Widen platform support for iOS 12 and tvOS 12

Package.swift

@@ -6,9 +6,11 @@ import PackageDescription
 let package = Package(
     name: "UID2",
     defaultLocalization: "en",
+    // NB: The UID2 framework code only runs on iOS 13 & tvOS 13, however this allows
+    // integration in apps supporting iOS 12.
     platforms: [
-        .iOS(.v13),
-        .tvOS(.v13)
+        .iOS(.v12),
+        .tvOS(.v12)
     ],
     products: [
         .library(

Sources/UID2/CryptoUtil.swift

@@ -9,6 +9,7 @@ import CryptoKit
 import Foundation
 import SwiftASN1
 
+@available(iOS 13, tvOS 13, *)
 struct CryptoUtil: Sendable {
     // Parses a server's public key and returns a newly generated public key and symmetric key.
     var parseKey: @Sendable (_ string: String) throws -> (SymmetricKey, P256.KeyAgreement.PublicKey)
@@ -17,6 +18,7 @@ struct CryptoUtil: Sendable {
     var encrypt: @Sendable (_ data: Data, _ key: SymmetricKey, _ authenticatedData: Data) throws -> AES.GCM.SealedBox
 }
 
+@available(iOS 13, tvOS 13, *)
 extension CryptoUtil {
     private static let serverPublicKeyPrefixLength = 9
 

Sources/UID2/Extensions/PublicKey+Extensions.swift

@@ -9,6 +9,7 @@ import CryptoKit
 import Foundation
 import SwiftASN1
 
+@available(iOS 13, tvOS 13, *)
 extension P256.KeyAgreement.PublicKey {
     // CryptoKit's implementation is only available in iOS 14
     var derRepresentation: Data {

Sources/UID2/Extensions/URLSession+Extensions.swift

@@ -7,6 +7,7 @@
 
 import Foundation
 
+@available(iOS 13, tvOS 13, *)
 extension URLSession: NetworkSession {
 
     func loadData(for request: URLRequest) async throws -> (Data, HTTPURLResponse) {

Sources/UID2/Internal/Broadcaster.swift

@@ -1,6 +1,7 @@
 import Foundation
 
 /// Send a value to multiple observers
+@available(iOS 13, tvOS 13, *)
 actor Broadcaster<Element: Sendable> {
     typealias Identifier = UUID
     private var continuations: [Identifier: AsyncStream<Element>.Continuation] = [:]

Sources/UID2/Internal/Queue.swift

@@ -3,6 +3,7 @@ import Foundation
 /// When bridging from a sync to async context using multiple `Task`s, order of execution is not guaranteed.
 /// Using an `AsyncStream` we can bridge enqueued work to an async context within a single `Task`.
 /// https://forums.swift.org/t/a-pitfall-when-using-didset-and-task-together-order-cant-be-guaranteed/71311/6
+@available(iOS 13, tvOS 13, *)
 final class Queue {
     typealias Operation = @Sendable () async -> Void
     private let continuation: AsyncStream<Operation>.Continuation

Sources/UID2/KeychainManager.swift

@@ -5,6 +5,7 @@
 import Foundation
 import Security
 
+@available(iOS 13, tvOS 13, *)
 extension Storage {
     static func keychainStorage() -> Storage {
         let storage = KeychainManager()
@@ -17,6 +18,7 @@ extension Storage {
 }
 
 /// Securely manages data in the Keychain
+@available(iOS 13, tvOS 13, *)
 actor KeychainManager {
 
     private let attrAccount = "uid2"

Sources/UID2/Networking/ClientGenerate.swift

@@ -9,6 +9,8 @@ import CryptoKit
 import Foundation
 
 extension Request {
+
+    @available(iOS 13, tvOS 13, *)
     static func clientGenerate(
         payload: Data,
         initializationVector: Data,
@@ -54,6 +56,7 @@ struct ClientGeneratePayload: Encodable {
     }
 }
 
+@available(iOS 13, tvOS 13, *)
 extension ClientGeneratePayload {
     init(_ identity: IdentityType) {
         switch identity {
@@ -87,6 +90,7 @@ struct ClientGenerateRequestBody: Encodable {
     }
 }
 
