Refactor RttCommand to work with ios 13

Signed-off-by: Piotr Piotrowski <piotr@synadia.com>

Package.swift

@@ -6,7 +6,7 @@ let package = Package(
     name: "nats-swift",
     platforms: [
         .macOS(.v13),
-        .iOS(.v16)
+        .iOS(.v13)
     ],
     products: [
         .library(name: "Nats", targets: ["Nats"])

Sources/Nats/NatsClient/NatsClient.swift

@@ -158,7 +158,7 @@ extension NatsClient {
         return try await connectionHandler.subscribe(subject)
     }
 
-    public func rtt() async throws -> Duration {
+    public func rtt() async throws -> TimeInterval {
         guard let connectionHandler = self.connectionHandler else {
             throw NatsClientError("internal error: empty connection handler")
         }

Sources/Nats/NatsConnection.swift

@@ -288,7 +288,7 @@ class ConnectionHandler: ChannelInboundHandler {
             let tlsConfig = try makeTLSConfig()
             let sslContext = try NIOSSLContext(configuration: tlsConfig)
             let sslHandler = try NIOSSLClientHandler(
-                context: sslContext, serverHostname: s.host())
+                context: sslContext, serverHostname: s.host)
             try await self.channel?.pipeline.addHandler(sslHandler, position: .first)
         }
 
@@ -375,7 +375,7 @@ class ConnectionHandler: ChannelInboundHandler {
                         let sslContext = try NIOSSLContext(
                             configuration: tlsConfig)
                         let sslHandler = try NIOSSLClientHandler(
-                            context: sslContext, serverHostname: server.host()!)
+                            context: sslContext, serverHostname: server.host!)
                         //Fixme(jrm): do not ignore error from addHandler future.
                         channel.pipeline.addHandler(sslHandler).flatMap { _ in
                             channel.pipeline.addHandler(self)

Sources/Nats/RttCommand.swift

@@ -11,27 +11,29 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+import Foundation
 import NIOCore
 
 internal class RttCommand {
-    let startTime = ContinuousClock().now
-    let promise: EventLoopPromise<Duration>?
+    let startTime = DispatchTime.now()
+    let promise: EventLoopPromise<TimeInterval>?
 
     static func makeFrom(channel: Channel?) -> RttCommand {
-        RttCommand(promise: channel?.eventLoop.makePromise(of: Duration.self))
+        RttCommand(promise: channel?.eventLoop.makePromise(of: TimeInterval.self))
     }
 
-    private init(promise: EventLoopPromise<Duration>?) {
+    private init(promise: EventLoopPromise<TimeInterval>?) {
         self.promise = promise
     }
 
     func setRoundTripTime() {
-        let now: ContinuousClock.Instant = ContinuousClock().now
-        let rtt: Duration = now - startTime
+        let now = DispatchTime.now()
+        let nanoTime = now.uptimeNanoseconds - startTime.uptimeNanoseconds
+        let rtt = TimeInterval(nanoTime) / 1_000_000_000  // Convert nanos to seconds
         promise?.succeed(rtt)
     }
 
-    func getRoundTripTime() async throws -> Duration {
-        try await promise?.futureResult.get() ?? Duration.zero
+    func getRoundTripTime() async throws -> TimeInterval {
+        try await promise?.futureResult.get() ?? 0
     }
 }

Tests/NatsTests/Integration/ConnectionTests.swift

@@ -54,8 +54,8 @@ class CoreNatsTests: XCTestCase {
             .build()
         try await client.connect()
 
-        let rtt: Duration = try await client.rtt()
-        XCTAssertGreaterThan(rtt, Duration.zero, "should have RTT")
+        let rtt: TimeInterval = try await client.rtt()
+        XCTAssertGreaterThan(rtt, 0, "should have RTT")
 
         try await client.close()
     }