Prepare accessor function descriptors for properties: get set

Author: ktoso

Sources/ExampleSwiftLibrary/MySwiftLibrary.swift

@@ -55,6 +55,8 @@ public class MySwiftClass {
     p("Deinit, self = 0x\(String(addr, radix: 16, uppercase: true))")
   }
 
+  public var counter: Int32 = 0
+
   public func voidMethod() {
     p("")
   }

Sources/JExtractSwift/ImportedDecls.swift

@@ -16,6 +16,7 @@ import Foundation
 import JavaTypes
 import SwiftSyntax
 
+/// Any imported (Swift) declaration
 protocol ImportedDecl {
 
 }
@@ -32,6 +33,7 @@ public struct ImportedNominalType: ImportedDecl {
 
   public var initializers: [ImportedFunc] = []
   public var methods: [ImportedFunc] = []
+  public var variables: [ImportedVariable] = []
 
   public init(swiftTypeName: String, javaType: JavaType, swiftMangledName: String? = nil, kind: NominalTypeKind) {
     self.swiftTypeName = swiftTypeName
@@ -195,7 +197,7 @@ public struct ImportedFunc: ImportedDecl, CustomStringConvertible {
 
   public var swiftMangledName: String = ""
 
-  public var swiftDeclRaw: String? = nil
+  public var syntax: String? = nil
 
   public var isInit: Bool = false
 
@@ -221,7 +223,160 @@ public struct ImportedFunc: ImportedDecl, CustomStringConvertible {
 
     Swift mangled name:
       Imported from:
-      \(swiftDeclRaw ?? "<no swift source>")
+      \(syntax?.description ?? "<no swift source>")
+    }
+    """
+  }
+}
+
+public enum VariableAccessorKind {
+  case get
+  case set
+
+  public var renderDescFieldName: String {
+    switch self {
+    case .get: "DESC_GET"
+    case .set: "DESC_SET"
+    }
+  }
+}
+
+public struct ImportedVariable: ImportedDecl, CustomStringConvertible {
+  /// If this function/method is member of a class/struct/protocol,
+  /// this will contain that declaration's imported name.
+  ///
+  /// This is necessary when rendering accessor Java code we need the type that "self" is expecting to have.
+  public var parentName: TranslatedType?
+  public var hasParent: Bool { parentName != nil }
+
+  /// This is a full name such as "counter".
+  public var identifier: String
+
+  /// Which accessors are we able to expose.
+  /// 
+  /// Usually this will be all the accessors the variable declares,
+  /// however if the getter is async or throwing we may not be able to import it
+  /// (yet), and therefore would skip it from the supported set.
+  public var supportedAccessorKinds: Set<VariableAccessorKind> = [.get, .set]
+
+  /// This is the base identifier for the function, e.g., "init" for an
+  /// initializer or "f" for "f(a:b:)".
+  public var baseIdentifier: String {
+    guard let idx = identifier.firstIndex(of: "(") else {
+      return identifier
+    }
+    return String(identifier[..<idx])
+  }
+
+  /// A display name to use to refer to the Swift declaration with its
+  /// enclosing type, if there is one.
+  public var displayName: String {
+    if let parentName {
+      return "\(parentName.swiftTypeName).\(identifier)"
+    }
+
+    return identifier
+  }
+
+  public var returnType: TranslatedType
+
+  /// Synthetic signature of an accessor function of the given kind of this property
+  public func accessorFunc(kind: VariableAccessorKind) -> ImportedFunc? {
+    guard self.supportedAccessorKinds.contains(kind) else {
+      return nil
+    }
+
+    switch kind {
+    case .set:
+      let newValueParam: FunctionParameterSyntax = "_ newValue: \(self.returnType.cCompatibleSwiftType)"
+      var funcDecl = ImportedFunc(
+        parentName: self.parentName,
+        identifier: self.identifier,
+        returnType: TranslatedType.void,
+        parameters: [.init(param: newValueParam, type: self.returnType)])
+      funcDecl.swiftMangledName = self.swiftMangledName + "s" // form mangled name of the getter by adding the suffix
+      return funcDecl
+
+    case .get:
+      var funcDecl = ImportedFunc(
+        parentName: self.parentName,
+        identifier: self.identifier,
+        returnType: self.returnType,
+        parameters: [])
+      funcDecl.swiftMangledName = self.swiftMangledName + "g" // form mangled name of the getter by adding the suffix
+      return funcDecl
+    }
+  }
+
+  public func effectiveAccessorParameters(_ kind: VariableAccessorKind, selfVariant: SelfParameterVariant?) -> [ImportedParam] {
+    var params: [ImportedParam] = []
+
+    if kind == .set {
+      let newValueParam: FunctionParameterSyntax = "_ newValue: \(raw: self.returnType.swiftTypeName)"
+      params.append(
+        ImportedParam(
+          param: newValueParam,
+          type: self.returnType)
+        )
+    }
+
+    if let parentName {
+      // Add `self: Self` for method calls on a member
+      //
+      // allocating initializer takes a Self.Type instead, but it's also a pointer
+      switch selfVariant {
+      case nil, .wrapper:
+        break
+
+      case .pointer:
+        let selfParam: FunctionParameterSyntax = "self$: $swift_pointer"
+        params.append(
+          ImportedParam(
+            param: selfParam,
+            type: parentName
+          )
+        )
+
+      case .memorySegment:
+        let selfParam: FunctionParameterSyntax = "self$: $java_lang_foreign_MemorySegment"
+        var parentForSelf = parentName
+        parentForSelf.javaType = .javaForeignMemorySegment
+        params.append(
+          ImportedParam(
+            param: selfParam,
+            type: parentForSelf
+          )
+        )
+      }
+    }
+
+    return params
+  }
+
+  public var swiftMangledName: String = ""
+
+  public var syntax: VariableDeclSyntax? = nil
+
+  public init(
+    parentName: TranslatedType?,
+    identifier: String,
+    returnType: TranslatedType
+  ) {
+    self.parentName = parentName
+    self.identifier = identifier
+    self.returnType = returnType
+  }
+
+  public var description: String {
+    """
+    ImportedFunc {
+      mangledName: \(swiftMangledName)
+      identifier: \(identifier)
+      returnType: \(returnType)
+
+    Swift mangled name:
+      Imported from:
+      \(syntax?.description ?? "<no swift source>")
     }
     """
   }

