move lua/ up to the top level directory where python/ lives

PiperOrigin-RevId: 486786325
diff --git a/lua/main.c b/lua/main.c
new file mode 100644
index 0000000..9daf509
--- /dev/null
+++ b/lua/main.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2009-2021, Google LLC
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of Google LLC nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL Google LLC BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <lauxlib.h>
+#include <lua.h>
+#include <lualib.h>
+#include <signal.h>
+
+#include "lua/upb.h"
+
+lua_State* L;
+
+static void interrupt(lua_State* L, lua_Debug* ar) {
+  (void)ar;
+  lua_sethook(L, NULL, 0, 0);
+  luaL_error(L, "SIGINT");
+}
+
+static void sighandler(int i) {
+  fprintf(stderr, "Signal!\n");
+  signal(i, SIG_DFL);
+  lua_sethook(L, interrupt, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);
+}
+
+const char* init =
+    "package.preload['lupb'] = ... "
+    "package.path = '"
+    "./?.lua;"
+    "./third_party/lunit/?.lua;"
+    "external/com_google_protobuf/?.lua;"
+    "external/com_google_protobuf/src/?.lua;"
+    "bazel-bin/?.lua;"
+    "bazel-bin/external/com_google_protobuf/src/?.lua;"
+    "bazel-bin/external/com_google_protobuf/?.lua;"
+    "bazel-bin/external/com_google_protobuf/?.lua;"
+    "lua/?.lua"
+    "'";
+
+int main(int argc, char** argv) {
+  int ret = 0;
+  L = luaL_newstate();
+  luaL_openlibs(L);
+  lua_pushcfunction(L, luaopen_lupb);
+  ret = luaL_loadstring(L, init);
+  lua_pushcfunction(L, luaopen_lupb);
+
+  signal(SIGINT, sighandler);
+  ret = ret || lua_pcall(L, 1, LUA_MULTRET, 0) ||
+        luaL_dofile(L, "lua/test_upb.lua");
+  signal(SIGINT, SIG_DFL);
+
+  if (ret) {
+    fprintf(stderr, "error testing Lua: %s\n", lua_tostring(L, -1));
+    ret = 1;
+  }
+
+  lua_close(L);
+  return ret;
+}