The accessors should get the value from the holder and not from this.

These are all data properties and if they get invoked it means that
they should just return the value of the property from the holder.

BUG=v8:3461
LOG=Y
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/410923003

Patch from Erik Arvidsson <arv@chromium.org>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22575 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/accessors.cc

@@ -21,16 +21,6 @@ namespace v8 {
 namespace internal {
 
 
-// We have a slight impedance mismatch between the external API and the way we
-// use callbacks internally: Externally, callbacks can only be used with
-// v8::Object, but internally we even have callbacks on entities which are
-// higher in the hierarchy, so we can only return i::Object here, not
-// i::JSObject.
-Handle<Object> GetThisFrom(const v8::PropertyCallbackInfo<v8::Value>& info) {
-  return Utils::OpenHandle(*v8::Local<v8::Value>(info.This()));
-}
-
-
 Handle<AccessorInfo> Accessors::MakeAccessor(
     Isolate* isolate,
     Handle<String> name,
@@ -172,15 +162,8 @@ void Accessors::ArrayLengthGetter(
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
-  Object* object = *GetThisFrom(info);
-  // Traverse the prototype chain until we reach an array.
-  JSArray* holder = FindInstanceOf<JSArray>(isolate, object);
-  Object* result;
-  if (holder != NULL) {
-    result = holder->length();
-  } else {
-    result = Smi::FromInt(0);
-  }
+  JSArray* holder = JSArray::cast(*Utils::OpenHandle(*info.Holder()));
+  Object* result = holder->length();
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(result, isolate)));
 }
 
@@ -254,16 +237,19 @@ void Accessors::StringLengthGetter(
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
-  Object* value = *GetThisFrom(info);
-  Object* result;
-  if (value->IsJSValue()) value = JSValue::cast(value)->value();
-  if (value->IsString()) {
-    result = Smi::FromInt(String::cast(value)->length());
-  } else {
-    // If object is not a string we return 0 to be compatible with WebKit.
-    // Note: Firefox returns the length of ToString(object).
-    result = Smi::FromInt(0);
+
+  // We have a slight impedance mismatch between the external API and the way we
+  // use callbacks internally: Externally, callbacks can only be used with
+  // v8::Object, but internally we have callbacks on entities which are higher
+  // in the hierarchy, in this case for String values.
+
+  Object* value = *Utils::OpenHandle(*v8::Local<v8::Value>(info.This()));
+  if (!value->IsString()) {
+    // Not a string value. That means that we either got a String wrapper or
+    // a Value with a String wrapper in its prototype chain.
+    value = JSValue::cast(*Utils::OpenHandle(*info.Holder()))->value();
   }
+  Object* result = Smi::FromInt(String::cast(value)->length());
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(result, isolate)));
 }
 
@@ -839,21 +825,7 @@ Handle<AccessorInfo> Accessors::ScriptEvalFromFunctionNameInfo(
 //
 
 static Handle<Object> GetFunctionPrototype(Isolate* isolate,
-                                           Handle<Object> receiver) {
-  Handle<JSFunction> function;
-  {
-    DisallowHeapAllocation no_allocation;
-    JSFunction* function_raw = FindInstanceOf<JSFunction>(isolate, *receiver);
-    if (function_raw == NULL) return isolate->factory()->undefined_value();
-    while (!function_raw->should_have_prototype()) {
-      PrototypeIterator iter(isolate, function_raw);
-      function_raw = FindInstanceOf<JSFunction>(isolate, iter.GetCurrent());
-      // There has to be one because we hit the getter.
-      ASSERT(function_raw != NULL);
-    }
-    function = Handle<JSFunction>(function_raw, isolate);
-  }
-
+                                           Handle<JSFunction> function) {
   if (!function->has_prototype()) {
     Handle<Object> proto = isolate->factory()->NewFunctionPrototype(function);
     JSFunction::SetPrototype(function, proto);
@@ -919,8 +891,9 @@ void Accessors::FunctionPrototypeGetter(
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   HandleScope scope(isolate);
-  Handle<Object> object = GetThisFrom(info);
-  Handle<Object> result = GetFunctionPrototype(isolate, object);
+  Handle<JSFunction> function =
+      Handle<JSFunction>::cast(Utils::OpenHandle(*info.Holder()));
+  Handle<Object> result = GetFunctionPrototype(isolate, function);
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
@@ -959,29 +932,20 @@ void Accessors::FunctionLengthGetter(
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   HandleScope scope(isolate);
-  Handle<Object> object = GetThisFrom(info);
-  MaybeHandle<JSFunction> maybe_function;
-
-  {
-    DisallowHeapAllocation no_allocation;
-    JSFunction* function = FindInstanceOf<JSFunction>(isolate, *object);
-    if (function != NULL) maybe_function = Handle<JSFunction>(function);
-  }
+  Handle<JSFunction> function =
+      Handle<JSFunction>::cast(Utils::OpenHandle(*info.Holder()));
 
