Make the value-typed protocol options Sendable

Sources/SwiftNetwork/Connection/Connection.swift

@@ -1058,8 +1058,8 @@ public struct StreamBridge: StreamProtocol {
 public struct CustomLink: StreamProtocol {
     public typealias ContentType = Void
 
-    private var tx: ((Span<UInt8>) -> Void)? = nil
-    private var rx: ((@escaping (Span<UInt8>) -> Void) -> Void)? = nil
+    private var tx: (@Sendable (_ bytes: Span<UInt8>) -> Void)? = nil
+    private var rx: (@Sendable (_ inject: @escaping (_ bytes: Span<UInt8>) -> Void) -> Void)? = nil
 
     public let belowProtocol: Void
     /// Configure CustomLink for tx byte handling
@@ -1073,7 +1073,7 @@ public struct CustomLink: StreamProtocol {
     ///
     /// - Parameter handler: A closure that will be called with a
     /// span of bytes to be written to the network.
-    public func tx(_ handler: @escaping (Span<UInt8>) -> Void) -> Self {
+    public func tx(_ handler: @escaping @Sendable (_ bytes: Span<UInt8>) -> Void) -> Self {
         var mutableSelf = self
         mutableSelf.tx = handler
         return mutableSelf
@@ -1095,7 +1095,9 @@ public struct CustomLink: StreamProtocol {
     /// - Parameter handler: A closure that will be called with an
     /// escaping closure that should be stored for later use when bytes
     /// need to be injected into the protocol stack.
-    public func rx(_ handler: @escaping ((@escaping (Span<UInt8>) -> Void) -> Void)) -> Self {
+    public func rx(
+        _ handler: @escaping @Sendable (_ inject: @escaping (_ bytes: Span<UInt8>) -> Void) -> Void
+    ) -> Self {
         var mutableSelf = self
         mutableSelf.rx = handler
         return mutableSelf

Sources/SwiftNetwork/Protocols/BridgeProtocol.swift

@@ -28,7 +28,7 @@ internal import Synchronization
 
 @_spi(Essentials)
 @available(Network 0.1.0, *)
-public struct DatagramDrops: Equatable {
+public struct DatagramDrops: Equatable, Sendable {
     private var dropRanges: [ClosedRange<Int>]
     private var datagramCount = 0
     public var blockPacketGeneration = false
@@ -66,8 +66,8 @@ public struct DatagramDrops: Equatable {
     }
 }
 
-public typealias BridgeObserveFirstByteHandler = ((UInt8) -> Void)?
-public typealias BridgeObserveFrameHandler = ((UInt8, Int) -> Void)?
+public typealias BridgeObserveFirstByteHandler = (@Sendable (_ firstByte: UInt8) -> Void)?
+public typealias BridgeObserveFrameHandler = (@Sendable (_ firstByte: UInt8, _ byteCount: Int) -> Void)?
 
 @_spi(Essentials)
 @available(Network 0.1.0, *)
@@ -76,7 +76,7 @@ public struct BridgeDatagramProtocol: NetworkProtocol {
     public typealias Metadata = BridgeMetadata
     public typealias Instance = BridgeInstance
 
-    public struct BridgeOptions: PerProtocolOptions {
+    public struct BridgeOptions: PerProtocolOptions, Sendable {
         public var linkDelay: NetworkDuration = .zero
         public var observeFirstByteHandler: BridgeObserveFirstByteHandler = nil
         public var observeFrameHandler: BridgeObserveFrameHandler = nil
@@ -395,7 +395,7 @@ public struct BridgeStreamProtocol: NetworkProtocol {
     public typealias Metadata = BridgeMetadata
     public typealias Instance = BridgeInstance
 
-    public struct BridgeOptions: PerProtocolOptions {
+    public struct BridgeOptions: PerProtocolOptions, Sendable {
         init() {}
 
         init?(from serializedBytes: [UInt8]) {

Sources/SwiftNetwork/Protocols/CustomIPProtocol.swift

@@ -28,7 +28,7 @@ public struct CustomIPProtocol: NetworkProtocol {
     public typealias Options = CustomIPOptions
     public typealias Metadata = CustomIPMetadata
 
-    public struct CustomIPOptions: PerProtocolOptions {
+    public struct CustomIPOptions: PerProtocolOptions, Sendable {
         var ipProtocolNumber: UInt8 = 0
         init() {}
 

Sources/SwiftNetwork/Protocols/CustomLinkProtocol.swift

@@ -33,9 +33,9 @@ public struct CustomLinkProtocol: NetworkProtocol {
     public typealias Metadata = CustomLinkMetadata
     public typealias Instance = CustomLinkInstance
 
