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
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
package ioutils
import (
"errors"
"io"
"net/http"
"sync"
)
// WriteFlusher wraps the Write and Flush operation ensuring that every write
// is a flush. In addition, the Close method can be called to intercept
// Read/Write calls if the targets lifecycle has already ended.
type WriteFlusher struct {
mu sync.Mutex
w io.Writer
flusher http.Flusher
flushed bool
closed error
// TODO(stevvooe): Use channel for closed instead, remove mutex. Using a
// channel will allow one to properly order the operations.
}
var errWriteFlusherClosed = errors.New("writeflusher: closed")
func (wf *WriteFlusher) Write(b []byte) (n int, err error) {
wf.mu.Lock()
defer wf.mu.Unlock()
if wf.closed != nil {
return 0, wf.closed
}
n, err = wf.w.Write(b)
wf.flush() // every write is a flush.
return n, err
}
// Flush the stream immediately.
func (wf *WriteFlusher) Flush() {
wf.mu.Lock()
defer wf.mu.Unlock()
wf.flush()
}
// flush the stream immediately without taking a lock. Used internally.
func (wf *WriteFlusher) flush() {
if wf.closed != nil {
return
}
wf.flushed = true
wf.flusher.Flush()
}
// Flushed returns the state of flushed.
// If it's flushed, return true, or else it return false.
func (wf *WriteFlusher) Flushed() bool {
// BUG(stevvooe): Remove this method. Its use is inherently racy. Seems to
// be used to detect whether or a response code has been issued or not.
// Another hook should be used instead.
wf.mu.Lock()
defer wf.mu.Unlock()
return wf.flushed
}
// Close closes the write flusher, disallowing any further writes to the
// target. After the flusher is closed, all calls to write or flush will
// result in an error.
func (wf *WriteFlusher) Close() error {
wf.mu.Lock()
defer wf.mu.Unlock()
if wf.closed != nil {
return wf.closed
}
wf.closed = errWriteFlusherClosed
return nil
}
// NewWriteFlusher returns a new WriteFlusher.
func NewWriteFlusher(w io.Writer) *WriteFlusher {
var flusher http.Flusher
if f, ok := w.(http.Flusher); ok {
flusher = f
} else {
flusher = &NopFlusher{}
}
return &WriteFlusher{w: w, flusher: flusher}
}
|
