jextract: Support Java IntBinaryOperator func interface

Samples/SwiftAndJavaJarFFMSampleLib/Sources/MySwiftLibrary/MySwiftLibrary.swift

@@ -76,6 +76,10 @@ public func globalCallMeDoublePredicate(run: (Double) -> Bool) -> Bool {
   run(1.0)
 }
 
+public func globalCallMeIntBinaryOperator(run: (Int32, Int32) -> Int32) -> Int32 {
+  run(1, 2)
+}
+
 // ==== Internal helpers
 
 func p(_ msg: String, file: String = #fileID, line: UInt = #line, function: String = #function) {

Samples/SwiftAndJavaJarFFMSampleLib/src/test/java/com/example/swift/MySwiftLibraryTest.java

@@ -110,4 +110,10 @@ void call_globalCallMeDoublePredicate_noThrow() {
         boolean result = MySwiftLibrary.globalCallMeDoublePredicate((double a) -> { return true; });
         assertEquals(true, result);
     }
+
+    @Test
+    void call_globalCallMeIntBinaryOperator_noThrow() {
+        int result = MySwiftLibrary.globalCallMeIntBinaryOperator((int a, int b) -> { return a + b; });
+        assertEquals(3, result);
+    }
 }

Samples/SwiftJavaExtractFFMSampleApp/Sources/MySwiftLibrary/MySwiftLibrary.swift

@@ -88,6 +88,10 @@ public func globalCallMeDoublePredicate(run: (Double) -> Bool) -> Bool {
   run(1.0)
 }
 
+public func globalCallMeIntBinaryOperator(run: (Int32, Int32) -> Int32) -> Int32 {
+  run(1, 2)
+}
+
 public func globalReceiveRawBuffer(buf: UnsafeRawBufferPointer) -> Int {
   buf.count
 }

Samples/SwiftJavaExtractFFMSampleApp/src/test/java/com/example/swift/MySwiftLibraryTest.java

@@ -222,4 +222,10 @@ void call_globalCallMeDoublePredicate_noThrow() {
         boolean result = MySwiftLibrary.globalCallMeDoublePredicate((double a) -> { return true; });
         assertEquals(true, result);
     }
+
+    @Test
+    void call_globalCallMeIntBinaryOperator_noThrow() {
+        int result = MySwiftLibrary.globalCallMeIntBinaryOperator((int a, int b) -> { return a + b; });
+        assertEquals(3, result);
+    }
 }

Samples/SwiftJavaExtractJNISampleApp/Sources/MySwiftLibrary/Closures.swift

@@ -61,6 +61,10 @@ public func globalCallMeDoublePredicate(run: (Double) -> Bool) -> Bool {
   run(1.0)
 }
 
+public func globalCallMeIntBinaryOperator(run: (Int32, Int32) -> Int32) -> Int32 {
+  run(1, 2)
+}
+
 public func closureMultipleArguments(
   input1: Int64,
   input2: Int64,

Samples/SwiftJavaExtractJNISampleApp/src/test/java/com/example/swift/ClosuresTest.java

@@ -104,4 +104,10 @@ void globalCallMeDoublePredicate() {
         boolean result = MySwiftLibrary.globalCallMeDoublePredicate((double a) -> { return true; });
         assertEquals(true, result);
     }
+
+    @Test
+    void globalCallMeIntBinaryOperator() {
+        int result = MySwiftLibrary.globalCallMeIntBinaryOperator((int a, int b) -> { return a + b; });
+        assertEquals(3, result);
+    }
 }

Sources/ExampleSwiftLibrary/MySwiftLibrary.swift

@@ -83,6 +83,10 @@ public func globalCallMeDoublePredicate(run: (Double) -> Bool) -> Bool {
   run(1.0)
 }
 
+public func globalCallMeIntBinaryOperator(run: (Int32, Int32) -> Int32) -> Int32 {
+  run(1, 2)
+}
+
 public func globalReceiveRawBuffer(buf: UnsafeRawBufferPointer) -> Int {
   buf.count
 }

Sources/JExtractSwiftLib/JavaTypes/JavaType+JDK.swift

@@ -80,6 +80,11 @@ extension JavaType {
     .class(package: "java.util.function", name: "DoublePredicate")
   }
 
+  /// The description of the type java.util.function.IntBinaryOperator.
+  static var javaUtilFunctionIntBinaryOperator: JavaType {
+    .class(package: "java.util.function", name: "IntBinaryOperator")
+  }
+
   /// The description of the type java.lang.Class.
   static var javaLangClass: JavaType {
     .class(package: "java.lang", name: "Class")

Sources/JExtractSwiftLib/KnownFunctionalInterfaces.swift

@@ -99,6 +99,13 @@ struct KnownJavaFunctionalInterface: Sendable {
     result: .boolean
   )
 
+  static let intBinaryOperator = KnownJavaFunctionalInterface(
+    JavaType.javaUtilFunctionIntBinaryOperator,
+    method: "applyAsInt",
+    parameters: [.int, .int],
+    result: .int
+  )
+
   static let all: [KnownJavaFunctionalInterface] = [
     .runnable,
     .booleanSupplier,
@@ -111,6 +118,7 @@ struct KnownJavaFunctionalInterface: Sendable {
     .intPredicate,
     .longPredicate,
     .doublePredicate,
+    .intBinaryOperator,
   ]
 
   static func find(parameters: [JavaType], result: JavaType) -> KnownJavaFunctionalInterface? {
@@ -185,6 +193,17 @@ struct KnownJavaFunctionalInterface: Sendable {
       }
     }
 
