Move downloader and socket input parsing to xpc services (#675)

* XPC updater POC

* WIP

* obo

* WIP

* Working

* .

* .

* .

* Cleanup

* Cleanup

* Throw restrict

* Remove dead protocol.

* .

* Fix ECDSA test.

* Scripts

Sources/SecretAgent/AppDelegate.swift

@@ -34,11 +34,13 @@ class AppDelegate: NSObject, NSApplicationDelegate {
     func applicationDidFinishLaunching(_ aNotification: Notification) {
         logger.debug("SecretAgent finished launching")
         Task {
+            let inputParser = try XPCAgentInputParser()
             for await session in socketController.sessions {
                 Task {
                     do {
                         for await message in session.messages {
-                            let agentResponse = try await agent.handle(data: message, provenance: session.provenance)
+                            let request = try await inputParser.parse(data: message)
+                            let agentResponse = await agent.handle(request: request, provenance: session.provenance)
                             try await session.write(agentResponse)
                         }
                     } catch {

Sources/SecretAgent/XPCInputParser.swift

@@ -0,0 +1,23 @@
+import Foundation
+import SecretAgentKit
+import Brief
+import XPCWrappers
+
+/// Delegates all agent input parsing to an XPC service which wraps OpenSSH
+public final class XPCAgentInputParser: SSHAgentInputParserProtocol {
+
+    private let session: XPCTypedSession<SSHAgent.Request, SSHAgentInputParser.AgentParsingError>
+
+    public init() throws {
+        session = try XPCTypedSession(serviceName: "com.maxgoedjen.Secretive.AgentRequestParser", warmup: true)
+    }
+
+    public func parse(data: Data) async throws -> SSHAgent.Request {
+        try await session.send(data)
+    }
+
+    deinit {
+        session.complete()
+    }
+
+}