mvdan.cc
1// Copyright 2019 CUE Authors
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15// Package struct defines utilities for struct types.
16package structs
17
18import (
19 "cuelang.org/go/cue/errors"
20 "cuelang.org/go/cue/token"
21 "cuelang.org/go/internal/core/adt"
22 "cuelang.org/go/internal/pkg"
23)
24
25// MinFields validates the minimum number of fields that are part of a struct.
26// It can only be used as a validator, for instance `MinFields(3)`.
27//
28// Only fields that are part of the data model count. This excludes hidden
29// fields, optional fields, and definitions.
30func MinFields(object pkg.Struct, n int) (bool, error) {
31 count := object.Len()
32 code := adt.EvalError
33 if object.IsOpen() || count+object.NumConstraintFields() >= n {
34 code = adt.IncompleteError
35 }
36 if count < n {
37 return false, pkg.ValidationError{B: &adt.Bottom{
38 Code: code,
39 Err: errors.Newf(token.NoPos, "len(fields) < MinFields(%[2]d) (%[1]d < %[2]d)", count, n),
40 }}
41 }
42 return true, nil
43}
44
45// MaxFields validates the maximum number of fields that are part of a struct.
46// It can only be used as a validator, for instance `MaxFields(3)`.
47//
48// Only fields that are part of the data model count. This excludes hidden
49// fields, optional fields, and definitions.
50func MaxFields(object pkg.Struct, n int) (bool, error) {
51 count := object.Len()
52 if count > n {
53 return false, pkg.ValidationError{B: &adt.Bottom{
54 Code: adt.EvalError,
55 Err: errors.Newf(token.NoPos, "len(fields) > MaxFields(%[2]d) (%[1]d > %[2]d)", count, n),
56 }}
57 }
58
59 return true, nil
60}