Introduce an API to force the deletion of a property ignoring...

src/objects.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 367 matching lines @@
   Handle<String> name_handle(name);
   Handle<Object> value_handle(value);
   bool pending_exception;
   LoadLazy(Handle<JSObject>(JSObject::cast(result->GetLazyValue())),
            &pending_exception);
   if (pending_exception) return Failure::Exception();
   return this_handle->SetProperty(*name_handle, *value_handle, attributes);
 }
 
 
-Object* JSObject::DeleteLazyProperty(LookupResult* result, String* name) {
+Object* JSObject::DeleteLazyProperty(LookupResult* result,
+                                     String* name,
+                                     DeleteMode mode) {
   HandleScope scope;
   Handle<JSObject> this_handle(this);
   Handle<String> name_handle(name);
   bool pending_exception;
   LoadLazy(Handle<JSObject>(JSObject::cast(result->GetLazyValue())),
            &pending_exception);
   if (pending_exception) return Failure::Exception();
-  return this_handle->DeleteProperty(*name_handle);
+  return this_handle->DeleteProperty(*name_handle, mode);
 }
 
 
 Object* Object::GetProperty(Object* receiver,
                             LookupResult* result,
                             String* name,
                             PropertyAttributes* attributes) {
   // Make sure that the top context does not change when doing
   // callbacks or interceptor calls.
   AssertNoContextChange ncc;
@@ skipping 1706 matching lines @@
   if (FLAG_trace_normalization) {
     PrintF("Object elements have been normalized:\n");
     Print();
   }
 #endif
 
   return this;
 }
 
 
-Object* JSObject::DeletePropertyPostInterceptor(String* name) {
+Object* JSObject::DeletePropertyPostInterceptor(String* name, DeleteMode mode) {
   // Check local property, ignore interceptor.
   LookupResult result;
   LocalLookupRealNamedProperty(name, &result);
   if (!result.IsValid()) return Heap::true_value();
 
   // Normalize object if needed.
   Object* obj = NormalizeProperties(CLEAR_INOBJECT_PROPERTIES);
   if (obj->IsFailure()) return obj;
 
   ASSERT(!HasFastProperties());
   // Attempt to remove the property from the property dictionary.
   Dictionary* dictionary = property_dictionary();
   int entry = dictionary->FindStringEntry(name);
-  if (entry != -1) return dictionary->DeleteProperty(entry);
+  if (entry != -1) return dictionary->DeleteProperty(entry, mode);
   return Heap::true_value();
 }
 
 
 Object* JSObject::DeletePropertyWithInterceptor(String* name) {
   HandleScope scope;
   Handle<InterceptorInfo> interceptor(GetNamedInterceptor());
   Handle<String> name_handle(name);
   Handle<JSObject> this_handle(this);
   if (!interceptor->deleter()->IsUndefined()) {
     v8::NamedPropertyDeleter deleter =
         v8::ToCData<v8::NamedPropertyDeleter>(interceptor->deleter());
     Handle<Object> data_handle(interceptor->data());
     LOG(ApiNamedPropertyAccess("interceptor-named-delete", *this_handle, name));
     v8::AccessorInfo info(v8::Utils::ToLocal(this_handle),
                           v8::Utils::ToLocal(data_handle),
                           v8::Utils::ToLocal(this_handle));
     v8::Handle<v8::Boolean> result;
     {
       // Leaving JavaScript.
       VMState state(EXTERNAL);
       result = deleter(v8::Utils::ToLocal(name_handle), info);
     }
     RETURN_IF_SCHEDULED_EXCEPTION();
     if (!result.IsEmpty()) {
       ASSERT(result->IsBoolean());
       return *v8::Utils::OpenHandle(*result);
     }
   }
-  Object* raw_result = this_handle->DeletePropertyPostInterceptor(*name_handle);
+  Object* raw_result =
+      this_handle->DeletePropertyPostInterceptor(*name_handle, NORMAL_DELETION);
   RETURN_IF_SCHEDULED_EXCEPTION();
   return raw_result;
 }
 
 
-Object* JSObject::DeleteElementPostInterceptor(uint32_t index) {
+Object* JSObject::DeleteElementPostInterceptor(uint32_t index,
+                                               DeleteMode mode) {
   if (HasFastElements()) {
     uint32_t length = IsJSArray() ?
       static_cast<uint32_t>(Smi::cast(JSArray::cast(this)->length())->value()) :
       static_cast<uint32_t>(FixedArray::cast(elements())->length());
     if (index < length) {
       FixedArray::cast(elements())->set_the_hole(index);
     }
     return Heap::true_value();
   }
   ASSERT(!HasFastElements());
   Dictionary* dictionary = element_dictionary();
   int entry = dictionary->FindNumberEntry(index);
-  if (entry != -1) return dictionary->DeleteProperty(entry);
+  if (entry != -1) return dictionary->DeleteProperty(entry, mode);
   return Heap::true_value();
 }
 
 
 Object* JSObject::DeleteElementWithInterceptor(uint32_t index) {
   // Make sure that the top context does not change when doing
   // callbacks or interceptor calls.
   AssertNoContextChange ncc;
   HandleScope scope;
   Handle<InterceptorInfo> interceptor(GetIndexedInterceptor());
@@ skipping 10 matching lines @@
   {
     // Leaving JavaScript.
     VMState state(EXTERNAL);
     result = deleter(index, info);
   }
   RETURN_IF_SCHEDULED_EXCEPTION();
   if (!result.IsEmpty()) {
     ASSERT(result->IsBoolean());
     return *v8::Utils::OpenHandle(*result);
   }
-  Object* raw_result = this_handle->DeleteElementPostInterceptor(index);
+  Object* raw_result =
+      this_handle->DeleteElementPostInterceptor(index, NORMAL_DELETION);
   RETURN_IF_SCHEDULED_EXCEPTION();
   return raw_result;
 }
 
