add requests for file watching in the bsp

Author: Richard Howell

Sources/BuildServerProtocol/Messages.swift

@@ -13,12 +13,14 @@ import LanguageServerProtocol
 
 fileprivate let requestTypes: [_RequestType.Type] = [
   InitializeBuild.self,
+  RegisterForChanges.self,
   ShutdownBuild.self,
   SourceKitOptions.self,
 ]
 
 fileprivate let notificationTypes: [NotificationType.Type] = [
   ExitBuildNotification.self,
+  FileOptionsChangedNotification.self,
   InitializedBuildNotification.self,
 ]
 

Sources/BuildServerProtocol/RegisterForChangeNotifications.swift

@@ -0,0 +1,54 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2019 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
+//
+//===----------------------------------------------------------------------===//
+import LanguageServerProtocol
+
+
+/// The register for changes request is sent from the language
+/// server to the build server to register or unregister for
+/// changes in file options or dependencies. On changes a
+/// FileOptionsChangedNotification is sent.
+public struct RegisterForChanges: RequestType {
+  public static let method: String = "textDocument/registerForChanges"
+  public typealias Response = VoidResponse
+
+  /// The URL of the document to get options for.
+  public var uri: URL
+
+  /// Whether to register or unregister for the file.
+  public var action: RegisterAction
+
+  public init(uri: URL, action: RegisterAction) {
+    self.uri = uri
+    self.action = action
+  }
+}
+
+public enum RegisterAction: String, Hashable, Codable {
+  case register = "register"
+  case unregister = "unregister"
+}
+
+/// The FileOptionsChangedNotification is sent from the
+/// build server to the language server when it detects
+/// changes to a registered files build settings.
+public struct FileOptionsChangedNotification: NotificationType {
+  public static let method: String = "build/sourceKitOptionsChanged"
+
+  /// The URL of the document that has changed settings.
+  public var uri: URL
+
+  /// The updated options for the registered file.
+  public var options: [String]
+
+  /// The working directory for the compile command.
+  public var workingDirectory: String?
+}