Add CallAsFunction method to the Object class in the API

Patch by Peter Varga.

BUG=v8:1336
TEST=cctest/test-api/CallAsFunction

Review URL: http://codereview.chromium.org/6883045

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7781 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -1606,6 +1606,14 @@ class Object : public Value {
   V8EXPORT ExternalArrayType GetIndexedPropertiesExternalArrayDataType();
   V8EXPORT int GetIndexedPropertiesExternalArrayDataLength();
 
+  /**
+   * Call an Object as a function if a callback is set by the 
+   * ObjectTemplate::SetCallAsFunctionHandler method.
+   */
+  V8EXPORT Local<Value> CallAsFunction(Handle<Object> recv,
+                                       int argc,
+                                       Handle<Value> argv[]);
+
   V8EXPORT static Local<Object> New();
   static inline Object* Cast(Value* obj);
  private:

src/api.cc

@@ -3255,6 +3255,37 @@ int v8::Object::GetIndexedPropertiesExternalArrayDataLength() {
 }
 
 
+Local<v8::Value> Object::CallAsFunction(v8::Handle<v8::Object> recv, int argc,
+                                        v8::Handle<v8::Value> argv[]) {
+  i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
+  ON_BAILOUT(isolate, "v8::Object::CallAsFunction()",
+             return Local<v8::Value>());
+  LOG_API(isolate, "Object::CallAsFunction");
+  ENTER_V8(isolate);
+  HandleScope scope;
+  i::Handle<i::JSObject> obj = Utils::OpenHandle(this);
+  i::Handle<i::Object> recv_obj = Utils::OpenHandle(*recv);
+  STATIC_ASSERT(sizeof(v8::Handle<v8::Value>) == sizeof(i::Object**));
+  i::Object*** args = reinterpret_cast<i::Object***>(argv);
+  i::Handle<i::JSFunction> fun = i::Handle<i::JSFunction>();
+  if (obj->IsJSFunction()) {
+    fun = i::Handle<i::JSFunction>::cast(obj);
+  } else {
+    EXCEPTION_PREAMBLE(isolate);
+    i::Handle<i::Object> delegate =
+        i::Execution::TryGetFunctionDelegate(obj, &has_pending_exception);
+    EXCEPTION_BAILOUT_CHECK(isolate, Local<Value>());
+    fun = i::Handle<i::JSFunction>::cast(delegate);
+    recv_obj = obj;
+  }
+  EXCEPTION_PREAMBLE(isolate);
+  i::Handle<i::Object> returned =
+      i::Execution::Call(fun, recv_obj, argc, args, &has_pending_exception);
+  EXCEPTION_BAILOUT_CHECK(isolate, Local<Value>());
+  return scope.Close(Utils::ToLocal(returned));
+}
+
+
 Local<v8::Object> Function::NewInstance() const {
   return NewInstance(0, NULL);
 }

src/execution.cc

@@ -234,6 +234,30 @@ Handle<Object> Execution::GetFunctionDelegate(Handle<Object> object) {
 }
 
 
+Handle<Object> Execution::TryGetFunctionDelegate(Handle<Object> object,
+                                                 bool* has_pending_exception) {
+  ASSERT(!object->IsJSFunction());
+  Isolate* isolate = Isolate::Current();
+
+  // Objects created through the API can have an instance-call handler
+  // that should be used when calling the object as a function.
+  if (object->IsHeapObject() &&
+      HeapObject::cast(*object)->map()->has_instance_call_handler()) {
+    return Handle<JSFunction>(
+        isolate->global_context()->call_as_function_delegate());
+  }
+
+  // If the Object doesn't have an instance-call handler we should
+  // throw a non-callable exception.
+  i::Handle<i::Object> error_obj = isolate->factory()->NewTypeError(
+      "called_non_callable", i::HandleVector<i::Object>(&object, 1));
+  isolate->Throw(*error_obj);
+  *has_pending_exception = true;
+
+  return isolate->factory()->undefined_value();
+}
+
+
 Handle<Object> Execution::GetConstructorDelegate(Handle<Object> object) {
   ASSERT(!object->IsJSFunction());
   Isolate* isolate = Isolate::Current();

src/execution.h

@@ -138,6 +138,8 @@ class Execution : public AllStatic {
   // Get a function delegate (or undefined) for the given non-function
   // object. Used for support calling objects as functions.
   static Handle<Object> GetFunctionDelegate(Handle<Object> object);
+  static Handle<Object> TryGetFunctionDelegate(Handle<Object> object,
+                                               bool* has_pending_exception);
 
