Add SocketAddress to NetworkTypes

Sources/NetworkTypes/SocketAddress.swift

@@ -0,0 +1,108 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift HTTP API Proposal open source project
+//
+// Copyright (c) 2026 Apple Inc. and the Swift HTTP API Proposal project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift HTTP API Proposal project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+/// An address to which a socket may connect or bind to.
+public struct SocketAddress: Hashable, Sendable {
+    /// Represents an IPv4 address.
+    public struct IPv4: Hashable, Sendable {
+        /// The resolved host address.
+        public var host: String
+        /// The port to connect to.
+        public var port: Int
+
+        /// Creates a new IPv4 address.
+        ///
+        /// - Parameters:
+        ///   - host: Resolved host address.
+        ///   - port: Port to connect to.
+        public init(host: String, port: Int) {
+            self.host = host
+            self.port = port
+        }
+    }
+
+    /// Represents an IPv6 address.
+    public struct IPv6: Hashable, Sendable {
+        /// The resolved host address.
+        public var host: String
+        /// The port to connect to.
+        public var port: Int
+
+        /// Creates a new IPv6 address.
+        ///
+        /// - Parameters:
+        ///   - host: Resolved host address.
+        ///   - port: Port to connect to.
+        public init(host: String, port: Int) {
+            self.host = host
+            self.port = port
+        }
+    }
+
+    enum Base: Hashable, Sendable {
+        case ipv4(IPv4)
+        case ipv6(IPv6)
+    }
+
+    let base: Base
+
+    /// Creates an IPv4 socket address.
+    public static func ipv4(host: String, port: Int) -> Self {
+        Self(base: .ipv4(.init(host: host, port: port)))
+    }
+
+    /// Creates an IPv6 socket address.
+    public static func ipv6(host: String, port: Int) -> Self {
+        Self(base: .ipv6(.init(host: host, port: port)))
+    }
+
+    /// Returns the address as an IPv4 address, if possible.
+    public var ipv4: IPv4? {
+        guard case .ipv4(let address) = self.base else {
+            return nil
+        }
+
+        return address
+    }
+
+    /// Returns the address as an IPv6 address, if possible.
+    public var ipv6: IPv6? {
+        guard case .ipv6(let address) = self.base else {
+            return nil
+        }
+
+        return address
+    }
+
+    /// The ``SocketAddress``'s host.
+    public var host: String {
+        switch self.base {
+        case .ipv4(let ipv4):
+            return ipv4.host
+        case .ipv6(let ipv6):
+            return ipv6.host
+        }
+    }
+
+    /// The ``SocketAddress``'s port.
+    public var port: Int {
+        switch self.base {
+        case .ipv4(let ipv4):
+            return ipv4.port
+
+        case .ipv6(let ipv6):
+            return ipv6.port
+        }
+    }
+}