src: do proper StringBytes error handling

- Return `MaybeLocal`s from `StringBytes::Encode`
- Add an `error` out parameter to pass JS exceptions to the callers
  (instead of directly throwing)
- Simplify some of the string generation methods in `string_bytes.cc`
  by unifying the `EXTERN_APEX` logic
- Reduce usage of deprecated V8 APIs.
- Remove error handling logic from JS, the `buffer.*Slice()` methods
  now throw errors themselves.
- Left TODO comments for future semver-major error message
  improvements.

This paves the way for better error messages coming out of the
StringBytes methods.

Ref: https://github.com/nodejs/node/issues/3175
PR-URL: https://github.com/nodejs/node/pull/12765
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

1 files changed, 9 insertions, 5 deletions

diff --git a/src/fs_event_wrap.cc b/src/fs_event_wrap.cc
index a747f71c40..bc3b33027a 100644
--- a/src/fs_event_wrap.cc
+++ b/src/fs_event_wrap.cc
@@ -39,6 +39,7 @@ using v8::FunctionTemplate;
 using v8::HandleScope;
 using v8::Integer;
 using v8::Local;
+using v8::MaybeLocal;
 using v8::Object;
 using v8::String;
 using v8::Value;
@@ -187,17 +188,20 @@ void FSEventWrap::OnEvent(uv_fs_event_t* handle, const char* filename,
   };
 
   if (filename != nullptr) {
-    Local<Value> fn = StringBytes::Encode(env->isolate(),
-                                          filename,
-                                          wrap->encoding_);
+    Local<Value> error;
+    MaybeLocal<Value> fn = StringBytes::Encode(env->isolate(),
+                                               filename,
+                                               wrap->encoding_,
+                                               &error);
     if (fn.IsEmpty()) {
       argv[0] = Integer::New(env->isolate(), UV_EINVAL);
       argv[2] = StringBytes::Encode(env->isolate(),
                                     filename,
                                     strlen(filename),
-                                    BUFFER);
+                                    BUFFER,
+                                    &error).ToLocalChecked();
     } else {
-      argv[2] = fn;
+      argv[2] = fn.ToLocalChecked();
     }
   }