/
chunk.go
66 lines (58 loc) · 2.09 KB
/
chunk.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
// Copyright (c) 2020 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package iotest
import (
"errors"
"io"
)
// Borrowed from tchannel-go/testutils/testreader
// ErrUser is returned by ChunkReader when the user requests an error.
var ErrUser = errors.New("error set by user")
// ChunkReader returns a reader that returns chunks written to the control channel.
// The caller should write byte chunks to return to the channel, or write nil if they
// want the Reader to return an error. The control channel should be closed to signal EOF.
func ChunkReader() (chan<- []byte, io.Reader) {
reader := &errorReader{
c: make(chan []byte, 100),
}
return reader.c, reader
}
type errorReader struct {
c chan []byte
remaining []byte
}
func (r *errorReader) Read(bs []byte) (int, error) {
for len(r.remaining) == 0 {
var ok bool
r.remaining, ok = <-r.c
if !ok {
return 0, io.EOF
}
if r.remaining == nil {
return 0, ErrUser
}
if len(r.remaining) == 0 {
return 0, nil
}
}
n := copy(bs, r.remaining)
r.remaining = r.remaining[n:]
return n, nil
}