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
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
|
// 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 poll
import (
"errors"
"io"
"sync"
"time"
)
type FD struct {
// Lock sysfd and serialize access to Read and Write methods.
fdmu fdMutex
Destroy func()
// deadlines
rmu sync.Mutex
wmu sync.Mutex
raio *asyncIO
waio *asyncIO
rtimer *time.Timer
wtimer *time.Timer
rtimedout bool // set true when read deadline has been reached
wtimedout bool // set true when write deadline has been reached
// Whether this is a normal file.
// On Plan 9 we do not use this package for ordinary files,
// so this is always false, but the field is present because
// shared code in fd_mutex.go checks it.
isFile bool
}
// We need this to close out a file descriptor when it is unlocked,
// but the real implementation has to live in the net package because
// it uses os.File's.
func (fd *FD) destroy() error {
if fd.Destroy != nil {
fd.Destroy()
}
return nil
}
// Close handles the locking for closing an FD. The real operation
// is in the net package.
func (fd *FD) Close() error {
if !fd.fdmu.increfAndClose() {
return errClosing(fd.isFile)
}
return nil
}
// Read implements io.Reader.
func (fd *FD) Read(fn func([]byte) (int, error), b []byte) (int, error) {
if err := fd.readLock(); err != nil {
return 0, err
}
defer fd.readUnlock()
if len(b) == 0 {
return 0, nil
}
fd.rmu.Lock()
if fd.rtimedout {
fd.rmu.Unlock()
return 0, ErrDeadlineExceeded
}
fd.raio = newAsyncIO(fn, b)
fd.rmu.Unlock()
n, err := fd.raio.Wait()
fd.raio = nil
if isHangup(err) {
err = io.EOF
}
if isInterrupted(err) {
err = ErrDeadlineExceeded
}
return n, err
}
// Write implements io.Writer.
func (fd *FD) Write(fn func([]byte) (int, error), b []byte) (int, error) {
if err := fd.writeLock(); err != nil {
return 0, err
}
defer fd.writeUnlock()
fd.wmu.Lock()
if fd.wtimedout {
fd.wmu.Unlock()
return 0, ErrDeadlineExceeded
}
fd.waio = newAsyncIO(fn, b)
fd.wmu.Unlock()
n, err := fd.waio.Wait()
fd.waio = nil
if isInterrupted(err) {
err = ErrDeadlineExceeded
}
return n, err
}
// SetDeadline sets the read and write deadlines associated with fd.
func (fd *FD) SetDeadline(t time.Time) error {
return setDeadlineImpl(fd, t, 'r'+'w')
}
// SetReadDeadline sets the read deadline associated with fd.
func (fd *FD) SetReadDeadline(t time.Time) error {
return setDeadlineImpl(fd, t, 'r')
}
// SetWriteDeadline sets the write deadline associated with fd.
func (fd *FD) SetWriteDeadline(t time.Time) error {
return setDeadlineImpl(fd, t, 'w')
}
func setDeadlineImpl(fd *FD, t time.Time, mode int) error {
d := t.Sub(time.Now())
if mode == 'r' || mode == 'r'+'w' {
fd.rmu.Lock()
defer fd.rmu.Unlock()
if fd.rtimer != nil {
fd.rtimer.Stop()
fd.rtimer = nil
}
fd.rtimedout = false
}
if mode == 'w' || mode == 'r'+'w' {
fd.wmu.Lock()
defer fd.wmu.Unlock()
if fd.wtimer != nil {
fd.wtimer.Stop()
fd.wtimer = nil
}
fd.wtimedout = false
}
if !t.IsZero() && d > 0 {
// Interrupt I/O operation once timer has expired
if mode == 'r' || mode == 'r'+'w' {
var timer *time.Timer
timer = time.AfterFunc(d, func() {
fd.rmu.Lock()
defer fd.rmu.Unlock()
if fd.rtimer != timer {
// deadline was changed
return
}
fd.rtimedout = true
if fd.raio != nil {
fd.raio.Cancel()
}
})
fd.rtimer = timer
}
if mode == 'w' || mode == 'r'+'w' {
var timer *time.Timer
timer = time.AfterFunc(d, func() {
fd.wmu.Lock()
defer fd.wmu.Unlock()
if fd.wtimer != timer {
// deadline was changed
return
}
fd.wtimedout = true
if fd.waio != nil {
fd.waio.Cancel()
}
})
fd.wtimer = timer
}
}
if !t.IsZero() && d <= 0 {
// Interrupt current I/O operation
if mode == 'r' || mode == 'r'+'w' {
fd.rtimedout = true
if fd.raio != nil {
fd.raio.Cancel()
}
}
if mode == 'w' || mode == 'r'+'w' {
fd.wtimedout = true
if fd.waio != nil {
fd.waio.Cancel()
}
}
}
return nil
}
// On Plan 9 only, expose the locking for the net code.
// ReadLock wraps FD.readLock.
func (fd *FD) ReadLock() error {
return fd.readLock()
}
// ReadUnlock wraps FD.readUnlock.
func (fd *FD) ReadUnlock() {
fd.readUnlock()
}
func isHangup(err error) bool {
return err != nil && stringsHasSuffix(err.Error(), "Hangup")
}
func isInterrupted(err error) bool {
return err != nil && stringsHasSuffix(err.Error(), "interrupted")
}
// IsPollDescriptor reports whether fd is the descriptor being used by the poller.
// This is only used for testing.
func IsPollDescriptor(fd uintptr) bool {
return false
}
// RawControl invokes the user-defined function f for a non-IO
// operation.
func (fd *FD) RawControl(f func(uintptr)) error {
return errors.New("not implemented")
}
// RawRead invokes the user-defined function f for a read operation.
func (fd *FD) RawRead(f func(uintptr) bool) error {
return errors.New("not implemented")
}
// RawWrite invokes the user-defined function f for a write operation.
func (fd *FD) RawWrite(f func(uintptr) bool) error {
return errors.New("not implemented")
}
|
