src: rework (mostly internal) functions to use Maybes

Rework all affected functions to use Maybes, thus improving error
handling substantially in internal functions, API functions as well as
utilities.

Co-authored-by: Michaël Zasso <targos@protonmail.com>
PR-URL: https://github.com/nodejs/node/pull/21935
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

10 files changed, 149 insertions, 117 deletions

diff --git a/src/node_buffer.cc b/src/node_buffer.cc
index 9a280f7c12..d2cb79d414 100644
--- a/src/node_buffer.cc
+++ b/src/node_buffer.cc
@@ -236,7 +236,9 @@ MaybeLocal<Object> New(Isolate* isolate,
                        enum encoding enc) {
   EscapableHandleScope scope(isolate);
 
-  const size_t length = StringBytes::Size(isolate, string, enc);
+  size_t length;
+  if (!StringBytes::Size(isolate, string, enc).To(&length))
+    return Local<Object>();
   size_t actual = 0;
   char* data = nullptr;
 
@@ -828,7 +830,8 @@ void IndexOfString(const FunctionCallbackInfo<Value>& args) {
   const size_t haystack_length = (enc == UCS2) ?
       ts_obj_length &~ 1 : ts_obj_length;  // NOLINT(whitespace/operators)
 
-  const size_t needle_length = StringBytes::Size(isolate, needle, enc);
+  size_t needle_length;
+  if (!StringBytes::Size(isolate, needle, enc).To(&needle_length)) return;
 
   int64_t opt_offset = IndexOfOffset(haystack_length,
                                      offset_i64,
@@ -868,7 +871,7 @@ void IndexOfString(const FunctionCallbackInfo<Value>& args) {
 
     if (IsBigEndian()) {
       StringBytes::InlineDecoder decoder;
-      decoder.Decode(env, needle, args[3], UCS2);
+      if (decoder.Decode(env, needle, args[3], UCS2).IsNothing()) return;
       const uint16_t* decoded_string =
           reinterpret_cast<const uint16_t*>(decoder.out());
 
diff --git a/src/node_crypto.cc b/src/node_crypto.cc
index 93c71001b3..8f77440530 100644
--- a/src/node_crypto.cc
+++ b/src/node_crypto.cc
@@ -3059,7 +3059,8 @@ void CipherBase::Update(const FunctionCallbackInfo<Value>& args) {
   // Only copy the data if we have to, because it's a string
   if (args[0]->IsString()) {
     StringBytes::InlineDecoder decoder;
-    if (!decoder.Decode(env, args[0].As<String>(), args[1], UTF8))
+    if (!decoder.Decode(env, args[0].As<String>(), args[1], UTF8)
+             .FromMaybe(false))
       return;
     r = cipher->Update(decoder.out(), decoder.size(), &out, &out_len);
   } else {
@@ -3249,7 +3250,8 @@ void Hmac::HmacUpdate(const FunctionCallbackInfo<Value>& args) {
   bool r = false;
   if (args[0]->IsString()) {
     StringBytes::InlineDecoder decoder;
-    if (decoder.Decode(env, args[0].As<String>(), args[1], UTF8)) {
+    if (decoder.Decode(env, args[0].As<String>(), args[1], UTF8)
+            .FromMaybe(false)) {
       r = hmac->HmacUpdate(decoder.out(), decoder.size());
     }
   } else {
@@ -3356,7 +3358,8 @@ void Hash::HashUpdate(const FunctionCallbackInfo<Value>& args) {
   bool r = true;
   if (args[0]->IsString()) {
     StringBytes::InlineDecoder decoder;
-    if (!decoder.Decode(env, args[0].As<String>(), args[1], UTF8)) {
+    if (!decoder.Decode(env, args[0].As<String>(), args[1], UTF8)
+             .FromMaybe(false)) {
       args.GetReturnValue().Set(false);
       return;
     }
diff --git a/src/node_encoding.cc b/src/node_encoding.cc
index d5c6bcab48..21d3275097 100644
--- a/src/node_encoding.cc
+++ b/src/node_encoding.cc
@@ -121,7 +121,7 @@ ssize_t DecodeBytes(Isolate* isolate,
                     enum encoding encoding) {
   HandleScope scope(isolate);
 
