s4/dsdb-schema: Index attributes on msDS-IntId value

O(n) search for dsdb_attribute by msDS-IntId value was
replaced by binary-search in ordered index.

I've choosen the approach of separate index on msDS-IntId values
as I think it is more clear what we are searching for.
And it should little bit faster as we can clearly determine
in which index to perform the search based on ATTID value -
ATTIDs based on prefixMap and ATTIDs based on msDS-IntId
are in separate ranges.

Other way to implement this index was to merge msDS-IntId values
in attributeID_id index.
This led me to a shorted but not so obvious implementation.

3 files changed, 28 insertions, 7 deletions

diff --git a/source4/dsdb/schema/schema.h b/source4/dsdb/schema/schema.h
index 0cbc21868f..34423be809 100644
--- a/source4/dsdb/schema/schema.h
+++ b/source4/dsdb/schema/schema.h
@@ -209,6 +209,8 @@ struct dsdb_schema {
 	struct dsdb_attribute **attributes_by_attributeID_id;
 	struct dsdb_attribute **attributes_by_attributeID_oid;
 	struct dsdb_attribute **attributes_by_linkID;
+	uint32_t num_int_id_attr;
+	struct dsdb_attribute **attributes_by_msDS_IntId;
 
 	struct {
 		bool we_are_master;
diff --git a/source4/dsdb/schema/schema_query.c b/source4/dsdb/schema/schema_query.c
index 4ff84185f8..8ea79ff4bb 100644
--- a/source4/dsdb/schema/schema_query.c
+++ b/source4/dsdb/schema/schema_query.c
@@ -65,11 +65,9 @@ const struct dsdb_attribute *dsdb_attribute_by_attributeID_id(const struct dsdb_
 
 	/* check for msDS-IntId type attribute */
 	if (dsdb_pfm_get_attid_type(id) == dsdb_attid_type_intid) {
-		for (c = schema->attributes; c; c = c->next) {
-			if (c->msDS_IntId == id) {
-				return c;
-			}
-		}
+		BINARY_ARRAY_SEARCH_P(schema->attributes_by_msDS_IntId,
+				      schema->num_int_id_attr, msDS_IntId, id, uint32_cmp, c);
+		return c;
 	}
 
 	BINARY_ARRAY_SEARCH_P(schema->attributes_by_attributeID_id,
diff --git a/source4/dsdb/schema/schema_set.c b/source4/dsdb/schema/schema_set.c
index 5ecbad214f..fc255a1cd3 100644
--- a/source4/dsdb/schema/schema_set.c
+++ b/source4/dsdb/schema/schema_set.c
@@ -230,6 +230,7 @@ static int dsdb_setup_sorted_accessors(struct ldb_context *ldb,
 	struct dsdb_class *cur;
 	struct dsdb_attribute *a;
 	unsigned int i;
+	unsigned int num_int_id;
 
 	talloc_free(schema->classes_by_lDAPDisplayName);
 	talloc_free(schema->classes_by_governsID_id);
@@ -268,35 +269,54 @@ static int dsdb_setup_sorted_accessors(struct ldb_context *ldb,
 	/* now build the attribute accessor arrays */
 	talloc_free(schema->attributes_by_lDAPDisplayName);
 	talloc_free(schema->attributes_by_attributeID_id);
+	talloc_free(schema->attributes_by_msDS_IntId);
 	talloc_free(schema->attributes_by_attributeID_oid);
 	talloc_free(schema->attributes_by_linkID);
 
-	/* count the attributes */
-	for (i=0, a=schema->attributes; a; i++, a=a->next) /* noop */ ;
+	/* count the attributes
+	 * and attributes with msDS-IntId set */
+	num_int_id = 0;
+	for (i=0, a=schema->attributes; a; i++, a=a->next) {
+		if (a->msDS_IntId != 0) {
+			num_int_id++;
+		}
+	}
 	schema->num_attributes = i;
+	schema->num_int_id_attr = num_int_id;
 
 	/* setup attributes_by_* */
 	schema->attributes_by_lDAPDisplayName = talloc_array(schema, struct dsdb_attribute *, i);
 	schema->attributes_by_attributeID_id    = talloc_array(schema, struct dsdb_attribute *, i);
+	schema->attributes_by_msDS_IntId        = talloc_array(schema,
+	                                                       struct dsdb_attribute *, num_int_id);
 	schema->attributes_by_attributeID_oid   = talloc_array(schema, struct dsdb_attribute *, i);
 	schema->attributes_by_linkID              = talloc_array(schema, struct dsdb_attribute *, i);
 	if (schema->attributes_by_lDAPDisplayName == NULL ||
 	    schema->attributes_by_attributeID_id == NULL ||
+	    schema->attributes_by_msDS_IntId == NULL ||
 	    schema->attributes_by_attributeID_oid == NULL ||
 	    schema->attributes_by_linkID == NULL) {
 		goto failed;
 	}
 
+	num_int_id = 0;
 	for (i=0, a=schema->attributes; a; i++, a=a->next) {
 		schema->attributes_by_lDAPDisplayName[i] = a;
 		schema->attributes_by_attributeID_id[i]    = a;
 		schema->attributes_by_attributeID_oid[i]   = a;
 		schema->attributes_by_linkID[i]          = a;
+		/* append attr-by-msDS-IntId values */
+		if (a->msDS_IntId != 0) {
+			schema->attributes_by_msDS_IntId[num_int_id] = a;
+			num_int_id++;
+		}
 	}
+	SMB_ASSERT(num_int_id == schema->num_int_id_attr);
 
 	/* sort the arrays */
 	TYPESAFE_QSORT(schema->attributes_by_lDAPDisplayName, schema->num_attributes, dsdb_compare_attribute_by_lDAPDisplayName);
 	TYPESAFE_QSORT(schema->attributes_by_attributeID_id, schema->num_attributes, dsdb_compare_attribute_by_attributeID_id);
+	TYPESAFE_QSORT(schema->attributes_by_msDS_IntId, schema->num_int_id_attr, dsdb_compare_attribute_by_attributeID_id);
 	TYPESAFE_QSORT(schema->attributes_by_attributeID_oid, schema->num_attributes, dsdb_compare_attribute_by_attributeID_oid);
 	TYPESAFE_QSORT(schema->attributes_by_linkID, schema->num_attributes, dsdb_compare_attribute_by_linkID);
 
@@ -309,6 +329,7 @@ failed:
 	schema->classes_by_cn = NULL;
 	schema->attributes_by_lDAPDisplayName = NULL;
 	schema->attributes_by_attributeID_id = NULL;
+	schema->attributes_by_msDS_IntId = NULL;
 	schema->attributes_by_attributeID_oid = NULL;
 	schema->attributes_by_linkID = NULL;
 	ldb_oom(ldb);