libgo/go/testing/iotest/logger.go

   1 // Copyright 2009 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 iotest
   6
   7 import (
   8         "io"
   9         "log"
  10 )
  11
  12 type writeLogger struct {
  13         prefix string
  14         w      io.Writer
  15 }
  16
  17 func (l *writeLogger) Write(p []byte) (n int, err error) {
  18         n, err = l.w.Write(p)
  19         if err != nil {
  20                 log.Printf("%s %x: %v", l.prefix, p[0:n], err)
  21         } else {
  22                 log.Printf("%s %x", l.prefix, p[0:n])
  23         }
  24         return
  25 }
  26
  27 // NewWriteLogger returns a writer that behaves like w except
  28 // that it logs (using log.Printf) each write to standard error,
  29 // printing the prefix and the hexadecimal data written.
  30 func NewWriteLogger(prefix string, w io.Writer) io.Writer {
  31         return &writeLogger{prefix, w}
  32 }
  33
  34 type readLogger struct {
  35         prefix string
  36         r      io.Reader
  37 }
  38
  39 func (l *readLogger) Read(p []byte) (n int, err error) {
  40         n, err = l.r.Read(p)
  41         if err != nil {
  42                 log.Printf("%s %x: %v", l.prefix, p[0:n], err)
  43         } else {
  44                 log.Printf("%s %x", l.prefix, p[0:n])
  45         }
  46         return
  47 }
  48
  49 // NewReadLogger returns a reader that behaves like r except
  50 // that it logs (using log.Print) each read to standard error,
  51 // printing the prefix and the hexadecimal data written.
  52 func NewReadLogger(prefix string, r io.Reader) io.Reader {
  53         return &readLogger{prefix, r}
  54 }