-  return StringBytes::Size(isolate, val, encoding);
+  return StringBytes::Size(isolate, val, encoding).FromMaybe(-1);
 }
 
 // Returns number of bytes written.
diff --git a/src/node_file.cc b/src/node_file.cc
index c1a936810f..4299945bbb 100644
--- a/src/node_file.cc
+++ b/src/node_file.cc
@@ -1819,7 +1819,7 @@ static void WriteString(const FunctionCallbackInfo<Value>& args) {
 
   if (is_async) {  // write(fd, string, pos, enc, req)
     CHECK_NOT_NULL(req_wrap_async);
-    len = StringBytes::StorageSize(env->isolate(), value, enc);
+    if (!StringBytes::StorageSize(env->isolate(), value, enc).To(&len)) return;
     FSReqBase::FSReqBuffer& stack_buffer =
         req_wrap_async->Init("write", len, enc);
     // StorageSize may return too large a char, so correct the actual length
@@ -1847,7 +1847,8 @@ static void WriteString(const FunctionCallbackInfo<Value>& args) {
     FSReqWrapSync req_wrap_sync;
     FSReqBase::FSReqBuffer stack_buffer;
     if (buf == nullptr) {
-      len = StringBytes::StorageSize(env->isolate(), value, enc);
+      if (!StringBytes::StorageSize(env->isolate(), value, enc).To(&len))
+        return;
       stack_buffer.AllocateSufficientStorage(len + 1);
       // StorageSize may return too large a char, so correct the actual length
       // by the write size
diff --git a/src/spawn_sync.cc b/src/spawn_sync.cc
index ba29aaeef0..77449b9569 100644
--- a/src/spawn_sync.cc
+++ b/src/spawn_sync.cc
@@ -37,7 +37,11 @@ using v8::FunctionCallbackInfo;
 using v8::HandleScope;
 using v8::Integer;
 using v8::Isolate;
+using v8::Just;
 using v8::Local;
+using v8::Maybe;
+using v8::MaybeLocal;
+using v8::Nothing;
 using v8::Null;
 using v8::Number;
 using v8::Object;
@@ -372,7 +376,8 @@ void SyncProcessRunner::Spawn(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
   env->PrintSyncTrace();
   SyncProcessRunner p(env);
-  Local<Value> result = p.Run(args[0]);
+  Local<Value> result;
+  if (!p.Run(args[0]).ToLocal(&result)) return;
   args.GetReturnValue().Set(result);
 }
 
@@ -430,22 +435,21 @@ Environment* SyncProcessRunner::env() const {
   return env_;
 }
 
-
-Local<Object> SyncProcessRunner::Run(Local<Value> options) {
+MaybeLocal<Object> SyncProcessRunner::Run(Local<Value> options) {
   EscapableHandleScope scope(env()->isolate());
 
   CHECK_EQ(lifecycle_, kUninitialized);
 
-  TryInitializeAndRunLoop(options);
+  Maybe<bool> r = TryInitializeAndRunLoop(options);
   CloseHandlesAndDeleteLoop();
+  if (r.IsNothing()) return MaybeLocal<Object>();
 
   Local<Object> result = BuildResultObject();
 
   return scope.Escape(result);
 }
 
-
-void SyncProcessRunner::TryInitializeAndRunLoop(Local<Value> options) {
+Maybe<bool> SyncProcessRunner::TryInitializeAndRunLoop(Local<Value> options) {
   int r;
 
