github.com/hasnat/dolt/go@v0.0.0-20210628190320-9eb5d843fbb7/store/atomicerr/atomic_error.go (about) 1 // Copyright 2019 Dolthub, Inc. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package atomicerr 16 17 import ( 18 "sync" 19 "sync/atomic" 20 ) 21 22 type AtomicError struct { 23 once *sync.Once 24 val *atomic.Value 25 } 26 27 func New() *AtomicError { 28 return &AtomicError{&sync.Once{}, &atomic.Value{}} 29 } 30 31 func (ae *AtomicError) SetIfError(err error) bool { 32 if err != nil { 33 ae.once.Do(func() { 34 ae.val.Store(err) 35 }) 36 37 return true 38 } 39 40 return false 41 } 42 43 func (ae *AtomicError) SetIfErrAndCheck(err error) bool { 44 ae.SetIfError(err) 45 return ae.IsSet() 46 } 47 48 func (ae *AtomicError) IsSet() bool { 49 val := ae.val.Load() 50 return val != nil 51 } 52 53 func (ae *AtomicError) Get() error { 54 val := ae.val.Load() 55 56 if val == nil { 57 return nil 58 } 59 60 return val.(error) 61 } 62 63 func (ae *AtomicError) Error() string { 64 err := ae.Get() 65 66 if err != nil { 67 return err.Error() 68 } 69 70 return "" 71 }