use lua_clonefunction for load lua file

3rd/lua/lauxlib.c

@@ -638,7 +638,7 @@ static int skipcomment (LoadF *lf, int *cp) {
 }
 
 
-LUALIB_API int luaL_loadfilex (lua_State *L, const char *filename,
+static int luaL_loadfilex_ (lua_State *L, const char *filename,
                                              const char *mode) {
   LoadF lf;
   int status, readstatus;
@@ -970,3 +970,123 @@ LUALIB_API void luaL_checkversion_ (lua_State *L, lua_Number ver, size_t sz) {
                   ver, *v);
 }
 
+// use clonefunction
+
+#define LOCK(q) while (__sync_lock_test_and_set(&(q)->lock,1)) {}
+#define UNLOCK(q) __sync_lock_release(&(q)->lock);
+
+struct codecache {
+	int lock;
+	lua_State *L;
+};
+
+static struct codecache CC = { 0 , NULL };
+
+static void
+clearcache() {
+	if (CC.L == NULL)
+		return;
+	LOCK(&CC)
+		lua_close(CC.L);
+		CC.L = luaL_newstate();
+	UNLOCK(&CC)
+}
+
+static void
+init() {
+	CC.lock = 0;
+	CC.L = luaL_newstate();
+}
+
+static const void *
+load(const char *key) {
+  if (CC.L == NULL)
+    return NULL;
+  LOCK(&CC)
+    lua_State *L = CC.L;
+    lua_pushstring(L, key);
+    lua_rawget(L, LUA_REGISTRYINDEX);
+    const void * result = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+  UNLOCK(&CC)
+
+  return result;
+}
+
+static const void *
+save(const char *key, const void * proto) {
+  lua_State *L;
+  const void * result = NULL;
+
+  LOCK(&CC)
+    if (CC.L == NULL) {
+      init();
+      L = CC.L;
+    } else {
+      L = CC.L;
+      lua_pushstring(L, key);
+      lua_pushvalue(L, -1);
+      lua_rawget(L, LUA_REGISTRYINDEX);
+      result = lua_touserdata(L, -1); /* stack: key oldvalue */
+      if (result == NULL) {
+        lua_pop(L,1);
+        lua_pushlightuserdata(L, (void *)proto);
+        lua_rawset(L, LUA_REGISTRYINDEX);
+      } else {
+        lua_pop(L,2);
+      }
+    }
+  UNLOCK(&CC)
+  return result;
+}
+
+LUALIB_API int luaL_loadfilex (lua_State *L, const char *filename,
+                                             const char *mode) {
+  const void * proto = load(filename);
+  if (proto) {
+    lua_clonefunction(L, proto);
+    return LUA_OK;
+  }
+  lua_State * eL = luaL_newstate();
+  if (eL == NULL) {
+    lua_pushliteral(L, "New state failed");
+    return LUA_ERRMEM;
+  }
+  int err = luaL_loadfilex_(eL, filename, mode);
+  if (err != LUA_OK) {
+    size_t sz = 0;
+    const char * msg = lua_tolstring(eL, -1, &sz);
+    lua_pushlstring(L, msg, sz);
+    lua_close(eL);
+    return err;
+  }
+  proto = lua_topointer(eL, -1);
+  const void * oldv = save(filename, proto);
+  if (oldv) {
+    lua_close(eL);
+    lua_clonefunction(L, oldv);
+  } else {
+    lua_clonefunction(L, proto);
+    /* Never close it. notice: memory leak */
+  }
+
+  return LUA_OK;
+}
+
+static int
+cache_clear(lua_State *L) {
+	(void)(L);
+	clearcache();
+	return 0;
+}
+
+LUAMOD_API int luaopen_cache(lua_State *L) {
+	luaL_Reg l[] = {
+		{ "clear", cache_clear },
+		{ NULL, NULL },
+	};
+	luaL_newlib(L,l);
+	lua_getglobal(L, "loadfile");
+	lua_setfield(L, -2, "loadfile");
+	return 1;
+}