   // There is no recovery from failure inside TryInitializeAndRunLoop - the
@@ -454,18 +458,24 @@ void SyncProcessRunner::TryInitializeAndRunLoop(Local<Value> options) {
   lifecycle_ = kInitialized;
 
   uv_loop_ = new uv_loop_t;
-  if (uv_loop_ == nullptr)
-    return SetError(UV_ENOMEM);
+  if (uv_loop_ == nullptr) {
+    SetError(UV_ENOMEM);
+    return Just(false);
+  }
   CHECK_EQ(uv_loop_init(uv_loop_), 0);
 
-  r = ParseOptions(options);
-  if (r < 0)
-    return SetError(r);
+  if (!ParseOptions(options).To(&r)) return Nothing<bool>();
+  if (r < 0) {
+    SetError(r);
+    return Just(false);
+  }
 
   if (timeout_ > 0) {
     r = uv_timer_init(uv_loop_, &uv_timer_);
-    if (r < 0)
-      return SetError(r);
+    if (r < 0) {
+      SetError(r);
+      return Just(false);
+    }
 
     uv_unref(reinterpret_cast<uv_handle_t*>(&uv_timer_));
 
@@ -477,22 +487,28 @@ void SyncProcessRunner::TryInitializeAndRunLoop(Local<Value> options) {
     // which implicitly stops it, so there is no risk that the timeout callback
     // runs when the process didn't start.
     r = uv_timer_start(&uv_timer_, KillTimerCallback, timeout_, 0);
-    if (r < 0)
-      return SetError(r);
+    if (r < 0) {
+      SetError(r);
+      return Just(false);
+    }
   }
 
   uv_process_options_.exit_cb = ExitCallback;
   r = uv_spawn(uv_loop_, &uv_process_, &uv_process_options_);
-  if (r < 0)
-    return SetError(r);
+  if (r < 0) {
+    SetError(r);
+    return Just(false);
+  }
   uv_process_.data = this;
 
   for (uint32_t i = 0; i < stdio_count_; i++) {
     SyncProcessStdioPipe* h = stdio_pipes_[i].get();
     if (h != nullptr) {
       r = h->Start();
-      if (r < 0)
-        return SetPipeError(r);
+      if (r < 0) {
+        SetPipeError(r);
+        return Just(false);
+      }
     }
   }
 
@@ -503,6 +519,7 @@ void SyncProcessRunner::TryInitializeAndRunLoop(Local<Value> options) {
 
   // If we get here the process should have exited.
   CHECK_GE(exit_status_, 0);
+  return Just(true);
 }
 
 
@@ -724,46 +741,41 @@ Local<Array> SyncProcessRunner::BuildOutputArray() {
   return scope.Escape(js_output);
 }
 
-
-int SyncProcessRunner::ParseOptions(Local<Value> js_value) {
+Maybe<int> SyncProcessRunner::ParseOptions(Local<Value> js_value) {
   HandleScope scope(env()->isolate());
   int r;
 
-  if (!js_value->IsObject())
-    return UV_EINVAL;
+  if (!js_value->IsObject()) return Just<int>(UV_EINVAL);
 
   Local<Context> context = env()->context();
   Local<Object> js_options = js_value.As<Object>();
 
   Local<Value> js_file =
       js_options->Get(context, env()->file_string()).ToLocalChecked();
-  r = CopyJsString(js_file, &file_buffer_);
-  if (r < 0)
-    return r;
+  if (!CopyJsString(js_file, &file_buffer_).To(&r)) return Nothing<int>();
+  if (r < 0) return Just(r);
   uv_process_options_.file = file_buffer_;
 
   Local<Value> js_args =
       js_options->Get(context, env()->args_string()).ToLocalChecked();
-  r = CopyJsStringArray(js_args, &args_buffer_);
-  if (r < 0)
-    return r;
+  if (!CopyJsStringArray(js_args, &args_buffer_).To(&r)) return Nothing<int>();
+  if (r < 0) return Just(r);
   uv_process_options_.args = reinterpret_cast<char**>(args_buffer_);
 
