| // Copyright 2010 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 io |
| |
| import "os" |
| |
| type multiReader struct { |
| readers []Reader |
| } |
| |
| func (mr *multiReader) Read(p []byte) (n int, err os.Error) { |
| for len(mr.readers) > 0 { |
| n, err = mr.readers[0].Read(p) |
| if n > 0 || err != os.EOF { |
| if err == os.EOF { |
| // This shouldn't happen. |
| // Well-behaved Readers should never |
| // return non-zero bytes read with an |
| // EOF. But if so, we clean it. |
| err = nil |
| } |
| return |
| } |
| mr.readers = mr.readers[1:] |
| } |
| return 0, os.EOF |
| } |
| |
| // MultiReader returns a Reader that's the logical concatenation of |
| // the provided input readers. They're read sequentially. Once all |
| // inputs are drained, Read will return os.EOF. |
| func MultiReader(readers ...Reader) Reader { |
| return &multiReader{readers} |
| } |
| |
| type multiWriter struct { |
| writers []Writer |
| } |
| |
| func (t *multiWriter) Write(p []byte) (n int, err os.Error) { |
| for _, w := range t.writers { |
| n, err = w.Write(p) |
| if err != nil { |
| return |
| } |
| if n != len(p) { |
| err = ErrShortWrite |
| return |
| } |
| } |
| return len(p), nil |
| } |
| |
| // MultiWriter creates a writer that duplicates its writes to all the |
| // provided writers, similar to the Unix tee(1) command. |
| func MultiWriter(writers ...Writer) Writer { |
| return &multiWriter{writers} |
| } |