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

use std::cell::RefCell;
use std::collections::VecDeque;
use std::fmt;
use std::num::NonZeroU16;
use std::rc::Rc;

use bytes::Bytes;
use bytestring::ByteString;
use futures::future::{err, Either, Future, TryFutureExt};
use ntex::channel::{mpsc, oneshot};

use super::codec as mqtt;

pub struct MqttSink(Rc<RefCell<MqttSinkInner>>);

pub(crate) struct MqttSinkInner {
    idx: u16,
    queue: VecDeque<(u16, oneshot::Sender<()>)>,
    sink: Option<mpsc::Sender<mqtt::Packet>>,
}

impl Clone for MqttSink {
    fn clone(&self) -> Self {
        MqttSink(self.0.clone())
    }
}

impl MqttSink {
    pub(crate) fn new(sink: mpsc::Sender<mqtt::Packet>) -> Self {
        MqttSink(Rc::new(RefCell::new(MqttSinkInner {
            idx: 0,
            sink: Some(sink),
            queue: VecDeque::new(),
        })))
    }

    /// Close mqtt connection
    pub fn close(&self) {
        let _ = self.0.borrow_mut().sink.take();
    }

    /// Create publish message builder
    pub fn publish(&self, topic: ByteString, payload: Bytes) -> PublishBuilder<'_> {
        PublishBuilder {
            packet: Some(mqtt::Publish {
                topic,
                payload,
                dup: false,
                retain: false,
                qos: mqtt::QoS::AtMostOnce,
                packet_id: None,
            }),
            sink: self,
        }
    }

    pub(crate) fn complete_publish_qos1(&self, packet_id: NonZeroU16) {
        if let Some((idx, tx)) = self.0.borrow_mut().queue.pop_front() {
            if idx != packet_id.get() {
                log::trace!(
                    "MQTT protocol error, packet_id order does not match, expected {}, got: {}",
                    idx,
                    packet_id
                );
            } else {
                log::trace!("Ack publish packet with id: {}", packet_id);
                let _ = tx.send(());
                return;
            }
        } else {
            log::trace!("Unexpected PublishAck packet");
        }
        self.close();
    }
}

impl fmt::Debug for MqttSink {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.debug_struct("MqttSink").finish()
    }
}

pub struct PublishBuilder<'a> {
    sink: &'a MqttSink,
    packet: Option<mqtt::Publish>,
}

impl<'a> PublishBuilder<'a> {
    /// this might be re-delivery of an earlier attempt to send the Packet.
    pub fn dup(&mut self, val: bool) -> &mut Self {
        if let Some(ref mut packet) = self.packet {
            packet.dup = val;
        }
        self
    }

    pub fn retain(&mut self) -> &mut Self {
        if let Some(ref mut packet) = self.packet {
            packet.retain = true;
        }
        self
    }

    /// Send publish packet with QoS 0
    pub fn at_most_once(&mut self) {
        if let Some(packet) = self.packet.take() {
            if let Some(ref sink) = self.sink.0.borrow().sink {
                log::trace!("Publish (QoS-0) to {:?}", packet.topic);
                let _ = sink.send(mqtt::Packet::Publish(packet)).map_err(|_| {
                    log::error!("Mqtt sink is disconnected");
                });
            } else {
                log::error!("Mqtt sink is disconnected");
            }
        } else {
            panic!("PublishBuilder can be used only once.");
        }
    }

    /// Send publish packet with QoS 1
    pub fn at_least_once(&mut self) -> impl Future<Output = Result<(), ()>> {
        if let Some(mut packet) = self.packet.take() {
            let mut inner = self.sink.0.borrow_mut();

            if inner.sink.is_some() {
                let (tx, rx) = oneshot::channel();

                inner.idx += 1;
                if inner.idx == 0 {
                    inner.idx = 1
                }
                let idx = inner.idx;
                inner.queue.push_back((idx, tx));

                packet.qos = mqtt::QoS::AtLeastOnce;
                packet.packet_id = NonZeroU16::new(inner.idx);

                log::trace!("Publish (QoS1) to {:#?}", packet);
                if inner
                    .sink
                    .as_ref()
                    .unwrap()
                    .send(mqtt::Packet::Publish(packet))
                    .is_err()
                {
                    Either::Right(err(()))
                } else {
                    Either::Left(rx.map_err(|_| ()))
                }
            } else {
                Either::Right(err(()))
            }
        } else {
            panic!("PublishBuilder can be used only once.");
        }
    }
}