   Local<Value> js_cwd =
       js_options->Get(context, env()->cwd_string()).ToLocalChecked();
   if (IsSet(js_cwd)) {
-    r = CopyJsString(js_cwd, &cwd_buffer_);
-    if (r < 0)
-      return r;
+    if (!CopyJsString(js_cwd, &cwd_buffer_).To(&r)) return Nothing<int>();
+    if (r < 0) return Just(r);
     uv_process_options_.cwd = cwd_buffer_;
   }
 
   Local<Value> js_env_pairs =
       js_options->Get(context, env()->env_pairs_string()).ToLocalChecked();
   if (IsSet(js_env_pairs)) {
-    r = CopyJsStringArray(js_env_pairs, &env_buffer_);
-    if (r < 0)
-      return r;
+    if (!CopyJsStringArray(js_env_pairs, &env_buffer_).To(&r))
+      return Nothing<int>();
+    if (r < 0) return Just(r);
 
     uv_process_options_.env = reinterpret_cast<char**>(env_buffer_);
   }
@@ -827,10 +839,9 @@ int SyncProcessRunner::ParseOptions(Local<Value> js_value) {
   Local<Value> js_stdio =
       js_options->Get(context, env()->stdio_string()).ToLocalChecked();
   r = ParseStdioOptions(js_stdio);
-  if (r < 0)
-    return r;
+  if (r < 0) return Just(r);
 
-  return 0;
+  return Just(0);
 }
 
 
@@ -970,9 +981,8 @@ bool SyncProcessRunner::IsSet(Local<Value> value) {
   return !value->IsUndefined() && !value->IsNull();
 }
 
-
-int SyncProcessRunner::CopyJsString(Local<Value> js_value,
-                                    const char** target) {
+Maybe<int> SyncProcessRunner::CopyJsString(Local<Value> js_value,
+                                           const char** target) {
   Isolate* isolate = env()->isolate();
   Local<String> js_string;
   size_t size, written;
@@ -980,12 +990,14 @@ int SyncProcessRunner::CopyJsString(Local<Value> js_value,
 
   if (js_value->IsString())
     js_string = js_value.As<String>();
-  else
-    js_string = js_value->ToString(env()->isolate()->GetCurrentContext())
-                    .ToLocalChecked();
+  else if (!js_value->ToString(env()->isolate()->GetCurrentContext())
+                .ToLocal(&js_string))
+    return Nothing<int>();
 
   // Include space for null terminator byte.
-  size = StringBytes::StorageSize(isolate, js_string, UTF8) + 1;
+  if (!StringBytes::StorageSize(isolate, js_string, UTF8).To(&size))
+    return Nothing<int>();
+  size += 1;
 
   buffer = new char[size];
 
@@ -993,12 +1005,11 @@ int SyncProcessRunner::CopyJsString(Local<Value> js_value,
   buffer[written] = '\0';
 
   *target = buffer;
-  return 0;
+  return Just(0);
 }
 
-
-int SyncProcessRunner::CopyJsStringArray(Local<Value> js_value,
-                                         char** target) {
+Maybe<int> SyncProcessRunner::CopyJsStringArray(Local<Value> js_value,
+                                                char** target) {
   Isolate* isolate = env()->isolate();
   Local<Array> js_array;
   uint32_t length;
@@ -1006,8 +1017,7 @@ int SyncProcessRunner::CopyJsStringArray(Local<Value> js_value,
   char** list;
   char* buffer;
 
-  if (!js_value->IsArray())
-    return UV_EINVAL;
+  if (!js_value->IsArray()) return Just<int>(UV_EINVAL);
 
   Local<Context> context = env()->context();
   js_array = js_value.As<Array>()->Clone().As<Array>();
@@ -1025,15 +1035,22 @@ int SyncProcessRunner::CopyJsStringArray(Local<Value> js_value,
   for (uint32_t i = 0; i < length; i++) {
     auto value = js_array->Get(context, i).ToLocalChecked();
 
