Golang Message.Header方法代码示例

func (r *req) SendHook(m *mangos.Message) bool {

	if r.raw {
		// Raw mode has no automatic retry, and must include the
		// request id in the header coming down.
		return true
	}
	r.Lock()
	defer r.Unlock()

	// We need to generate a new request id, and append it to the header.
	r.reqid = r.nextID()
	v := r.reqid
	m.Header = append(m.Header,
		byte(v>>24), byte(v>>16), byte(v>>8), byte(v))

	r.reqmsg = m.Dup()

	// Schedule a retry, in case we don't get a reply.
	if r.retry > 0 {
		r.waker.Reset(r.retry)
	} else {
		r.waker.Stop()
	}

	r.sock.SetRecvError(nil)

	return true
}

func (x *star) SendHook(m *mangos.Message) bool {

	if x.raw {
		// TTL header must be present.
		return true
	}
	// new message has a zero hop count
	m.Header = append(m.Header, 0, 0, 0, 0)
	return true
}

// We save the backtrace from this message.  This means that if the app calls
// Recv before calling Send, the saved backtrace will be lost.  This is how
// the application discards / cancels a request to which it declines to reply.
// This is only done in cooked mode.
func (r *rep) RecvHook(m *mangos.Message) bool {
	if r.raw {
		return true
	}
	r.sock.SetSendError(nil)
	r.backtraceL.Lock()
	r.backtrace = append(r.backtracebuf[0:0], m.Header...)
	r.backtraceL.Unlock()
	m.Header = nil
	return true
}

func (x *resp) SendHook(m *mangos.Message) bool {
	if x.raw {
		// Raw mode senders expected to have prepared header already.
		return true
	}
	x.sock.SetSendError(mangos.ErrProtoState)
	x.Lock()
	m.Header = append(m.Header[0:0], x.backtrace...)
	x.backtrace = nil
	x.Unlock()
	if len(m.Header) == 0 {
		return false
	}
	return true
}

func (r *rep) SendHook(m *mangos.Message) bool {
	// Store our saved backtrace.  Note that if none was previously stored,
	// there is no one to reply to, and we drop the message.  We only
	// do this in cooked mode.
	if r.raw {
		return true
	}
	r.sock.SetSendError(mangos.ErrProtoState)
	r.backtraceL.Lock()
	m.Header = append(m.Header[0:0], r.backtrace...)
	r.backtrace = nil
	r.backtraceL.Unlock()
	if m.Header == nil {
		return false
	}
	return true
}

func (r *rep) sender() {
	defer r.w.Done()
	sq := r.sock.SendChannel()
	cq := r.sock.CloseChannel()

	for {
		var m *mangos.Message

		select {
		case m = <-sq:
		case <-cq:
			return
		}

		// Lop off the 32-bit peer/pipe ID.  If absent, drop.
		if len(m.Header) < 4 {
			m.Free()
			continue
		}
		id := binary.BigEndian.Uint32(m.Header)
		m.Header = m.Header[4:]
		r.Lock()
		pe := r.eps[id]
		r.Unlock()
		if pe == nil {
			m.Free()
			continue
		}

		select {
		case pe.q <- m:
		default:
			// If our queue is full, we have no choice but to
			// throw it on the floor.  This shoudn't happen,
			// since each partner should be running synchronously.
			// Devices are a different situation, and this could
			// lead to lossy behavior there.  Initiators will
			// resend if this happens.  Devices need to have deep
			// enough queues and be fast enough to avoid this.
			m.Free()
		}
	}
}

func (x *resp) sender() {
	// This is pretty easy because we have only one peer at a time.
	// If the peer goes away, we'll just drop the message on the floor.

	defer x.w.Done()
	cq := x.sock.CloseChannel()
	sq := x.sock.SendChannel()
	for {
		var m *mangos.Message
		select {
		case m = <-sq:
		case <-cq:
			return
		}

		// Lop off the 32-bit peer/pipe ID.  If absent, drop.
		if len(m.Header) < 4 {
			m.Free()
			continue
		}

		id := binary.BigEndian.Uint32(m.Header)
		m.Header = m.Header[4:]

		x.Lock()
		peer := x.peers[id]
		x.Unlock()

		if peer == nil {
			m.Free()
			continue
		}

		// Put it on the outbound queue
		select {
		case peer.q <- m:
		default:
			// Backpressure, drop it.
			m.Free()
		}
	}
}

func (x *bus) RecvHook(m *mangos.Message) bool {
	if !x.raw && len(m.Header) >= 4 {
		m.Header = m.Header[4:]
	}
	return true
}