aa_value,
		&keys );

	if( rc != LDAP_SUCCESS ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, 
			   "equality_candidates: (%s%s) MR filter failed (%d\n",
			   dbname, LDBM_SUFFIX, rc );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= equality_candidates: (%s%s) MR filter failed (%d)\n",
			dbname, LDBM_SUFFIX, rc );
#endif

		return idl;
	}

	if( keys == NULL ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, 
		   "equality_candidates: no keys (%s%s)\n", dbname, LDBM_SUFFIX, 0 );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= equality_candidates: no keys (%s%s)\n",
			dbname, LDBM_SUFFIX, 0 );
#endif

		return idl;
	}

	db = ldbm_cache_open( be, dbname, LDBM_SUFFIX, LDBM_WRCREAT );
	
	if ( db == NULL ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, "equality_candidates: db open failed (%s%s)\n",
			dbname, LDBM_SUFFIX, 0 );
#else
		Debug( LDAP_DEBUG_ANY,
		    "<= equality_candidates db open failed (%s%s)\n",
			dbname, LDBM_SUFFIX, 0 );
#endif

		return idl;
	}

	for ( i= 0; keys[i].bv_val != NULL; i++ ) {
		ID_BLOCK *save;
		ID_BLOCK *tmp;

		rc = key_read( be, db, &keys[i], &tmp );

		if( rc != LDAP_SUCCESS ) {
			idl_free( idl );
			idl = NULL;
#ifdef NEW_LOGGING
			LDAP_LOG( FILTER, ERR, 
				   "equality_candidates: key read failed (%d)\n", rc, 0, 0 );
#else
			Debug( LDAP_DEBUG_TRACE,
				"<= equality_candidates key read failed (%d)\n",
			    rc, 0, 0 );
#endif

			break;
		}

		if( tmp == NULL ) {
			idl_free( idl );
			idl = NULL;
#ifdef NEW_LOGGING
			LDAP_LOG( FILTER, INFO, "equality_candidates NULL\n", 0, 0, 0 );
#else
			Debug( LDAP_DEBUG_TRACE,
				"<= equality_candidates NULL\n",
			    0, 0, 0 );
#endif

			break;
		}

		save = idl;
		idl = idl_intersection( be, idl, tmp );
		idl_free( save );
		idl_free( tmp );

		if( idl == NULL ) break;
	}

	ber_bvarray_free( keys );

	ldbm_cache_close( be, db );


#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, 
		   "equality_candidates: return %ld\n", 
		   idl ? ID_BLOCK_NIDS(idl) : 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "<= equality_candidates %ld\n",
	    idl ? ID_BLOCK_NIDS(idl) : 0, 0, 0 );
#endif

	return( idl );
}

static ID_BLOCK *
approx_candidates(
    Backend	*be,
	AttributeAssertion *ava
)
{
	ID_BLOCK *idl;
	DBCache	*db;
	int i;
	int rc;
	char *dbname;
	slap_mask_t mask;
	struct berval prefix = {0, NULL};
	struct berval *keys = NULL;
	MatchingRule *mr;

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, "approx_candidates: enter\n", 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "=> approx_candidates\n", 0, 0, 0 );
#endif


	idl = idl_allids( be );

	rc = index_param( be, ava->aa_desc, LDAP_FILTER_APPROX,
		&dbname, &mask, &prefix );

	if( rc != LDAP_SUCCESS ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, 
			   "approx_candidates: index_param returned %d\n", rc, 0, 0 );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= approx_candidates: index_param returned=%d\n",
			rc, 0, 0 );
#endif

		return idl;
	}

	if( dbname == NULL ) {
		/* not indexed */
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, "approx_candidates: not indexed\n", 0, 0, 0 );
#else
		Debug( LDAP_DEBUG_ANY,
		    "<= approx_candidates: not indexed\n",
			0, 0, 0 );
#endif

		return idl;
	}

	mr = ava->aa_desc->ad_type->sat_approx;
	if( !mr ) {
		/* no approx matching rule, try equality matching rule */
		mr = ava->aa_desc->ad_type->sat_equality;
	}

	if( !mr ) {
		return idl;
	}

	if( !mr->smr_filter ) {
		return idl;
	}

	rc = (mr->smr_filter)(
		LDAP_FILTER_APPROX,
		mask,
		ava->aa_desc->ad_type->sat_syntax,
		mr,
		&prefix,
		&ava->aa_value,
		&keys );

