Verify a bit more about external 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 5281 matching lines @@
   i::Handle<i::String> str = Utils::OpenHandle(this);
   return i::StringShape(*str).IsExternalTwoByte();
 }
 
 
 bool v8::String::IsExternalOneByte() const {
   i::Handle<i::String> str = Utils::OpenHandle(this);
   return i::StringShape(*str).IsExternalOneByte();
 }
 
-
-void v8::String::VerifyExternalStringResource(
-    v8::String::ExternalStringResource* value) const {
+void v8::String::VerifyExternalStringResourceBase(
+    const v8::String::ExternalStringResourceBase* value,
+    Encoding encoding) const {
   i::Handle<i::String> str = Utils::OpenHandle(this);
-  const v8::String::ExternalStringResource* expected;
-  if (i::StringShape(*str).IsExternalTwoByte()) {
-    const void* resource =
-        i::Handle<i::ExternalTwoByteString>::cast(str)->resource();
-    expected = reinterpret_cast<const ExternalStringResource*>(resource);
+  const v8::String::ExternalStringResourceBase* expected = nullptr;
+  Encoding expected_encoding;
+  const void* actual_data_ptr = nullptr;
+  size_t actual_length = 0;
+  if (i::StringShape(*str).IsExternalOneByte()) {
+    const ExternalOneByteStringResource* resource =
+        reinterpret_cast<const ExternalOneByteStringResource*>(
+            i::Handle<i::ExternalOneByteString>::cast(str)->resource());
+    expected = static_cast<const ExternalStringResourceBase*>(resource);
+    expected_encoding = ONE_BYTE_ENCODING;
+    actual_data_ptr = reinterpret_cast<const void*>(resource->data());
+    actual_length = resource->length();
+  } else if (i::StringShape(*str).IsExternalTwoByte()) {
+    const ExternalStringResource* resource =
+        reinterpret_cast<const ExternalStringResource*>(
+            i::Handle<i::ExternalTwoByteString>::cast(str)->resource());
+    expected = static_cast<const ExternalStringResourceBase*>(resource);
+    expected_encoding = TWO_BYTE_ENCODING;
+    actual_data_ptr = reinterpret_cast<const void*>(resource->data());
+    actual_length = resource->length();
   } else {
-    expected = NULL;
-  }
-  CHECK_EQ(expected, value);
-}
-
-void v8::String::VerifyExternalStringResourceBase(
-    v8::String::ExternalStringResourceBase* value, Encoding encoding) const {
-  i::Handle<i::String> str = Utils::OpenHandle(this);
-  const v8::String::ExternalStringResourceBase* expected;
-  Encoding expectedEncoding;
-  if (i::StringShape(*str).IsExternalOneByte()) {
-    const void* resource =
-        i::Handle<i::ExternalOneByteString>::cast(str)->resource();
-    expected = reinterpret_cast<const ExternalStringResourceBase*>(resource);
-    expectedEncoding = ONE_BYTE_ENCODING;
-  } else if (i::StringShape(*str).IsExternalTwoByte()) {
-    const void* resource =
-        i::Handle<i::ExternalTwoByteString>::cast(str)->resource();
-    expected = reinterpret_cast<const ExternalStringResourceBase*>(resource);
-    expectedEncoding = TWO_BYTE_ENCODING;
-  } else {
-    expected = NULL;
-    expectedEncoding =
+    expected_encoding =
         str->IsOneByteRepresentation() ? ONE_BYTE_ENCODING : TWO_BYTE_ENCODING;
   }
   CHECK_EQ(expected, value);
-  CHECK_EQ(expectedEncoding, encoding);
+  CHECK_EQ(expected_encoding, encoding);
+  CHECK_EQ(i::Handle<i::ExternalString>::cast(str)->resource_data(),
+           actual_data_ptr);
+  CHECK_EQ(str->length(), static_cast<int>(actual_length));
 }
 
