BridgeJS: Support protocol types in closure parameters and returns

Plugins/BridgeJS/Sources/BridgeJSCore/ClosureCodegen.swift

@@ -12,9 +12,9 @@ public struct ClosureCodegen {
     public init() {}
 
     private func swiftClosureType(for signature: ClosureSignature) -> String {
-        let closureParams = signature.parameters.map { "\($0.swiftType)" }.joined(separator: ", ")
+        let closureParams = signature.parameters.map { "\($0.closureSwiftType)" }.joined(separator: ", ")
         let swiftEffects = (signature.isAsync ? " async" : "") + (signature.isThrows ? " throws" : "")
-        let swiftReturnType = signature.returnType.swiftType
+        let swiftReturnType = signature.returnType.closureSwiftType
         return "(\(closureParams))\(swiftEffects) -> \(swiftReturnType)"
     }
 
@@ -158,7 +158,26 @@ public struct ClosureCodegen {
                 printer.write(closureCallExpr.description)
             } else {
                 printer.write("let result = \(closureCallExpr)")
-                printer.write("return result.bridgeJSLowerReturn()")
+                switch signature.returnType {
+                case .swiftProtocol:
+                    printer.write(
+                        "return (result as! _BridgedSwiftProtocolExportable).bridgeJSLowerAsProtocolReturn()"
+                    )
+                case .nullable(.swiftProtocol, _):
+                    printer.write("if let result {")
+                    printer.indent {
+                        printer.write(
+                            "_swift_js_return_optional_object(1, (result as! _BridgedSwiftProtocolExportable).bridgeJSLowerAsProtocolReturn())"
+                        )
+                    }
+                    printer.write("} else {")
+                    printer.indent {
+                        printer.write("_swift_js_return_optional_object(0, 0)")
+                    }
+                    printer.write("}")
+                default:
+                    printer.write("return result.bridgeJSLowerReturn()")
+                }
             }
         }
 

Plugins/BridgeJS/Sources/BridgeJSCore/ExportSwift.swift

@@ -1454,6 +1454,16 @@ extension BridgeType {
         }
     }
 
+    var closureSwiftType: String {
+        switch self {
+        case .swiftProtocol(let name): return "any \(name)"
+        case .nullable(let wrappedType, let kind):
+            let wrappedClosureType = wrappedType.closureSwiftType
+            return kind == .null ? "Optional<\(wrappedClosureType)>" : "JSUndefinedOr<\(wrappedClosureType)>"
+        default: return swiftType
+        }
+    }
+
     var isClosureType: Bool {
         if case .closure = self { return true }
         return false

Plugins/BridgeJS/Sources/BridgeJSCore/ImportTS.swift

@@ -163,8 +163,28 @@ public struct ImportTS {
                         }
                     )
                 )
+            } else if case .nullable(.swiftProtocol, _) = param.type, context == .exportSwift {
+                body.write("let \(pattern): (Int32, Int32)")
+                body.write("if let \(param.name) {")
+                body.indent {
+                    body.write(
+                        "\(pattern) = (1, (\(param.name) as! _BridgedSwiftProtocolExportable).bridgeJSLowerAsProtocolReturn())"
+                    )
+                }
+                body.write("} else {")
+                body.indent {
+                    body.write("\(pattern) = (0, 0)")
+                }
+                body.write("}")
             } else {
-                let initializerExpr = ExprSyntax("\(raw: param.name).bridgeJSLowerParameter()")
+                let initializerExpr: ExprSyntax
+                if case .swiftProtocol = param.type, context == .exportSwift {
+                    initializerExpr = ExprSyntax(
+                        "(\(raw: param.name) as! _BridgedSwiftProtocolExportable).bridgeJSLowerAsProtocolReturn()"
+                    )
+                } else {
+                    initializerExpr = ExprSyntax("\(raw: param.name).bridgeJSLowerParameter()")
+                }
 
                 if loweringInfo.loweredParameters.isEmpty {
                     stackLoweringStmts.insert("let _ = \(initializerExpr)", at: 0)
@@ -817,7 +837,12 @@ extension BridgeType {
         case .swiftHeapObject:
             return LoweringParameterInfo(loweredParameters: [("pointer", .pointer)])
         case .swiftProtocol:
-            throw BridgeJSCoreError("swiftProtocol is not supported in imported signatures")
+            switch context {
+            case .importTS:
+                throw BridgeJSCoreError("swiftProtocol is not supported in imported signatures")
+            case .exportSwift:
+                return LoweringParameterInfo(loweredParameters: [("objectId", .i32)])
+            }
         case .caseEnum:
             switch context {
             case .importTS:
@@ -891,7 +916,12 @@ extension BridgeType {
         case .swiftHeapObject:
             return LiftingReturnInfo(valueToLift: .pointer)
         case .swiftProtocol:
-            throw BridgeJSCoreError("swiftProtocol is not supported in imported signatures")
+            switch context {
+            case .importTS:
+                throw BridgeJSCoreError("swiftProtocol is not supported in imported signatures")
+            case .exportSwift:
+                return LiftingReturnInfo(valueToLift: .i32)
+            }
         case .caseEnum:
             switch context {
             case .importTS:

Plugins/BridgeJS/Tests/BridgeJSToolTests/Inputs/MacroSwift/ProtocolInClosure.swift

@@ -0,0 +1,18 @@
+import JavaScriptKit
+
+@JS protocol Renderable {
+    func render() -> String
+}
+
+@JS class Widget {
+    @JS var name: String
+
+    @JS init(name: String) {
+        self.name = name
+    }
+}
+
+@JS func processRenderable(_ item: Renderable, transform: (Renderable) -> String) -> String
+@JS func makeRenderableFactory(defaultName: String) -> () -> Renderable
+@JS func roundtripRenderable(_ callback: (Renderable) -> Renderable) -> (Renderable) -> Renderable
+@JS func processOptionalRenderable(_ callback: (Renderable?) -> String) -> String