Format Toolchain.swift file

Author: kateinoigakukun

Sources/SwiftToolchain/Toolchain.swift

@@ -0,0 +1,43 @@
+// Copyright 2020 Carton contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import CartonHelpers
+
+enum ToolchainError: Error, CustomStringConvertible {
+  case directoryDoesNotExist(AbsolutePath)
+  case invalidInstallationArchive(AbsolutePath)
+  case invalidVersion(version: String)
+  case invalidResponse(url: String, status: Int)
+  case unsupportedOperatingSystem
+  case noInstallationDirectory(path: String)
+
+  var description: String {
+    switch self {
+    case let .directoryDoesNotExist(path):
+      return "Directory at path \(path.pathString) does not exist and could not be created"
+    case let .invalidInstallationArchive(path):
+      return "Invalid toolchain/SDK archive was installed at path \(path)"
+    case let .invalidVersion(version):
+      return "Invalid version \(version)"
+    case let .invalidResponse(url: url, status: status):
+      return "Response from \(url) had invalid status \(status) or didn't contain body"
+    case .unsupportedOperatingSystem:
+      return "This version of the operating system is not supported"
+    case let .noInstallationDirectory(path):
+      return """
+        Failed to infer toolchain installation directory. Please make sure that \(path) exists.
+        """
+    }
+  }
+}