389-ds-base/ldap/servers/plugins/views/views.c

/** BEGIN COPYRIGHT BLOCK
 * This Program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; version 2 of the License.
 * 
 * This Program 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 General Public License along with
 * this Program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place, Suite 330, Boston, MA 02111-1307 USA.
 * 
 * In addition, as a special exception, Red Hat, Inc. gives You the additional
 * right to link the code of this Program with code not covered under the GNU
 * General Public License ("Non-GPL Code") and to distribute linked combinations
 * including the two, subject to the limitations in this paragraph. Non-GPL Code
 * permitted under this exception must only link to the code of this Program
 * through those well defined interfaces identified in the file named EXCEPTION
 * found in the source code files (the "Approved Interfaces"). The files of
 * Non-GPL Code may instantiate templates or use macros or inline functions from
 * the Approved Interfaces without causing the resulting work to be covered by
 * the GNU General Public License. Only Red Hat, Inc. may make changes or
 * additions to the list of Approved Interfaces. You must obey the GNU General
 * Public License in all respects for all of the Program code and other code used
 * in conjunction with the Program except the Non-GPL Code covered by this
 * exception. If you modify this file, you may extend this exception to your
 * version of the file, but you are not obligated to do so. If you do not wish to
 * provide this exception without modification, you must delete this exception
 * statement from your version and license this file solely under the GPL without
 * exception. 
 * 
 * 
 * Copyright (C) 2001 Sun Microsystems, Inc. Used by permission.
 * Copyright (C) 2005 Red Hat, Inc.
 * All rights reserved.
 * END COPYRIGHT BLOCK **/
/* plugin which implements directory server views */

#include <stdio.h>
#include <string.h>
#include "portable.h"
#include "slapi-plugin.h"
#include <dirlite_strings.h> /* PLUGIN_MAGIC_VENDOR_STR */
#include "dirver.h"
#include "statechange.h"
#include "views.h"

#include "slapi-plugin-compat4.h"
#include "slapi-private.h"


#define VIEW_OBJECTCLASS "nsView"
#define VIEW_FILTER_ATTR	"nsViewFilter"
#define STATECHANGE_VIEWS_ID "Views"
#define STATECHANGE_VIEWS_CONFG_FILTER "objectclass=" VIEW_OBJECTCLASS

/* get file mode flags for unix */
#ifndef _WIN32
#include <sys/stat.h>
#endif

#define VIEWS_PLUGIN_SUBSYSTEM   "views-plugin"   /* used for logging */

/* cache data structs */

struct _viewLinkedList
{
	void *pNext;
	void *pPrev;
};
typedef struct _viewLinkedList viewLinkedList;

#if defined(DEBUG)
#define _VIEW_DEBUG_FILTERS  /* Turning on hurts performance */
#endif

struct _viewEntry
{
	viewLinkedList list;
	char *pDn;
	char *viewfilter; /* the raw view */
	Slapi_Filter *includeAncestorFiltersFilter; /* the filter with all ancestor filters */
	Slapi_Filter *excludeAllButDescendentViewsFilter; /* for building the view of views */
	Slapi_Filter *excludeChildFiltersFilter; /* NOT all children views, for one level searches */
	Slapi_Filter *excludeGrandChildViewsFilter; /* view filter for one level searches */
	Slapi_Filter *includeChildViewsFilter; /* view filter for subtree searches */
#ifdef _VIEW_DEBUG_FILTERS
	/* monitor the cached filters with these */
	char includeAncestorFiltersFilter_str[1024]; /* the filter with all ancestor filters */
	char excludeAllButDescendentViewsFilter_str[1024]; /* for building the view of views */
	char excludeChildFiltersFilter_str[1024]; /* NOT all children views, for one level searches */
	char excludeGrandChildViewsFilter_str[1024]; /* view filter for one level searches */
	char includeChildViewsFilter_str[1024]; /* view filter for subtree searches */
#endif
	char *pSearch_base; /* the parent of the top most view */
	void *pParent;
	void **pChildren;
	int child_count;
	unsigned long entryid;  /* unique identifier for this entry */
	unsigned long parentid; /* unique identifier for the parent entry */
};
typedef struct _viewEntry viewEntry;

struct _globalViewCache
{
	viewEntry *pCacheViews;
	viewEntry **ppViewIndex;
	int cache_built;
	int view_count;
	PRThread *currentUpdaterThread;
};
typedef struct _globalViewCache golbalViewCache;

static golbalViewCache theCache;

/* other function prototypes */
int views_init( Slapi_PBlock *pb ); 
static int views_start( Slapi_PBlock *pb );
static int views_close( Slapi_PBlock *pb );
static int views_cache_create();
static void views_update_views_cache( Slapi_Entry *e, char *dn, int modtype, Slapi_PBlock *pb, void *caller_data );
static int views_cache_build_view_list(viewEntry **pViews);
static int views_cache_index();
static int 	views_dn_views_cb (Slapi_Entry* e, void *callback_data);
static int views_cache_add_dn_views(char *dn, viewEntry **pViews);
static void views_cache_add_ll_entry(void** attrval, void *theVal);
static void views_cache_discover_parent(viewEntry *pView);
static void views_cache_discover_children(viewEntry *pView);
static void views_cache_discover_view_scope(viewEntry *pView);
static void views_cache_create_applied_filter(viewEntry *pView);
static void views_cache_create_exclusion_filter(viewEntry *pView);
static void views_cache_create_inclusion_filter(viewEntry *pView);
Slapi_Filter *views_cache_create_descendent_filter(viewEntry *ancestor, PRBool useID);
static int view_search_rewrite_callback(Slapi_PBlock *pb);
static void views_cache_backend_state_change(void *handle, char *be_name, int old_be_state, int new_be_state); 
static void views_cache_act_on_change_thread(void *arg);
static viewEntry *views_cache_find_view(char *view);

/* our api broker published api */
static void *api[3];
static int _internal_api_views_entry_exists(char *view_dn, Slapi_Entry *e);
static int _internal_api_views_entry_dn_exists(char *view_dn, char *e_dn);
static int _internal_api_views_entry_exists_general(char *view_dn, Slapi_Entry *e, char *e_dn);


static Slapi_PluginDesc pdesc = { "views", PLUGIN_MAGIC_VENDOR_STR, PRODUCTTEXT,
	"virtual directory information tree views plugin" };

static void * view_plugin_identity = NULL;

static PRRWLock *g_views_cache_lock;

#ifdef _WIN32
int *module_ldap_debug = 0;

void plugin_init_debug_level(int *level_ptr)
{
	module_ldap_debug = level_ptr;
}
#endif

/*
** Plugin identity mgmt
*/

void view_set_plugin_identity(void * identity) 
{
	view_plugin_identity=identity;
}

void * view_get_plugin_identity()
{
	return view_plugin_identity;
}

/* 
	views_init
	--------
	adds our callbacks to the list
*/
int views_init( Slapi_PBlock *pb )
{
	int ret = 0;
	void * plugin_identity=NULL;

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "--> views_init\n");