   int length = 0;
-  Handle<JSFunction> function;
-  if (maybe_function.ToHandle(&function)) {
-    if (function->shared()->is_compiled()) {
+  if (function->shared()->is_compiled()) {
+    length = function->shared()->length();
+  } else {
+    // If the function isn't compiled yet, the length is not computed
+    // correctly yet. Compile it now and return the right length.
+    if (Compiler::EnsureCompiled(function, KEEP_EXCEPTION)) {
       length = function->shared()->length();
-    } else {
-      // If the function isn't compiled yet, the length is not computed
-      // correctly yet. Compile it now and return the right length.
-      if (Compiler::EnsureCompiled(function, KEEP_EXCEPTION)) {
-        length = function->shared()->length();
-      }
-      if (isolate->has_pending_exception()) {
-        isolate->OptionalRescheduleException(false);
-      }
+    }
+    if (isolate->has_pending_exception()) {
+      isolate->OptionalRescheduleException(false);
     }
   }
   Handle<Object> result(Smi::FromInt(length), isolate);
@@ -1017,22 +981,9 @@ void Accessors::FunctionNameGetter(
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   HandleScope scope(isolate);
-  Handle<Object> object = GetThisFrom(info);
-  MaybeHandle<JSFunction> maybe_function;
-
-  {
-    DisallowHeapAllocation no_allocation;
-    JSFunction* function = FindInstanceOf<JSFunction>(isolate, *object);
-    if (function != NULL) maybe_function = Handle<JSFunction>(function);
-  }
-
-  Handle<JSFunction> function;
-  Handle<Object> result;
-  if (maybe_function.ToHandle(&function)) {
-    result = Handle<Object>(function->shared()->name(), isolate);
-  } else {
-    result = isolate->factory()->undefined_value();
-  }
+  Handle<JSFunction> function =
+      Handle<JSFunction>::cast(Utils::OpenHandle(*info.Holder()));
+  Handle<Object> result(function->shared()->name(), isolate);
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
@@ -1166,22 +1117,9 @@ void Accessors::FunctionArgumentsGetter(
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   HandleScope scope(isolate);
-  Handle<Object> object = GetThisFrom(info);
-  MaybeHandle<JSFunction> maybe_function;
-
-  {
-    DisallowHeapAllocation no_allocation;
-    JSFunction* function = FindInstanceOf<JSFunction>(isolate, *object);
-    if (function != NULL) maybe_function = Handle<JSFunction>(function);
-  }
-
-  Handle<JSFunction> function;
-  Handle<Object> result;
-  if (maybe_function.ToHandle(&function)) {
-    result = GetFunctionArguments(isolate, function);
-  } else {
-    result = isolate->factory()->undefined_value();
-  }
+  Handle<JSFunction> function =
+      Handle<JSFunction>::cast(Utils::OpenHandle(*info.Holder()));
+  Handle<Object> result = GetFunctionArguments(isolate, function);
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
@@ -1321,26 +1259,16 @@ void Accessors::FunctionCallerGetter(
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   HandleScope scope(isolate);
-  Handle<Object> object = GetThisFrom(info);
-  MaybeHandle<JSFunction> maybe_function;
-  {
-    DisallowHeapAllocation no_allocation;
-    JSFunction* function = FindInstanceOf<JSFunction>(isolate, *object);
-    if (function != NULL) maybe_function = Handle<JSFunction>(function);
-  }
-  Handle<JSFunction> function;
+  Handle<JSFunction> function =
+      Handle<JSFunction>::cast(Utils::OpenHandle(*info.Holder()));
   Handle<Object> result;
-  if (maybe_function.ToHandle(&function)) {
-    MaybeHandle<JSFunction> maybe_caller;
-    maybe_caller = FindCaller(isolate, function);
-    Handle<JSFunction> caller;
-    if (maybe_caller.ToHandle(&caller)) {
-      result = caller;
-    } else {
-      result = isolate->factory()->null_value();
-    }
+  MaybeHandle<JSFunction> maybe_caller;
+  maybe_caller = FindCaller(isolate, function);
+  Handle<JSFunction> caller;
+  if (maybe_caller.ToHandle(&caller)) {
+    result = caller;
   } else {
-    result = isolate->factory()->undefined_value();
+    result = isolate->factory()->null_value();
   }
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }