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			86 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
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			86 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
|  | /*
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|  | Copyright 2012 Google Inc.
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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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|  | */
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|  | 
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|  | package singleflight
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|  | 
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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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|  | 
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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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|  | 
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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", err)
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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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|  | 
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|  | func TestDoDupSuppress(t *testing.T) {
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|  | 	var g Group
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|  | 	c := make(chan string)
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|  | 	var calls int32
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|  | 	fn := func() (interface{}, error) {
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|  | 		atomic.AddInt32(&calls, 1)
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|  | 		return <-c, nil
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|  | 	}
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|  | 
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|  | 	const n = 10
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|  | 	var wg sync.WaitGroup
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|  | 	for i := 0; i < n; i++ {
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|  | 		wg.Add(1)
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|  | 		go func() {
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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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|  | 			}
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|  | 			if v.(string) != "bar" {
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|  | 				t.Errorf("got %q; want %q", v, "bar")
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|  | 			}
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|  | 			wg.Done()
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|  | 		}()
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|  | 	}
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|  | 	time.Sleep(100 * time.Millisecond) // let goroutines above block
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|  | 	c <- "bar"
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|  | 	wg.Wait()
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|  | 	if got := atomic.LoadInt32(&calls); got != 1 {
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|  | 		t.Errorf("number of calls = %d; want 1", got)
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|  | 	}
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|  | }
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