	if( rc != LDAP_SUCCESS ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, 
			   "approx_candidates: (%s%s) MR filter failed (%d)\n",
			   dbname, LDBM_SUFFIX, rc );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= approx_candidates: (%s%s) MR filter failed (%d)\n",
			dbname, LDBM_SUFFIX, rc );
#endif

		return idl;
	}

	if( keys == NULL ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, INFO, 
			   "approx_candidates: no keys (%s%s)\n",
			   dbname, LDBM_SUFFIX, 0 );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= approx_candidates: no keys (%s%s)\n",
			dbname, LDBM_SUFFIX, 0 );
#endif

		return idl;
	}

	db = ldbm_cache_open( be, dbname, LDBM_SUFFIX, LDBM_WRCREAT );
	
	if ( db == NULL ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, 
			"approx_candidates db open failed (%s%s)\n", 
			dbname, LDBM_SUFFIX, 0 );
#else
		Debug( LDAP_DEBUG_ANY,
		    "<= approx_candidates db open failed (%s%s)\n",
			dbname, LDBM_SUFFIX, 0 );
#endif

		return idl;
	}

	for ( i= 0; keys[i].bv_val != NULL; i++ ) {
		ID_BLOCK *save;
		ID_BLOCK *tmp;

		rc = key_read( be, db, &keys[i], &tmp );

		if( rc != LDAP_SUCCESS ) {
			idl_free( idl );
			idl = NULL;
#ifdef NEW_LOGGING
			LDAP_LOG( FILTER, ERR, 
				   "approx_candidates: key read failed (%d)\n", rc, 0, 0 );
#else
			Debug( LDAP_DEBUG_TRACE, "<= approx_candidates key read failed (%d)\n",
			    rc, 0, 0 );
#endif

			break;
		}

		if( tmp == NULL ) {
			idl_free( idl );
			idl = NULL;
#ifdef NEW_LOGGING
			LDAP_LOG( FILTER, INFO, "approx_candidates: NULL\n", 0, 0, 0 );
#else
			Debug( LDAP_DEBUG_TRACE, "<= approx_candidates NULL\n",
			    0, 0, 0 );
#endif

			break;
		}

		save = idl;
		idl = idl_intersection( be, idl, tmp );
		idl_free( save );
		idl_free( tmp );

		if( idl == NULL ) break;
	}

	ber_bvarray_free( keys );

	ldbm_cache_close( be, db );

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, 
		"approx_candidates: return %ld\n", 
		idl ? ID_BLOCK_NIDS(idl) : 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "<= approx_candidates %ld\n",
	    idl ? ID_BLOCK_NIDS(idl) : 0, 0, 0 );
#endif

	return( idl );
}

static ID_BLOCK *
list_candidates(
    Backend	*be,
    Filter	*flist,
    int		ftype
)
{
	ID_BLOCK	*idl, *tmp, *tmp2;
	Filter	*f;

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, "list_candidates: 0x%x\n", ftype, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "=> list_candidates 0x%x\n", ftype, 0, 0 );
#endif


	idl = NULL;
	for ( f = flist; f != NULL; f = f->f_next ) {
		if ( (tmp = filter_candidates( be, f )) == NULL &&
		    ftype == LDAP_FILTER_AND ) {
#ifdef NEW_LOGGING
			LDAP_LOG( FILTER, INFO, "list_candidates: NULL\n", 0, 0, 0 );
#else
			Debug( LDAP_DEBUG_TRACE,
			       "<= list_candidates NULL\n", 0, 0, 0 );
#endif

			idl_free( idl );
			return( NULL );
		}

		tmp2 = idl;
		if ( idl == NULL ) {
			idl = tmp;
		} else if ( ftype == LDAP_FILTER_AND ) {
			idl = idl_intersection( be, idl, tmp );
			idl_free( tmp );
			idl_free( tmp2 );
		} else {
			idl = idl_union( be, idl, tmp );
			idl_free( tmp );
			idl_free( tmp2 );
		}
	}

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, "list_candidates: return %ld\n",
		   idl ? ID_BLOCK_NIDS(idl) : 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "<= list_candidates %ld\n",
	    idl ? ID_BLOCK_NIDS(idl) : 0, 0, 0 );
#endif

	return( idl );
}

static ID_BLOCK *
substring_candidates(
    Backend	*be,
    SubstringsAssertion	*sub
)
{
	ID_BLOCK *idl;
	DBCache	*db;
	int i;
	int rc;
	char *dbname;
	slap_mask_t mask;
	struct berval prefix = {0, NULL};
	struct berval *keys = NULL;
	MatchingRule *mr;

