ast: add GrantRoleStmt to support GRANT ROLE (pingcap#242)

ast/misc.go

@@ -1640,6 +1640,60 @@ func (n *GrantStmt) Accept(v Visitor) (Node, bool) {
 	return v.Leave(n)
 }
 
+// GrantRoleStmt is the struct for GRANT TO statement.
+type GrantRoleStmt struct {
+	stmtNode
+
+	Roles []*auth.RoleIdentity
+	Users []*auth.UserIdentity
+}
+
+// Accept implements Node Accept interface.
+func (n *GrantRoleStmt) Accept(v Visitor) (Node, bool) {
+	newNode, skipChildren := v.Enter(n)
+	if skipChildren {
+		return v.Leave(newNode)
+	}
+	n = newNode.(*GrantRoleStmt)
+	return v.Leave(n)
+}
+
+// Restore implements Node interface.
+func (n *GrantRoleStmt) Restore(ctx *RestoreCtx) error {
+	ctx.WriteKeyWord("GRANT ")
+	if len(n.Roles) > 0 {
+		for i, role := range n.Roles {
+			if i != 0 {
+				ctx.WritePlain(", ")
+			}
+			if err := role.Restore(ctx); err != nil {
+				return errors.Annotatef(err, "An error occurred while restore GrantRoleStmt.Roles[%d]", i)
+			}
+		}
+	}
+	ctx.WriteKeyWord(" TO ")
+	for i, v := range n.Users {
+		if i != 0 {
+			ctx.WritePlain(", ")
+		}
+		if err := v.Restore(ctx); err != nil {
+			return errors.Annotatef(err, "An error occurred while restore GrantStmt.Users[%d]", i)
+		}
+	}
+	return nil
+}
+
+// SecureText implements SensitiveStatement interface.
+func (n *GrantRoleStmt) SecureText() string {
+	text := n.text
+	// Filter "identified by xxx" because it would expose password information.
+	idx := strings.Index(strings.ToLower(text), "identified")
+	if idx > 0 {
+		text = text[:idx]
+	}
+	return text
+}
+
 // Ident is the table identifier composed of schema name and table name.
 type Ident struct {
 	Schema model.CIStr

parser.y

@@ -7688,6 +7688,10 @@ GrantStmt:
 GrantRoleStmt:
 	 "GRANT" RolenameList "TO" UsernameList
 	 {
+		$$ = &ast.GrantRoleStmt {
+			Roles: $2.([]*auth.RoleIdentity),
+			Users: $4.([]*auth.UserIdentity),
+		}
 	 }
 
 WithGrantOptionOpt: