jextract/ffm: Support throwing funcs in FFM mode (#658)

* jextract/ffm: support throwing functions in ffm

* script to jextract parts of SwiftKit, like SwiftJavaError

* jextract/ffm: initial SwiftJavaError support in FFM mode

Fix misleading Java output path in regeneration script

The script echoed ${TYPE}.java but the generator may remap the
Java class name (e.g. SwiftJavaError -> SwiftJavaErrorException).
Print the output directory instead of guessing the filename.

cleanups

* re-run the ./scripts/swiftkit-ffm-generate-bindings.sh

* fix formatting and license

Author: ktoso

Samples/SwiftJavaExtractFFMSampleApp/Sources/MySwiftLibrary/MySwiftLibrary.swift

@@ -125,6 +125,33 @@ public func globalStringIdentity(string: String) -> String {
   string
 }
 
+// ==== -----------------------------------------------------------------------
+// MARK: Throwing functions
+
+public struct SwiftExampleError: Error {
+  public let message: String
+}
+
+public func globalThrowingVoid(doThrow: Bool) throws {
+  if doThrow {
+    throw SwiftExampleError(message: "expected error in globalThrowingVoid")
+  }
+}
+
+public func globalThrowingReturn(doThrow: Bool) throws -> Int {
+  if doThrow {
+    throw SwiftExampleError(message: "expected error in globalThrowingReturn")
+  }
+  return 42
+}
+
+public func globalThrowingString(doThrow: Bool) throws -> String {
+  if doThrow {
+    throw SwiftExampleError(message: "expected error in globalThrowingString")
+  }
+  return "Hello from throwing Swift!"
+}
+
 // ==== -----------------------------------------------------------------------
 // MARK: Overloaded functions
 

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

@@ -16,6 +16,7 @@
 
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
+import org.swift.swiftkit.ffm.generated.SwiftJavaErrorException;
 
 import java.util.concurrent.CountDownLatch;
 
@@ -95,4 +96,56 @@ public void apply() {
         assertEquals(0, countDownLatch.getCount());
     }
 
+    // ==== ----------------------------------------------------------------
+    // Throwing functions
+
+    @Test
+    void call_globalThrowingVoid_noThrow() throws SwiftJavaErrorException {
+        MySwiftLibrary.globalThrowingVoid(false);
+    }
+
+    @Test
+    void call_globalThrowingVoid_throws() {
+        assertThrows(SwiftJavaErrorException.class, () -> {
+            MySwiftLibrary.globalThrowingVoid(true);
+        });
+    }
+
+    @Test
+    void call_globalThrowingReturn_noThrow() throws SwiftJavaErrorException {
+        long result = MySwiftLibrary.globalThrowingReturn(false);
+        assertEquals(42, result);
+    }
+
+    @Test
+    void call_globalThrowingReturn_throws() {
+        assertThrows(SwiftJavaErrorException.class, () -> {
+            MySwiftLibrary.globalThrowingReturn(true);
+        });
+    }
+
+    @Test
+    void call_globalThrowingString_noThrow() throws SwiftJavaErrorException {
+        String result = MySwiftLibrary.globalThrowingString(false);
+        assertEquals("Hello from throwing Swift!", result);
+    }
+
+    @Test
+    void call_globalThrowingString_throws() {
+        assertThrows(SwiftJavaErrorException.class, () -> {
+            MySwiftLibrary.globalThrowingString(true);
+        });
+    }
+
+    @Test
+    void call_globalThrowingString_throws_checkMessage() {
+        SwiftJavaErrorException error = assertThrows(SwiftJavaErrorException.class, () -> {
+            MySwiftLibrary.globalThrowingString(true);
+        });
+        assertEquals(
+                "org.swift.swiftkit.ffm.generated.SwiftJavaErrorException: SwiftExampleError(message: \"expected error in globalThrowingString\")",
+                error.toString()
+        );
+    }
+
 }

Sources/CodePrinting/CodePrinter.swift

@@ -107,6 +107,16 @@ public struct CodePrinter {
     print("}", .sloc, function: function, file: file, line: line)
   }
 
+  public mutating func printIfBlock(
+    _ condition: Any,
+    function: String = #function,
+    file: String = #fileID,
+    line: UInt = #line,
+    body: (inout CodePrinter) throws -> Void
+  ) rethrows {
+    try printBraceBlock("if (\(condition))", function: function, file: file, line: line, body: body)
+  }
+
   public mutating func printParts(
     _ parts: String...,
     terminator: PrinterTerminator = .newLine,