-    if (!value->IsString())
+    if (!value->IsString()) {
+      Local<String> string;
+      if (!value->ToString(env()->isolate()->GetCurrentContext())
+               .ToLocal(&string))
+        return Nothing<int>();
       js_array
           ->Set(context,
                 i,
                 value->ToString(env()->isolate()->GetCurrentContext())
                     .ToLocalChecked())
           .FromJust();
+    }
 
-    data_size += StringBytes::StorageSize(isolate, value, UTF8) + 1;
+    Maybe<size_t> maybe_size = StringBytes::StorageSize(isolate, value, UTF8);
+    if (maybe_size.IsNothing()) return Nothing<int>();
+    data_size += maybe_size.FromJust() + 1;
     data_size = ROUND_UP(data_size, sizeof(void*));
   }
 
@@ -1057,7 +1074,7 @@ int SyncProcessRunner::CopyJsStringArray(Local<Value> js_value,
   list[length] = nullptr;
 
   *target = buffer;
-  return 0;
+  return Just(0);
 }
 
 
diff --git a/src/spawn_sync.h b/src/spawn_sync.h
index fed1453296..adb2618cc5 100644
--- a/src/spawn_sync.h
+++ b/src/spawn_sync.h
@@ -152,8 +152,8 @@ class SyncProcessRunner {
 
   inline Environment* env() const;
 
-  v8::Local<v8::Object> Run(v8::Local<v8::Value> options);
-  void TryInitializeAndRunLoop(v8::Local<v8::Value> options);
+  v8::MaybeLocal<v8::Object> Run(v8::Local<v8::Value> options);
+  v8::Maybe<bool> TryInitializeAndRunLoop(v8::Local<v8::Value> options);
   void CloseHandlesAndDeleteLoop();
 
   void CloseStdioPipes();
@@ -172,7 +172,7 @@ class SyncProcessRunner {
   v8::Local<v8::Object> BuildResultObject();
   v8::Local<v8::Array> BuildOutputArray();
 
-  int ParseOptions(v8::Local<v8::Value> js_value);
+  v8::Maybe<int> ParseOptions(v8::Local<v8::Value> js_value);
   int ParseStdioOptions(v8::Local<v8::Value> js_value);
   int ParseStdioOption(int child_fd, v8::Local<v8::Object> js_stdio_option);
 
@@ -184,8 +184,10 @@ class SyncProcessRunner {
   inline int AddStdioInheritFD(uint32_t child_fd, int inherit_fd);
 
   static bool IsSet(v8::Local<v8::Value> value);
-  int CopyJsString(v8::Local<v8::Value> js_value, const char** target);
-  int CopyJsStringArray(v8::Local<v8::Value> js_value, char** target);
+  v8::Maybe<int> CopyJsString(v8::Local<v8::Value> js_value,
+                              const char** target);
+  v8::Maybe<int> CopyJsStringArray(v8::Local<v8::Value> js_value,
+                                   char** target);
 
   static void ExitCallback(uv_process_t* handle,
                            int64_t exit_status,
diff --git a/src/stream_base.cc b/src/stream_base.cc
index bb46ea1feb..f429f3593f 100644
--- a/src/stream_base.cc
+++ b/src/stream_base.cc
@@ -108,11 +108,12 @@ int StreamBase::Writev(const FunctionCallbackInfo<Value>& args) {
       enum encoding encoding = ParseEncoding(env->isolate(),
                                              chunks->Get(i * 2 + 1));
       size_t chunk_size;
-      if (encoding == UTF8 && string->Length() > 65535)
-        chunk_size = StringBytes::Size(env->isolate(), string, encoding);
-      else
-        chunk_size = StringBytes::StorageSize(env->isolate(), string, encoding);
-
+      if (encoding == UTF8 && string->Length() > 65535 &&
+          !StringBytes::Size(env->isolate(), string, encoding).To(&chunk_size))
+        return 0;
+      else if (!StringBytes::StorageSize(env->isolate(), string, encoding)
+                    .To(&chunk_size))
+        return 0;
       storage_size += chunk_size;
     }
 
