golang logger 代码
文件路径：/src/testing/iotest/logger.go
/ Copyright 2009 The Go Authors. All rights reserved.
/ Use of this source code is governed by a BSD-style
/ license that can be found in the LICENSE file.
package iotest
import (
"io"
"log"
)
type writeLogger struct {
prefix string
w io.Writer
}
func (l *writeLogger) Write(p []byte) (n int, err error) {
n, err = l.w.Write(p)
if err != nil {
log.Printf("%s %x: %v", l.prefix, p[0:n], err)
} else {
log.Printf("%s %x", l.prefix, p[0:n])
}
return
}
/ NewWriteLogger returns a writer that behaves like w except
/ that it logs (using log.Printf) each write to standard error,
/ printing the prefix and the hexadecimal data written.
func NewWriteLogger(prefix string, w io.Writer) io.Writer {
return &writeLogger{prefix, w}
}
type readLogger struct {
prefix string
r io.Reader
}
func (l *readLogger) Read(p []byte) (n int, err error) {
n, err = l.r.Read(p)
if err != nil {
log.Printf("%s %x: %v", l.prefix, p[0:n], err)
} else {
log.Printf("%s %x", l.prefix, p[0:n])
}
return
}
/ NewReadLogger returns a reader that behaves like r except
/ that it logs (using log.Printf) each read to standard error,
/ printing the prefix and the hexadecimal data read.
func NewReadLogger(prefix string, r io.Reader) io.Reader {
return &readLogger{prefix, r}
}