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, "substrings_candidates: enter\n", 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "=> substrings_candidates\n", 0, 0, 0 );
#endif


	idl = idl_allids( be );

	rc = index_param( be, sub->sa_desc, LDAP_FILTER_SUBSTRINGS,
		&dbname, &mask, &prefix );

	if( rc != LDAP_SUCCESS ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, 
			   "substrings_candidates: index_param returned %d\n", rc, 0, 0 );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= substrings_candidates: index_param returned=%d\n",
			rc, 0, 0 );
#endif

		return idl;
	}

	if( dbname == NULL ) {
		/* not indexed */
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, "substrings_candidates: not indexed\n", 0, 0, 0);
#else
		Debug( LDAP_DEBUG_ANY,
		    "<= substrings_candidates: not indexed\n",
			0, 0, 0 );
#endif

		return idl;
	}

	mr = sub->sa_desc->ad_type->sat_substr;

	if( !mr ) {
		return idl;
	}

	if( !mr->smr_filter ) {
		return idl;
	}

	rc = (mr->smr_filter)(
		LDAP_FILTER_SUBSTRINGS,
		mask,
		sub->sa_desc->ad_type->sat_syntax,
		mr,
		&prefix,
		sub,
		&keys );

	if( rc != LDAP_SUCCESS ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, 
			   "substrings_candidates: (%s%s) MR filter failed (%d)\n",
			   dbname, LDBM_SUFFIX, rc );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= substrings_candidates: (%s%s) MR filter failed (%d)\n",
			dbname, LDBM_SUFFIX, rc );
#endif

		return idl;
	}

	if( keys == NULL ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, 
			   "substrings_candidates: (0x%04lx) no keys (%s%s)\n",
			   mask, dbname, LDBM_SUFFIX );
#else
		Debug( LDAP_DEBUG_TRACE,
		    "<= substrings_candidates: (0x%04lx) no keys (%s%s)\n",
			mask, dbname, LDBM_SUFFIX );
#endif

		return idl;
	}

	db = ldbm_cache_open( be, dbname, LDBM_SUFFIX, LDBM_WRCREAT );
	
	if ( db == NULL ) {
#ifdef NEW_LOGGING
		LDAP_LOG( FILTER, ERR, 
			   "substrings_candidates: db open failed (%s%s)\n",
			   dbname, LDBM_SUFFIX, 0 );
#else
		Debug( LDAP_DEBUG_ANY,
		    "<= substrings_candidates db open failed (%s%s)\n",
			dbname, LDBM_SUFFIX, 0 );
#endif

		return idl;
	}

	for ( i= 0; keys[i].bv_val != NULL; i++ ) {
		ID_BLOCK *save;
		ID_BLOCK *tmp;

		rc = key_read( be, db, &keys[i], &tmp );

		if( rc != LDAP_SUCCESS ) {
			idl_free( idl );
			idl = NULL;
#ifdef NEW_LOGGING
			LDAP_LOG( FILTER, ERR, 
				   "substrings_candidates: key read failed (%d)\n", rc, 0, 0 );
#else
			Debug( LDAP_DEBUG_TRACE, "<= substrings_candidates key read failed (%d)\n",
			    rc, 0, 0 );
#endif

			break;
		}

		if( tmp == NULL ) {
			idl_free( idl );
			idl = NULL;
#ifdef NEW_LOGGING
			LDAP_LOG( FILTER, INFO, "substrings_candidates: NULL\n", 0, 0, 0 );
#else
			Debug( LDAP_DEBUG_TRACE, "<= substrings_candidates NULL\n",
			    0, 0, 0 );
#endif

			break;
		}

		save = idl;
		idl = idl_intersection( be, idl, tmp );
		idl_free( save );
		idl_free( tmp );

		if( idl == NULL ) break;
	}

	ber_bvarray_free( keys );

	ldbm_cache_close( be, db );

#ifdef NEW_LOGGING
	LDAP_LOG( FILTER, ENTRY, 
		   "substrings_candidates: return %ld\n",
		   idl ? ID_BLOCK_NIDS(idl) : 0, 0, 0 );
#else
	Debug( LDAP_DEBUG_TRACE, "<= substrings_candidates %ld\n",
	    idl ? ID_BLOCK_NIDS(idl) : 0, 0, 0 );
#endif

	return( idl );
}
