Remove CancellationToken

This is no longer needed because we handle cancellation on the `Task` level.

Sources/LSPTestSupport/TestJSONRPCConnection.swift

@@ -129,9 +129,7 @@ public final class TestMessageHandler: MessageHandler {
     from clientID: ObjectIdentifier,
     reply: @escaping (LSPResult<R.Response>) -> Void
   ) {
-    let cancellationToken = CancellationToken()
-
-    let request = Request(params, id: id, clientID: clientID, cancellation: cancellationToken, reply: reply)
+    let request = Request(params, id: id, clientID: clientID, reply: reply)
 
     guard !oneShotRequestHandlers.isEmpty else {
       fatalError("unexpected request \(request)")
@@ -179,14 +177,11 @@ public final class TestServer: MessageHandler {
     from clientID: ObjectIdentifier,
     reply: @escaping (LSPResult<R.Response>) -> Void
   ) {
-    let cancellationToken = CancellationToken()
-
     if let params = params as? EchoRequest {
       let req = Request(
         params,
         id: id,
         clientID: clientID,
-        cancellation: cancellationToken,
         reply: { result in
           reply(result.map({ $0 as! R.Response }))
         }
@@ -197,7 +192,6 @@ public final class TestServer: MessageHandler {
         params,
         id: id,
         clientID: clientID,
-        cancellation: cancellationToken,
         reply: { result in
           reply(result.map({ $0 as! R.Response }))
         }

Sources/LanguageServerProtocol/CMakeLists.txt

@@ -1,6 +1,5 @@
 add_library(LanguageServerProtocol STATIC
   AsyncQueue.swift
-  Cancellation.swift
   Connection.swift
   CustomCodable.swift
   Error.swift

Sources/LanguageServerProtocol/Cancellation.swift

@@ -1,27 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-// TODO: implement
-public final class CancellationToken {
-
-  public var isCancelled: Bool { return false }
-
-  public init() {}
-
-  public func addCancellationHandler(_ handler: @escaping () -> Void) {
-
-  }
-
-  public func cancel() {
-
-  }
-}

Sources/LanguageServerProtocol/Connection.swift

@@ -157,9 +157,9 @@ extension Connection {
   ///   use the version with a completion handler.
   public func send<R: RequestType>(_ request: R) async throws -> R.Response {
     let requestIDWrapper = ThreadSafeBox<RequestID?>(initialValue: nil)
-    try Task.checkCancellation()
     return try await withTaskCancellationHandler {
-      try await withCheckedThrowingContinuation { continuation in
+      try Task.checkCancellation()
+      return try await withCheckedThrowingContinuation { continuation in
         let requestID = self.send(request) { result in
           continuation.resume(with: result)
         }

Sources/LanguageServerProtocol/Request.swift

@@ -38,20 +38,15 @@ public final class Request<R: RequestType> {
     }
   }
 
-  /// The request's cancellation state.
-  public let cancellationToken: CancellationToken
-
   public init(
     _ request: Params,
     id: RequestID,
     clientID: ObjectIdentifier,
-    cancellation: CancellationToken,
     reply: @escaping (LSPResult<Response>) -> Void
   ) {
     self.id = id
     self.clientID = clientID
     self.params = request
-    self.cancellationToken = cancellation
     self.replyBlock = reply
   }
 
@@ -71,9 +66,6 @@ public final class Request<R: RequestType> {
   public func reply(_ result: Response) {
     reply(.success(result))
   }
-
-  /// Whether the result has been cancelled.
-  public var isCancelled: Bool { return cancellationToken.isCancelled }
 }
 
 /// A request object, wrapping the parameters of a `NotificationType`.

Sources/SourceKitLSP/Clang/ClangLanguageServer.swift

@@ -298,7 +298,6 @@ actor ClangLanguageServerShim: ToolchainLanguageServer, MessageHandler {
         params,
         id: id,
         clientID: clientID,
-        cancellation: CancellationToken(),
         reply: { result in
           reply(result)
         }

Sources/SourceKitLSP/SourceKitServer.swift

@@ -703,13 +703,10 @@ extension SourceKitServer: MessageHandler {
   ) async {
     let startDate = Date()
 
-    let cancellationToken = CancellationToken()
-
     let request = Request(
       params,
       id: id,
       clientID: clientID,
-      cancellation: cancellationToken,
       reply: { [weak self] result in
         reply(result)
         let endDate = Date()