Protocolizing filehandle reader/writer

SecretAgent/AppDelegate.swift

@@ -28,7 +28,7 @@ class AppDelegate: NSObject, NSApplicationDelegate {
     func applicationDidFinishLaunching(_ aNotification: Notification) {
         os_log(.debug, "SecretAgent finished launching")
         DispatchQueue.main.async {
-            self.socketController.handler = self.agent.handle(fileHandle:)
+            self.socketController.handler = self.agent.handle(reader:writer:)
         }
         notifier.prompt()
         updateSink = updater.$update.sink { release in

SecretAgentKit/Agent.swift

@@ -21,18 +21,19 @@ public class Agent {
 
 extension Agent {
 
-    public func handle(fileHandle: FileHandle) {
+    public func handle(reader: FileHandleReader, writer: FileHandleWriter) {
         os_log(.debug, "Agent handling new data")
-        let data = fileHandle.availableData
+        let data = reader.availableData
         guard !data.isEmpty else { return }
         let requestTypeInt = data[4]
         guard let requestType = SSHAgent.RequestType(rawValue: requestTypeInt) else { return }
         os_log(.debug, "Agent handling request of type %@", requestType.debugDescription)
         let subData = Data(data[5...])
-        handle(requestType: requestType, data: subData, fileHandle: fileHandle)
+        let response = handle(requestType: requestType, data: subData, reader: reader)
+        writer.write(response)
     }
 
-    func handle(requestType: SSHAgent.RequestType, data: Data, fileHandle: FileHandle) {
+    func handle(requestType: SSHAgent.RequestType, data: Data, reader: FileHandleReader) -> Data {
         var response = Data()
         do {
             switch requestType {
@@ -42,7 +43,7 @@ extension Agent {
                 os_log(.debug, "Agent returned %@", SSHAgent.ResponseType.agentIdentitiesAnswer.debugDescription)
             case .signRequest:
                 response.append(SSHAgent.ResponseType.agentSignResponse.data)
-                response.append(try sign(data: data, from: fileHandle.fileDescriptor))
+                response.append(try sign(data: data, from: reader.fileDescriptor))
                 os_log(.debug, "Agent returned %@", SSHAgent.ResponseType.agentSignResponse.debugDescription)
             }
         } catch {
@@ -51,7 +52,7 @@ extension Agent {
             os_log(.debug, "Agent returned %@", SSHAgent.ResponseType.agentFailure.debugDescription)
         }
         let full = OpenSSHKeyWriter().lengthAndData(of: response)
-        fileHandle.write(full)
+        return full
     }
 
 }

SecretAgentKit/FileHandleProtocols.swift

@@ -0,0 +1,16 @@
+import Foundation
+
+public protocol FileHandleReader {
+
+    var availableData: Data { get }
+    var fileDescriptor: Int32 { get }
+
+}
+
+public protocol FileHandleWriter {
+
+    func write(_ data: Data)
+
+}
+
+extension FileHandle: FileHandleReader, FileHandleWriter {}

SecretAgentKit/SocketController.swift

@@ -5,7 +5,7 @@ public class SocketController {
 
     fileprivate var fileHandle: FileHandle?
     fileprivate var port: SocketPort?
-    public var handler: ((FileHandle) -> Void)?
+    public var handler: ((FileHandleReader, FileHandleWriter) -> Void)?
 
     public init(path: String) {
         os_log(.debug, "Socket controller setting up at %@", path)
@@ -52,7 +52,7 @@ public class SocketController {
     @objc func handleConnectionAccept(notification: Notification) {
         os_log(.debug, "Socket controller accepted connection")
         guard let new = notification.userInfo?[NSFileHandleNotificationFileHandleItem] as? FileHandle else { return }
-        handler?(new)
+        handler?(new, new)
         new.waitForDataInBackgroundAndNotify()
         fileHandle?.acceptConnectionInBackgroundAndNotify(forModes: [RunLoop.current.currentMode!])
     }
@@ -61,7 +61,7 @@ public class SocketController {
         os_log(.debug, "Socket controller has new data available")
         guard let new = notification.object as? FileHandle else { return }
         os_log(.debug, "Socket controller received new file handle")
-        handler?(new)
+        handler?(new, new)
     }
 
