| // Copyright 2011 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 ( |
| "internal/errinternal" |
| "runtime" |
| ) |
| |
| // New returns an error that formats as the given text. |
| // |
| // The returned error contains a Frame set to the caller's location and |
| // implements Formatter to show this information when printed with details. |
| func New(text string) error { |
| // Inline call to errors.Callers to improve performance. |
| var s Frame |
| runtime.Callers(2, s.frames[:]) |
| return &errorString{text, nil, s} |
| } |
| |
| func init() { |
| errinternal.NewError = func(text string, err error) error { |
| var s Frame |
| runtime.Callers(3, s.frames[:]) |
| return &errorString{text, err, s} |
| } |
| } |
| |
| // errorString is a trivial implementation of error. |
| type errorString struct { |
| s string |
| err error |
| frame Frame |
| } |
| |
| func (e *errorString) Error() string { |
| if e.err != nil { |
| return e.s + ": " + e.err.Error() |
| } |
| return e.s |
| } |
| |
| func (e *errorString) FormatError(p Printer) (next error) { |
| p.Print(e.s) |
| e.frame.Format(p) |
| return e.err |
| } |