Small clean up of externalizing strings.

src/api.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 "src/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 5457 matching lines @@
   CHECK(resource && resource->data());
   i::Handle<i::String> result = NewExternalStringHandle(i_isolate, resource);
   i_isolate->heap()->external_string_table()->AddString(*result);
   return Utils::ToLocal(result);
 }
 
 
 bool v8::String::MakeExternal(v8::String::ExternalStringResource* resource) {
   i::Handle<i::String> obj = Utils::OpenHandle(this);
   i::Isolate* isolate = obj->GetIsolate();
-  if (i::StringShape(*obj).IsExternalTwoByte()) {
+  if (i::StringShape(*obj).IsExternal()) {
     return false;  // Already an external string.
   }
   ENTER_V8(isolate);
   if (isolate->string_tracker()->IsFreshUnusedString(obj)) {
     return false;
   }
   if (isolate->heap()->IsInGCPostProcessing()) {
     return false;
   }
   CHECK(resource && resource->data());
 
   bool result = obj->MakeExternal(resource);
+  // Assert that if CanMakeExternal(), then externalizing actually succeeds.
+  DCHECK(!CanMakeExternal() || result);
   if (result) {
     DCHECK(obj->IsExternalString());
     isolate->heap()->external_string_table()->AddString(*obj);
   }
   return result;
 }
 
 
 Local<String> v8::String::NewExternal(
     Isolate* isolate,
     v8::String::ExternalAsciiStringResource* resource) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   EnsureInitializedForIsolate(i_isolate, "v8::String::NewExternal()");
   LOG_API(i_isolate, "String::NewExternal");
   ENTER_V8(i_isolate);
   CHECK(resource && resource->data());
   i::Handle<i::String> result =
       NewExternalAsciiStringHandle(i_isolate, resource);
   i_isolate->heap()->external_string_table()->AddString(*result);
   return Utils::ToLocal(result);
 }
 
 
 bool v8::String::MakeExternal(
     v8::String::ExternalAsciiStringResource* resource) {
   i::Handle<i::String> obj = Utils::OpenHandle(this);
   i::Isolate* isolate = obj->GetIsolate();
-  if (i::StringShape(*obj).IsExternalTwoByte()) {
+  if (i::StringShape(*obj).IsExternal()) {
     return false;  // Already an external string.
   }
   ENTER_V8(isolate);
   if (isolate->string_tracker()->IsFreshUnusedString(obj)) {
     return false;
   }
   if (isolate->heap()->IsInGCPostProcessing()) {
     return false;
   }
   CHECK(resource && resource->data());
 
   bool result = obj->MakeExternal(resource);
+  // Assert that if CanMakeExternal(), then externalizing actually succeeds.
+  DCHECK(!CanMakeExternal() || result);
   if (result) {
     DCHECK(obj->IsExternalString());
     isolate->heap()->external_string_table()->AddString(*obj);
   }
   return result;
 }
 
 
 bool v8::String::CanMakeExternal() {
   if (!internal::FLAG_clever_optimizations) return false;
@@ skipping 2093 matching lines @@
   Isolate* isolate = reinterpret_cast<Isolate*>(info.GetIsolate());
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 } }  // namespace v8::internal