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https://github.com/golang/go
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519474451a
This is a subset of https://golang.org/cl/20022 with only the copyright header lines, so the next CL will be smaller and more reviewable. Go policy has been single space after periods in comments for some time. The copyright header template at: https://golang.org/doc/contribute.html#copyright also uses a single space. Make them all consistent. Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0 Reviewed-on: https://go-review.googlesource.com/20111 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
88 lines
1.8 KiB
Go
88 lines
1.8 KiB
Go
// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package singleflight
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import (
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"errors"
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"fmt"
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"sync"
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"sync/atomic"
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"testing"
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"time"
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)
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func TestDo(t *testing.T) {
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var g Group
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v, err, _ := g.Do("key", func() (interface{}, error) {
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return "bar", nil
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})
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if got, want := fmt.Sprintf("%v (%T)", v, v), "bar (string)"; got != want {
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t.Errorf("Do = %v; want %v", got, want)
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}
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if err != nil {
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t.Errorf("Do error = %v", err)
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}
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}
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func TestDoErr(t *testing.T) {
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var g Group
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someErr := errors.New("Some error")
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v, err, _ := g.Do("key", func() (interface{}, error) {
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return nil, someErr
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})
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if err != someErr {
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t.Errorf("Do error = %v; want someErr %v", err, someErr)
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}
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if v != nil {
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t.Errorf("unexpected non-nil value %#v", v)
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}
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}
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func TestDoDupSuppress(t *testing.T) {
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var g Group
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var wg1, wg2 sync.WaitGroup
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c := make(chan string, 1)
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var calls int32
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fn := func() (interface{}, error) {
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if atomic.AddInt32(&calls, 1) == 1 {
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// First invocation.
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wg1.Done()
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}
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v := <-c
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c <- v // pump; make available for any future calls
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time.Sleep(10 * time.Millisecond) // let more goroutines enter Do
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return v, nil
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}
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const n = 10
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wg1.Add(1)
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for i := 0; i < n; i++ {
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wg1.Add(1)
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wg2.Add(1)
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go func() {
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defer wg2.Done()
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wg1.Done()
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v, err, _ := g.Do("key", fn)
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if err != nil {
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t.Errorf("Do error: %v", err)
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return
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}
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if s, _ := v.(string); s != "bar" {
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t.Errorf("Do = %T %v; want %q", v, v, "bar")
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}
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}()
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}
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wg1.Wait()
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// At least one goroutine is in fn now and all of them have at
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// least reached the line before the Do.
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c <- "bar"
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wg2.Wait()
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if got := atomic.LoadInt32(&calls); got <= 0 || got >= n {
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t.Errorf("number of calls = %d; want over 0 and less than %d", got, n)
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}
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}
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