forked from cloudfoundry/cli
/
listen.go
50 lines (43 loc) · 1.04 KB
/
listen.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
// Copyright 2013 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 netutil provides network utility functions, complementing the more
// common ones in the net package.
package netutil
import (
"net"
"sync"
)
// LimitListener returns a Listener that accepts at most n simultaneous
// connections from the provided Listener.
func LimitListener(l net.Listener, n int) net.Listener {
ch := make(chan struct{}, n)
for i := 0; i < n; i++ {
ch <- struct{}{}
}
return &limitListener{l, ch}
}
type limitListener struct {
net.Listener
ch chan struct{}
}
func (l *limitListener) Accept() (net.Conn, error) {
<-l.ch
c, err := l.Listener.Accept()
if err != nil {
return nil, err
}
return &limitListenerConn{Conn: c, ch: l.ch}, nil
}
type limitListenerConn struct {
net.Conn
ch chan<- struct{}
close sync.Once
}
func (l *limitListenerConn) Close() error {
err := l.Conn.Close()
l.close.Do(func() {
l.ch <- struct{}{}
})
return err
}