Scott Baker | beb3cfa | 2019-10-01 14:44:30 -0700 | [diff] [blame] | 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 | |
| 21 | package atomic |
| 22 | |
| 23 | // Error is an atomic type-safe wrapper around Value for errors |
| 24 | type 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. |
| 29 | type errorHolder struct{ err error } |
| 30 | |
| 31 | // NewError creates new atomic error object |
| 32 | func 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 |
| 41 | func (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. |
| 53 | func (e *Error) Store(err error) { |
| 54 | e.v.Store(errorHolder{err: err}) |
| 55 | } |