Create formatter for GitHub Actions (#746)

Sources/PeripheryKit/Formatters/ActionsFormatter.swift

@@ -0,0 +1,35 @@
+import Foundation
+import Shared
+import SystemPackage
+
+final class ActionsFormatter: OutputFormatter {
+    let configuration: Configuration
+    lazy var currentFilePath: FilePath = { .current }()
+
+    init(configuration: Configuration) {
+        self.configuration = configuration
+    }
+
+    func format(_ results: [ScanResult]) throws -> String {
+        guard results.count > 0 else { return "" }
+        guard configuration.relativeResults else { throw PeripheryError.usageError("`periphery scan` must be ran with `--relative-results` when using the actions formatter")}
+
+        return results.flatMap { result in
+            describe(result, colored: false).map { (location, description) in
+                prefix(for: location, result: result) + description
+            }
+        }
+        .joined(separator: "\n")
+    }
+
+    // MARK: - Private
+
+    private func prefix(for location: SourceLocation, result: ScanResult) -> String {
+        let path = outputPath(location)
+        let lineNum = String(location.line)
+        let column = location.column
+        let title = describe(result.annotation)
+
+        return "::warning file=\(path),line=\(lineNum),col=\(column),title=\(title)::"
+    }
+}

Sources/PeripheryKit/Formatters/OutputFormatter.swift

@@ -105,6 +105,8 @@ public extension OutputFormat {
             return JsonFormatter.self
         case .checkstyle:
             return CheckstyleFormatter.self
+        case .actions:
+            return ActionsFormatter.self
         }
     }
 }

Sources/Shared/OutputFormat.swift

@@ -6,6 +6,7 @@ public enum OutputFormat: String, CaseIterable {
     case json
     case checkstyle
     case codeclimate
+    case actions
 
     public static let `default` = OutputFormat.xcode