121 lines
2.7 KiB
Go
121 lines
2.7 KiB
Go
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// Copyright (c) 2016 Matthias Neugebauer
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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package startstopper
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import (
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"bytes"
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"context"
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"sync"
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)
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// Group StartStopper together and run them as one.
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type Group struct {
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StartStopper
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sss []StartStopper
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}
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// GroupError is the concrete error type returned by Group structs. It bundles
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// the errors that could be returned by the StartStoppers.
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type GroupError struct {
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Errors []error
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}
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// Error implements the error interface.
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func (g GroupError) Error() string {
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var buffer bytes.Buffer
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for _, err := range g.Errors {
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if err != nil {
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buffer.WriteString(err.Error())
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buffer.WriteString(", ")
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}
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}
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str := buffer.String()
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return str[:len(str)-2]
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}
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// NewGroup creates a new group.
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func NewGroup(sss []StartStopper) *Group {
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group := &Group{sss: sss}
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group.StartStopper = NewGo(RunnerFunc(group.run))
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return group
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}
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func (g *Group) run(ctx context.Context, stopChan <-chan struct{}) error {
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var once sync.Once
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errorOccured := false
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setErrorOccured := func() {
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once.Do(func() {
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errorOccured = true
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})
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}
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groupErr := GroupError{
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Errors: make([]error, len(g.sss)),
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}
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for i, ss := range g.sss {
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groupErr.Errors[i] = ss.Start(ctx)
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if groupErr.Errors[i] != nil {
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setErrorOccured()
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}
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}
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if errorOccured {
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return groupErr
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}
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select {
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case <-stopChan:
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case <-ctx.Done():
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}
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var wg sync.WaitGroup
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wg.Add(len(g.sss))
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for _i, _ss := range g.sss {
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i, ss := _i, _ss
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go func() {
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err := ss.Stop(ctx)
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if err == nil {
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err = ss.Err(ctx)
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}
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if err != nil {
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setErrorOccured()
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}
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groupErr.Errors[i] = err
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wg.Done()
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}()
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}
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wg.Wait()
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if errorOccured {
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return groupErr
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}
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return nil
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}
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