mqtt_topic_engine/
qos.rs

1//! Quality of Service (QoS) levels for MQTT
2//!
3//! Defines the three standard MQTT QoS levels independent of any specific
4//! MQTT client implementation.
5//!
6//! This module provides conversions to/from popular MQTT client libraries:
7//! - `rumqttc` - Enable with feature `rumqttc`
8//! - `paho-mqtt` - Enable with feature `paho-mqtt`
9//! - `ntex-mqtt` - Enable with feature `ntex-mqtt`
10//!
11//! These features only add **type conversions** between [`QoS`] and the client's
12//! own QoS type — they pull in the client crate purely for its types and do not
13//! drive any connection. How that client itself is built stays under your
14//! control: this crate depends on each with `default-features = false`, so it
15//! never forces a native toolchain on you. In particular `paho-mqtt` links a
16//! C library — its default `bundled` feature builds it from source (needs CMake)
17//! while otherwise it expects a system-installed Paho C library. Since you would
18//! only enable the `paho-mqtt` feature when you already use `paho-mqtt` as your
19//! client, Cargo's (additive) feature unification applies your own build choice
20//! there, and everything links as expected.
21
22use std::fmt;
23
24/// MQTT Quality of Service levels
25///
26/// Defines delivery guarantees for MQTT messages:
27/// - `AtMostOnce` (0): Best effort delivery, no guarantees
28/// - `AtLeastOnce` (1): Message delivered at least once, duplicates possible
29/// - `ExactlyOnce` (2): Message delivered exactly once, highest guarantee
30#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
31#[repr(u8)]
32pub enum QoS {
33	/// QoS 0: At most once delivery (fire and forget)
34	AtMostOnce = 0,
35	/// QoS 1: At least once delivery (acknowledged delivery)
36	AtLeastOnce = 1,
37	/// QoS 2: Exactly once delivery (assured delivery)
38	ExactlyOnce = 2,
39}
40
41impl QoS {
42	/// Convert to rumqttc QoS type
43	///
44	/// # Example
45	/// ```ignore
46	/// let qos = QoS::AtLeastOnce;
47	/// let rumqttc_qos = qos.to_rumqttc();
48	/// ```
49	#[cfg(feature = "rumqttc")]
50	pub fn to_rumqttc(self) -> rumqttc::QoS {
51		match self {
52			| QoS::AtMostOnce => rumqttc::QoS::AtMostOnce,
53			| QoS::AtLeastOnce => rumqttc::QoS::AtLeastOnce,
54			| QoS::ExactlyOnce => rumqttc::QoS::ExactlyOnce,
55		}
56	}
57
58	/// Convert to paho-mqtt QoS type
59	///
60	/// # Example
61	/// ```ignore
62	/// let qos = QoS::AtLeastOnce;
63	/// let paho_qos = qos.to_paho_mqtt();
64	/// ```
65	#[cfg(feature = "paho-mqtt")]
66	pub fn to_paho_mqtt(self) -> paho_mqtt::QoS {
67		match self {
68			| QoS::AtMostOnce => paho_mqtt::QoS::AtMostOnce,
69			| QoS::AtLeastOnce => paho_mqtt::QoS::AtLeastOnce,
70			| QoS::ExactlyOnce => paho_mqtt::QoS::ExactlyOnce,
71		}
72	}
73
74	/// Convert to ntex-mqtt QoS type
75	///
76	/// # Example
77	/// ```ignore
78	/// let qos = QoS::AtLeastOnce;
79	/// let ntex_qos = qos.to_ntex_mqtt();
80	/// ```
81	#[cfg(feature = "ntex-mqtt")]
82	pub fn to_ntex_mqtt(self) -> ntex_mqtt::QoS {
83		match self {
84			| QoS::AtMostOnce => ntex_mqtt::QoS::AtMostOnce,
85			| QoS::AtLeastOnce => ntex_mqtt::QoS::AtLeastOnce,
86			| QoS::ExactlyOnce => ntex_mqtt::QoS::ExactlyOnce,
87		}
88	}
89}
90
91#[cfg(feature = "rumqttc")]
92impl From<rumqttc::QoS> for QoS {
93	fn from(qos: rumqttc::QoS) -> Self {
94		match qos {
95			| rumqttc::QoS::AtMostOnce => QoS::AtMostOnce,
96			| rumqttc::QoS::AtLeastOnce => QoS::AtLeastOnce,
97			| rumqttc::QoS::ExactlyOnce => QoS::ExactlyOnce,
98		}
99	}
100}
101
102#[cfg(feature = "paho-mqtt")]
103impl From<paho_mqtt::QoS> for QoS {
104	fn from(qos: paho_mqtt::QoS) -> Self {
105		match qos {
106			| paho_mqtt::QoS::AtMostOnce => QoS::AtMostOnce,
107			| paho_mqtt::QoS::AtLeastOnce => QoS::AtLeastOnce,
108			| paho_mqtt::QoS::ExactlyOnce => QoS::ExactlyOnce,
109		}
110	}
111}
112
113#[cfg(feature = "ntex-mqtt")]
114impl From<ntex_mqtt::QoS> for QoS {
115	fn from(qos: ntex_mqtt::QoS) -> Self {
116		match qos {
117			| ntex_mqtt::QoS::AtMostOnce => QoS::AtMostOnce,
118			| ntex_mqtt::QoS::AtLeastOnce => QoS::AtLeastOnce,
119			| ntex_mqtt::QoS::ExactlyOnce => QoS::ExactlyOnce,
120		}
121	}
122}
123
124impl fmt::Display for QoS {
125	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
126		match self {
127			| QoS::AtMostOnce => write!(f, "QoS0"),
128			| QoS::AtLeastOnce => write!(f, "QoS1"),
129			| QoS::ExactlyOnce => write!(f, "QoS2"),
130		}
131	}
132}
mqtt_topic_engine/qos.rs

mqtt_topic_engine/
qos.rs
