s4:dsdb - introduce a only constant-time "get_last_structural_class()" call

With the redesign of the previous patches this has become possible.

3 files changed, 18 insertions, 37 deletions

diff --git a/source4/dsdb/samdb/ldb_modules/descriptor.c b/source4/dsdb/samdb/ldb_modules/descriptor.c
index f2afe742af..0a4b1da39f 100644
--- a/source4/dsdb/samdb/ldb_modules/descriptor.c
+++ b/source4/dsdb/samdb/ldb_modules/descriptor.c
@@ -542,8 +542,7 @@ static int descriptor_add(struct ldb_module *module, struct ldb_request *req)
 		return ldb_operr(ldb);
 	}
 
-	objectclass = get_last_structural_class(schema, objectclass_element,
-						true);
+	objectclass = get_last_structural_class(schema, objectclass_element);
 	if (objectclass == NULL) {
 		return ldb_operr(ldb);
 	}
@@ -661,8 +660,7 @@ static int descriptor_modify(struct ldb_module *module, struct ldb_request *req)
 		return ldb_operr(ldb);
 	}
 
-	objectclass = get_last_structural_class(schema, objectclass_element,
-						true);
+	objectclass = get_last_structural_class(schema, objectclass_element);
 	if (objectclass == NULL) {
 		return ldb_operr(ldb);
 	}
diff --git a/source4/dsdb/samdb/ldb_modules/objectclass.c b/source4/dsdb/samdb/ldb_modules/objectclass.c
index b8422ee86e..033330c86c 100644
--- a/source4/dsdb/samdb/ldb_modules/objectclass.c
+++ b/source4/dsdb/samdb/ldb_modules/objectclass.c
@@ -470,8 +470,7 @@ static int objectclass_do_add(struct oc_context *ac)
 		 * unrelated structural classes
 		 */
 		objectclass = get_last_structural_class(ac->schema,
-							objectclass_element,
-							true);
+							objectclass_element);
 		if (objectclass == NULL) {
 			ldb_asprintf_errstring(ldb,
 					       "Failed to find a structural class for %s",
@@ -955,8 +954,7 @@ static int objectclass_do_mod(struct oc_context *ac)
 		 * Get the new top-most structural object class and check for
 		 * unrelated structural classes
 		 */
-		objectclass = get_last_structural_class(ac->schema, oc_el_entry,
-							true);
+		objectclass = get_last_structural_class(ac->schema, oc_el_entry);
 		if (objectclass == NULL) {
 			ldb_set_errstring(ldb,
 					  "objectclass: cannot delete all structural objectclasses!");
@@ -1132,8 +1130,7 @@ static int objectclass_do_rename2(struct oc_context *ac)
 			/* existing entry without a valid object class? */
 			return ldb_operr(ldb);
 		}
-		objectclass = get_last_structural_class(ac->schema, oc_el_entry,
-							false);
+		objectclass = get_last_structural_class(ac->schema, oc_el_entry);
 		if (objectclass == NULL) {
 			/* existing entry without a valid object class? */
 			return ldb_operr(ldb);
diff --git a/source4/dsdb/samdb/ldb_modules/schema.c b/source4/dsdb/samdb/ldb_modules/schema.c
index d24d388d25..333fb1b0a6 100644
--- a/source4/dsdb/samdb/ldb_modules/schema.c
+++ b/source4/dsdb/samdb/ldb_modules/schema.c
@@ -31,43 +31,29 @@
 
 /*
  * This function determines the (last) structural or 88 object class of a passed
- * "objectClass" attribute.
- * Without schema this does not work and hence NULL is returned. If the
- * "objectClass" attribute has already been sorted then only a check on the
- * last value is necessary (MS-ADTS 3.1.1.1.4)
+ * "objectClass" attribute - per MS-ADTS 3.1.1.1.4 this is the last value.
+ * Without schema this does not work and hence NULL is returned.
  */
 const struct dsdb_class *get_last_structural_class(const struct dsdb_schema *schema,
-						   const struct ldb_message_element *element,
-						   bool sorted)
+						   const struct ldb_message_element *element)
 {
-	const struct dsdb_class *last_class = NULL;
-	unsigned int i = 0;
+	const struct dsdb_class *last_class;
 
 	if (schema == NULL) {
 		return NULL;
 	}
 
-	if (sorted && (element->num_values > 1)) {
-		i = element->num_values - 1;
+	if (element->num_values == 0) {
+		return NULL;
 	}
 
-	for (; i < element->num_values; i++){
-		const struct dsdb_class *tmp_class = dsdb_class_by_lDAPDisplayName_ldb_val(schema, &element->values[i]);
-
-		if(tmp_class == NULL) {
-			continue;
-		}
-
-		if(tmp_class->objectClassCategory > 1) {
-			continue;
-		}
-
-		if (!last_class) {
-			last_class = tmp_class;
-		} else {
-			if (tmp_class->subClass_order > last_class->subClass_order)
-				last_class = tmp_class;
-		}
+	last_class = dsdb_class_by_lDAPDisplayName_ldb_val(schema,
+							   &element->values[element->num_values-1]);
+	if (last_class == NULL) {
+		return NULL;
+	}
+	if (last_class->objectClassCategory > 1) {
+		return NULL;
 	}
 
 	return last_class;