[Minor] Allow to require some Lua function in C

diff --git a/src/lua/lua_common.c b/src/lua/lua_common.c
index b4493168207b7e1f6c3710a9508d1bc174f64436..f484c02b930295cdccb3796d4bc576b7b8b269f7 100644 (file)
--- a/src/lua/lua_common.c
+++ b/src/lua/lua_common.c
@@ -1897,3 +1897,49 @@ rspamd_lua_add_ref_dtor (lua_State *L, rspamd_mempool_t *pool,
                rspamd_mempool_add_destructor (pool, rspamd_lua_ref_dtor, cbdata);
        }
 }
+
+gboolean
+rspamd_lua_require_function (lua_State *L, const gchar *modname,
+               const gchar *funcname)
+{
+       gint table_pos;
+
+       lua_getglobal (L, "require");
+
+       if (lua_isnil (L, -1)) {
+               lua_pop (L, 1);
+
+               return FALSE;
+       }
+
+       lua_pushstring (L, modname);
+
+       /* Now try to call */
+       if (lua_pcall (L, 1, 1, 0) != 0) {
+               lua_pop (L, 1);
+
+               return FALSE;
+       }
+
+       /* Now we should have a table with results */
+       if (!lua_istable (L, -1)) {
+               lua_pop (L, 1);
+
+               return FALSE;
+       }
+
+       table_pos = lua_gettop (L);
+       lua_pushstring (L, funcname);
+       lua_gettable (L, -2);
+
+       if (lua_type (L, -1) == LUA_TFUNCTION) {
+               /* Remove table, preserve just a function */
+               lua_remove (L, table_pos);
+
+               return TRUE;
+       }
+
+       lua_pop (L, 2);
+
+       return FALSE;
+}

diff --git a/src/lua/lua_common.h b/src/lua/lua_common.h
index 0d95d909275492cc2696f5859df6daec271bd3fc..310a5504c127209eb23da09f9fb05a70279083b1 100644 (file)
--- a/src/lua/lua_common.h
+++ b/src/lua/lua_common.h
@@ -390,5 +390,15 @@ gboolean rspamd_lua_run_postloads (lua_State *L, struct rspamd_config *cfg,
 void rspamd_lua_add_ref_dtor (lua_State *L, rspamd_mempool_t *pool,
                gint ref);
 
+/**
+ * Tries to load some module using `require` and get some method from it
+ * @param L
+ * @param modname
+ * @param funcname
+ * @return TRUE if function exists in that module, the function is pushed in stack, otherwise stack is unchanged and FALSE is returned
+ */
+gboolean rspamd_lua_require_function (lua_State *L, const gchar *modname,
+               const gchar *funcname);
+
 #endif /* WITH_LUA */
 #endif /* RSPAMD_LUA_H */