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Scott Bakerf579f132019-10-24 14:31:41 -07001// Copyright (c) 2016 Uber Technologies, Inc.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a copy
4// of this software and associated documentation files (the "Software"), to deal
5// in the Software without restriction, including without limitation the rights
6// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7// copies of the Software, and to permit persons to whom the Software is
8// furnished to do so, subject to the following conditions:
9//
10// The above copyright notice and this permission notice shall be included in
11// all copies or substantial portions of the Software.
12//
13// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
19// THE SOFTWARE.
20
21package atomic
22
23// Error is an atomic type-safe wrapper around Value for errors
24type Error struct{ v Value }
25
26// errorHolder is non-nil holder for error object.
27// atomic.Value panics on saving nil object, so err object needs to be
28// wrapped with valid object first.
29type errorHolder struct{ err error }
30
31// NewError creates new atomic error object
32func NewError(err error) *Error {
33 e := &Error{}
34 if err != nil {
35 e.Store(err)
36 }
37 return e
38}
39
40// Load atomically loads the wrapped error
41func (e *Error) Load() error {
42 v := e.v.Load()
43 if v == nil {
44 return nil
45 }
46
47 eh := v.(errorHolder)
48 return eh.err
49}
50
51// Store atomically stores error.
52// NOTE: a holder object is allocated on each Store call.
53func (e *Error) Store(err error) {
54 e.v.Store(errorHolder{err: err})
55}