[JExtract/JNI] Import enums

Samples/JExtractJNISampleApp/Sources/MySwiftLibrary/Alignment.swift

@@ -0,0 +1,18 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+public enum Alignment: String {
+  case horizontal
+  case vertical
+}

Samples/JExtractJNISampleApp/Sources/MySwiftLibrary/Vehicle.swift

@@ -0,0 +1,54 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+public enum Vehicle {
+  case bicycle
+  case car(String)
+  case motorbike(String, horsePower: Int64)
+
+  public init?(name: String) {
+    switch name {
+      case "bicycle": self = .bicycle
+      case "car": self = .car("Unknown")
+      case "motorbike": self = .motorbike("Unknown", horsePower: 0)
+      default: return nil
+    }
+  }
+
+  public var name: String {
+    switch self {
+    case .bicycle: "bicycle"
+    case .car: "car"
+    case .motorbike: "motorbike"
+    }
+  }
+
+  public func isFasterThan(other: Vehicle) -> Bool {
+    switch (self, other) {
+      case (.bicycle, .bicycle), (.bicycle, .car), (.bicycle, .motorbike): false
+      case (.car, .bicycle): true
+      case (.car, .motorbike), (.car, .car): false
+      case (.motorbike, .bicycle), (.motorbike, .car): true
+      case (.motorbike, .motorbike): false
+    }
+  }
+
+  public mutating func upgrade() {
+    switch self {
+      case .bicycle: self = .car("Unknown")
+      case .car: self = .motorbike("Unknown", horsePower: 0)
+      case .motorbike: break
+    }
+  }
+}

Samples/JExtractJNISampleApp/Sources/MySwiftLibrary/swift-java.config

@@ -1,4 +1,5 @@
 {
   "javaPackage": "com.example.swift",
   "mode": "jni",
+  "logLevel": ["debug"]
 }

Samples/JExtractJNISampleApp/src/test/java/com/example/swift/AlignmentTest.java

@@ -0,0 +1,40 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+package com.example.swift;
+
+import org.junit.jupiter.api.Test;
+import org.swift.swiftkit.core.ConfinedSwiftMemorySession;
+
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class AlignmentTest {
+    @Test
+    void rawValue() {
+        try (var arena = new ConfinedSwiftMemorySession()) {
+            Optional<Alignment> invalid = Alignment.init("invalid", arena);
+            assertFalse(invalid.isPresent());
+
+            Optional<Alignment> horizontal = Alignment.init("horizontal", arena);
+            assertTrue(horizontal.isPresent());
+            assertEquals("horizontal", horizontal.get().getRawValue());
+
+            Optional<Alignment> vertical = Alignment.init("vertical", arena);
+            assertTrue(vertical.isPresent());
+            assertEquals("vertical", vertical.get().getRawValue());
+        }
+    }
+}

