Classes runtime

src/runtime/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdlib.h>
 #include <limits>
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
@@ skipping 343 matching lines @@
   DCHECK(args.length() == 4);
   CONVERT_ARG_HANDLE_CHECKED(Object, receiver, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, home_object, 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 2);
   CONVERT_ARG_HANDLE_CHECKED(Name, name, 3);
 
   return StoreToSuper(isolate, home_object, receiver, name, value, SLOPPY);
 }
 
 
+RUNTIME_FUNCTION(Runtime_DefineClass) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 3);
+  CONVERT_ARG_HANDLE_CHECKED(Object, name, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, super_class, 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, constructor, 2);
+
+  Handle<Object> prototype_parent;
+  Handle<Object> constructor_parent;
+  bool has_constructor_parent = false;
+
+  if (super_class->IsTheHole()) {
+    prototype_parent = isolate->initial_object_prototype();

[Dmitry Lomov (no reviews), 2014/10/07 10:28:32]

What happens, per spec, if user assigns to Object.prototype?

[arv (Not doing code reviews), 2014/10/07 14:47:09]

The spec uses %ObjectPrototype% which is the original Object.prototype.

https://people.mozilla.org/~jorendorff/es6-draft.html#sec-runtime-semantics-c...

+  } else {
+    if (super_class->IsNull()) {
+      prototype_parent = isolate->factory()->null_value();
+    } else if (super_class->IsSpecFunction()) {
+      ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+          isolate, prototype_parent,
+          Runtime::GetObjectProperty(isolate, super_class,
+                                     isolate->factory()->prototype_string()));
+      if (!prototype_parent->IsNull() && !prototype_parent->IsSpecObject()) {
+        Handle<Object> args[1] = {prototype_parent};
+        THROW_NEW_ERROR_RETURN_FAILURE(
+            isolate, NewTypeError("prototype_parent_not_an_object",
+                                  HandleVector(args, 1)));
+      }
+      constructor_parent = super_class;
+      has_constructor_parent = true;
+    } else {
+      // TODO(arv): Should be IsConstructor.
+      Handle<Object> args[1] = {super_class};
+      THROW_NEW_ERROR_RETURN_FAILURE(
+          isolate,
+          NewTypeError("extends_value_not_a_function", HandleVector(args, 1)));
+    }
+  }
+
+  Handle<JSObject> prototype =
+      isolate->factory()->NewJSObject(isolate->object_function());
+  RETURN_FAILURE_ON_EXCEPTION(
+      isolate, JSObject::SetPrototype(prototype, prototype_parent, false));

[Dmitry Lomov (no reviews), 2014/10/07 10:28:32]

Instead of SetPrototype here, I suggest using NewJSObjectFromMap with an
appropriate Map (the prototype field of which is set to prototype_parent), so
that we can avoid prototype mutation.

[arv (Not doing code reviews), 2014/10/07 14:47:09]

Done.

I used to have a todo for this... I'm not sure when the todo dissappeared...
well now it is done.

+
+  Handle<String> name_string = name->IsString()
+                                   ? Handle<String>::cast(name)
+                                   : isolate->factory()->empty_string();
+
+  Handle<JSFunction> ctor;
+  if (constructor->IsSpecFunction()) {
+    ctor = Handle<JSFunction>::cast(constructor);
+    JSFunction::SetPrototype(ctor, prototype);
+    PropertyAttributes attribs =
+        static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY);
+    RETURN_FAILURE_ON_EXCEPTION(
+        isolate,
+        JSObject::SetOwnPropertyIgnoreAttributes(
+            ctor, isolate->factory()->prototype_string(), prototype, attribs));
+  } else {
+    // TODO(arv): This should not use an empty function but a function that
+    // calls super.
+    Handle<Code> code(isolate->builtins()->builtin(Builtins::kEmptyFunction));
+    ctor = isolate->factory()->NewFunction(name_string, code, prototype, true);
+  }
+
+  Handle<Symbol> home_object_symbol(isolate->heap()->home_object_symbol());
+  RETURN_FAILURE_ON_EXCEPTION(
+      isolate, JSObject::SetOwnPropertyIgnoreAttributes(
+                   ctor, home_object_symbol, prototype, DONT_ENUM));
+
+  if (has_constructor_parent) {
+    RETURN_FAILURE_ON_EXCEPTION(
+        isolate, JSObject::SetPrototype(ctor, constructor_parent, false));
+  }
+
+  JSObject::AddProperty(prototype, isolate->factory()->constructor_string(),
+                        ctor, DONT_ENUM);
+
+  return *ctor;
+}
+
+
 RUNTIME_FUNCTION(Runtime_IsExtensible) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_CHECKED(JSObject, obj, 0);
   if (obj->IsJSGlobalProxy()) {
     PrototypeIterator iter(isolate, obj);
     if (iter.IsAtEnd()) return isolate->heap()->false_value();
     DCHECK(iter.GetCurrent()->IsJSGlobalObject());
     obj = JSObject::cast(iter.GetCurrent());
   }
@@ skipping 3060 matching lines @@
   }
   return NULL;
 }
 
 
 const Runtime::Function* Runtime::FunctionForId(Runtime::FunctionId id) {
   return &(kIntrinsicFunctions[static_cast<int>(id)]);
 }
 }
 }  // namespace v8::internal