Kill child process and close pty on exit

- Adds kill() method to LibuvUtils.
- Adds close() method to Pipe.

addons/godot_xterm/native/src/pipe.cpp

@@ -31,7 +31,7 @@ void Pipe::_register_methods() {
 }
 
 Pipe::Pipe() {}
-Pipe::~Pipe() {}
+Pipe::~Pipe() { close(); }
 
 void Pipe::_init() {}
 
@@ -39,6 +39,8 @@ void _poll_connection();
 
 void _read_cb(uv_stream_t *handle, ssize_t nread, const uv_buf_t *buf);
 
+void _close_cb(uv_handle_t *handle);
+
 void _write_cb(uv_write_t *req, int status);
 
 void _alloc_buffer(uv_handle_t *handle, size_t suggested_size, uv_buf_t *buf);
@@ -56,6 +58,11 @@ godot_error Pipe::open(int fd, bool ipc = false) {
   return GODOT_OK;
 }
 
+void Pipe::close() {
+  uv_close((uv_handle_t *)&handle, NULL);
+  uv_run(uv_default_loop(), UV_RUN_NOWAIT);
+}
+
 godot_error Pipe::write(String p_data) {
   char *s = p_data.alloc_c_string();
   ULONG len = strlen(s);
@@ -88,10 +95,10 @@ void _read_cb(uv_stream_t *handle, ssize_t nread, const uv_buf_t *buf) {
     switch (nread) {
     case UV_EOF:
       // Normal after shell exits.
-      return;
     case UV_EIO:
       // Can happen when the process exits.
       // As long as PTY has caught it, we should be fine.
+      uv_read_stop(handle);
       return;
     default:
       UV_ERR_PRINT(nread);