Parent studios (#595)

* Refactor getMultiCriterionClause
Co-authored-by: Anon247 <61889302+Anon247@users.noreply.github.com>

pkg/manager/studio.go

@@ -0,0 +1,36 @@
+package manager
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/jmoiron/sqlx"
+	"github.com/stashapp/stash/pkg/models"
+)
+
+func ValidateModifyStudio(studio models.StudioPartial, tx *sqlx.Tx) error {
+	if studio.ParentID == nil || !studio.ParentID.Valid {
+		return nil
+	}
+
+	// ensure there is no cyclic dependency
+	thisID := studio.ID
+	qb := models.NewStudioQueryBuilder()
+
+	currentParentID := *studio.ParentID
+
+	for currentParentID.Valid {
+		if currentParentID.Int64 == int64(thisID) {
+			return errors.New("studio cannot be an ancestor of itself")
+		}
+
+		currentStudio, err := qb.Find(int(currentParentID.Int64), tx)
+		if err != nil {
+			return fmt.Errorf("error finding parent studio: %s", err.Error())
+		}
+
+		currentParentID = currentStudio.ParentID
+	}
+
+	return nil
+}