Sources/JExtractSwift/Swift2JavaTranslator+Printing.swift

@@ -437,7 +437,7 @@ extension Swift2JavaTranslator {
        * Create an instance of {@code \(parentName.unqualifiedJavaTypeName)}.
        *
        * {@snippet lang=swift :
-       * \(decl.swiftDeclRaw ?? "")
+       * \(decl.syntax ?? "")
        * }
        */
       public \(parentName.unqualifiedJavaTypeName)(\(renderJavaParamDecls(decl, selfVariant: .wrapper))) {
@@ -470,7 +470,7 @@ extension Swift2JavaTranslator {
       /**
        * Function descriptor for:
        * {@snippet lang=swift :
-       * \(/*TODO: make a printSnippet func*/decl.swiftDeclRaw ?? "")
+       * \(/*TODO: make a printSnippet func*/decl.syntax ?? "")
        * }
        */
       public static FunctionDescriptor \(decl.baseIdentifier)$descriptor() {
@@ -484,7 +484,7 @@ extension Swift2JavaTranslator {
       /**
        * Downcall method handle for:
        * {@snippet lang=swift :
-       * \(/*TODO: make a printSnippet func*/decl.swiftDeclRaw ?? "")
+       * \(/*TODO: make a printSnippet func*/decl.syntax ?? "")
        * }
        */
       public static MethodHandle \(decl.baseIdentifier)$handle() {
@@ -498,7 +498,7 @@ extension Swift2JavaTranslator {
       /**
        * Address for:
        * {@snippet lang=swift :
-       * \(/*TODO: make a printSnippet func*/decl.swiftDeclRaw ?? "")
+       * \(/*TODO: make a printSnippet func*/decl.syntax ?? "")
        * }
        */
       public static MemorySegment \(decl.baseIdentifier)$address() {
@@ -557,7 +557,7 @@ extension Swift2JavaTranslator {
         """
         /**
          * {@snippet lang=swift :
-         * \(/*TODO: make a printSnippet func*/decl.swiftDeclRaw ?? "")
+         * \(/*TODO: make a printSnippet func*/decl.syntax ?? "")
          * }
          */
         public \(returnTy) \(decl.baseIdentifier)(\(renderJavaParamDecls(decl, selfVariant: .wrapper))) {
@@ -572,7 +572,60 @@ extension Swift2JavaTranslator {
       """
       /**
        * {@snippet lang=swift :
-       * \(/*TODO: make a printSnippet func*/decl.swiftDeclRaw ?? "")
+       * \(/*TODO: make a printSnippet func*/decl.syntax ?? "")
+       * }
+       */
+      public static \(returnTy) \(decl.baseIdentifier)(\(renderJavaParamDecls(decl, selfVariant: selfVariant))) {
+        var mh$ = \(decl.baseIdentifier).HANDLE;
+        try {
+          if (TRACE_DOWNCALLS) {
+             traceDowncall(\(renderForwardParams(decl, selfVariant: .memorySegment)));
+          }
+          \(maybeReturnCast) mh$.invokeExact(\(renderForwardParams(decl, selfVariant: selfVariant)));
+        } catch (Throwable ex$) {
+          throw new AssertionError("should not reach here", ex$);
+        }
+      }
+      """
+    )
+  }
+
+  public func printPropertyAccessorDowncallMethod(
+    _ printer: inout CodePrinter,
+    decl: ImportedFunc,
+    selfVariant: SelfParameterVariant?
+  ) {
+    let returnTy = decl.returnType.javaType
+
+    let maybeReturnCast: String
+    if decl.returnType.javaType == .void {
+      maybeReturnCast = ""  // nothing to return or cast to
+    } else {
+      maybeReturnCast = "return (\(returnTy))"
+    }
+
+    if selfVariant == SelfParameterVariant.wrapper {
+      // delegate to the MemorySegment "self" accepting overload
+      printer.print(
+        """
+        /**
+         * {@snippet lang=swift :
+         * \(/*TODO: make a printSnippet func*/decl.syntax ?? "")
+         * }
+         */
+        public \(returnTy) \(decl.baseIdentifier)(\(renderJavaParamDecls(decl, selfVariant: .wrapper))) {
+          \(maybeReturnCast) \(decl.baseIdentifier)(\(renderForwardParams(decl, selfVariant: .wrapper)));
+        }
+        """
+      )
+      return
+    }
+
+    printer.print(
+      """
+      /**
+       * {@snippet lang=swift :
+       * \(/*TODO: make a printSnippet func*/decl.syntax ?? "")
        * }
        */
       public static \(returnTy) \(decl.baseIdentifier)(\(renderJavaParamDecls(decl, selfVariant: selfVariant))) {
@@ -656,8 +709,11 @@ extension Swift2JavaTranslator {
     return ps.joined(separator: ", ")
   }
 
-  public func printFunctionDescriptorValue(_ printer: inout CodePrinter, _ decl: ImportedFunc) {
-    printer.start("public static final FunctionDescriptor DESC = ")
+  public func printFunctionDescriptorValue(
+    _ printer: inout CodePrinter,
+    _ decl: ImportedFunc,
+    fieldName: String = "DESC") {
+    printer.start("public static final FunctionDescriptor \(fieldName) = ")
 
     let parameterLayoutDescriptors = javaMemoryLayoutDescriptors(
       forParametersOf: decl,
@@ -692,4 +748,15 @@ extension Swift2JavaTranslator {
     printer.outdent();
     printer.print(");");
   }
+
+  public func printPropertyAccessorDescriptorValue(
+    _ printer: inout CodePrinter,
+    _ decl: ImportedVariable,
+    _ kind: VariableAccessorKind) {
+    guard let funcDecl = decl.accessorFunc(kind: kind) else {
+      return
+    }
+
+    printFunctionDescriptorValue(&printer, funcDecl, fieldName: kind.renderDescFieldName)
+  }
 }