	/*
	** Store the plugin identity for later use.
	** Used for internal operations
	*/
	
    slapi_pblock_get (pb, SLAPI_PLUGIN_IDENTITY, &plugin_identity);
	view_set_plugin_identity(plugin_identity);

	if (	slapi_pblock_set( pb, SLAPI_PLUGIN_VERSION,
	    			SLAPI_PLUGIN_VERSION_01 ) != 0 ||
	        slapi_pblock_set(pb, SLAPI_PLUGIN_START_FN,
        	         (void *) views_start ) != 0 ||
	        slapi_pblock_set(pb, SLAPI_PLUGIN_CLOSE_FN,
        	         (void *) views_close ) != 0 ||
			slapi_pblock_set( pb, SLAPI_PLUGIN_DESCRIPTION,
                     (void *)&pdesc ) != 0 )
    {
        slapi_log_error( SLAPI_LOG_FATAL, VIEWS_PLUGIN_SUBSYSTEM,
                         "views_init: failed to register plugin\n" );
		ret = -1;
    }

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "<-- views_init\n");
    return ret;
}

void views_read_lock()
{
	PR_RWLock_Rlock(g_views_cache_lock);
}

void views_write_lock()
{
	PR_RWLock_Wlock(g_views_cache_lock);
}

void views_unlock()
{
	PR_RWLock_Unlock(g_views_cache_lock);
}

/*
	views_start
	---------
	This function publishes the interface for this plugin
*/
static int views_start( Slapi_PBlock *pb )
{
	int ret = 0;
	void **statechange_api;

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "--> views_start\n");

	theCache.cache_built = 0;
	g_views_cache_lock = PR_NewRWLock(PR_RWLOCK_RANK_NONE, "views");

	/* first register our backend state change func (we'll use func pointer as handle) */
	slapi_register_backend_state_change((void *)views_cache_backend_state_change, views_cache_backend_state_change); 

	/* create the view cache */

	views_cache_create();

	/* register callbacks for filter and search rewriting */
	slapi_compute_add_search_rewriter(view_search_rewrite_callback);

	/* register for state changes to view configuration */
    if(!slapi_apib_get_interface(StateChange_v1_0_GUID, &statechange_api))
    {
        statechange_register(statechange_api, STATECHANGE_VIEWS_ID, NULL, STATECHANGE_VIEWS_CONFG_FILTER, NULL, views_update_views_cache);
    }

	/* register our api so that other subsystems can be views aware */
	api[0] = NULL; /* reserved for api broker use */
	api[1] = (void *)_internal_api_views_entry_exists;
	api[2] = (void *)_internal_api_views_entry_dn_exists;

	if( slapi_apib_register(Views_v1_0_GUID, api) )
	{
		slapi_log_error( SLAPI_LOG_FATAL, VIEWS_PLUGIN_SUBSYSTEM, "views: failed to publish views interface\n");
		ret = -1;
	}

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "<-- views_start\n");
	return ret;
}

/* _internal_api_views_entry_exists()
 * ----------------------------------
 * externally published api to allow other subsystems to
 * be views aware.  Given a view and an entry, this function
 * returns PR_TRUE if the entry would be returned by a subtree
 * search on the view, PR_FALSE otherwise.
 */
static int _internal_api_views_entry_exists(char *view_dn, Slapi_Entry *e)
{
	return _internal_api_views_entry_exists_general(view_dn, e, NULL);
}

static int _internal_api_views_entry_dn_exists(char *view_dn, char *e_dn)
{
	return _internal_api_views_entry_exists_general(view_dn, NULL, e_dn);
}

static int _internal_api_views_entry_exists_general(char *view_dn, Slapi_Entry *e, char *e_dn)
{
	int ret = 0;
	viewEntry *view;
	char *dn;

	/* there are two levels of scope for a view,
	 * from the parent of the view without a view filter
	 * and the parent of the top most view including a
	 * view filter - either match will do
	 */

	/* find the view */
	view = views_cache_find_view(view_dn);
	if(0==view)
	{
		/* this is not the entry you are looking for */
		goto bail;
	}

	/* normal scope - is the view an ancestor of the entry */
	if(e_dn)
		dn = e_dn;
	else
		dn = slapi_entry_get_ndn(e);

	if(slapi_dn_issuffix(dn, view_dn))
	{
		/* this entry is physically contained in the view hiearchy */
		ret = -1;
		goto bail;
	}

	/* view scope - view hiearchy scope plus view filter */
	if(slapi_dn_issuffix(dn, view->pSearch_base))
	{
		if(0==e)
		{
			Slapi_DN *sdn = slapi_sdn_new_dn_byref(dn);

			slapi_search_internal_get_entry( sdn, NULL, &e , view_get_plugin_identity());

			slapi_sdn_free(&sdn);
		}

		/* so far so good, apply filter */
		if(0==slapi_filter_test_simple(e,view->includeAncestorFiltersFilter))
		{
			/* this entry would appear in the view */
			ret = -1;
		}
	}

bail:
	return ret;
}

void views_cache_free()
{
	viewEntry *head = theCache.pCacheViews;
	viewEntry *current;

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "--> views_cache_free\n");

	/* free the cache */
	current = head; 
	
	while(current != NULL)
	{
		viewEntry *theView = current;
		current = current->list.pNext;

		/* free the view */
		slapi_ch_free((void**)&theView->pDn);
		slapi_ch_free((void**)&theView->viewfilter);
		slapi_filter_free(theView->includeAncestorFiltersFilter,1); 
		slapi_filter_free(theView->excludeAllButDescendentViewsFilter,1);
		slapi_filter_free(theView->excludeChildFiltersFilter,1);
		slapi_filter_free(theView->excludeGrandChildViewsFilter,1);
		slapi_filter_free(theView->includeChildViewsFilter,1);
		slapi_ch_free((void**)&theView->pSearch_base);
		slapi_ch_free((void**)&theView->pChildren);
		slapi_ch_free((void**)&theView);
	}

	theCache.pCacheViews = NULL;
	
	slapi_ch_free((void**)&theCache.ppViewIndex);
	
	theCache.view_count = 0;

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "<-- views_cache_free\n");
}

/*
	views_close
	---------
	unregisters the interface for this plugin
*/
static int views_close( Slapi_PBlock *pb )
{
	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "--> views_close\n");
	
	/* unregister backend state change notification */
	slapi_unregister_backend_state_change((void *)views_cache_backend_state_change);

	views_cache_free();

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "<-- views_close\n");

	return 0;
}


/*
	views_cache_create
	---------------------
	Walks the views in the DIT and populates the cache.
*/
static int views_cache_create()
{
	int ret = -1;

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "--> views_cache_create\n");


	/* lock cache */
	views_write_lock();

	theCache.currentUpdaterThread = PR_GetCurrentThread(); /* to avoid deadlock */

	if(theCache.pCacheViews)
	{
		/* need to get rid of the existing views */
		views_cache_free();
	}

	/* grab the view entries */
	ret = views_cache_build_view_list(&(theCache.pCacheViews));
	if(!ret && theCache.pCacheViews)
	{
		viewEntry *head = theCache.pCacheViews;
		viewEntry *current;
		
