Sendable conformance (#104)

* Setup Sendable conformance

* swift format

* Don't need _MQTTSendableProtocol

* Revert var -> let so we don't make breaking change

* Remove unnecessary @preconcurrency

* swift format

* comment

Sources/MQTTNIO/AsyncAwaitSupport/Sendable.swift

@@ -0,0 +1,18 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the MQTTNIO project
+//
+// Copyright (c) 2020-2021 Adam Fowler
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+#if compiler(>=5.6)
+public typealias _MQTTSendable = Sendable
+#else
+public typealias _MQTTSendable = Any
+#endif

Sources/MQTTNIO/MQTTClient.swift

@@ -739,3 +739,9 @@ extension Logger {
         return logger
     }
 }
+
+#if compiler(>=5.6)
+// All public members of the class are immutable and the class manages access to the
+// internal mutable state via Locks
+extension MQTTClient: @unchecked Sendable {}
+#endif

Sources/MQTTNIO/MQTTCoreTypes.swift

@@ -11,9 +11,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-import NIO
+#if compiler(>=5.6)
+@preconcurrency import NIOCore
+#else
+import NIOCore
+#endif
 
-public enum MQTTQoS: UInt8 {
+public enum MQTTQoS: UInt8, _MQTTSendable {
     /// fire and forget
     case atMostOnce = 0
     /// wait for PUBACK, if you don't receive it after a period of time retry sending
@@ -22,7 +26,7 @@ public enum MQTTQoS: UInt8 {
     case exactlyOnce = 2
 }
 
-public enum MQTTPacketType: UInt8 {
+public enum MQTTPacketType: UInt8, _MQTTSendable {
     case CONNECT = 0x10
     case CONNACK = 0x20
     case PUBLISH = 0x30
@@ -41,7 +45,7 @@ public enum MQTTPacketType: UInt8 {
 }
 
 /// MQTT PUBLISH packet parameters.
-public struct MQTTPublishInfo {
+public struct MQTTPublishInfo: _MQTTSendable {
     /// Quality of Service for message.
     public let qos: MQTTQoS
 
@@ -73,7 +77,7 @@ public struct MQTTPublishInfo {
 }
 
 /// MQTT SUBSCRIBE packet parameters.
-public struct MQTTSubscribeInfo {
+public struct MQTTSubscribeInfo: _MQTTSendable {
     /// Topic filter to subscribe to.
     public let topicFilter: String
 
@@ -89,8 +93,8 @@ public struct MQTTSubscribeInfo {
 /// MQTT Sub ACK
 ///
 /// Contains data returned in subscribe ack packets
-public struct MQTTSuback {
-    public enum ReturnCode: UInt8 {
+public struct MQTTSuback: _MQTTSendable {
+    public enum ReturnCode: UInt8, _MQTTSendable {
         case grantedQoS0 = 0
         case grantedQoS1 = 1
         case grantedQoS2 = 2

Sources/MQTTNIO/MQTTCoreTypesV5.swift

@@ -11,10 +11,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-import NIO
-
 /// MQTT V5 Connack
-public struct MQTTConnackV5 {
+public struct MQTTConnackV5: _MQTTSendable {
     /// is using session state from previous session
     public let sessionPresent: Bool
     /// connect reason code
@@ -24,7 +22,7 @@ public struct MQTTConnackV5 {
 }
 
 /// MQTT V5 ACK information. Returned with PUBACK, PUBREL
-public struct MQTTAckV5 {
+public struct MQTTAckV5: _MQTTSendable {
     /// MQTT v5 reason code
     public let reason: MQTTReasonCode
     /// MQTT v5 properties
@@ -37,9 +35,9 @@ public struct MQTTAckV5 {
 }
 