 }

Secretive.xcodeproj/project.pbxproj

@@ -45,6 +45,7 @@
 		507CE4F02420A4C50029F750 /* SigningWitness.swift in Sources */ = {isa = PBXBuildFile; fileRef = 507CE4EF2420A4C50029F750 /* SigningWitness.swift */; };
 		507CE4F42420A8C10029F750 /* SigningRequestProvenance.swift in Sources */ = {isa = PBXBuildFile; fileRef = 507CE4F32420A8C10029F750 /* SigningRequestProvenance.swift */; };
 		507CE4F62420A96F0029F750 /* SigningRequestTracer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 507CE4F52420A96F0029F750 /* SigningRequestTracer.swift */; };
+		507EE34224281E12003C4FE3 /* FileHandleProtocols.swift in Sources */ = {isa = PBXBuildFile; fileRef = 507EE34124281E12003C4FE3 /* FileHandleProtocols.swift */; };
 		508A58AA241E06B40069DC07 /* PreviewUpdater.swift in Sources */ = {isa = PBXBuildFile; fileRef = 508A58A9241E06B40069DC07 /* PreviewUpdater.swift */; };
 		508A58B3241ED2180069DC07 /* AgentStatusChecker.swift in Sources */ = {isa = PBXBuildFile; fileRef = 508A58B2241ED2180069DC07 /* AgentStatusChecker.swift */; };
 		508A58B5241ED48F0069DC07 /* PreviewAgentStatusChecker.swift in Sources */ = {isa = PBXBuildFile; fileRef = 508A58B4241ED48F0069DC07 /* PreviewAgentStatusChecker.swift */; };
@@ -238,6 +239,7 @@
 		507CE4EF2420A4C50029F750 /* SigningWitness.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SigningWitness.swift; sourceTree = "<group>"; };
 		507CE4F32420A8C10029F750 /* SigningRequestProvenance.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SigningRequestProvenance.swift; sourceTree = "<group>"; };
 		507CE4F52420A96F0029F750 /* SigningRequestTracer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SigningRequestTracer.swift; sourceTree = "<group>"; };
+		507EE34124281E12003C4FE3 /* FileHandleProtocols.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FileHandleProtocols.swift; sourceTree = "<group>"; };
 		508A58A9241E06B40069DC07 /* PreviewUpdater.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreviewUpdater.swift; sourceTree = "<group>"; };
 		508A58AB241E121B0069DC07 /* Config.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = Config.xcconfig; sourceTree = "<group>"; };
 		508A58B2241ED2180069DC07 /* AgentStatusChecker.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AgentStatusChecker.swift; sourceTree = "<group>"; };
@@ -529,6 +531,7 @@
 				507CE4F32420A8C10029F750 /* SigningRequestProvenance.swift */,
 				507CE4F52420A96F0029F750 /* SigningRequestTracer.swift */,
 				50A3B79F24026B9900D209EA /* Agent.swift */,
+				507EE34124281E12003C4FE3 /* FileHandleProtocols.swift */,
 				5099A06F240242BA0062B6F2 /* Info.plist */,
 			);
 			path = SecretAgentKit;
@@ -957,6 +960,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				507EE34224281E12003C4FE3 /* FileHandleProtocols.swift in Sources */,
 				507CE4EE2420A3CA0029F750 /* SocketController.swift in Sources */,
 				5099A08A240242C20062B6F2 /* SSHAgentProtocol.swift in Sources */,
 				507CE4ED2420A3C70029F750 /* Agent.swift in Sources */,