		/* OK, we have a basic cache, now we need to
		 * fix up parent and children pointers
		 */
		for(current = head; current != NULL; current = current->list.pNext)
		{
			views_cache_discover_parent(current);
			views_cache_discover_children(current);
		}

		/* scope of views and cache search filters... */
		for(current = head; current != NULL; current = current->list.pNext)
		{
			views_cache_discover_view_scope(current);
			views_cache_create_applied_filter(current);
			views_cache_create_exclusion_filter(current);
			views_cache_create_inclusion_filter(current);
		}

		/* create the view index */
		ret = views_cache_index();
		if(ret != 0)
		{
			/* currently we cannot go on without the indexes */
			slapi_log_error(SLAPI_LOG_FATAL, VIEWS_PLUGIN_SUBSYSTEM, "views_cache_create: failed to index cache\n");			
		}
		else
			theCache.cache_built = 1;
	}
	else
	{
		/* its ok to not have views to cache */
		theCache.cache_built = 0;
		ret = 0;
	}

	theCache.currentUpdaterThread = 0;

	/* unlock cache */
	views_unlock();

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "<-- views_cache_create\n");
	return ret;
}

/*
 * views_cache_view_compare
 * -----------------------
 * compares the dns of two views - used for sorting the index
 */
int views_cache_view_compare(const void *e1, const void *e2)
{
	int ret;
	Slapi_DN *dn1 = slapi_sdn_new_dn_byval((*(viewEntry**)e1)->pDn);
	Slapi_DN *dn2 = slapi_sdn_new_dn_byval((*(viewEntry**)e2)->pDn);

	ret = slapi_sdn_compare(dn1, dn2);

	slapi_sdn_free(&dn1);
	slapi_sdn_free(&dn2);

	return ret;
}

/*
 * views_cache_dn_compare
 * -----------------------
 * compares a dn with the dn of a view - used for searching the index
 */
int views_cache_dn_compare(const void *e1, const void *e2)
{
	int ret;
	Slapi_DN *dn1 = slapi_sdn_new_dn_byval((char*)e1);
	Slapi_DN *dn2 = slapi_sdn_new_dn_byval(((viewEntry*)e2)->pDn);

	ret = slapi_sdn_compare(dn1, dn2);

	slapi_sdn_free(&dn1);
	slapi_sdn_free(&dn2);

	return ret;
}
/*
 * views_cache_index
 * ----------------
 * indexes the cache for fast look up of views
 */
static int views_cache_index()
{
	int ret = -1;
	int i;
	viewEntry *theView = theCache.pCacheViews;
	viewEntry *current = 0;

	if(theCache.ppViewIndex)
		slapi_ch_free((void**)&theCache.ppViewIndex);

	theCache.view_count = 0;

	/* lets count the views */
	for(current = theCache.pCacheViews; current != NULL; current = current->list.pNext)
		theCache.view_count++;
	

	theCache.ppViewIndex = (viewEntry**)calloc(theCache.view_count, sizeof(viewEntry*));
	if(theCache.ppViewIndex)
	{
		/* copy over the views */
		for(i=0; i<theCache.view_count; i++)
		{
			theCache.ppViewIndex[i] = theView;
			theView = theView->list.pNext;
		}

		/* sort the views */
		qsort(theCache.ppViewIndex, theCache.view_count, sizeof(viewEntry*), views_cache_view_compare);

		ret = 0;
	}

	return ret;
}


/*
	views_cache_view_index_bsearch - RECURSIVE
	----------------------------------------
	performs a binary search on the cache view index
	return -1 if key is not found
*/
viewEntry *views_cache_view_index_bsearch( const char *key, int lower, int upper )
{
	viewEntry *ret = 0;
	int index = 0;
	int compare_ret = 0;

	if(upper >= lower)
	{
		if(upper != 0)
			index = ((upper-lower)/2) + lower;
		else
			index = 0;

		compare_ret = views_cache_dn_compare(key, theCache.ppViewIndex[index]);
		
		if(!compare_ret)
		{
			ret = (theCache.ppViewIndex)[index];
		}
		else
		{
			/* seek elsewhere */
			if(compare_ret < 0)
			{
				/* take the low road */
				ret = views_cache_view_index_bsearch(key, lower, index-1);
			}
			else
			{
				/* go high */
				ret = views_cache_view_index_bsearch(key, index+1, upper);
			}
		}
	}

	return ret;
}


/*
	views_cache_find_view
	-------------------
	searches for a view, and if found returns it, null otherwise
*/
static viewEntry *views_cache_find_view(char *view)
{
	viewEntry *ret = 0;  /* assume failure */

	if(theCache.view_count != 1)
		ret = views_cache_view_index_bsearch(view, 0, theCache.view_count-1);
	else
	{
		/* only one view (that will fool our bsearch) lets check it here */
		if(!slapi_utf8casecmp((unsigned char*)view, (unsigned char*)theCache.ppViewIndex[0]->pDn))
		{
			ret = theCache.ppViewIndex[0];
		}
	}

	return ret;
}


/*
	views_cache_discover_parent
	------------------------------
	finds the parent of this view and caches it in view
*/
static void views_cache_discover_parent(viewEntry *pView)
{
	viewEntry *head = theCache.pCacheViews;
	viewEntry *current;
	int found = 0;
	
	for(current = head; current != NULL  && !found; current = current->list.pNext)
	{
		if(slapi_dn_isparent( current->pDn, pView->pDn ))
		{
			found = 1;
			pView->pParent = current;
		}
	}

	if(!found)
	{
		/* this is a top view */
		pView->pParent = NULL;
	}
}


/*
	views_cache_discover_children
	------------------------------
	finds the children of this view and caches them in view
*/
static void views_cache_discover_children(viewEntry *pView)
{
	viewEntry *head = theCache.pCacheViews;
	viewEntry *current;
	int child_count = 0;
	int add_count = 0;

	if(pView->pChildren)
	{
		slapi_ch_free((void**)&pView->pChildren);
		pView->pChildren = NULL;
	}

	/* first lets count the children */
	for(current = head; current != NULL; current = current->list.pNext)
	{
		if(slapi_dn_isparent(pView->pDn, current->pDn))
			child_count++;
	}

	/* make the space for them */
	pView->child_count = child_count;
	
	pView->pChildren = calloc(child_count, sizeof(viewEntry*));

	/* add them */
	for(current = head; current != NULL; current = current->list.pNext)
	{
		if(slapi_dn_isparent(pView->pDn, current->pDn))
		{
			((viewEntry**)pView->pChildren)[add_count] = current;
			add_count++;
		}
	}
}


