jextract (ffm, jni): Subscripts support (#459)

Co-authored-by: pelekon <[email protected]>

Author: pelekon

Samples/SwiftJavaExtractFFMSampleApp/Sources/MySwiftLibrary/MySwiftStruct.swift

@@ -16,10 +16,14 @@ public struct MySwiftStruct {
 
   private var cap: Int
   private var len: Int
+  private var subscriptValue: Int
+  private var subscriptArray: [Int] 
 
   public init(cap: Int, len: Int) {
     self.cap = cap
     self.len = len
+    self.subscriptValue = 0
+    self.subscriptArray = [10, 20, 15, 75]
   }
 
   public func voidMethod() {
@@ -61,4 +65,22 @@ public struct MySwiftStruct {
   public func makeRandomIntMethod() -> Int {
     return Int.random(in: 1..<256)
   }
+
+  public func getSubscriptValue() -> Int {
+    return self.subscriptValue
+  }
+
+  public func getSubscriptArrayValue(index: Int) -> Int {
+    return self.subscriptArray[index]
+  }
+
+  public subscript() -> Int {
+    get { return subscriptValue }
+    set { subscriptValue = newValue }
+  }
+
+  public subscript(index: Int) -> Int {
+    get { return subscriptArray[index] }
+    set { subscriptArray[index] = newValue }
+  }
 }

Samples/SwiftJavaExtractFFMSampleApp/src/test/java/org/swift/swiftkitffm/MySwiftStructTest.java

@@ -33,4 +33,26 @@ void create_struct() {
             assertEquals(len, struct.getLength());
         }
     }
+
+    @Test
+    void testSubscript() {
+        try (var arena = AllocatingSwiftArena.ofConfined()) {
+            MySwiftStruct s = MySwiftStruct.init(1337, 42, arena);
+            long currentValue = s.getSubscript();
+            s.setSubscript(66);
+            assertEquals(0, currentValue);
+            assertEquals(66, s.getSubscriptValue());
+        }
+    }
+
+    @Test
+    void testSubscriptWithParams() {
+        try (var arena = AllocatingSwiftArena.ofConfined()) {
+            MySwiftStruct s = MySwiftStruct.init(1337, 42, arena);
+            long currentValue = s.getSubscript(1);
+            s.setSubscript(1, 66);
+            assertEquals(20, currentValue);
+            assertEquals(66, s.getSubscriptArrayValue(1));
+        }
+    }
 }

Samples/SwiftJavaExtractJNISampleApp/Sources/MySwiftLibrary/MySwiftStruct.swift

@@ -15,10 +15,14 @@
 public struct MySwiftStruct {
   private var cap: Int64
   public var len: Int64
+  private var subscriptValue: Int64
+  private var subscriptArray: [Int64]
 
   public init(cap: Int64, len: Int64) {
     self.cap = cap
     self.len = len
+    self.subscriptValue = 0
+    self.subscriptArray = [10, 20, 15, 75]
   }
 
   public init?(doInit: Bool) {
@@ -38,4 +42,22 @@ public struct MySwiftStruct {
     self.cap += value
     return self.cap
   }
+
+  public func getSubscriptValue() -> Int64 {
+    return self.subscriptValue
+  }
+
+  public func getSubscriptArrayValue(index: Int64) -> Int64 {
+    return self.subscriptArray[Int(index)]
+  }
+
+  public subscript() -> Int64 {
+    get { return subscriptValue }
+    set { subscriptValue = newValue }
+  }
+
+  public subscript(index: Int64) -> Int64 {
+    get { return subscriptArray[Int(index)] }
+    set { subscriptArray[Int(index)] = newValue }
+  }
 }

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

@@ -61,4 +61,26 @@ void increaseCap() {
             assertEquals(1347, s.getCapacity());
         }
     }
+
+    @Test
+    void testSubscript() {
+        try (var arena = SwiftArena.ofConfined()) {
+            MySwiftStruct s = MySwiftStruct.init(1337, 42, arena);
+            long currentValue = s.getSubscript();
+            s.setSubscript(66);
+            assertEquals(0, currentValue);
+            assertEquals(66, s.getSubscriptValue());
+        }
+    }
+
+    @Test
+    void testSubscriptWithParams() {
+        try (var arena = SwiftArena.ofConfined()) {
+            MySwiftStruct s = MySwiftStruct.init(1337, 42, arena);
+            long currentValue = s.getSubscript(1);
+            s.setSubscript(1, 66);
+            assertEquals(20, currentValue);
+            assertEquals(66, s.getSubscriptArrayValue(1));
+        }
+    }
 }

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

@@ -812,11 +812,10 @@ extension LoweredFunctionSignature {
 
     // Build callee expression.
     let callee: ExprSyntax = if let selfExpr {
-      if case .initializer = apiKind {
+      switch apiKind {
         // Don't bother to create explicit ${Self}.init expression.
-        selfExpr
-      } else {
-        ExprSyntax(MemberAccessExprSyntax(base: selfExpr, name: .identifier(swiftAPIName)))
+        case .initializer, .subscriptGetter, .subscriptSetter: selfExpr
+        default: ExprSyntax(MemberAccessExprSyntax(base: selfExpr, name: .identifier(swiftAPIName)))
       }
     } else {
       ExprSyntax(DeclReferenceExprSyntax(baseName: .identifier(swiftAPIName)))
@@ -845,6 +844,18 @@ extension LoweredFunctionSignature {
     case .enumCase:
       // This should not be called, but let's fatalError.
       fatalError("Enum cases are not supported with FFM.")
+
+    case .subscriptGetter:
+      let parameters = paramExprs.map { $0.description }.joined(separator: ", ")
+      resultExpr = "\(callee)[\(raw: parameters)]"
+    case .subscriptSetter:
+      assert(paramExprs.count >= 1)
+
+      var argumentsWithoutNewValue = paramExprs
+      let newValueArgument = argumentsWithoutNewValue.removeLast()
+
+      let parameters = argumentsWithoutNewValue.map { $0.description }.joined(separator: ", ")
+      resultExpr = "\(callee)[\(raw: parameters)] = \(newValueArgument)"
     }
 
     // Lower the result.

Sources/JExtractSwiftLib/FFM/FFMSwift2JavaGenerator+JavaTranslation.swift

@@ -144,8 +144,8 @@ extension FFMSwift2JavaGenerator {
 
       // Name.
       let javaName = switch decl.apiKind {
-      case .getter: decl.javaGetterName
-      case .setter: decl.javaSetterName
+      case .getter, .subscriptGetter: decl.javaGetterName
+      case .setter, .subscriptSetter: decl.javaSetterName
       case .function, .initializer, .enumCase: decl.name
       }
 

Sources/JExtractSwiftLib/ImportedDecls.swift

@@ -23,6 +23,8 @@ package enum SwiftAPIKind {
   case getter
   case setter
   case enumCase
+  case subscriptGetter
+  case subscriptSetter
 }
 
 /// Describes a Swift nominal type (e.g., a class, struct, enum) that has been
@@ -179,6 +181,8 @@ public final class ImportedFunc: ImportedDecl, CustomStringConvertible {
     case .setter: "setter:"
     case .enumCase: "case:"
     case .function, .initializer: ""
+    case .subscriptGetter: "subscriptGetter:"
+    case .subscriptSetter: "subscriptSetter:"
     }
 
     let context = if let parentType {

Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+JavaTranslation.swift

@@ -176,8 +176,8 @@ extension JNISwift2JavaGenerator {
 
       // Name.
       let javaName = switch decl.apiKind {
-      case .getter: decl.javaGetterName
-      case .setter: decl.javaSetterName
+      case .getter, .subscriptGetter: decl.javaGetterName
+      case .setter, .subscriptSetter: decl.javaSetterName
       case .function, .initializer, .enumCase: decl.name
       }
 

Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+SwiftThunkPrinting.swift

@@ -348,6 +348,19 @@ extension JNISwift2JavaGenerator {
       }
 
       result = "\(callee).\(decl.name) = \(newValueArgument)"
+    case .subscriptGetter:
+      let parameters = arguments.joined(separator: ", ")
+      result = "\(callee)[\(parameters)]"
+    case .subscriptSetter:
+      guard let newValueArgument = arguments.last else {
+        fatalError("Setter did not contain newValue parameter: \(decl)")
+      }
+
+      var argumentsWithoutNewValue = arguments
+      argumentsWithoutNewValue.removeLast()
+
+      let parameters = argumentsWithoutNewValue.joined(separator: ", ")
+      result = "\(callee)[\(parameters)] = \(newValueArgument)"
     }
 
     // Lower the result.