@@ -214,10 +215,12 @@ int StreamBase::WriteString(const FunctionCallbackInfo<Value>& args) {
   // For UTF8 strings that are very long, go ahead and take the hit for
   // computing their actual size, rather than tripling the storage.
   size_t storage_size;
-  if (enc == UTF8 && string->Length() > 65535)
-    storage_size = StringBytes::Size(env->isolate(), string, enc);
-  else
-    storage_size = StringBytes::StorageSize(env->isolate(), string, enc);
+  if (enc == UTF8 && string->Length() > 65535 &&
+      !StringBytes::Size(env->isolate(), string, enc).To(&storage_size))
+    return 0;
+  else if (!StringBytes::StorageSize(env->isolate(), string, enc)
+                .To(&storage_size))
+    return 0;
 
   if (storage_size > INT_MAX)
     return UV_ENOBUFS;
diff --git a/src/string_bytes.cc b/src/string_bytes.cc
index 82d699db9a..c38f368d41 100644
--- a/src/string_bytes.cc
+++ b/src/string_bytes.cc
@@ -41,8 +41,11 @@ namespace node {
 
 using v8::HandleScope;
 using v8::Isolate;
+using v8::Just;
 using v8::Local;
+using v8::Maybe;
 using v8::MaybeLocal;
+using v8::Nothing;
 using v8::String;
 using v8::Value;
 
@@ -399,19 +402,20 @@ bool StringBytes::IsValidString(Local<String> string,
 // Quick and dirty size calculation
 // Will always be at least big enough, but may have some extra
 // UTF8 can be as much as 3x the size, Base64 can have 1-2 extra bytes
-size_t StringBytes::StorageSize(Isolate* isolate,
-                                Local<Value> val,
-                                enum encoding encoding) {
+Maybe<size_t> StringBytes::StorageSize(Isolate* isolate,
+                                       Local<Value> val,
+                                       enum encoding encoding) {
   HandleScope scope(isolate);
   size_t data_size = 0;
   bool is_buffer = Buffer::HasInstance(val);
 
   if (is_buffer && (encoding == BUFFER || encoding == LATIN1)) {
-    return Buffer::Length(val);
+    return Just(Buffer::Length(val));
   }
 
-  Local<String> str =
-      val->ToString(isolate->GetCurrentContext()).ToLocalChecked();
+  Local<String> str;
+  if (!val->ToString(isolate->GetCurrentContext()).ToLocal(&str))
+    return Nothing<size_t>();
 
   switch (encoding) {
     case ASCII:
@@ -445,40 +449,40 @@ size_t StringBytes::StorageSize(Isolate* isolate,
       break;
   }
 
-  return data_size;
+  return Just(data_size);
 }
 
-
-size_t StringBytes::Size(Isolate* isolate,
-                         Local<Value> val,
-                         enum encoding encoding) {
+Maybe<size_t> StringBytes::Size(Isolate* isolate,
+                                Local<Value> val,
+                                enum encoding encoding) {
   HandleScope scope(isolate);
 
   if (Buffer::HasInstance(val) && (encoding == BUFFER || encoding == LATIN1))
-    return Buffer::Length(val);
+    return Just(Buffer::Length(val));
 
