src: move OnMessage to node_errors.cc

Rename the per-isolate message listener to `PerIsolateMessageListener`
and move it to `node_errors.cc` since it's part of the error
handling process. It also creates an external reference so it needs
to be exposed in `node_errors.h` for a snapshot builder to know.

PR-URL: https://github.com/nodejs/node/pull/27304
Reviewed-By: Anna Henningsen <anna@addaleax.net>

src/node_errors.cc

@@ -6,6 +6,7 @@
 #ifdef NODE_REPORT
 #include "node_report.h"
 #endif
+#include "node_process.h"
 #include "node_v8_platform-inl.h"
 
 namespace node {
@@ -739,6 +740,32 @@ const char* errno_string(int errorno) {
   }
 }
 
+void PerIsolateMessageListener(Local<Message> message, Local<Value> error) {
+  Isolate* isolate = message->GetIsolate();
+  switch (message->ErrorLevel()) {
+    case Isolate::MessageErrorLevel::kMessageWarning: {
+      Environment* env = Environment::GetCurrent(isolate);
+      if (!env) {
+        break;
+      }
+      Utf8Value filename(isolate, message->GetScriptOrigin().ResourceName());
+      // (filename):(line) (message)
+      std::stringstream warning;
+      warning << *filename;
+      warning << ":";
+      warning << message->GetLineNumber(env->context()).FromMaybe(-1);
+      warning << " ";
+      v8::String::Utf8Value msg(isolate, message->Get());
+      warning << *msg;
+      USE(ProcessEmitWarningGeneric(env, warning.str().c_str(), "V8"));
+      break;
+    }
+    case Isolate::MessageErrorLevel::kMessageError:
+      FatalException(isolate, error, message);
+      break;
+  }
+}
+
 }  // namespace errors
 
 void DecorateErrorStack(Environment* env,