+@available(iOS 13, tvOS 13, *)
 fileprivate extension String {
     func sha256hash() -> Data {
         let digest = SHA256.hash(data: Data(self.utf8))

Sources/UID2/Networking/DataEnvelope.swift

@@ -8,6 +8,7 @@
 import CryptoKit
 import Foundation
 
+@available(iOS 13, tvOS 13, *)
 internal enum DataEnvelope {
 
     /// Decrypts raw response envelope data, which is expected to be a base64 encoded string.
@@ -44,7 +45,7 @@
 extension Data {
     /// A convenience initializer for converting from a Data representation of a base64 encoded string to its decoded Data.
     init?(base64EncodedData: Data, options: Data.Base64DecodingOptions = []) {
         guard let base64String = String(data: base64EncodedData, encoding: .utf8) else {
             return nil
         }
         self.init(base64Encoded: base64String, options: options)

Sources/UID2/Networking/NetworkSession.swift

@@ -8,6 +8,7 @@
 import Foundation
 
 /// Common interface for networking and unit testing
+@available(iOS 13, tvOS 13, *)
 protocol NetworkSession: Sendable {
 
     func loadData(for request: URLRequest) async throws -> (Data, HTTPURLResponse)

Sources/UID2/UID2Client.swift

@@ -14,6 +14,7 @@
 #endif
 @preconcurrency import OSLog
 
+@available(iOS 13, tvOS 13, *)
 internal final class UID2Client: Sendable {
     private let clientVersion: String
     private let environment: Environment
@@ -120,7 +121,7 @@
         let decoder = JSONDecoder.apiDecoder()
         guard response.statusCode == 200 else {
             let statusCode = response.statusCode
             let responseText = String(data: data, encoding: .utf8) ?? "<none>"
             os_log("Request failure (%d) %@", log: log, type: .error, statusCode, responseText)
             if environment != .production {
                 os_log("Failed request is using non-production API endpoint %@, is this intentional?", log: log, type: .error, baseURL.description)

Sources/UID2/UID2Manager.State.swift

@@ -4,6 +4,7 @@
 
 import Foundation
 
+@available(iOS 13, tvOS 13, *)
 extension UID2Manager {
     public enum State: Hashable, Sendable, Codable {
         case optout
@@ -15,6 +16,7 @@ extension UID2Manager {
     }
 }
 
+@available(iOS 13, tvOS 13, *)
 extension UID2Manager.State {
     /// A 'case path' returning the current `IdentityStatus`.
     public var identityStatus: IdentityStatus {
@@ -49,6 +51,7 @@ extension UID2Manager.State {
     }
 }
 
+@available(iOS 13, tvOS 13, *)
 extension UID2Manager.State {
     init?(_ package: IdentityPackage) {
         switch package.status {

Sources/UID2/UID2Manager.swift

@@ -10,7 +10,8 @@
 import OSLog
 
 // swiftlint:disable:next type_body_length
+@available(iOS 13, tvOS 13, *)
 public final actor UID2Manager {
     private enum InitializationState {
         case pending
         case complete
@@ -453,4 +454,4 @@
             generate = { newValue }
         }
     }
 }

Tests/TestHelpers/TestCryptoUtil.swift

@@ -36,6 +36,7 @@ private final class Atomic<Value: Sendable>: @unchecked Sendable {
 
 /// A test convenience which exposes the Symmetric Key it generates for the client.
 /// This key can then be used to encrypt stub responses for the client.
+@available(iOS 13, tvOS 13, *)
 public final class TestCryptoUtil {
     private let atomicSymmetricKey: Atomic<SymmetricKey?>
 

Tests/TestHelpers/XCTest+Extensions.swift

@@ -8,6 +8,7 @@
 import XCTest
 
 /// `XCTAssertThrowsError` doesn't support async expressions.
+@available(iOS 13, tvOS 13, *)
 public func assertThrowsError<T>(
     _ expression: @escaping @autoclosure () async throws -> T,
     _ message: @autoclosure () -> String = "",

UID2.podspec.json

@@ -12,8 +12,8 @@
     "tag": "v1.5.0"
   },
   "platforms": {
-    "ios": "13.0",
-    "tvos": "13.0"
+    "ios": "12.0",
+    "tvos": "12.0"
   },
   "swift_versions": [
     "5"