Function BsonUnwindEmptyArray

pg_documentdb/src/aggregation/bson_unwind.c:495–524

* BsonUnwindEmptyArray produces the output document when an empty array is found * at the unwind target * document -> source document * path -> path being unwound * indexFieldName -> optional name for the index field to be added */

 *    indexFieldName -> optional name for the index field to be added
 */
static pgbson *
BsonUnwindEmptyArray(pgbson *document, char *path, char *indexFieldName)
{
	pgbson_writer projectSpecWriter;
	PgbsonWriterInit(&projectSpecWriter);

	bool value = false;
	PgbsonWriterAppendBool(&projectSpecWriter, path, strlen(path),
						   value);

	if (indexFieldName != NULL)
	{
		/* Single elements have null index */
		PgbsonWriterAppendNull(&projectSpecWriter, indexFieldName, strlen(
								   indexFieldName));
	}

	bson_iter_t projectSpec;
	PgbsonWriterGetIterator(&projectSpecWriter, &projectSpec);

	bool forceProjectId = true;
	bool allowInclusionExclusion = true;

	pgbson *variableSpec = NULL;
	const BsonProjectionQueryState *projectionState =
		GetProjectionStateForBsonProject(&projectSpec,
										 forceProjectId, allowInclusionExclusion,
										 variableSpec);
	return ProjectDocumentWithState(document, projectionState);
}


/*