| package main |
| |
| import ( |
| "io" |
| "io/ioutil" |
| "log" |
| ) |
| |
| // ByteReader implements an io.Reader that emits a stream of its byte value. |
| type ByteReader byte |
| |
| func (b ByteReader) Read(buf []byte) (int, error) { |
| for i := range buf { |
| buf[i] = byte(b) |
| } |
| return len(buf), nil |
| } |
| |
| type LogReader struct { |
| io.Reader |
| } |
| |
| func (r LogReader) Read(b []byte) (int, error) { |
| n, err := r.Reader.Read(b) |
| log.Printf("read %d bytes, error: %v", n, err) |
| return n, err |
| } |
| |
| func main() { |
| r := LogReader{ByteReader('A')} |
| io.CopyN(ioutil.Discard, r, 1e6) |
| } |