/*
	views_cache_discover_view_scope
	------------------------------
	finds the parent of the top most view and sets the scope of the view search
*/

static void views_cache_discover_view_scope(viewEntry *pView)
{
	viewEntry *current = pView;
	
	if(pView->pSearch_base)
		slapi_ch_free((void**)&pView->pSearch_base);

	while(current != NULL)
	{
		if(current->pParent == NULL)
		{
			/* found top */
			pView->pSearch_base = slapi_dn_parent(current->pDn);
		}

		current = current->pParent; 
	}

}


/*
	views_cache_create_applied_filter
	--------------------------------
	builds the filters for:
	char *includeAncestorFiltersFilter;  the view with all ancestor views 
*/
static void views_cache_create_applied_filter(viewEntry *pView)
{
	viewEntry *current = pView;
	Slapi_Filter *pCurrentFilter = 0;
	Slapi_Filter *pBuiltFilter = 0;
	Slapi_Filter *pViewEntryExcludeFilter = 0;

	if(pView->includeAncestorFiltersFilter)
	{
		/* release the current filter */
		slapi_filter_free(pView->includeAncestorFiltersFilter, 1);
		pView->includeAncestorFiltersFilter = 0;
	}

	/* create applied view filter (this view filter plus ancestors) */
	while(current != NULL)
	{
		/* add this view filter to the built filter using AND */
		char *buf;
			
		if(!current->viewfilter)
		{
			current = current->pParent; 
			continue; /* skip this view */
		}

		buf = slapi_ch_strdup(current->viewfilter);

		pCurrentFilter = slapi_str2filter( buf );
		if(pBuiltFilter && pCurrentFilter)
			pBuiltFilter = slapi_filter_join_ex( LDAP_FILTER_AND, pBuiltFilter, pCurrentFilter, 0 );
		else
			pBuiltFilter = pCurrentFilter;

		slapi_ch_free((void **)&buf);

		current = current->pParent; 
	}

	/* filter for removing view entries from search */
	pViewEntryExcludeFilter = slapi_str2filter( "(!(objectclass=" VIEW_OBJECTCLASS "))" );

	if(pBuiltFilter)
		pView->includeAncestorFiltersFilter = slapi_filter_join_ex( LDAP_FILTER_AND, pBuiltFilter, pViewEntryExcludeFilter, 0 );
	else
		pView->includeAncestorFiltersFilter = pViewEntryExcludeFilter;

#ifdef _VIEW_DEBUG_FILTERS
	slapi_filter_to_string(pView->includeAncestorFiltersFilter, pView->includeAncestorFiltersFilter_str, sizeof(pView->includeAncestorFiltersFilter_str));
#endif
}

/* views_cache_create_exclusion_filter
 * ----------------------------------
 * makes a filter which is used for one level searches
 * so that views show up correctly if the client filter
 * allows: excludeGrandChildViewsFilter
 *
 * Also makes the filter which excludes entries which
 * belong in descendent views: excludeChildFiltersFilter 
 */
static void views_cache_create_exclusion_filter(viewEntry *pView)
{
/*
	viewEntry *current = pView;
	Slapi_Filter *pOrSubFilter = 0;
	int child_count = 0;
*/
	Slapi_Filter *excludeChildFiltersFilter = 0;
	char *buf = 0;

	/* create exclusion filter for one level searches
	 * this requires the rdns of the grandchildren of
	 * this view to be in a filter
	 */

	if(pView->excludeGrandChildViewsFilter)
	{
		/* release the current filter */
		slapi_filter_free(pView->excludeGrandChildViewsFilter, 1);
		pView->excludeGrandChildViewsFilter = 0;
	}

	if(pView->excludeChildFiltersFilter)
	{
		/* release the current filter */
		slapi_filter_free(pView->excludeChildFiltersFilter, 1);
		pView->excludeChildFiltersFilter = 0;
	}

/*	if(pView->child_count == 0)
	{
*/		/* this view has no children */
/*		pView->excludeGrandChildViewsFilter = 0;
		pView->excludeChildFiltersFilter = 0;
		return;
	}


	while(child_count < pView->child_count)
	{
		current = pView->pChildren[child_count];

		if(current->child_count == 0)
		{
*/			/* no grandchildren here, skip */
/*			child_count++;
			continue;
		}
*/
		/* for each child we need to add its descendants */
/*		if(pOrSubFilter)
		{
			Slapi_Filter *pDescendents = views_cache_create_descendent_filter(current, TRUE);
			if(pDescendents)
				pOrSubFilter = slapi_filter_join_ex( LDAP_FILTER_OR, pOrSubFilter, pDescendents, 0 );
		}
		else
			pOrSubFilter = views_cache_create_descendent_filter(current, TRUE);
		
		child_count++;
	}
*/
	buf=PR_smprintf("(parentid=%lu)", pView->entryid);
	pView->excludeGrandChildViewsFilter = slapi_str2filter( buf );
	PR_smprintf_free(buf);

/*	if(pOrSubFilter)
		pView->excludeGrandChildViewsFilter = slapi_filter_join_ex( LDAP_FILTER_NOT, pOrSubFilter, NULL, 0 );*/

	excludeChildFiltersFilter = views_cache_create_descendent_filter(pView, PR_FALSE);
	if(excludeChildFiltersFilter)
		pView->excludeChildFiltersFilter = slapi_filter_join_ex( LDAP_FILTER_NOT, excludeChildFiltersFilter, NULL, 0 );

#ifdef _VIEW_DEBUG_FILTERS
	slapi_filter_to_string(pView->excludeGrandChildViewsFilter, pView->excludeGrandChildViewsFilter_str, sizeof(pView->excludeGrandChildViewsFilter_str));
	slapi_filter_to_string(pView->excludeChildFiltersFilter, pView->excludeChildFiltersFilter_str, sizeof(pView->excludeChildFiltersFilter_str));
#endif
}


Slapi_Filter *views_cache_create_descendent_filter(viewEntry *ancestor, PRBool useEntryID)
{
	int child_count = 0;
	Slapi_Filter *pOrSubFilter = 0;

	while(child_count < ancestor->child_count)
	{
		Slapi_Filter *pDescendentSubFilter = 0;
/*
		Slapi_RDN *rdn = 0;
		char *str_rdn = 0;
		int len = 0;
*/
		Slapi_Filter *pCurrentFilter = 0;
		viewEntry *currentChild = ancestor->pChildren[child_count];
		char *buf = 0;

		/* for each child we need to add its descendants
		 * we do this now before processing this view
		 * to try to help the filter code out by having
		 * the most significant filters first
		 */
		pDescendentSubFilter = views_cache_create_descendent_filter(currentChild, useEntryID);
		if(pDescendentSubFilter)
			if(pOrSubFilter)
				pOrSubFilter = slapi_filter_join_ex( LDAP_FILTER_OR, pOrSubFilter, pDescendentSubFilter, 0 );
			else
				pOrSubFilter = pDescendentSubFilter;

		if(useEntryID)
		{
			/* we need the RDN of this child */
/*			rdn = slapi_rdn_new_dn(currentChild->pDn);
			str_rdn = (char *)slapi_rdn_get_rdn(rdn);
			len = strlen(str_rdn);
			
			buf=PR_smprintf("(%s)", str_rdn);*/

			/* uniquely identify this child */
			buf=PR_smprintf("(parentid=%lu)", currentChild->entryid);
		}
		else
		{
			/* this is a filter based filter */
			if(currentChild->viewfilter)
			{
				buf=PR_smprintf("%s",currentChild->viewfilter);
			}
		}

		if(buf)
		{
			pCurrentFilter = slapi_str2filter( buf );
			if(pOrSubFilter)
				pOrSubFilter = slapi_filter_join_ex( LDAP_FILTER_OR, pOrSubFilter, pCurrentFilter, 0 );
			else
				pOrSubFilter = pCurrentFilter;

			PR_smprintf_free(buf);
		}


		child_count++;
	}

	return pOrSubFilter;
}


/* views_cache_create_inclusion_filter
 * ----------------------------------
 * makes a filter which is used for subtree searches
 * so that views show up correctly if the client filter
 * allows
 */
static void views_cache_create_inclusion_filter(viewEntry *pView)
{
#if 0
	viewEntry *head = theCache.pCacheViews;
#endif
/*	viewEntry *current; */
/*	Slapi_Filter *view_filter; */
	char *view_filter_str;

	if(pView->includeChildViewsFilter)
	{
		/* release the current filter */
		slapi_filter_free(pView->includeChildViewsFilter, 1);
		pView->includeChildViewsFilter = 0;
	}
#if 0
	for(current = head; current != NULL; current = current->list.pNext)
	{
		Slapi_DN *viewDN;
		Slapi_RDN *viewRDN;
		char *viewRDNstr;
		char *buf = 0;
		Slapi_Filter *viewSubFilter;

		/* if this is this a descendent, ignore it */
		if(slapi_dn_issuffix(current->pDn,pView->pDn) && !(current == pView))
			continue;

		viewDN = slapi_sdn_new_dn_byref(current->pDn);
		viewRDN = slapi_rdn_new();

		slapi_sdn_get_rdn(viewDN,viewRDN);
		viewRDNstr = (char *)slapi_rdn_get_rdn(viewRDN);

		buf = slapi_ch_calloc(1, strlen(viewRDNstr) + 11 ); /* 3 for filter */
		sprintf(buf, "(%s)", viewRDNstr );
		viewSubFilter = slapi_str2filter( buf );
		
		if(pView->includeChildViewsFilter)
			pView->includeChildViewsFilter = slapi_filter_join_ex( LDAP_FILTER_OR, pView->includeChildViewsFilter, viewSubFilter, 0 );
		else
			pView->includeChildViewsFilter = viewSubFilter;

		slapi_ch_free((void **)&buf);
		slapi_sdn_free(&viewDN);
		slapi_rdn_free(&viewRDN);

		child_count++;
	}
#endif

	/* exclude all other view entries but decendents */
/*	pView->includeChildViewsFilter = slapi_filter_join_ex( LDAP_FILTER_NOT, pView->includeChildViewsFilter, NULL, 0 );
*/
	/* it seems reasonable to include entries which
	 * may not fit the view decription but which
	 * are actually *contained* in the view
	 * therefore we use parentids for the view
	 * filter
	 */


	/* add decendents */
	pView->includeChildViewsFilter = views_cache_create_descendent_filter(pView, PR_TRUE);

	/* add this view */
	view_filter_str = PR_smprintf("(parentid=%lu)", pView->entryid);

	if(pView->includeChildViewsFilter)
	{
		pView->includeChildViewsFilter = slapi_filter_join_ex( LDAP_FILTER_OR, slapi_str2filter( view_filter_str ), pView->includeChildViewsFilter, PR_FALSE);
	}
	else
	{
		pView->includeChildViewsFilter = slapi_str2filter( view_filter_str );
	}
	PR_smprintf_free(view_filter_str);
	view_filter_str = NULL;

	/* and make sure the this applies only to views */

/*	if(pView->includeChildViewsFilter)
	{*/
/*  Not necessary since we now use entryid in the filter,
	so all will be views anyway, and the less sub-filters
	the better
		view_filter_str = strdup("(objectclass=" VIEW_OBJECTCLASS ")");
		view_filter = slapi_str2filter( view_filter_str );
*/
		/* child views first because entryid indexed
		 * and makes evaluation faster when a bunch
		 * of indexed filter evaluations with only one
		 * target are evaluated first rather than an
		 * indexed filter which will provide many entries
		 * that may trigger an index evaluation short
		 * circuit.  i.e. if one of the child filters is
		 * true then we have one entry, if not, then we
		 * have used indexes completely to determine that
		 * no entry matches and (objectclass=nsview) is never
		 * evaluated.
		 * I should imagine this will hold for all but the
		 * very deepest, widest view trees when subtree
		 * searches are performed from the top
		 */
/*		pView->includeChildViewsFilter = slapi_filter_join_ex( LDAP_FILTER_AND, pView->includeChildViewsFilter, view_filter, 0 );
	}
	else
	{
		view_filter_str = strdup("(objectclass=nsviewincludenone)");  *//* hackery to get the right result */
/*		pView->includeChildViewsFilter = slapi_str2filter( view_filter_str );
	}
*/
#ifdef _VIEW_DEBUG_FILTERS
	slapi_filter_to_string(pView->includeChildViewsFilter, pView->includeChildViewsFilter_str, sizeof(pView->includeChildViewsFilter_str));
#endif
}


/*
	views_cache_build_view_list
	-------------------------------
	builds the list of views by searching for them throughout the DIT
*/
static int views_cache_build_view_list(viewEntry **pViews)
{
	int ret = 0;
	Slapi_PBlock *pSuffixSearch = 0;
	Slapi_Entry **pSuffixList = 0;
	Slapi_Attr *suffixAttr;
	struct berval **suffixVals;
	char *attrType = 0;
	char *attrs[2];
	int suffixIndex = 0;
	int valIndex = 0;

	slapi_log_error(SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "--> views_cache_build_view_list\n");

	/*
		the views may be anywhere in the DIT,
		so our first task is to find them.
	*/

	attrs[0] = "namingcontexts";
	attrs[1] = 0;

	slapi_log_error(SLAPI_LOG_PLUGIN, VIEWS_PLUGIN_SUBSYSTEM, "views: Building view cache.\n");

	pSuffixSearch = slapi_search_internal("",LDAP_SCOPE_BASE,"(objectclass=*)",NULL,attrs,0);
	if(pSuffixSearch)
		slapi_pblock_get( pSuffixSearch, SLAPI_PLUGIN_INTOP_RESULT, &ret);

	if(pSuffixSearch && ret == LDAP_SUCCESS)
	{
		/* iterate through the suffixes and search for views */
		slapi_pblock_get( pSuffixSearch, SLAPI_PLUGIN_INTOP_SEARCH_ENTRIES, &pSuffixList);
		if(pSuffixList)
		{
			while(pSuffixList[suffixIndex])
			{
				if(!slapi_entry_first_attr(pSuffixList[suffixIndex], &suffixAttr))
				{
					do
					{
						attrType = 0;
						slapi_attr_get_type(suffixAttr, &attrType);
						if(attrType && !slapi_utf8casecmp((unsigned char*)attrType, (unsigned char*)"namingcontexts"))
						{
							if(!slapi_attr_get_bervals_copy(suffixAttr, &suffixVals))
							{
								valIndex = 0;

								if(suffixVals)
								{
									while(suffixVals[valIndex])
									{
										/* here's a suffix, lets search it... */
										if(suffixVals[valIndex]->bv_val)
											views_cache_add_dn_views(suffixVals[valIndex]->bv_val ,pViews);
										
										valIndex++;
									}


									ber_bvecfree( suffixVals );
									suffixVals = NULL;
								}
							}
						}

					} while(!slapi_entry_next_attr(pSuffixList[suffixIndex], suffixAttr, &suffixAttr));
				}
				suffixIndex++;
			}
		}
	}
	else
	{
		slapi_log_error(SLAPI_LOG_PLUGIN, VIEWS_PLUGIN_SUBSYSTEM, "views_cache_build_view_list: failed to find suffixes\n");
		ret = -1;
	}

	/* clean up */
	if(pSuffixSearch)
	{
		slapi_free_search_results_internal(pSuffixSearch);
		slapi_pblock_destroy(pSuffixSearch);
	}


	slapi_log_error(SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "<-- views_cache_build_view_list\n");
	return ret;
}

/* struct to support search callback API */
struct dn_views_info {
	viewEntry **pViews;
	int ret;
};

/* does same funcationality as views_add_dn_views except it is invoked via a callback */

static int	views_dn_views_cb (Slapi_Entry* e, void *callback_data) {
	struct dn_views_info *info;
	char *pDn = 0;
	struct berval **dnVals;
	Slapi_Attr *dnAttr;
	char *attrType = 0;
	char *attrs[3];
	viewEntry *pView;
	
	attrs[0] = VIEW_FILTER_ATTR;
	attrs[1] = "entryid";
	attrs[2] = 0;
	info=(struct dn_views_info *)callback_data;
	
	info->ret = 0;

	pDn = slapi_entry_get_ndn(e);
	
	/* create the view */
	pView = calloc(1, sizeof(viewEntry));
	pView->pDn = slapi_ch_strdup(pDn);

	if(!slapi_entry_first_attr(e, &dnAttr))
	{
		do
		{
			attrType = 0;		


			/* get the filter */
			slapi_attr_get_type(dnAttr, &attrType);		
			if(attrType && !strcasecmp(attrType,VIEW_FILTER_ATTR))
			{
				if(!slapi_attr_get_bervals_copy(dnAttr, &dnVals))
				{
					/* add filter */
					pView->viewfilter = slapi_ch_strdup(dnVals[0]->bv_val);
				}

				ber_bvecfree( dnVals );
				dnVals = NULL;
			}

			if(attrType && !strcasecmp(attrType,"entryid"))
			{
				Slapi_Value *val = 0;

				slapi_attr_first_value(dnAttr, &val);
				pView->entryid = slapi_value_get_ulong(val);
			}
			
			if(attrType && !strcasecmp(attrType,"parentid"))
			{
				Slapi_Value *val = 0;

				slapi_attr_first_value(dnAttr, &val);
				pView->parentid = slapi_value_get_ulong(val);
			}

		} while(!slapi_entry_next_attr(e, dnAttr, &dnAttr));

	}		

	/* add view to the cache */
	views_cache_add_ll_entry((void**)info->pViews, (void *)pView);

	return info->ret;
}


/*
	views_cache_add_dn_views
	-------------------------
	takes a dn as argument and searches the dn for views,
	adding any found to the view cache. Change to use search callback API
*/

#define DN_VIEW_FILTER "(objectclass=" VIEW_OBJECTCLASS ")"

static int views_cache_add_dn_views(char *dn, viewEntry **pViews)
{
	Slapi_PBlock *pDnSearch = 0;
	struct dn_views_info info;
    pDnSearch = slapi_pblock_new();
	if (pDnSearch) {
		info.ret=-1;
		info.pViews=pViews;
		slapi_search_internal_set_pb(pDnSearch, dn, LDAP_SCOPE_SUBTREE,
									 DN_VIEW_FILTER,NULL,0,
									 NULL,NULL,view_get_plugin_identity(),0);
		slapi_search_internal_callback_pb(pDnSearch,
								  &info /* callback_data */,
								  NULL/* result_callback */,
								  views_dn_views_cb,
								  NULL /* referral_callback */);
		slapi_pblock_destroy (pDnSearch);
	}
	return info.ret;
}

/*
	views_cache_add_ll_entry
	---------------------------------------------------
	the element is added to the head of the linked list

	*NOTE* this function assumes and *requires* that the structures
	passed to it in "attrval" and "theVal" have a viewLinkedList
	member, and it is the *first* member of the structure.  This
	is safe because this is a module level function, and all functions
	which call this one are part of the same sub-system.
*/
static void views_cache_add_ll_entry(void** attrval, void *theVal)
{
	slapi_log_error(SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "--> views_cache_add_ll_entry\n");

	if(*attrval)
	{
		/* push this to the start of the list (because its quick) */
		((viewLinkedList*)theVal)->pNext = *attrval;
		((viewLinkedList*)(*attrval))->pPrev = theVal;
		*attrval = theVal;
	}
	else
	{
		/* new or end of list */
		((viewLinkedList*)theVal)->pNext = NULL;
		((viewLinkedList*)theVal)->pPrev = NULL;
		*attrval = theVal;
	}

	slapi_log_error(SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "<-- views_cache_add_ll_entry\n");
}


/*
	views_update_views_cache
	-----------------------

	update internal view cache after state change
*/
static void views_update_views_cache( Slapi_Entry *e, char *dn, int modtype, Slapi_PBlock *pb, void *caller_data )
{
	char *pDn;
	viewEntry *theView;
	viewEntry *current;
	Slapi_Attr *attr;
	struct berval val;
	int build_cache = 0;

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "--> views_update_views_cache\n");

	views_write_lock();

	if(!theCache.cache_built)
	{
		/* zarro views = no cache,
		 * this is probably an add op
		 * lets build the cache
		 */
		build_cache = 1;
		goto unlock_cache;
	}

	pDn = slapi_entry_get_ndn(e);
	theView = views_cache_find_view(pDn);

	switch(modtype)
	{
	case LDAP_CHANGETYPE_MODIFY:
		/* if still a view and exists
		 * update string filter
		 * update the filters of all views
		 * if just became a view fall through to add op
		 * if stopped being a view fall through to delete op
		 */

		/* determine what happenned - does the view exist currently? */
		if(theView)
		{
			/* does it have the view objectclass? */
			if(!slapi_entry_attr_find( e, "objectclass", &attr ))
			{
				val.bv_len = 8;
				val.bv_val = VIEW_OBJECTCLASS;

				if(!slapi_attr_value_find( attr, &val))
				{
					/* it is a view */
					attr = 0;

					/* has the filter changed? */
					slapi_entry_attr_find( e, VIEW_FILTER_ATTR, &attr );

					if(attr)
					{
						if(theView->viewfilter) /* NULL means a filter added */
						{
							/* we could translate the string filter into
							 * a real filter and compare against
							 * the view - that would tell us if the filter
							 * was substantively changed.
							 *
							 * But we're not gonna do that :)
							 */
							val.bv_len = strlen(theView->viewfilter)+1;
							val.bv_val = theView->viewfilter;

							if(!slapi_attr_value_find( attr, &val))
							{
								/* filter unchanged */
								break;
							}
						}
					}
					else
					{
						/* if no filter in view, then no change */
						if(theView->viewfilter == 0)
							break;
					}

					/* this was indeed a significant mod, add the new filter */
					if(theView->viewfilter)
						slapi_ch_free((void**)&theView->viewfilter);

					if(attr)
					{
						Slapi_Value *v;
						slapi_attr_first_value( attr, &v );
						theView->viewfilter = slapi_ch_strdup(slapi_value_get_string(v));
					}

					/* update all filters */
					for(current = theCache.pCacheViews; current != NULL; current = current->list.pNext)
					{
						views_cache_create_applied_filter(current);
						views_cache_create_exclusion_filter(current);
						views_cache_create_inclusion_filter(current);
					}
				}
				else
				{
					/* this is a delete operation */
					modtype = LDAP_CHANGETYPE_DELETE;
				}
			}
			else
				/* thats bad */
				break;
		}
		else
		{
			/* this is an add operation */
			modtype = LDAP_CHANGETYPE_ADD;
		}

	case LDAP_CHANGETYPE_DELETE:
		/* remove view entry from list
		 * update children of parent
		 * update all child filters
		 * re-index
		 */
		if(modtype == LDAP_CHANGETYPE_DELETE)
		{

			if(theCache.view_count-1)
			{
				/* detach view */
				if(theView->list.pPrev)
					((viewEntry*)(theView->list.pPrev))->list.pNext = theView->list.pNext;

				if(theView->list.pNext)
				{
					((viewEntry*)(theView->list.pNext))->list.pPrev = theView->list.pPrev;

					if(theView->list.pPrev == NULL) /* if this is the head */
						theCache.pCacheViews = (viewEntry*)(theView->list.pNext);
				}

				/* update children */
				if(theView->pParent)
					views_cache_discover_children((viewEntry*)theView->pParent);

				/* update filters */
				for(current = theCache.pCacheViews; current != NULL; current = current->list.pNext)
				{
					views_cache_create_applied_filter(current);
					views_cache_create_exclusion_filter(current);
					views_cache_create_inclusion_filter(current);
				}

				/* reindex */
				views_cache_index();
			}
			else
			{
				theCache.pCacheViews = NULL;
				theCache.view_count = 0;
				theCache.cache_built = 0;
			}

			/* free the view */
			slapi_ch_free((void**)&theView->pDn);
			slapi_ch_free((void**)&theView->viewfilter);
			slapi_filter_free(theView->includeAncestorFiltersFilter,1); 
			slapi_filter_free(theView->excludeAllButDescendentViewsFilter,1);
			slapi_filter_free(theView->excludeChildFiltersFilter,1);
			slapi_filter_free(theView->excludeGrandChildViewsFilter,1);
			slapi_filter_free(theView->includeChildViewsFilter,1);
			slapi_ch_free((void**)&theView->pSearch_base);
			slapi_ch_free((void**)&theView->pChildren);
			slapi_ch_free((void**)&theView);

			break;
		}

	case LDAP_CHANGETYPE_ADD:
		/* create view entry
		 * add it to list
		 * update children of parent
		 * update all child filters
		 * re-index
		 */
		if(modtype == LDAP_CHANGETYPE_ADD)
		{
			theView = calloc(1, sizeof(viewEntry));
			theView->pDn = slapi_ch_strdup(pDn);
			
			/* get the view filter, the entryid, and the parentid */
			slapi_entry_attr_find( e, VIEW_FILTER_ATTR, &attr );

			if(attr)
			{
				Slapi_Value *v;
				slapi_attr_first_value( attr, &v );
				theView->viewfilter = slapi_ch_strdup(slapi_value_get_string(v));
			}
			else
				theView->viewfilter = NULL;

			slapi_entry_attr_find( e, "entryid", &attr );

			if(attr)
			{
				Slapi_Value *v;
				slapi_attr_first_value( attr, &v );
				theView->entryid = slapi_value_get_ulong(v);
			}
			else
				theView->entryid = 0;

			slapi_entry_attr_find( e, "parentid", &attr );

			if(attr)
			{
				Slapi_Value *v;
				slapi_attr_first_value( attr, &v );
				theView->parentid = slapi_value_get_ulong(v);
			}
			else
				theView->parentid = 0;

			/* add view to the cache */
			views_cache_add_ll_entry((void**)theCache.pCacheViews, (void *)theView);

			views_cache_discover_parent(theView);
			if(theView->pParent)
				views_cache_discover_children((viewEntry*)theView->pParent);

			/* update filters */
			for(current = theCache.pCacheViews; current != NULL; current = current->list.pNext)
			{
				views_cache_discover_view_scope(current); /* if ns-view oc added, new view may be top */
				views_cache_create_applied_filter(current);
				views_cache_create_exclusion_filter(current);
				views_cache_create_inclusion_filter(current);
			}

			/* reindex */
			views_cache_index();
			break;
		}

	case LDAP_CHANGETYPE_MODDN:
		/* get old dn to find the view
		 * change dn
		 * update parents and children
		 * update all filters
		 * reindex 
		 */

		{
			char *old_dn;
			Slapi_Entry *old_entry;

			slapi_pblock_get( pb, SLAPI_ENTRY_PRE_OP, &old_entry );
			old_dn = slapi_entry_get_ndn(old_entry);

			theView = views_cache_find_view(old_dn);
			if(theView)
			{
				slapi_ch_free((void**)&theView->pDn);
				theView->pDn = slapi_ch_strdup(pDn);

				for(current = theCache.pCacheViews; current != NULL; current = current->list.pNext)
				{
					views_cache_discover_parent(current);
					views_cache_discover_children(current);
				}

				for(current = theCache.pCacheViews; current != NULL; current = current->list.pNext)
				{
					views_cache_discover_view_scope(current);
					views_cache_create_applied_filter(current);
					views_cache_create_exclusion_filter(current);
					views_cache_create_inclusion_filter(current);
				}
			}
			/* reindex */
			views_cache_index();
			break;
		}

	default:
		/* we don't care about this op */
		break;
	}

unlock_cache:
	views_unlock();

	if(build_cache)
	{
		views_cache_create();
	}

	slapi_log_error( SLAPI_LOG_TRACE, VIEWS_PLUGIN_SUBSYSTEM, "<-- views_update_views_cache\n");
}



