example_pool_test.go

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package sync_test
     6  
     7  import (
     8  	"bytes"
     9  	"io"
    10  	"os"
    11  	"sync"
    12  	"time"
    13  )
    14  
    15  var bufPool = sync.Pool{
    16  	New: func() any {
    17  		// The Pool's New function should generally only return pointer
    18  		// types, since a pointer can be put into the return interface
    19  		// value without an allocation:
    20  		return new(bytes.Buffer)
    21  	},
    22  }
    23  
    24  // timeNow is a fake version of time.Now for tests.
    25  func timeNow() time.Time {
    26  	return time.Unix(1136214245, 0)
    27  }
    28  
    29  func Log(w io.Writer, key, val string) {
    30  	b := bufPool.Get().(*bytes.Buffer)
    31  	b.Reset()
    32  	// Replace this with time.Now() in a real logger.
    33  	b.WriteString(timeNow().UTC().Format(time.RFC3339))
    34  	b.WriteByte(' ')
    35  	b.WriteString(key)
    36  	b.WriteByte('=')
    37  	b.WriteString(val)
    38  	w.Write(b.Bytes())
    39  	bufPool.Put(b)
    40  }
    41  
    42  func ExamplePool() {
    43  	Log(os.Stdout, "path", "/search?q=flowers")
    44  	// Output: 2006-01-02T15:04:05Z path=/search?q=flowers
    45  }
    46
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