 
-Object* JSObject::DeleteElement(uint32_t index) {
+Object* JSObject::DeleteElement(uint32_t index, DeleteMode mode) {
   // Check access rights if needed.
   if (IsAccessCheckNeeded() &&
       !Top::MayIndexedAccess(this, index, v8::ACCESS_DELETE)) {
     Top::ReportFailedAccessCheck(this, v8::ACCESS_DELETE);
     return Heap::false_value();
   }
 
   if (IsJSGlobalProxy()) {
     Object* proto = GetPrototype();
     if (proto->IsNull()) return Heap::false_value();
     ASSERT(proto->IsJSGlobalObject());
-    return JSGlobalObject::cast(proto)->DeleteElement(index);
+    return JSGlobalObject::cast(proto)->DeleteElement(index, mode);
   }
 
   if (HasIndexedInterceptor()) {
+    // Skip interceptor if forcing deletion.
+    if (mode == FORCE_DELETION) {
+      return DeleteElementPostInterceptor(index, mode);
+    }
     return DeleteElementWithInterceptor(index);
   }
 
   if (HasFastElements()) {
     uint32_t length = IsJSArray() ?
       static_cast<uint32_t>(Smi::cast(JSArray::cast(this)->length())->value()) :
       static_cast<uint32_t>(FixedArray::cast(elements())->length());
     if (index < length) {
       FixedArray::cast(elements())->set_the_hole(index);
     }
     return Heap::true_value();
   } else {
     Dictionary* dictionary = element_dictionary();
     int entry = dictionary->FindNumberEntry(index);
-    if (entry != -1) return dictionary->DeleteProperty(entry);
+    if (entry != -1) return dictionary->DeleteProperty(entry, mode);
   }
   return Heap::true_value();
 }
 
 
-Object* JSObject::DeleteProperty(String* name) {
+Object* JSObject::DeleteProperty(String* name, DeleteMode mode) {
   // ECMA-262, 3rd, 8.6.2.5
   ASSERT(name->IsString());
 
   // Check access rights if needed.
   if (IsAccessCheckNeeded() &&
       !Top::MayNamedAccess(this, name, v8::ACCESS_DELETE)) {
     Top::ReportFailedAccessCheck(this, v8::ACCESS_DELETE);
     return Heap::false_value();
   }
 
   if (IsJSGlobalProxy()) {
     Object* proto = GetPrototype();
     if (proto->IsNull()) return Heap::false_value();
     ASSERT(proto->IsJSGlobalObject());
-    return JSGlobalObject::cast(proto)->DeleteProperty(name);
+    return JSGlobalObject::cast(proto)->DeleteProperty(name, mode);
   }
 
   uint32_t index = 0;
   if (name->AsArrayIndex(&index)) {
-    return DeleteElement(index);
+    return DeleteElement(index, mode);
   } else {
     LookupResult result;
     LocalLookup(name, &result);
     if (!result.IsValid()) return Heap::true_value();
-    if (result.IsDontDelete()) return Heap::false_value();
+    // Ignore attributes if forcing a deletion.
+    if (result.IsDontDelete() && mode != FORCE_DELETION) {
+      return Heap::false_value();
+    }
     // Check for interceptor.
     if (result.type() == INTERCEPTOR) {
+      // Skip interceptor if forcing a deletion.
+      if (mode == FORCE_DELETION) {
+        return DeletePropertyPostInterceptor(name, mode);
+      }
       return DeletePropertyWithInterceptor(name);
     }
     if (!result.IsLoaded()) {
-      return JSObject::cast(this)->DeleteLazyProperty(&result, name);
+      return JSObject::cast(this)->DeleteLazyProperty(&result,
+                                                      name,
+                                                      mode);
     }
     // Normalize object if needed.
     Object* obj = NormalizeProperties(CLEAR_INOBJECT_PROPERTIES);
     if (obj->IsFailure()) return obj;
     // Make sure the properties are normalized before removing the entry.
     Dictionary* dictionary = property_dictionary();
     int entry = dictionary->FindStringEntry(name);
-    if (entry != -1) return dictionary->DeleteProperty(entry);
+    if (entry != -1) return dictionary->DeleteProperty(entry, mode);
     return Heap::true_value();
   }
 }
 
 
 // Check whether this object references another object.
 bool JSObject::ReferencesObject(Object* obj) {
   AssertNoAllocation no_alloc;
 
   // Is the object the constructor for this object?
@@ skipping 4627 matching lines @@
         removed_entries++;
       }
     }
   }
 
   // Update the number of elements.
   SetNumberOfElements(NumberOfElements() - removed_entries);
 }
 
 
-Object* Dictionary::DeleteProperty(int entry) {
+Object* Dictionary::DeleteProperty(int entry, JSObject::DeleteMode mode) {
   PropertyDetails details = DetailsAt(entry);
-  if (details.IsDontDelete()) return Heap::false_value();
+  // Ignore attributes if forcing a deletion.
+  if (details.IsDontDelete() && mode == JSObject::NORMAL_DELETION) {
+    return Heap::false_value();
+  }
   SetEntry(entry, Heap::null_value(), Heap::null_value(), Smi::FromInt(0));
   ElementRemoved();
   return Heap::true_value();
 }
 
 
 int Dictionary::FindStringEntry(String* key) {
   StringKey k(key);
   return FindEntry(&k);
 }
@@ skipping 578 matching lines @@
   // No break point.
   if (break_point_objects()->IsUndefined()) return 0;
   // Single beak point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif
 
 } }  // namespace v8::internal