/*
 * view_search_rewrite_callback
 * ----------------------------
 * this is the business end of the plugin
 * this function is called from slapd
 * rewrites the search to conform to the view
 * Meaning of the return code :
 * -1 : keep looking
 *  0 : rewrote OK
 *  1 : refuse to do this search
 *  2 : operations error
 */
static int view_search_rewrite_callback(Slapi_PBlock *pb)
{
	int ret = -1;
	char *base = 0;
	Slapi_Filter *clientFilter = 0;
	Slapi_Filter *includeAncestorFiltersFilter = 0; /* the view with all ancestor views */
	Slapi_Filter *excludeChildFiltersFilter = 0; /* NOT all children views, for one level searches */
	Slapi_Filter *excludeGrandChildViewsFilter = 0; /* view filter for one level searches */
	Slapi_Filter *includeChildViewsFilter = 0; /* view filter for subtree searches */
	Slapi_Filter *seeViewsFilter = 0; /* view filter to see views */
	Slapi_Filter *outFilter = 0;
	int scope = 0;
	int set_scope = LDAP_SCOPE_SUBTREE;
	viewEntry *theView = 0;

#ifdef _VIEW_DEBUG_FILTERS
	char outFilter_str[1024];
	char clientFilter_str[1024];
	char includeAncestorFiltersFilter_str[1024];
	char excludeChildFiltersFilter_str[1024];
	char excludeGrandChildViewsFilter_str[1024];
	char includeChildViewsFilter_str[1024];
#endif

	/* if no cache, no views */
	if(!theCache.cache_built)
		goto end;

	/* avoid locking if this thread is the updater */
	if(theCache.currentUpdaterThread)
	{
		PRThread *thisThread = PR_GetCurrentThread();
		if(thisThread == theCache.currentUpdaterThread)
			goto end;
	}

	/* first, find out if this is a base search (we do nothing) */
	slapi_pblock_get(pb, SLAPI_SEARCH_SCOPE, &scope);
	if(scope == LDAP_SCOPE_BASE)
		goto end;

	/* if base of the search is a view */
	slapi_pblock_get(pb, SLAPI_SEARCH_TARGET, &base);

	/* Read lock the cache */
	views_read_lock();

	theView = views_cache_find_view(base);

	/* if the view is disabled (we service subtree searches in this case) */
	if(!theView || !theView->viewfilter && scope == LDAP_SCOPE_ONELEVEL)
	{
		/* unlock the cache */
		views_unlock();
		goto end;
	}


	/* this is a view search, and we are smokin' */

	/* grab the view filters we are going to need now so we can release the cache lock */
	if(scope == LDAP_SCOPE_ONELEVEL)
	{
		excludeChildFiltersFilter = slapi_filter_dup(theView->excludeChildFiltersFilter); 
		excludeGrandChildViewsFilter = slapi_filter_dup(theView->excludeGrandChildViewsFilter); 

#ifdef _VIEW_DEBUG_FILTERS
		slapi_filter_to_string(excludeChildFiltersFilter, excludeChildFiltersFilter_str, sizeof(excludeChildFiltersFilter_str));
		slapi_filter_to_string(excludeGrandChildViewsFilter, excludeGrandChildViewsFilter_str, sizeof(excludeGrandChildViewsFilter_str));
#endif

	}

	includeChildViewsFilter = slapi_filter_dup(theView->includeChildViewsFilter); 

#ifdef _VIEW_DEBUG_FILTERS
	slapi_filter_to_string(includeChildViewsFilter, includeChildViewsFilter_str, sizeof(includeChildViewsFilter_str));
#endif

	/* always used */
	includeAncestorFiltersFilter = slapi_filter_dup(theView->includeAncestorFiltersFilter); 

#ifdef _VIEW_DEBUG_FILTERS
		slapi_filter_to_string(includeAncestorFiltersFilter, includeAncestorFiltersFilter_str, sizeof(includeAncestorFiltersFilter_str));
#endif

	/* unlock the cache */
	views_unlock();

	/* rewrite search scope and base*/
	slapi_pblock_set(pb, SLAPI_SEARCH_SCOPE, &set_scope);

	base = slapi_ch_strdup(theView->pSearch_base);
	slapi_pblock_set(pb, SLAPI_SEARCH_TARGET, base);

	/* concatenate the filters */
	
	/* grab the client filter - we need 2 copies */
	slapi_pblock_get(pb, SLAPI_SEARCH_FILTER, &clientFilter);

#ifdef _VIEW_DEBUG_FILTERS
	slapi_filter_to_string(clientFilter, clientFilter_str, sizeof(clientFilter_str));
#endif

	/* client supplied filter AND inclusion filter - make sure we can see views */
	if(scope == LDAP_SCOPE_ONELEVEL)
	{
		Slapi_Filter *clientSeeViewsFilter = 0; /* view filter to see views */

		clientSeeViewsFilter = slapi_filter_dup(clientFilter);
		if(excludeGrandChildViewsFilter)
			seeViewsFilter = slapi_filter_join_ex( LDAP_FILTER_AND, excludeGrandChildViewsFilter, clientSeeViewsFilter, 0 );
		else
			seeViewsFilter = clientSeeViewsFilter;
	}

	/* this filter is to lock our view to the subtree at hand */
	if(seeViewsFilter && includeChildViewsFilter)
		seeViewsFilter = slapi_filter_join_ex( LDAP_FILTER_AND, includeChildViewsFilter, seeViewsFilter, 0 );
	else
	{
		if(includeChildViewsFilter)
			seeViewsFilter = includeChildViewsFilter; 
	}
	
	/* create target filter */
	if(includeAncestorFiltersFilter)
		outFilter = slapi_filter_join_ex( LDAP_FILTER_AND, includeAncestorFiltersFilter, clientFilter, 0 );
	else
		outFilter = clientFilter;

	if(scope == LDAP_SCOPE_ONELEVEL)
	{
		if(excludeChildFiltersFilter)
			outFilter = slapi_filter_join_ex( LDAP_FILTER_AND, outFilter, excludeChildFiltersFilter, 0  );
	}

	if(seeViewsFilter)
		outFilter = slapi_filter_join_ex( LDAP_FILTER_OR, outFilter, seeViewsFilter, 0 );

#ifdef _VIEW_DEBUG_FILTERS
	slapi_filter_to_string(outFilter, outFilter_str, sizeof(outFilter_str));
#endif

	/* make it happen */
	slapi_pblock_set(pb, SLAPI_SEARCH_FILTER, outFilter);

	ret = -2;

end:
	return ret;
}

/*
 * views_cache_backend_state_change()
 * --------------------------------
 * This is called when a backend changes state
 * We simply signal to rebuild the cache in this case
 *
 */
static void views_cache_backend_state_change(void *handle, char *be_name, 
     int old_be_state, int new_be_state) 
{
	/* we will create a thread to do this since
	 * calling views_cache_create() directly will
	 * hold up the op
	 */
	if ((PR_CreateThread (PR_USER_THREAD, 
					views_cache_act_on_change_thread, 
					NULL,
					PR_PRIORITY_NORMAL, 
					PR_GLOBAL_THREAD, 
					PR_UNJOINABLE_THREAD, 
					SLAPD_DEFAULT_THREAD_STACKSIZE)) == NULL )
	{
		slapi_log_error( SLAPI_LOG_FATAL, VIEWS_PLUGIN_SUBSYSTEM,
			   "views_cache_backend_state_change: PR_CreateThread failed\n" );
	}
}

static void views_cache_act_on_change_thread(void *arg)
{
	views_cache_create();
}