| // Copyright 2018 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package errors implements functions to manipulate errors. |
| package errors |
| |
| import ( |
| "fmt" |
| |
| "google.golang.org/protobuf/internal/detrand" |
| ) |
| |
| // New formats a string according to the format specifier and arguments and |
| // returns an error that has a "proto" prefix. |
| func New(f string, x ...interface{}) error { |
| for i := 0; i < len(x); i++ { |
| if e, ok := x[i].(*prefixError); ok { |
| x[i] = e.s // avoid "proto: " prefix when chaining |
| } |
| } |
| return &prefixError{s: fmt.Sprintf(f, x...)} |
| } |
| |
| type prefixError struct{ s string } |
| |
| var prefix = func() string { |
| // Deliberately introduce instability into the error message string to |
| // discourage users from performing error string comparisons. |
| if detrand.Bool() { |
| return "proto: " // use non-breaking spaces (U+00a0) |
| } else { |
| return "proto: " // use regular spaces (U+0020) |
| } |
| }() |
| |
| func (e *prefixError) Error() string { |
| return prefix + e.s |
| } |
| |
| func InvalidUTF8(name string) error { |
| return New("field %v contains invalid UTF-8", name) |
| } |
| |
| func RequiredNotSet(name string) error { |
| return New("required field %v not set", name) |
| } |