Support function call with this

Author: kateinoigakukun

src/swift/Sources/JavaScriptKit/JSFunction.swift

@@ -28,6 +28,22 @@ public class JSFunctionRef: Equatable {
         return result.jsValue()
     }
 
+    public func apply(this: JSObjectRef, arguments: [JSValue]) -> JSValue {
+        let result = arguments.withRawJSValues { rawValues in
+            rawValues.withUnsafeBufferPointer { bufferPointer -> RawJSValue in
+                let argv = bufferPointer.baseAddress
+                let argc = bufferPointer.count
+                var result = RawJSValue()
+                _call_function_with_this(this.id,
+                    self.id, argv, Int32(argc),
+                    &result.kind, &result.payload1, &result.payload2
+                )
+                return result
+            }
+        }
+        return result.jsValue()
+    }
+
     public func new(_ arguments: [JSValue]) -> JSObjectRef {
         return arguments.withRawJSValues { rawValues in
             rawValues.withUnsafeBufferPointer { bufferPointer in

src/swift/Sources/JavaScriptKit/XcodeSupport.swift

@@ -39,6 +39,13 @@ func _call_function(
     _ result_kind: UnsafeMutablePointer<JavaScriptValueKind>!,
     _ result_payload1: UnsafeMutablePointer<JavaScriptPayload>!,
     _ result_payload2: UnsafeMutablePointer<JavaScriptPayload>!) { fatalError() }
+func _call_function_with_this(
+    _ _this: JavaScriptObjectRef,
+    _ func_ref: JavaScriptObjectRef,
+    _ argv: UnsafePointer<RawJSValue>!, _ argc: Int32,
+    _ result_kind: UnsafeMutablePointer<JavaScriptValueKind>!,
+    _ result_payload1: UnsafeMutablePointer<JavaScriptPayload>!,
+    _ result_payload2: UnsafeMutablePointer<JavaScriptPayload>!) { fatalError() }
 func _call_new(
     _ ref: JavaScriptObjectRef,
     _ argv: UnsafePointer<RawJSValue>!, _ argc: Int32,

src/swift/Sources/_CJavaScriptKit/include/_CJavaScriptKit.h

@@ -34,8 +34,7 @@ __attribute__((
 ))
 extern void _set_prop(
     const JavaScriptObjectRef _this,
-    const char *prop,
-    const int length,
+    const char *prop, const int length,
     const JavaScriptValueKind kind,
     const JavaScriptPayload payload1,
     const JavaScriptPayload payload2
@@ -47,8 +46,7 @@ __attribute__((
 ))
 extern void _get_prop(
     const JavaScriptObjectRef _this,
-    const char *prop,
-    const int length,
+    const char *prop, const int length,
     JavaScriptValueKind *kind,
     JavaScriptPayload *payload1,
     JavaScriptPayload *payload2
@@ -99,6 +97,19 @@ extern void _call_function(
     JavaScriptPayload *result_payload2
 );
 
+__attribute__((
+    __import_module__("javascript_kit"),
+    __import_name__("swjs_call_function_with_this")
+))
+extern void _call_function_with_this(
+    const JavaScriptObjectRef _this,
+    const JavaScriptObjectRef func_ref,
+    const RawJSValue *argv, const int argc,
+    JavaScriptValueKind *result_kind,
+    JavaScriptPayload *result_payload1,
+    JavaScriptPayload *result_payload2
+);
+
 __attribute__((
     __import_module__("javascript_kit"),
     __import_name__("swjs_call_new")

src/web/src/index.ts

@@ -281,6 +281,20 @@ export class SwiftRuntime {
                 writeUint32(payload1_ptr, payload1);
                 writeUint32(payload2_ptr, payload2);
             },
+            swjs_call_function_with_this: (
+                obj_ref: ref, func_ref: ref,
+                argv: pointer, argc: number,
+                kind_ptr: pointer,
+                payload1_ptr: pointer, payload2_ptr: pointer
+            ) => {
+                const obj = this._heapValues[obj_ref]
+                const func = this._heapValues[func_ref]
+                const result = Reflect.apply(func, obj, decodeValues(argv, argc))
+                const { kind, payload1, payload2 } = encodeValue(result);
+                writeUint32(kind_ptr, kind);
+                writeUint32(payload1_ptr, payload1);
+                writeUint32(payload2_ptr, payload2);
+            },
             swjs_create_function: (
                 host_func_id: number,
                 func_ref_ptr: pointer,

test/JavaScriptKitExec/Sources/JavaScriptKitExec/main.swift

@@ -182,3 +182,33 @@ New_Object_Construction: do {
 } catch {
     print(error)
 }
+
+Call_Function_With_This: do {
+
+    // ```js
+    // global.Animal = function(name, age, isCat) {
+    //   this.name = name
+    //   this.age = age
+    //   this.bark = () => {
+    //     return isCat ? "nyan" : "wan"
+    //   }
+    //   this.isCat = isCat
+    //   this.getIsCat = function() {
+    //     return this.isCat
+    //   }
+    // }
+    // ```
+    let objectConstructor = try expectFunction(getJSValue(this: .global(), name: "Animal"))
+    let cat1 = objectConstructor.new([.string("Tama"), .number(3), .boolean(true)])
+    let getIsCat = try expectFunction(getJSValue(this: cat1, name: "getIsCat"))
+
+    // Direct call without this
+    try expectEqual(getIsCat(), .undefined)
+
+    // Call with this
+    let gotIsCat = getIsCat.apply(this: cat1, arguments: [])
+    try expectEqual(gotIsCat, .boolean(true))
+
+} catch {
+    print(error)
+}

test/index.js

@@ -50,6 +50,10 @@ global.Animal = function(name, age, isCat) {
   this.bark = () => {
     return isCat ? "nyan" : "wan"
   }
+  this.isCat = isCat
+  this.getIsCat = function() {
+    return this.isCat
+  }
 }
 
 const startWasiTask = async () => {