-  Local<String> str =
-      val->ToString(isolate->GetCurrentContext()).ToLocalChecked();
+  Local<String> str;
+  if (!val->ToString(isolate->GetCurrentContext()).ToLocal(&str))
+    return Nothing<size_t>();
 
   switch (encoding) {
     case ASCII:
     case LATIN1:
-      return str->Length();
+      return Just<size_t>(str->Length());
 
     case BUFFER:
     case UTF8:
-      return str->Utf8Length(isolate);
+      return Just<size_t>(str->Utf8Length(isolate));
 
     case UCS2:
-      return str->Length() * sizeof(uint16_t);
+      return Just(str->Length() * sizeof(uint16_t));
 
     case BASE64: {
       String::Value value(isolate, str);
-      return base64_decoded_size(*value, value.length());
+      return Just(base64_decoded_size(*value, value.length()));
     }
 
     case HEX:
-      return str->Length() / 2;
+      return Just<size_t>(str->Length() / 2);
   }
 
   UNREACHABLE();
diff --git a/src/string_bytes.h b/src/string_bytes.h
index 5f5fcd9fa0..8280e37987 100644
--- a/src/string_bytes.h
+++ b/src/string_bytes.h
@@ -35,29 +35,26 @@ class StringBytes {
  public:
   class InlineDecoder : public MaybeStackBuffer<char> {
    public:
-    inline bool Decode(Environment* env,
-                       v8::Local<v8::String> string,
-                       v8::Local<v8::Value> encoding,
-                       enum encoding _default) {
+    inline v8::Maybe<bool> Decode(Environment* env,
+                                  v8::Local<v8::String> string,
+                                  v8::Local<v8::Value> encoding,
+                                  enum encoding _default) {
       enum encoding enc = ParseEncoding(env->isolate(), encoding, _default);
       if (!StringBytes::IsValidString(string, enc)) {
         env->ThrowTypeError("Bad input string");
-        return false;
+        return v8::Just(false);
       }
 
-      const size_t storage = StringBytes::StorageSize(env->isolate(),
-                                                      string,
-                                                      enc);
+      size_t storage;
+      if (!StringBytes::StorageSize(env->isolate(), string, enc).To(&storage))
+        return v8::Nothing<bool>();
       AllocateSufficientStorage(storage);
-      const size_t length = StringBytes::Write(env->isolate(),
-                                               out(),
-                                               storage,
-                                               string,
-                                               enc);
+      const size_t length =
+          StringBytes::Write(env->isolate(), out(), storage, string, enc);
 
       // No zero terminator is included when using this method.
       SetLength(length);
-      return true;
+      return v8::Just(true);
     }
 
     inline size_t size() const { return length(); }
@@ -71,15 +68,15 @@ class StringBytes {
 
   // Fast, but can be 2 bytes oversized for Base64, and
   // as much as triple UTF-8 strings <= 65536 chars in length
-  static size_t StorageSize(v8::Isolate* isolate,
-                            v8::Local<v8::Value> val,
-                            enum encoding enc);
+  static v8::Maybe<size_t> StorageSize(v8::Isolate* isolate,
+                                       v8::Local<v8::Value> val,
+                                       enum encoding enc);
 
   // Precise byte count, but slightly slower for Base64 and
   // very much slower for UTF-8
-  static size_t Size(v8::Isolate* isolate,
-                     v8::Local<v8::Value> val,
-                     enum encoding enc);
+  static v8::Maybe<size_t> Size(v8::Isolate* isolate,
+                                v8::Local<v8::Value> val,
+                                enum encoding enc);
 
   // Write the bytes from the string or buffer into the char*
   // returns the number of bytes written, which will always be
diff --git a/src/util.cc b/src/util.cc
index b1b84d8f09..a0f0b0bf89 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -41,7 +41,9 @@ static void MakeUtf8String(Isolate* isolate,
   Local<String> string;
   if (!value->ToString(isolate->GetCurrentContext()).ToLocal(&string)) return;
 
-  const size_t storage = StringBytes::StorageSize(isolate, string, UTF8) + 1;
+  size_t storage;
+  if (!StringBytes::StorageSize(isolate, string, UTF8).To(&storage)) return;
+  storage += 1;
   target->AllocateSufficientStorage(storage);
   const int flags =
       String::NO_NULL_TERMINATION | String::REPLACE_INVALID_UTF8;