Merge pull request swiftlang#140 from Trzyipolkostkicukru/finding-config

Expose finding ".swift-format" file

Author: allevato

Sources/SwiftFormatConfiguration/Configuration.swift

@@ -120,6 +120,12 @@ public struct Configuration: Codable, Equatable {
     self.version = highestSupportedConfigurationVersion
   }
 
+  /// Constructs a Configuration by loading it from a configuration file.
+  public init(contentsOf url: URL) throws {
+    let data = try Data(contentsOf: url)
+    self = try JSONDecoder().decode(Configuration.self, from: data)
+  }
+
   public init(from decoder: Decoder) throws {
     let container = try decoder.container(keyedBy: CodingKeys.self)
 
@@ -189,6 +195,27 @@ public struct Configuration: Codable, Equatable {
       forKey: .lineBreakAroundMultilineExpressionChainComponents)
     try container.encode(rules, forKey: .rules)
   }
+
+  /// Returns the URL of the configuration file that applies to the given file or directory.
+  public static func url(forConfigurationFileApplyingTo url: URL) -> URL? {
+    var path = url.absoluteURL
+    let configFilename = ".swift-format"
+    var isDirectory: ObjCBool = false
+    if FileManager.default.fileExists(atPath: path.path, isDirectory: &isDirectory), 
+      isDirectory.boolValue {
+      // will be deleted in a loop
+      path.appendPathComponent("placeholder")
+    }
+    repeat {
+      path.deleteLastPathComponent()
+      let candidateFile = path.appendingPathComponent(configFilename)
+      if FileManager.default.isReadableFile(atPath: candidateFile.path) {
+        return candidateFile
+      }
+    } while path.path != "/"
+
+    return nil
+  }
 }
 
 /// Configuration for the NoPlaygroundLiterals rule.

Sources/swift-format/main.swift

@@ -88,54 +88,29 @@ fileprivate func processSources(
 fileprivate func loadConfiguration(
   forSwiftFile swiftFilePath: String?, configFilePath: String?
 ) -> Configuration {
-  if let path = configFilePath {
-    return decodedConfiguration(fromFileAtPath: path)
+  if let configFilePath = configFilePath {
+    return decodedConfiguration(fromFile: URL(fileURLWithPath: configFilePath))
   }
-  // Search for a ".swift-format" configuration file in the directory of the current .swift file,
-  // or its nearest parent.
-  var configurationFilePath: String? = nil
-  if let swiftFilePath = swiftFilePath {
-    configurationFilePath = findConfigurationFile(
-      forSwiftFile: URL(fileURLWithPath: swiftFilePath).path)
-  }
-  return decodedConfiguration(fromFileAtPath: configurationFilePath)
-}
 
-/// Look for a ".swift-format" configuration file in the same directory as "forSwiftFile", or its
-/// nearest parent. If one is not found, return "nil".
-fileprivate func findConfigurationFile(forSwiftFile: String) -> String? {
-  let cwd = FileManager.default.currentDirectoryPath
-  var path = URL(
-    fileURLWithPath: AbsolutePath(forSwiftFile, relativeTo: AbsolutePath(cwd)).pathString)
-  let configFilename = ".swift-format"
-
-  repeat {
-    path = path.deletingLastPathComponent()
-    let testPath = path.appendingPathComponent(configFilename).path
-    if FileManager.default.isReadableFile(atPath: testPath) {
-      return testPath
-    }
-  } while path.path != "/"
+  if let swiftFileURL = swiftFilePath.map(URL.init(fileURLWithPath:)), 
+    let configFileURL = Configuration.url(forConfigurationFileApplyingTo: swiftFileURL) {
+      return decodedConfiguration(fromFile: configFileURL)
+  }
 
-  return nil
+  return Configuration()
 }
 
+
 /// Loads and returns a `Configuration` from the given JSON file if it is found and is valid. If the
 /// file does not exist or there was an error decoding it, the program exits with a non-zero exit
 /// code.
-fileprivate func decodedConfiguration(fromFileAtPath path: String?) -> Configuration {
-  if let path = path {
-    do {
-      let url = URL(fileURLWithPath: path)
-      let data = try Data(contentsOf: url)
-      return try JSONDecoder().decode(Configuration.self, from: data)
-    } catch {
-      // TODO: Improve error message, write to stderr.
-      print("Could not load configuration at \(path): \(error)")
-      exit(1)
-    }
-  } else {
-    return Configuration()
+fileprivate func decodedConfiguration(fromFile url: Foundation.URL) -> Configuration {
+  do {
+    return try Configuration(contentsOf: url)
+  } catch {
+    // TODO: Improve error message, write to stderr.
+    print("Could not load configuration at \(url): \(error)")
+    exit(1)
   }
 }