Add VariableTypeInfo structure

Author: fwcd

Sources/SourceKitLSP/CMakeLists.txt

@@ -30,6 +30,7 @@ target_sources(SourceKitLSP PRIVATE
   Swift/SourceKitD+ResponseError.swift
   Swift/SwiftCommand.swift
   Swift/SwiftLanguageServer.swift)
+  Swift/VariableTypeInfo.swift
 set_target_properties(SourceKitLSP PROPERTIES
   INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_Swift_MODULE_DIRECTORY})
 # TODO(compnerd) reduce the exposure here, why is everything PUBLIC-ly linked?

Sources/SourceKitLSP/Swift/VariableTypeInfo.swift

@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 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 Dispatch
+import LanguageServerProtocol
+import SourceKitD
+
+/// A typed variable as returned by sourcekitd's CollectVariableType.
+struct VariableTypeInfo {
+  /// Range of the variable identifier in the source file.
+  var range: Range<Position>
+  /// The printed type of the variable.
+  var printedType: String
+
+  init?(_ dict: SKDResponseDictionary, in snapshot: DocumentSnapshot) {
+    let keys = dict.sourcekitd.keys
+
+    guard let offset: Int = dict[keys.variable_offset],
+          let length: Int = dict[keys.variable_length],
+          let startIndex = snapshot.positionOf(utf8Offset: offset),
+          let endIndex = snapshot.positionOf(utf8Offset: offset + length),
+          let printedType: String = dict[keys.variable_type] else {
+      return nil
+    }
+
+    self.range = startIndex..<endIndex
+    self.printedType = printedType
+  }
+}