1// Copyright 2018 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// Package errors implements functions to manipulate errors.
6package errors
7
8import (
9 "errors"
10 "fmt"
11
12 "google.golang.org/protobuf/internal/detrand"
13)
14
15// Error is a sentinel matching all errors produced by this package.
16var Error = errors.New("protobuf error")
17
18// New formats a string according to the format specifier and arguments and
19// returns an error that has a "proto" prefix.
20func New(f string, x ...any) error {
21 return &prefixError{s: format(f, x...)}
22}
23
24type prefixError struct{ s string }
25
26var prefix = func() string {
27 // Deliberately introduce instability into the error message string to
28 // discourage users from performing error string comparisons.
29 if detrand.Bool() {
30 return "proto: " // use non-breaking spaces (U+00a0)
31 } else {
32 return "proto: " // use regular spaces (U+0020)
33 }
34}()
35
36func (e *prefixError) Error() string {
37 return prefix + e.s
38}
39
40func (e *prefixError) Unwrap() error {
41 return Error
42}
43
44// Wrap returns an error that has a "proto" prefix, the formatted string described
45// by the format specifier and arguments, and a suffix of err. The error wraps err.
46func Wrap(err error, f string, x ...any) error {
47 return &wrapError{
48 s: format(f, x...),
49 err: err,
50 }
51}
52
53type wrapError struct {
54 s string
55 err error
56}
57
58func (e *wrapError) Error() string {
59 return format("%v%v: %v", prefix, e.s, e.err)
60}
61
62func (e *wrapError) Unwrap() error {
63 return e.err
64}
65
66func (e *wrapError) Is(target error) bool {
67 return target == Error
68}
69
70func format(f string, x ...any) string {
71 // avoid "proto: " prefix when chaining
72 for i := 0; i < len(x); i++ {
73 switch e := x[i].(type) {
74 case *prefixError:
75 x[i] = e.s
76 case *wrapError:
77 x[i] = format("%v: %v", e.s, e.err)
78 }
79 }
80 return fmt.Sprintf(f, x...)
81}
82
83func InvalidUTF8(name string) error {
84 return New("field %v contains invalid UTF-8", name)
85}
86
87func RequiredNotSet(name string) error {
88 return New("required field %v not set", name)
89}
90
91type SizeMismatchError struct {
92 Calculated, Measured int
93}
94
95func (e *SizeMismatchError) Error() string {
96 return fmt.Sprintf("size mismatch (see https://github.com/golang/protobuf/issues/1609): calculated=%d, measured=%d", e.Calculated, e.Measured)
97}
98
99func MismatchedSizeCalculation(calculated, measured int) error {
100 return &SizeMismatchError{
101 Calculated: calculated,
102 Measured: measured,
103 }
104}