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
5package iotest
6
7import (
8	"io"
9	"log"
10)
11
12type writeLogger struct {
13	prefix string
14	w      io.Writer
15}
16
17func (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.
30func NewWriteLogger(prefix string, w io.Writer) io.Writer {
31	return &writeLogger{prefix, w}
32}
33
34type readLogger struct {
35	prefix string
36	r      io.Reader
37}
38
39func (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.
52func NewReadLogger(prefix string, r io.Reader) io.Reader {
53	return &readLogger{prefix, r}
54}
55