Samples/JExtractJNISampleApp/src/test/java/com/example/swift/VehicleTest.java

@@ -0,0 +1,88 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+package com.example.swift;
+
+import org.junit.jupiter.api.Test;
+import org.swift.swiftkit.core.ConfinedSwiftMemorySession;
+
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class VehicleTest {
+    @Test
+    void bicycle() {
+        try (var arena = new ConfinedSwiftMemorySession()) {
+            Vehicle vehicle = Vehicle.bicycle(arena);
+            assertNotNull(vehicle);
+        }
+    }
+
+    @Test
+    void car() {
+        try (var arena = new ConfinedSwiftMemorySession()) {
+            Vehicle vehicle = Vehicle.car("Porsche 911", arena);
+            assertNotNull(vehicle);
+        }
+    }
+
+    @Test
+    void motorbike() {
+        try (var arena = new ConfinedSwiftMemorySession()) {
+            Vehicle vehicle = Vehicle.motorbike("Yamaha", 750, arena);
+            assertNotNull(vehicle);
+        }
+    }
+
+    @Test
+    void initName() {
+        try (var arena = new ConfinedSwiftMemorySession()) {
+            assertFalse(Vehicle.init("bus", arena).isPresent());
+            Optional<Vehicle> vehicle = Vehicle.init("car", arena);
+            assertTrue(vehicle.isPresent());
+            assertNotNull(vehicle.get());
+        }
+    }
+
+    @Test
+    void nameProperty() {
+        try (var arena = new ConfinedSwiftMemorySession()) {
+            Vehicle vehicle = Vehicle.bicycle(arena);
+            assertEquals("bicycle", vehicle.getName());
+        }
+    }
+
+    @Test
+    void isFasterThan() {
+        try (var arena = new ConfinedSwiftMemorySession()) {
+            Vehicle bicycle = Vehicle.bicycle(arena);
+            Vehicle car = Vehicle.car("Porsche 911", arena);
+            assertFalse(bicycle.isFasterThan(car));
+            assertTrue(car.isFasterThan(bicycle));
+        }
+    }
+
+    @Test
+    void upgrade() {
+        try (var arena = new ConfinedSwiftMemorySession()) {
+            Vehicle vehicle = Vehicle.bicycle(arena);
+            assertEquals("bicycle", vehicle.getName());
+            vehicle.upgrade();
+            assertEquals("car", vehicle.getName());
+            vehicle.upgrade();
+            assertEquals("motorbike", vehicle.getName());
+        }
+    }
+}

Sources/JExtractSwiftLib/Convenience/SwiftSyntax+Extensions.swift

@@ -253,6 +253,8 @@ extension DeclSyntaxProtocol {
           }
         ))
         .triviaSanitizedDescription
+    case .enumCaseDecl(let node):
+      node.triviaSanitizedDescription
     default:
       fatalError("unimplemented \(self.kind)")
     }

Sources/JExtractSwiftLib/FFM/CDeclLowering/FFMSwift2JavaGenerator+FunctionLowering.swift

@@ -835,6 +835,10 @@ extension LoweredFunctionSignature {
     case .setter:
       assert(paramExprs.count == 1)
       resultExpr = "\(callee) = \(paramExprs[0])"
+
+    case .enumCase:
+      // This should not be called, but let's fatalError.
+      fatalError("Enum cases are not supported with FFM.")
     }
 
     // Lower the result.

Sources/JExtractSwiftLib/FFM/FFMSwift2JavaGenerator+JavaTranslation.swift

@@ -146,7 +146,7 @@ extension FFMSwift2JavaGenerator {
       let javaName = switch decl.apiKind {
       case .getter: decl.javaGetterName
       case .setter: decl.javaSetterName
-      case .function, .initializer: decl.name
+      case .function, .initializer, .enumCase: decl.name
       }
 
       // Signature.

Sources/JExtractSwiftLib/ImportedDecls.swift

@@ -22,6 +22,7 @@ package enum SwiftAPIKind {
   case initializer
   case getter
   case setter
+  case enumCase
 }
 
 /// Describes a Swift nominal type (e.g., a class, struct, enum) that has been
@@ -32,6 +33,7 @@ package class ImportedNominalType: ImportedDecl {
   package var initializers: [ImportedFunc] = []
   package var methods: [ImportedFunc] = []
   package var variables: [ImportedFunc] = []
+  package var cases: [ImportedEnumCase] = []
 
   init(swiftNominal: SwiftNominalTypeDeclaration) {
     self.swiftNominal = swiftNominal
@@ -46,6 +48,33 @@ package class ImportedNominalType: ImportedDecl {
   }
 }
 