 /// MQTT SUBSCRIBE packet parameters.
-public struct MQTTSubscribeInfoV5 {
+public struct MQTTSubscribeInfoV5: _MQTTSendable {
     /// Retain handling options
-    public enum RetainHandling: UInt8 {
+    public enum RetainHandling: UInt8, _MQTTSendable {
         /// always send retain message
         case sendAlways = 0
         /// send retain if new
@@ -81,7 +79,7 @@ public struct MQTTSubscribeInfoV5 {
 /// MQTT V5 Sub ACK
 ///
 /// Contains data returned in subscribe/unsubscribe ack packets
-public struct MQTTSubackV5 {
+public struct MQTTSubackV5: _MQTTSendable {
     /// MQTT v5 subscription reason code
     public let reasons: [MQTTReasonCode]
     /// MQTT v5 properties
@@ -96,7 +94,7 @@ public struct MQTTSubackV5 {
 /// MQTT V5 Sub ACK
 ///
 /// Contains data returned in subscribe/unsubscribe ack packets
-public struct MQTTAuthV5 {
+public struct MQTTAuthV5: _MQTTSendable {
     /// MQTT v5 authentication reason code
     public let reason: MQTTReasonCode
     /// MQTT v5 properties

Sources/MQTTNIO/MQTTError.swift

@@ -14,7 +14,7 @@
 /// MQTTClient errors
 public enum MQTTError: Error {
     /// Value returned in connection error
-    public enum ConnectionReturnValue: UInt8 {
+    public enum ConnectionReturnValue: UInt8, _MQTTSendable {
         /// connection was accepted
         case accepted = 0
         /// The Server does not support the version of the MQTT protocol requested by the Client.

Sources/MQTTNIO/MQTTPacket.swift

@@ -11,15 +11,19 @@
 //
 //===----------------------------------------------------------------------===//
 
-import NIO
+#if compiler(>=5.6)
+@preconcurrency import NIOCore
+#else
+import NIOCore
+#endif
 
 internal enum InternalError: Swift.Error {
     case incompletePacket
     case notImplemented
 }
 
 /// Protocol for all MQTT packet types
-protocol MQTTPacket: CustomStringConvertible {
+protocol MQTTPacket: CustomStringConvertible, _MQTTSendable {
     /// packet type
     var type: MQTTPacketType { get }
     /// packet id (default to zero if not used)

Sources/MQTTNIO/MQTTProperties.swift

@@ -11,12 +11,16 @@
 //
 //===----------------------------------------------------------------------===//
 
-import NIO
+#if compiler(>=5.6)
+@preconcurrency import NIOCore
+#else
+import NIOCore
+#endif
 
 /// MQTT v5.0 properties. A property consists of a identifier and a value
-public struct MQTTProperties {
+public struct MQTTProperties: _MQTTSendable {
     /// MQTT Property
-    public enum Property: Equatable {
+    public enum Property: Equatable, _MQTTSendable {
         /// Payload format: 0 = bytes, 1 = UTF8 string (available for PUBLISH)
         case payloadFormat(UInt8)
         /// Message expiry indicates the lifetime of the message (available for PUBLISH)

Sources/MQTTNIO/MQTTReason.swift

@@ -15,7 +15,7 @@
 /// Reason codes less than 128 are considered successful. Codes greater than or equal to 128 are considered
 /// a failure. These are returned by CONNACK, PUBACK, PUBREC, PUBREL, PUBCOMP, DISCONNECT and
 /// AUTH packets
-public enum MQTTReasonCode: UInt8 {
+public enum MQTTReasonCode: UInt8, _MQTTSendable {
     /// Success (available for all). For SUBACK mean QoS0 is available
     case success = 0
     /// The subscription is accepted and the maximum QoS sent will be QoS 1. This might be a lower QoS than was requested.

Tests/MQTTNIOTests/MQTTNIOTests+async.swift

@@ -13,7 +13,6 @@
 
 #if compiler(>=5.5) && canImport(_Concurrency)
 
-import Foundation
 import Logging
 import NIO
 import NIOConcurrencyHelpers