// setRequestCancel sets the Cancel field of req, if deadline is
// non-zero. The RoundTripper's type is used to determine whether the legacy
// CancelRequest behavior should be used.
func setRequestCancel(req *Request, rt RoundTripper, deadline time.Time) (stopTimer func(), wasCanceled func() bool) {
if deadline.IsZero() {
return nop, alwaysFalse
}
initialReqCancel := req.Cancel // the user's original Request.Cancel, if any
cancel := make(chan struct{})
req.Cancel = cancel
wasCanceled = func() bool {
select {
case <-cancel:
return true
default:
return false
}
}
doCancel := func() {
// The new way:
close(cancel)
// The legacy compatibility way, used only
// for RoundTripper implementations written
// before Go 1.5 or Go 1.6.
type canceler interface {
CancelRequest(*Request)
}
switch v := rt.(type) {
case *Transport, *http2Transport:
// Do nothing. The net/http package's transports
// support the new Request.Cancel channel
case canceler:
v.CancelRequest(req)
}
}
stopTimerCh := make(chan struct{})
var once sync.Once
stopTimer = func() { once.Do(func() { close(stopTimerCh) }) }
timer := time.NewTimer(time.Until(deadline))
go func() {
select {
case <-initialReqCancel:
doCancel()
timer.Stop()
case <-timer.C:
doCancel()
case <-stopTimerCh:
timer.Stop()
}
}()
return stopTimer, wasCanceled
}
func setDeadlineImpl(fd *netFD, t time.Time, mode int) error {
diff := int64(time.Until(t))
d := runtimeNano() + diff
if d <= 0 && diff > 0 {
// If the user has a deadline in the future, but the delay calculation
// overflows, then set the deadline to the maximum possible value.
d = 1<<63 - 1
}
if t.IsZero() {
d = 0
}
if err := fd.incref(); err != nil {
return err
}
runtime_pollSetDeadline(fd.pd.runtimeCtx, d, mode)
fd.decref()
return nil
}
// WithDeadline returns a copy of the parent context with the deadline adjusted
// to be no later than d. If the parent's deadline is already earlier than d,
// WithDeadline(parent, d) is semantically equivalent to parent. The returned
// context's Done channel is closed when the deadline expires, when the returned
// cancel function is called, or when the parent context's Done channel is
// closed, whichever happens first.
//
// Canceling this context releases resources associated with it, so code should
// call cancel as soon as the operations running in this Context complete.
func WithDeadline(parent Context, deadline time.Time) (Context, CancelFunc) {
if cur, ok := parent.Deadline(); ok && cur.Before(deadline) {
// The current deadline is already sooner than the new one.
return WithCancel(parent)
}
c := &timerCtx{
cancelCtx: newCancelCtx(parent),
deadline: deadline,
}
propagateCancel(parent, c)
d := time.Until(deadline)
if d <= 0 {
c.cancel(true, DeadlineExceeded) // deadline has already passed
return c, func() { c.cancel(true, Canceled) }
}
c.mu.Lock()
defer c.mu.Unlock()
if c.err == nil {
c.timer = time.AfterFunc(d, func() {
c.cancel(true, DeadlineExceeded)
})
}
return c, func() { c.cancel(true, Canceled) }
}
// DialWithDialer connects to the given network address using dialer.Dial and
// then initiates a TLS handshake, returning the resulting TLS connection. Any
// timeout or deadline given in the dialer apply to connection and TLS
// handshake as a whole.
//
// DialWithDialer interprets a nil configuration as equivalent to the zero
// configuration; see the documentation of Config for the defaults.
func DialWithDialer(dialer *net.Dialer, network, addr string, config *Config) (*Conn, error) {
// We want the Timeout and Deadline values from dialer to cover the
// whole process: TCP connection and TLS handshake. This means that we
// also need to start our own timers now.
timeout := dialer.Timeout
if !dialer.Deadline.IsZero() {
deadlineTimeout := time.Until(dialer.Deadline)
if timeout == 0 || deadlineTimeout < timeout {
timeout = deadlineTimeout
}
}
var errChannel chan error
if timeout != 0 {
errChannel = make(chan error, 2)
time.AfterFunc(timeout, func() {
errChannel <- timeoutError{}
})
}
rawConn, err := dialer.Dial(network, addr)
if err != nil {
return nil, err
}
colonPos := strings.LastIndex(addr, ":")
if colonPos == -1 {
colonPos = len(addr)
}
hostname := addr[:colonPos]
if config == nil {
config = defaultConfig()
}
// If no ServerName is set, infer the ServerName
// from the hostname we're connecting to.
if config.ServerName == "" {
// Make a copy to avoid polluting argument or default.
c := config.Clone()
c.ServerName = hostname
config = c
}
conn := Client(rawConn, config)
if timeout == 0 {
err = conn.Handshake()
} else {
go func() {
errChannel <- conn.Handshake()
}()
err = <-errChannel
}
if err != nil {
rawConn.Close()
return nil, err
}
return conn, nil
}
func (c *timerCtx) String() string {
return fmt.Sprintf("%v.WithDeadline(%s [%s])", c.cancelCtx.Context, c.deadline, time.Until(c.deadline))
}