+public final class ImportedEnumCase: ImportedDecl, CustomStringConvertible {
+  /// The case name
+  public var name: String
+
+  /// The enum parameters
+  var parameters: [SwiftEnumCaseParameter]
+
+  /// A function that represents the Swift static "initializer" for cases
+  var caseFunction: ImportedFunc
+
+  init(name: String, parameters: [SwiftEnumCaseParameter], caseFunction: ImportedFunc) {
+    self.name = name
+    self.parameters = parameters
+    self.caseFunction = caseFunction
+  }
+
+  public var description: String {
+    """
+    ImportedEnumCase {
+      name: \(name),
+      parameters: \(parameters),
+      caseFunction: \(caseFunction)
+    }
+    """
+  }
+}
+
 public final class ImportedFunc: ImportedDecl, CustomStringConvertible {
   /// Swift module name (e.g. the target name where a type or function was declared)
   public var module: String
@@ -113,6 +142,7 @@ public final class ImportedFunc: ImportedDecl, CustomStringConvertible {
     let prefix = switch self.apiKind {
     case .getter: "getter:"
     case .setter: "setter:"
+    case .enumCase: "case:"
     case .function, .initializer: ""
     }
 

Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+JavaBindingsPrinting.swift

@@ -125,6 +125,11 @@ extension JNISwift2JavaGenerator {
 
       printer.println()
 
+      if decl.swiftNominal.kind == .enum {
+        printEnumHelpers(&printer, decl)
+        printer.println()
+      }
+
       for initializer in decl.initializers {
         printFunctionDowncallMethods(&printer, initializer)
         printer.println()
@@ -187,6 +192,43 @@ extension JNISwift2JavaGenerator {
     }
   }
 
+  private func printEnumHelpers(_ printer: inout CodePrinter, _ decl: ImportedNominalType) {
+    // TODO: Move this to seperate file +Enum?
+    printEnumDiscriminator(&printer, decl)
+    printer.println()
+    printEnumCaseInterface(&printer, decl)
+    printer.println()
+    printEnumStaticInitializers(&printer, decl)
+    printer.println()
+    printEnumCases(&printer, decl)
+  }
+
+  private func printEnumDiscriminator(_ printer: inout CodePrinter, _ decl: ImportedNominalType) {
+    printer.printBraceBlock("public enum Discriminator") { printer in
+      printer.print(
+        decl.cases.map { $0.name.uppercased() }.joined(separator: ",\n")
+      )
+    }
+  }
+
+  private func printEnumCaseInterface(_ printer: inout CodePrinter, _ decl: ImportedNominalType) {
+//    printer.print("public sealed interface Case {}")
+  }
+
+  private func printEnumStaticInitializers(_ printer: inout CodePrinter, _ decl: ImportedNominalType) {
+    for enumCase in decl.cases {
+      printFunctionDowncallMethods(&printer, enumCase.caseFunction)
+    }
+  }
+
+  private func printEnumCases(_ printer: inout CodePrinter, _ decl: ImportedNominalType) {
+//    for enumCase in decl.cases {
+//      printer.printBraceBlock("public static final \(enumCase.name.firstCharacterUppercased) implements Case") { printer in
+//
+//      }
+//    }
+  }
+
   private func printFunctionDowncallMethods(
     _ printer: inout CodePrinter,
     _ decl: ImportedFunc

Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+JavaTranslation.swift

@@ -61,7 +61,7 @@ extension JNISwift2JavaGenerator {
       let javaName = switch decl.apiKind {
       case .getter: decl.javaGetterName
       case .setter: decl.javaSetterName
-      case .function, .initializer: decl.name
+      case .function, .initializer, .enumCase: decl.name
       }
 
       // Swift -> Java
@@ -137,7 +137,7 @@ extension JNISwift2JavaGenerator {
       parentName: String
     ) throws -> TranslatedFunctionSignature {
       let parameters = try functionSignature.parameters.enumerated().map { idx, param in
-        let parameterName = param.parameterName ?? "arg\(idx))"
+        let parameterName = param.parameterName ?? "arg\(idx)"
         return try translateParameter(swiftType: param.type, parameterName: parameterName, methodName: methodName, parentName: parentName)
       }