guessHandleType in util.cpp

Summary:
guessHandleType functionality added in
util.cpp.

Reviewed By: neildhar

Differential Revision: D29746448

fbshipit-source-id: e731ebb762b459e6b4993464e3d4c948dd4ea8d3

tools/node-hermes/InternalBindings/util.cpp

@@ -12,11 +12,53 @@
 
 using namespace facebook;
 
+/// Returns the const char* equivalent of the uv_handle_type.
+static const char *handleType(uv_handle_type t) {
+  switch (t) {
+    case UV_TCP:
+      return "TCP";
+    case UV_TTY:
+      return "TTY";
+    case UV_UDP:
+      return "UDP";
+    case UV_FILE:
+      return "FILE";
+    case UV_NAMED_PIPE:
+      return "PIPE";
+    case UV_UNKNOWN_HANDLE:
+      return "UNKNOWN";
+    default:
+      llvm_unreachable("No other uv type exists.");
+  }
+}
+
+/// Given a file descriptor, this function will return the type it is. This
+/// function is just a wrapper for uv_guess_handle.
+static jsi::Value guessHandleType(
+    RuntimeState &rs,
+    const jsi::Value &,
+    const jsi::Value *args,
+    size_t count) {
+  jsi::Runtime &rt = rs.getRuntime();
+  if (count < 1) {
+    throw jsi::JSError(
+        rt,
+        "Not enough arguments being passed into synchronous guessHandleType call.");
+  }
+  int fd = args[0].asNumber();
+  uv_handle_type t = uv_guess_handle(fd);
+  const char *type = handleType(t);
+
+  return jsi::String::createFromAscii(rt, type);
+}
+
 /// Adds the 'util' object as a property of internalBinding.
 jsi::Value facebook::utilBinding(RuntimeState &rs) {
   jsi::Runtime &rt = rs.getRuntime();
   jsi::Object util{rt};
 
+  rs.defineJSFunction(guessHandleType, "guessHandleType", 1, util);
+
   rs.setInternalBindingProp("util", std::move(util));
   return rs.getInternalBindingProp("util");
 }

tools/node-hermes/nodelib/internal/bootstrap/switches/is_main_thread.js

@@ -33,8 +33,8 @@ var _require = require('internal/process/signal'),
 // process.on('removeListener', stopListeningIfSignal); // ---- keep the attachment of the wrappers above so that it's easier to ----
 // ----              compare the setups side-by-side                    -----
 
-// var _internalBinding = internalBinding('util'),
-//     guessHandleType = _internalBinding.guessHandleType;
+var _internalBinding = internalBinding('util'),
+    guessHandleType = _internalBinding.guessHandleType;
 
 function createWritableStdioStream(fd) {
   var stream; // Note stream._type is used for test-module-load-list.js