libgo/go/sync/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() interface{} {
  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 }