add support for failable initializers

Author: madsodgaard

Samples/JExtractJNISampleApp/Sources/MySwiftLibrary/Vehicle.swift

@@ -16,4 +16,39 @@ 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/src/test/java/com/example/swift/VehicleTest.java

@@ -17,8 +17,9 @@
 import org.junit.jupiter.api.Test;
 import org.swift.swiftkit.core.ConfinedSwiftMemorySession;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.*;
 
 public class VehicleTest {
     @Test
@@ -44,4 +45,44 @@ void motorbike() {
             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/JNI/JNISwift2JavaGenerator+JavaBindingsPrinting.swift

@@ -196,7 +196,11 @@ extension JNISwift2JavaGenerator {
     // 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) {
@@ -207,12 +211,24 @@ extension JNISwift2JavaGenerator {
     }
   }
 
+  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/Swift2JavaVisitor.swift

@@ -276,15 +276,6 @@ extension DeclSyntaxProtocol where Self: WithModifiersSyntax & WithAttributesSyn
       return false
     }
 
-    if let node = self.as(InitializerDeclSyntax.self) {
-      let isFailable = node.optionalMark != nil
-
-      if isFailable {
-        log.warning("Skip import '\(self.qualifiedNameForDebug)': failable initializer")
-        return false
-      }
-    }
-
     return true
   }
 }

Sources/JExtractSwiftLib/SwiftTypes/SwiftFunctionSignature.swift

@@ -71,11 +71,6 @@ extension SwiftFunctionSignature {
       throw SwiftFunctionTranslationError.missingEnclosingType(node)
     }
 
-    // We do not yet support failable initializers.
-    if node.optionalMark != nil {
-      throw SwiftFunctionTranslationError.failableInitializer(node)
-    }
-
     let (genericParams, genericRequirements) = try Self.translateGenericParameters(
       parameterClause: node.genericParameterClause,
       whereClause: node.genericWhereClause,
@@ -86,10 +81,12 @@ extension SwiftFunctionSignature {
       lookupContext: lookupContext
     )
 
+    let type = node.optionalMark != nil ? .optional(enclosingType) : enclosingType
+
     self.init(
       selfParameter: .initializer(enclosingType),
       parameters: parameters,
-      result: SwiftResult(convention: .direct, type: enclosingType),
+      result: SwiftResult(convention: .direct, type: type),
       effectSpecifiers: effectSpecifiers,
       genericParameters: genericParams,
       genericRequirements: genericRequirements