txetnoc/context.go at main · inkel/txetnoc

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package txetnoc

import (

"context"

"reflect"

"time"

)

var _ context.Context = &parentCtx{}

type parentCtx struct {

children []context.Context

err error

}

// Deadline implements context.Context

func (*parentCtx) Deadline() (deadline time.Time, ok bool) { return }

// Done implements context.Context

func (p *parentCtx) Done() <-chan struct{} {

cases := make([]reflect.SelectCase, len(p.children))

for i, ctx := range p.children {

cases[i] = reflect.SelectCase{

Dir: reflect.SelectRecv,

Chan: reflect.ValueOf(ctx.Done()),

}

i, _, _ := reflect.Select(cases)

ctx := p.children[i]

p.err = ctx.Err()

return ctx.Done()

}

// Err implements context.Context

func (p *parentCtx) Err() error { return p.err }

// Value implements context.Context

func (*parentCtx) Value(key any) any { return nil }

// WithChildren returns a new context that wraps all the children and

// waits on all of them for the first one to be Done.

func WithChildren(children ...context.Context) context.Context {

return &parentCtx{children, nil}

}