   // Get a function delegate (or undefined) for the given non-function
   // object. Used for support calling objects as constructors.

test/cctest/test-api.cc

@@ -6962,7 +6962,7 @@ THREADED_TEST(CallAsFunction) {
   v8::HandleScope scope;
   LocalContext context;
 
-  Local<v8::FunctionTemplate> t = v8::FunctionTemplate::New();
+  { Local<v8::FunctionTemplate> t = v8::FunctionTemplate::New();
     Local<ObjectTemplate> instance_template = t->InstanceTemplate();
     instance_template->SetCallAsFunctionHandler(call_as_function);
     Local<v8::Object> instance = t->GetFunction()->NewInstance();
@@ -7006,6 +7006,67 @@ THREADED_TEST(CallAsFunction) {
     value = CompileRun("new obj(43)");
     CHECK(!try_catch.HasCaught());
     CHECK_EQ(-43, value->Int32Value());
+
+    // Check that the call-as-function handler can be called through
+    // the API.
+    v8::Handle<Value> args[] = { v8_num(28) };
+    value = instance->CallAsFunction(instance, 1, args);
+    CHECK(!try_catch.HasCaught());
+    CHECK_EQ(28, value->Int32Value());
+  }
+
+  { Local<v8::FunctionTemplate> t = v8::FunctionTemplate::New();
+    Local<ObjectTemplate> instance_template = t->InstanceTemplate();
+    Local<v8::Object> instance = t->GetFunction()->NewInstance();
+    context->Global()->Set(v8_str("obj2"), instance);
+    v8::TryCatch try_catch;
+    Local<Value> value;
+    CHECK(!try_catch.HasCaught());
+
+    // Call an object without call-as-function handler through the JS
+    value = CompileRun("obj2(28)");
+    CHECK(value.IsEmpty());
+    CHECK(try_catch.HasCaught());
+    String::AsciiValue exception_value1(try_catch.Exception());
+    CHECK_EQ(*exception_value1,
+             "TypeError: Property 'obj2' of object "
+             "#<Object> is not a function");
+    try_catch.Reset();
+
+    // Call an object without call-as-function handler through the API
+    value = CompileRun("obj2(28)");
+    v8::Handle<Value> args[] = { v8_num(28) };
+    value = instance->CallAsFunction(instance, 1, args);
+    CHECK(value.IsEmpty());
+    CHECK(try_catch.HasCaught());
+    String::AsciiValue exception_value2(try_catch.Exception());
+    CHECK_EQ(*exception_value2, "TypeError: [object Object] is not a function");
+    try_catch.Reset();
+  }
+
+  { Local<v8::FunctionTemplate> t = v8::FunctionTemplate::New();
+    Local<ObjectTemplate> instance_template = t->InstanceTemplate();
+    instance_template->SetCallAsFunctionHandler(ThrowValue);
+    Local<v8::Object> instance = t->GetFunction()->NewInstance();
+    context->Global()->Set(v8_str("obj3"), instance);
+    v8::TryCatch try_catch;
+    Local<Value> value;
+    CHECK(!try_catch.HasCaught());
+
+    // Catch the exception which is thrown by call-as-function handler
+    value = CompileRun("obj3(22)");
+    CHECK(try_catch.HasCaught());
+    String::AsciiValue exception_value1(try_catch.Exception());
+    CHECK_EQ(*exception_value1, "22");
+    try_catch.Reset();
+
+    v8::Handle<Value> args[] = { v8_num(23) };
+    value = instance->CallAsFunction(instance, 1, args);
+    CHECK(try_catch.HasCaught());
+    String::AsciiValue exception_value2(try_catch.Exception());
+    CHECK_EQ(*exception_value2, "23");
+    try_catch.Reset();
+  }
 }