+
 const v8::String::ExternalOneByteStringResource*
 v8::String::GetExternalOneByteStringResource() const {
   i::Handle<i::String> str = Utils::OpenHandle(this);
+  const ExternalOneByteStringResource* result;
   if (i::StringShape(*str).IsExternalOneByte()) {
     const void* resource =
         i::Handle<i::ExternalOneByteString>::cast(str)->resource();
-    return reinterpret_cast<const ExternalOneByteStringResource*>(resource);
+    result = reinterpret_cast<const ExternalOneByteStringResource*>(resource);
   } else {
-    return NULL;
+    result = nullptr;
   }
+#ifdef V8_ENABLE_CHECKS
+  VerifyExternalStringResourceBase(result, ONE_BYTE_ENCODING);
+#endif
+  return result;
 }
 
 
 Local<Value> Symbol::Name() const {
   i::Handle<i::Symbol> sym = Utils::OpenHandle(this);
   i::Handle<i::Object> name(sym->name(), sym->GetIsolate());
   return Utils::ToLocal(name);
 }
 
 
@@ skipping 556 matching lines @@
   // TODO(dcarney): throw a context free exception.
   if (resource->length() > static_cast<size_t>(i::String::kMaxLength)) {
     return MaybeLocal<String>();
   }
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   ENTER_V8(i_isolate);
   LOG_API(i_isolate, "String::NewExternalTwoByte");
   i::Handle<i::String> string = i_isolate->factory()
                                     ->NewExternalStringFromTwoByte(resource)
                                     .ToHandleChecked();
+#ifdef V8_ENABLE_CHECKS
+  Utils::ToLocal(string)
+      ->VerifyExternalStringResourceBase(resource, TWO_BYTE_ENCODING);
+#endif
   i_isolate->heap()->external_string_table()->AddString(*string);
   return Utils::ToLocal(string);
 }
 
 
 Local<String> v8::String::NewExternal(
     Isolate* isolate, v8::String::ExternalStringResource* resource) {
   RETURN_TO_LOCAL_UNCHECKED(NewExternalTwoByte(isolate, resource), String);
 }
 
 
 MaybeLocal<String> v8::String::NewExternalOneByte(
     Isolate* isolate, v8::String::ExternalOneByteStringResource* resource) {
   CHECK(resource && resource->data());
   // TODO(dcarney): throw a context free exception.
   if (resource->length() > static_cast<size_t>(i::String::kMaxLength)) {
     return MaybeLocal<String>();
   }
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   ENTER_V8(i_isolate);
   LOG_API(i_isolate, "String::NewExternalOneByte");
   i::Handle<i::String> string = i_isolate->factory()
                                     ->NewExternalStringFromOneByte(resource)
                                     .ToHandleChecked();
   i_isolate->heap()->external_string_table()->AddString(*string);
+#ifdef V8_ENABLE_CHECKS
+  Utils::ToLocal(string)
+      ->VerifyExternalStringResourceBase(resource, ONE_BYTE_ENCODING);
+#endif
   return Utils::ToLocal(string);
 }
 
 
 Local<String> v8::String::NewExternal(
     Isolate* isolate, v8::String::ExternalOneByteStringResource* resource) {
   RETURN_TO_LOCAL_UNCHECKED(NewExternalOneByte(isolate, resource), String);
 }
 
 
@@ skipping 10 matching lines @@
   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());
+#ifdef V8_ENABLE_CHECKS
+    VerifyExternalStringResourceBase(resource, TWO_BYTE_ENCODING);
+#endif
     isolate->heap()->external_string_table()->AddString(*obj);
   }
   return result;
 }
 
 
 bool v8::String::MakeExternal(
     v8::String::ExternalOneByteStringResource* resource) {
   i::Handle<i::String> obj = Utils::OpenHandle(this);
   i::Isolate* isolate = obj->GetIsolate();
   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());
+#ifdef V8_ENABLE_CHECKS
+    VerifyExternalStringResourceBase(resource, ONE_BYTE_ENCODING);
+#endif
     isolate->heap()->external_string_table()->AddString(*obj);
   }
   return result;
 }
 
 
 bool v8::String::CanMakeExternal() {
   i::Handle<i::String> obj = Utils::OpenHandle(this);
   i::Isolate* isolate = obj->GetIsolate();
 
@@ skipping 2371 matching lines @@
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 }  // namespace internal
 }  // namespace v8