+    // Binary operators
+    if parameters.count == 2 && parameters[0].type == result && parameters[1].type == result {
+      let parameter = parameters[0].type
+      return switch () {
+      case _ where parameter.isInt32:
+        intBinaryOperator
+      default:
+        nil
+      }
+    }
+
     return nil
   }
 

Tests/JExtractSwiftTests/FuncCallbackImportTests.swift

@@ -47,6 +47,8 @@ final class FuncCallbackImportTests {
     public func callMeLongPredicate(callback: (Int64) -> Bool)
     public func callMeDoublePredicate(callback: (Double) -> Bool)
 
+    public func callMeIntBinaryOperator(callback: (Int32, Int32) -> Int32)
+
     public func callMeMore(callback: (UnsafeRawPointer, Float) -> Int, fn: () -> ())
     public func withBuffer(body: (UnsafeRawBufferPointer) -> Int)
     """
@@ -717,6 +719,49 @@ final class FuncCallbackImportTests {
     )
   }
 
+  @Test("Import: public func callMecallMeIntBinaryOperatorFunc(callback: (Int32, Int32) -> Int32)")
+  func func_callMecallMeIntBinaryOperatorFunc_callback() throws {
+    var config = Configuration()
+    config.swiftModule = "__FakeModule"
+    let st = makeSwiftJavaAnalyzer(config: config)
+    st.log.logLevel = .error
+
+    try st.analyze(path: "Fake.swift", text: Self.class_interfaceFile)
+
+    let funcDecl = st.extractedGlobalFuncs.first { $0.name == "callMeIntBinaryOperator" }!
+
+    let generator = FFMSwift2JavaGenerator(
+      config: config,
+      translator: st,
+      javaPackage: "com.example.swift",
+      swiftOutputDirectory: "/fake",
+      javaOutputDirectory: "/fake"
+    )
+
+    let output = JavaPrinter.toString { printer in
+      generator.printFunctionDowncallMethods(&printer, funcDecl)
+    }
+
+    assertOutput(
+      output,
+      expectedChunks: [
+        """
+        /**
+         * Downcall to Swift:
+         * {@snippet lang=swift :
+         * public func callMeIntBinaryOperator(callback: (Int32, Int32) -> Int32)
+         * }
+         */
+        public static void callMeIntBinaryOperator(java.util.function.IntBinaryOperator callback) {
+          try(var arena$ = Arena.ofConfined()) {
+            swiftjava___FakeModule_callMeIntBinaryOperator_callback.call(callMeIntBinaryOperator.$toUpcallStub(callback, arena$));
+          }
+        }
+        """
+      ]
+    )
+  }
+
   @Test("Import: public func withBuffer(body: (UnsafeRawBufferPointer) -> Int)")
   func func_withBuffer_body() throws {
     var config = Configuration()

Tests/JExtractSwiftTests/JNI/JNIClosureTests.swift

@@ -33,6 +33,8 @@ struct JNIClosureTests {
     public func closureLongPredicate(closure: (Int64) -> Bool) {}
     public func closureDoublePredicate(closure: (Double) -> Bool) {}
 
+    public func closureIntBinaryOperator(closure: (Int32, Int32) -> Int32) {}
+
     public func closureWithArgumentsAndReturn(closure: (Int64, Bool) -> Int64) {}
     """
 
@@ -311,6 +313,31 @@ struct JNIClosureTests {
     )
   }
 
+  @Test
+  func closureIntBinaryOperator_javaBindings() throws {
+    try assertOutput(
+      input: source,
+      .jni,
+      .java,
+      expectedChunks: [
+        """
+        /**
+         * Downcall to Swift:
+         * {@snippet lang=swift :
+         * public func closureIntBinaryOperator(closure: (Int32, Int32) -> Int32)
+         * }
+         */
+        public static void closureIntBinaryOperator(java.util.function.IntBinaryOperator closure) {
+          SwiftModule.$closureIntBinaryOperator(closure);
+        }
+        """,
+        """
+        private static native void $closureIntBinaryOperator(java.util.function.IntBinaryOperator closure);
+        """,
+      ]
+    )
+  }
+
   @Test
   func emptyClosure_swiftThunks() throws {
     try assertOutput(
@@ -586,6 +613,31 @@ struct JNIClosureTests {
     )
   }
 
+  @Test
+  func closureIntBinaryOperator_swiftThunks() throws {
+    try assertOutput(
+      input: source,
+      .jni,
+      .swift,
+      detectChunkByInitialLines: 1,
+      expectedChunks: [
+        """
+        @_cdecl("Java_com_example_swift_SwiftModule__00024closureIntBinaryOperator__Ljava_util_function_IntBinaryOperator_2")
+        public func Java_com_example_swift_SwiftModule__00024closureIntBinaryOperator__Ljava_util_function_IntBinaryOperator_2(environment: UnsafeMutablePointer<JNIEnv?>!, thisClass: jclass, closure: jobject?) {
+          SwiftModule.closureIntBinaryOperator(closure: {
+            let class$ = environment.interface.GetObjectClass(environment, closure)
+            let methodID$ = environment.interface.GetMethodID(environment, class$, "applyAsInt", "(II)I")!
+            environment.interface.DeleteLocalRef(environment, class$)
+            let arguments$: [jvalue] = [_0.getJValue(in: environment), _1.getJValue(in: environment)]
+            return Int32(fromJNI: environment.interface.CallIntMethodA(environment, closure, methodID$, arguments$), in: environment)
+          }
+          )
+        }
+        """
+      ]
+    )
+  }
+
   @Test
   func closureWithArgumentsAndReturn_javaBindings() throws {
     try assertOutput(