-    public struct CustomLinkOptions: PerProtocolOptions {
-        public var tx: ((Span<UInt8>) -> Void)? = nil
-        public var rx: ((@escaping (Span<UInt8>) -> Void) -> Void)? = nil
+    public struct CustomLinkOptions: PerProtocolOptions, Sendable {
+        public var tx: (@Sendable (_ bytes: Span<UInt8>) -> Void)? = nil
+        public var rx: (@Sendable (_ inject: @escaping (_ bytes: Span<UInt8>) -> Void) -> Void)? = nil
         init() {}
 
         init?(from serializedBytes: [UInt8]) {
@@ -87,8 +87,8 @@ public struct CustomLinkProtocol: NetworkProtocol {
         var log = NetworkLoggerState()
         public var eventManager = ProtocolEventManager()
         private var incomingFrames = FrameArray()
-        public var tx: ((Span<UInt8>) -> Void)? = nil
-        public var rx: ((@escaping (Span<UInt8>) -> Void) -> Void)? = nil
+        public var tx: (@Sendable (Span<UInt8>) -> Void)? = nil
+        public var rx: (@Sendable (@escaping (Span<UInt8>) -> Void) -> Void)? = nil
 
         public func setup(
             remote: Endpoint?,
@@ -179,12 +179,12 @@ public struct CustomLinkProtocol: NetworkProtocol {
 @_spi(Essentials)
 @available(Network 0.1.0, *)
 extension ProtocolOptions<CustomLinkProtocol> {
-    public var tx: ((Span<UInt8>) -> Void)? {
+    public var tx: (@Sendable (_ bytes: Span<UInt8>) -> Void)? {
         get { perProtocolOptions!.tx }
         set { perProtocolOptions!.tx = newValue }
     }
 
-    public var rx: ((@escaping (Span<UInt8>) -> Void) -> Void)? {
+    public var rx: (@Sendable (_ inject: @escaping (_ bytes: Span<UInt8>) -> Void) -> Void)? {
         get { perProtocolOptions!.rx }
         set { perProtocolOptions!.rx = newValue }
     }

Sources/SwiftNetwork/Protocols/DemuxProtocol.swift

@@ -120,7 +120,7 @@ public struct DemuxProtocol: NetworkProtocol {
     public typealias Options = DemuxOptions
     public typealias Metadata = DemuxMetadata
 
-    public struct DemuxOptions: PerProtocolOptions {
+    public struct DemuxOptions: PerProtocolOptions, Sendable {
         var demuxPatterns = Deque<DemuxPattern>()
 
         init() {}

Sources/SwiftNetwork/Protocols/IPProtocol.swift

@@ -69,7 +69,7 @@ public struct IPProtocol: NetworkProtocol {
         1280
     }
 
-    public enum Version: UInt8 {
+    public enum Version: UInt8, Sendable {
         /// Allows any IP version.
         case any = 0
         /// Uses only IP version 4 (IPv4).
@@ -78,7 +78,7 @@ public struct IPProtocol: NetworkProtocol {
         case v6 = 6
     }
 
-    public enum AddressPreference: UInt8 {
+    public enum AddressPreference: UInt8, Sendable {
         case any = 0
         case temporary = 1
         case stable = 2
@@ -110,7 +110,7 @@ public struct IPProtocol: NetworkProtocol {
         }
     }
 
-    public struct IPOptions: PerProtocolOptions {
+    public struct IPOptions: PerProtocolOptions, Sendable {
         var version: Version = .any
         var localAddressPreference: AddressPreference = .any
 

Sources/SwiftNetwork/Protocols/SwiftTLSProtocol.swift

@@ -87,7 +87,7 @@ public struct SwiftTLSProtocol: NetworkProtocol {
             _tlsOptions.externalPSK = .init(externalIdentity: identity, epsk: .init(data: epsk))
         }
         #else
-        private struct SwiftTLSOptionsStorage {
+        private struct SwiftTLSOptionsStorage: Sendable {
             var serverName: String?
             var quicTransportParameters: [UInt8]?
             var applicationProtocols: [String]?
@@ -1311,6 +1311,13 @@ public struct SwiftTLSProtocol: NetworkProtocol {
 
 }
 
+#if !EXPORT_SWIFTTLS
+// Under `EXPORT_SWIFTTLS` the options store a `SwiftTLSOptions`, which is not `Sendable`, so the options can only be
+// `Sendable` when they hold their own copy of the fields.
+@available(Network 0.1.0, *)
+extension SwiftTLSProtocol.SwiftTLSProtocolOptions: Sendable {}
+#endif
+
 @_spi(ProtocolProvider)
 @available(Network 0.1.0, *)
 extension ProtocolOptions<SwiftTLSProtocol> {

