1// 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} 56