Indexer Factory Function

The indexer factory function takes a parameter block from Directory Server. The function sets parameters such that Directory Server can update an index or sort results based on a matching rule.

The following figure shows how Directory Server uses the indexer factory function.

Figure 10–6 Indexer Factory Function Context

The following example shows the indexer factory function for the case exact matching rule.

Example 10–8 Indexer Factory Function (matchingrule.c)

#include "slapi-plugin.h"

#define PLG_OID       "1.3.6.1.4.1.42.2.27.999.4.1"
#define SUBSYS        "CaseExactMatching Plugin"

/* Functions to obtain connection information for logging.             */
static long mypblock_get_msgid( Slapi_PBlock * pb);
static int  mypblock_get_connid(Slapi_PBlock * pb);
static int  mypblock_get_opid(  Slapi_PBlock * pb);

static int
plg_indexer_create(Slapi_PBlock * pb)
{
    int    rc     = LDAP_UNAVAILABLE_CRITICAL_EXTENSION; /* Init failed*/
    char * mr_oid = NULL;              /* MR OID from the server       */
    
    if (slapi_pblock_get(pb, SLAPI_PLUGIN_MR_OID, mr_oid) ||
        (mr_oid == NULL)) {
        slapi_log_error_ex(
            -1, /* errorId */
            mypblock_get_msgid(pb),
            mypblock_get_connid(pb),
            mypblock_get_opid(pb),
            SUBSYS,
            SLAPI_INTERNAL_ERROR,
            "plg_indexer_create failed: NULL OID values are invalid.\n"
        );
    } else if (strcmp(mr_oid, PLG_OID) == 0) {
        if ( /* The MR OID from the server is handled by this plug-in. */
            (slapi_pblock_set(         /* This is for completeness.    */
                pb,                    /* Your plug-in may set a       */
                SLAPI_PLUGIN_MR_OID,   /* different OID than the one   */
                PLG_OID                /* provided by the server.      */
            ) == 0) &&
            (slapi_pblock_set(         /* Provide an appropriate       */
                pb,                    /* indexer function pointer.    */
                SLAPI_PLUGIN_MR_INDEX_FN,
                (void *)plg_index_entry
            ) == 0) &&
            (slapi_pblock_set(         /* Set the object destructor.   */
                pb,
                SLAPI_PLUGIN_DESTROY_FN,
                (void *)plg_filter_destroy
            ) == 0)) {
                rc = LDAP_SUCCESS;
        } else {
            slapi_log_error_ex(
                -1, /* errorId */
                mypblock_get_msgid(pb),
                mypblock_get_connid(pb),
                mypblock_get_opid(pb),
                SUBSYS,
                SLAPI_INTERNAL_ERROR,
                "plg_indexer_create failed %d \n", rc
            );
        }
    }
    
    return rc;
}

Here, PLG_OID is the object identifier for the matching rule. plg_index_entry() is the indexer. plg_filter_destroy() is the destructor. Notice that the function returns LDAP_UNAVAILABLE_CRITICAL_EXTENSION on failure.

Input Parameters for Indexer Factory Functions

An indexer factory function can read the values for the following from the parameter block:

• SLAPI_PLUGIN_MR_OID

• SLAPI_PLUGIN_MR_TYPE

• SLAPI_PLUGIN_MR_USAGE, indicates whether results must be sorted

• SLAPI_PLUGIN_PRIVATE, if your plug-in uses private data that you specify in the plug-in initialization function

Output Parameters for Indexer Factory Functions

An indexer factory function should set values for at least the following in the parameter block before returning control to Directory Server:

• SLAPI_PLUGIN_DESTROY_FN, a pointer to the indexer object destructor

• SLAPI_PLUGIN_MR_INDEX_FN, a pointer to the indexer

• SLAPI_PLUGIN_OBJECT, a pointer to the indexer object

Refer to Chapter 17, Parameter Block Reference for details about the parameter block.

Thread Safety and Indexer Factory Functions

This function must be thread safe. Directory Server can call this function concurrently.