wip on actually converting the optional values swift -> java optional

Author: ktoso

Samples/SwiftKitSampleApp/src/test/java/com/example/swift/generated/MySwiftClassTest.java

@@ -20,6 +20,8 @@
 import org.junit.jupiter.api.condition.DisabledOnOs;
 import org.junit.jupiter.api.condition.OS;
 
+import java.util.OptionalLong;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
@@ -56,4 +58,11 @@ void test_MySwiftClass_property_len() {
         assertEquals(12, got);
     }
 
+    @Test
+    void test_MySwiftClass_optionalInt() {
+        MySwiftClass o = new MySwiftClass(12, 42);
+        OptionalLong got = o.getOptionalInt(); // FIXME: we need to get the Swift optional as memory region, map it to the Java Optional
+        assertEquals(12, got);
+    }
+
 }

Sources/ExampleSwiftLibrary/MySwiftLibrary.swift

@@ -78,6 +78,10 @@ public class MySwiftClass {
     p("make int -> 12")
     return 12
   }
+
+  public func getOptionalInt() -> Int? {
+    return 12
+  }
 }
 
 @_silgen_name("swift_getTypeByMangledNameInEnvironment")

Sources/JExtractSwift/Swift2JavaTranslator+Printing.swift

@@ -456,7 +456,8 @@ extension Swift2JavaTranslator {
     printer.print(
       """
       static {
-          System.loadLibrary("swiftCore");
+          System.loadLibrary(SwiftKit.STDLIB_DYLIB_NAME);
+          System.loadLibrary(SwiftKit.SWIFTKIT_DYLIB_NAME);
           System.loadLibrary(LIB_NAME);
       }
       """

SwiftKit/src/main/java/org/swift/swiftkit/SwiftKit.java

@@ -27,15 +27,17 @@
 
 public class SwiftKit {
 
-    private static final String STDLIB_DYLIB_NAME = "swiftCore";
-    private static final String STDLIB_MACOS_DYLIB_PATH = "/usr/lib/swift/libswiftCore.dylib";
+    public static final String STDLIB_DYLIB_NAME = "swiftCore";
+    public static final String SWIFTKIT_DYLIB_NAME = "SwiftKitSwift";
 
-    private static final Arena LIBRARY_ARENA = Arena.ofAuto();
+    static final String STDLIB_MACOS_DYLIB_PATH = "/usr/lib/swift/libswiftCore.dylib";
+
+    static final Arena LIBRARY_ARENA = Arena.ofAuto();
     static final boolean TRACE_DOWNCALLS = Boolean.getBoolean("jextract.trace.downcalls");
 
     static {
         System.loadLibrary(STDLIB_DYLIB_NAME);
-        System.loadLibrary("SwiftKitSwift");
+        System.loadLibrary(SWIFTKIT_DYLIB_NAME);
     }
 
     static final SymbolLookup SYMBOL_LOOKUP = getSymbolLookup();

SwiftKit/src/main/java/org/swift/swiftkit/stdlib/SwiftOptional.java

@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 org.swift.swiftkit.stdlib;
+
+import org.swift.swiftkit.*;
+import org.swift.swiftkit.util.TypeToken;
+
+import java.lang.foreign.*;
+
+public class SwiftOptional<Wrapped extends SwiftInstance> implements SwiftValue {
+
+    // Pointer to the referred to class instance's "self".
+    private final MemorySegment selfMemorySegment;
+
+    static final String LIB_NAME = SwiftKit.STDLIB_DYLIB_NAME;
+
+    public SwiftOptional(MemorySegment selfMemorySegment) {
+        this.selfMemorySegment = selfMemorySegment;
+    }
+
+    public final MemorySegment $memorySegment() {
+        return this.selfMemorySegment;
+    }
+
+    public static final AddressLayout SWIFT_POINTER = ValueLayout.ADDRESS;
+
+    private static final GroupLayout $LAYOUT = MemoryLayout.structLayout(
+            SWIFT_POINTER
+    ).withName("Swift.Optional<T>");
+
+    @Override
+    public GroupLayout $layout() {
+        return $LAYOUT;
+    }
+
+    @Override
+    public SwiftAnyType $swiftType() {
+        var ty = new TypeToken<Wrapped>() {}.getType();
+        if (ty == Integer.class || ty == Long.class) {
+            return SwiftKit.getTypeByMangledNameInEnvironment("SiSg").get();
+        } else {
+            throw new RuntimeException("Other Optional type mappings not implemented yet");
+        }
+    }
+}

Tests/JExtractSwiftTests/OptionalImportTests.swift

@@ -113,4 +113,39 @@ final class OptionalImportTests {
       ]
     )
   }
+
+  @Test("Import: public func globalGetFloatOptional() -> Float?")
+  func globalGetFloatOptional() throws {
+    let st = Swift2JavaTranslator(
+      javaPackage: "com.example.swift",
+      swiftModuleName: "__FakeModule"
+    )
+    st.log.logLevel = .warning
+
+    assertOutput(
+      st,
+      input: class_interfaceFile,
+      expectedChunks: [
+        """
+        /**
+         * Downcall to Swift:
+         * {@snippet lang=swift :
+         * public func globalGetFloatOptional() -> Float?
+         * }
+         */
+        public static java.util.OptionalDouble globalGetFloatOptional() {
+            var mh$ = globalGetFloatOptional.HANDLE;
+            try {
+                if (TRACE_DOWNCALLS) {
+                    traceDowncall();
+                }
+                return (java.util.OptionalDouble) mh$.invokeExact();
+            } catch (Throwable ex$) {
+                throw new AssertionError("should not reach here", ex$);
+            }
+        }
+        """
+      ]
+    )
+  }
 }