libgo/go/net/dial_gen.go

   1 // Copyright 2012 The Go Authors.  All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 // +build windows plan9
   6
   7 package net
   8
   9 import (
  10         "time"
  11 )
  12
  13 var testingIssue5349 bool // used during tests
  14
  15 // dialChannel is the simple pure-Go implementation of dial, still
  16 // used on operating systems where the deadline hasn't been pushed
  17 // down into the pollserver. (Plan 9 and some old versions of Windows)
  18 func dialChannel(net string, ra Addr, dialer func(time.Time) (Conn, error), deadline time.Time) (Conn, error) {
  19         var timeout time.Duration
  20         if !deadline.IsZero() {
  21                 timeout = deadline.Sub(time.Now())
  22         }
  23         if timeout <= 0 {
  24                 return dialer(noDeadline)
  25         }
  26         t := time.NewTimer(timeout)
  27         defer t.Stop()
  28         type racer struct {
  29                 Conn
  30                 error
  31         }
  32         ch := make(chan racer, 1)
  33         go func() {
  34                 if testingIssue5349 {
  35                         time.Sleep(time.Millisecond)
  36                 }
  37                 c, err := dialer(noDeadline)
  38                 ch <- racer{c, err}
  39         }()
  40         select {
  41         case <-t.C:
  42                 return nil, &OpError{Op: "dial", Net: net, Addr: ra, Err: errTimeout}
  43         case racer := <-ch:
  44                 return racer.Conn, racer.error
  45         }
  46 }