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3d8826a3d4
* MultiError: Refactored MultiError for more concise and safe usage. * Less lines * Goland IDE was marking every usage of old MultiError "potential nil" error * It was easy to forgot using Err() when error was returned, now it's safely assured on compile time. NOTE: Potentially I would rename package to merrors. (: In different PR. Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com> * Addressed review comments. Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com> * Addressed comments. Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com> * Fix after rebase. Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
90 lines
2.3 KiB
Go
90 lines
2.3 KiB
Go
// Copyright 2016 The etcd Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package errors
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import (
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"bytes"
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"fmt"
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"io"
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)
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// multiError type allows combining multiple errors into one.
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type multiError []error
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// NewMulti returns multiError with provided errors added if not nil.
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func NewMulti(errs ...error) multiError { // nolint:golint
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m := multiError{}
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m.Add(errs...)
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return m
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}
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// Add adds single or many errors to the error list. Each error is added only if not nil.
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// If the error is a nonNilMultiError type, the errors inside nonNilMultiError are added to the main multiError.
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func (es *multiError) Add(errs ...error) {
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for _, err := range errs {
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if err == nil {
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continue
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}
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if merr, ok := err.(nonNilMultiError); ok {
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*es = append(*es, merr.errs...)
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continue
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}
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*es = append(*es, err)
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}
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}
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// Err returns the error list as an error or nil if it is empty.
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func (es multiError) Err() error {
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if len(es) == 0 {
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return nil
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}
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return nonNilMultiError{errs: es}
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}
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// nonNilMultiError implements the error interface, and it represents
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// multiError with at least one error inside it.
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// This type is needed to make sure that nil is returned when no error is combined in multiError for err != nil
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// check to work.
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type nonNilMultiError struct {
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errs multiError
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}
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// Error returns a concatenated string of the contained errors.
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func (es nonNilMultiError) Error() string {
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var buf bytes.Buffer
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if len(es.errs) > 1 {
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fmt.Fprintf(&buf, "%d errors: ", len(es.errs))
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}
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for i, err := range es.errs {
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if i != 0 {
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buf.WriteString("; ")
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}
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buf.WriteString(err.Error())
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}
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return buf.String()
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}
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// CloseAll closes all given closers while recording error in MultiError.
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func CloseAll(cs []io.Closer) error {
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errs := NewMulti()
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for _, c := range cs {
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errs.Add(c.Close())
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}
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return errs.Err()
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}
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