Add ClientError and ClientErrorListener

Sources/ElixxirDAppsSDK/Client.swift

@@ -5,6 +5,7 @@ public struct Client {
   public var waitForNetwork: NetworkWaiter
   public var isNetworkHealthy: NetworkHealthProvider
   public var monitorNetworkHealth: NetworkHealthListener
+  public var listenErrors: ClientErrorListener
   public var makeIdentity: IdentityMaker
   public var connect: ConnectionMaker
   public var waitForDelivery: MessageDeliveryWaiter
@@ -17,6 +18,7 @@ extension Client {
       waitForNetwork: .live(bindingsClient: bindingsClient),
       isNetworkHealthy: .live(bindingsClient: bindingsClient),
       monitorNetworkHealth: .live(bindingsClient: bindingsClient),
+      listenErrors: .live(bindingsClient: bindingsClient),
       makeIdentity: .live(bindingsClient: bindingsClient),
       connect: .live(bindingsClient: bindingsClient),
       waitForDelivery: .live(bindingsClient: bindingsClient)
@@ -31,6 +33,7 @@ extension Client {
     waitForNetwork: .failing,
     isNetworkHealthy: .failing,
     monitorNetworkHealth: .failing,
+    listenErrors: .failing,
     makeIdentity: .failing,
     connect: .failing,
     waitForDelivery: .failing

Sources/ElixxirDAppsSDK/ClientError.swift

+public struct ClientError: Error, Equatable {
+  public init(source: String, message: String, trace: String) {
+    self.source = source
+    self.message = message
+    self.trace = trace
+  }
+
+  public var source: String
+  public var message: String
+  public var trace: String
+}

Sources/ElixxirDAppsSDK/ClientErrorListener.swift

+import Bindings
+
+public struct ClientErrorListener {
+  public var listen: (@escaping (ClientError) -> Void) -> Void
+
+  public func callAsFunction(callback: @escaping (ClientError) -> Void) {
+    listen(callback)
+  }
+}
+
+extension ClientErrorListener {
+  public static func live(bindingsClient: BindingsClient) -> ClientErrorListener {
+    ClientErrorListener { callback in
+      let listener = Listener(onReport: callback)
+      bindingsClient.registerErrorCallback(listener)
+    }
+  }
+}
+
+private final class Listener: NSObject, BindingsClientErrorProtocol {
+  init(onReport: @escaping (ClientError) -> Void) {
+    self.onReport = onReport
+    super.init()
+  }
+
+  let onReport: (ClientError) -> Void
+
+  func report(_ source: String?, message: String?, trace: String?) {
+    guard let source = source else {
+      fatalError("BindingsClientError.source is `nil`")
+    }
+    guard let message = message else {
+      fatalError("BindingsClientError.message is `nil`")
+    }
+    guard let trace = trace else {
+      fatalError("BindingsClientError.trace is `nil`")
+    }
+    onReport(ClientError(source: source, message: message, trace: trace))
+  }
+}
+
+#if DEBUG
+extension ClientErrorListener {
+  public static let failing = ClientErrorListener { _ in
+    fatalError("Not implemented")
+  }
+}
+#endif