Sources/SwiftNetwork/Protocols/TCPProtocol.swift

@@ -55,7 +55,7 @@ public struct TCPProtocol: NetworkProtocol {
         16
     }
 
-    public struct TCPOptions: PerProtocolOptions {
+    public struct TCPOptions: PerProtocolOptions, Sendable {
 
         internal var _maximumSegmentSize: UInt32 = 0
         public var maximumSegmentSize: UInt32 {

Tests/SwiftNetworkTests/SwiftNetworkConnectionTests.swift

@@ -828,7 +828,9 @@ final class SwiftNetworkConnectionTests: NetTestCase {
     func testNoTransportCustomLink() {
         let group = DispatchGroup()
         group.enter()
-        var injection: ((Span<UInt8>) -> Void)?
+        // The rx handler writes this during connection setup, before the `.ready` update leaves `group`, and the
+        // test reads it only after `group.wait`, so the group orders the two accesses.
+        nonisolated(unsafe) var injection: ((Span<UInt8>) -> Void)?
         let c1 = NetworkConnection(
             to: Endpoint(address: IPv4Address.loopback, port: 7778),
             using: .parameters {

Tests/SwiftNetworkTests/SwiftNetworkQUICHarnessTests.swift

@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import Synchronization
 import XCTest
 
 #if !targetEnvironment(simulator) && (os(iOS) || os(macOS) || os(Linux))
@@ -762,11 +763,11 @@ final class SwiftNetworkQUICHarnessTests: NetTestCase {
         let clientOptions = QUICProtocol.options()
         clientOptions.connectionOptions.initialPacketSize = 1400
 
-        var observedInitialPacketSizes: [Int] = []
+        let observedInitialPacketSizes = Mutex<[Int]>([])
         let observeFrameHandler: BridgeObserveFrameHandler = { firstByte, byteCount in
             // Verify initial packet
             guard (firstByte & 0xF0) == 0xC0 else { return }
-            observedInitialPacketSizes.append(byteCount)
+            observedInitialPacketSizes.withLock { $0.append(byteCount) }
         }
 
         QUICTestHarness().runQUICTest(
@@ -777,8 +778,11 @@ final class SwiftNetworkQUICHarnessTests: NetTestCase {
             bridgeObserveFrameHandler: observeFrameHandler
         )
 
-        XCTAssertFalse(observedInitialPacketSizes.isEmpty, "Should have observed at least one Initial packet")
-        XCTAssertEqual(observedInitialPacketSizes.first, 1400)
+        XCTAssertFalse(
+            observedInitialPacketSizes.withLock { $0.isEmpty },
+            "Should have observed at least one Initial packet"
+        )
+        XCTAssertEqual(observedInitialPacketSizes.withLock { $0.first }, 1400)
     }
 
     func testQUICDatagramRemoteMaxDatagramFrameSize() {

Tests/SwiftNetworkTests/SwiftNetworkQUICSpinBitTests.swift

@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import Synchronization
 import XCTest
 
 #if !targetEnvironment(simulator) && (os(iOS) || os(macOS) || os(Linux))
@@ -64,10 +65,10 @@ final class SwiftNetworkQUICSpinBitTests: NetTestCase {
         // it from the server.
 
         var hasSpinBit = true
-        var observedSpinBitValues: Set<Bool> = []
+        let observedSpinBitValues = Mutex<Set<Bool>>([])
         let observeFirstByteHandler: BridgeObserveFirstByteHandler = { firstByte in
             guard (firstByte & 0xC0) == 0x40 else { return }
-            observedSpinBitValues.insert((firstByte & 0x20) != 0)
+            observedSpinBitValues.withLock { values -> Void in values.insert((firstByte & 0x20) != 0) }
         }
         QUICTestHarness().runQUICTest(
             dataBlock: Array("Hello World!".utf8),
@@ -99,11 +100,11 @@ final class SwiftNetworkQUICSpinBitTests: NetTestCase {
                 harness.context.async {
                     defer { expectation.fulfill() }
                     XCTAssertFalse(
-                        observedSpinBitValues.isEmpty,
+                        observedSpinBitValues.withLock { $0.isEmpty },
                         "BridgeDatagramProtocol should have observed short-header packets with spin bit values"
                     )
                     XCTAssertTrue(
-                        observedSpinBitValues.contains(true),
+                        observedSpinBitValues.withLock { $0.contains(true) },
                         "BridgeDatagramProtocol should have observed at least one packet with spin bit set"
                     )
                 }