Move lua_pcall wrapper function to utils

Author: mmd-osm

src/lua-utils.cpp

@@ -135,3 +135,34 @@ bool luaX_get_table_bool(lua_State *lua_state, char const *key, int table_index,
     throw std::runtime_error{
         "{} must contain a '{}' boolean field"_format(error_msg, key)};
 }
+
+static int pcall_error_traceback_handler(lua_State *lua_state)
+{
+    assert(lua_state);
+
+    char const *msg = lua_tostring(lua_state, 1);
+    if (msg == nullptr) { // is error object not a string?
+        if (luaL_callmeta(lua_state, 1,
+                          "__tostring") && // does it have a metamethod
+            lua_type(lua_state, -1) == LUA_TSTRING) { // that produces a string?
+            return 1;                                 // that is the message
+        } else {
+            msg = lua_pushfstring(lua_state, "(error object is a %s value)",
+                                  luaL_typename(lua_state, 1));
+        }
+    }
+    luaL_traceback(lua_state, lua_state, msg, 1); // append a standard traceback
+    return 1;                                     // return the traceback
+}
+
+// wrapper function for lua_pcall to include a stack traceback
+int luaX_pcall(lua_State *lua_state, int narg, int nres)
+{
+    int const base = lua_gettop(lua_state) - narg; // function index
+    lua_pushcfunction(lua_state,
+                      pcall_error_traceback_handler); // push message handler
+    lua_insert(lua_state, base); // put it under function and args
+    int const status = lua_pcall(lua_state, narg, nres, base);
+    lua_remove(lua_state, base); // remove message handler from the stack
+    return status;
+}

src/lua-utils.hpp

@@ -49,4 +49,6 @@ char const *luaX_get_table_string(lua_State *lua_state, char const *key,
 bool luaX_get_table_bool(lua_State *lua_state, char const *key, int table_index,
                          char const *error_msg, bool default_value);
 
+int luaX_pcall(lua_State *lua_state, int narg, int nres);
+
 #endif // OSM2PGSQL_FLEX_LUA_HPP

src/output-flex.cpp

@@ -983,35 +983,6 @@ void output_flex_t::add_row(table_connection_t *table_connection,
     }
 }
 
-static int msghandler(lua_State *lua_state)
-{
-    assert(lua_state);
-
-    char const *msg = lua_tostring(lua_state, 1);
-    if (msg == nullptr) {                                // is error object not a string?
-        if (luaL_callmeta(lua_state, 1, "__tostring") && // does it have a metamethod
-            lua_type(lua_state, -1) == LUA_TSTRING) {    // that produces a string?
-            return 1;                                    // that is the message
-        }
-        else {
-            msg = lua_pushfstring(lua_state, "(error object is a %s value)",
-                                  luaL_typename(lua_state, 1));
-        }
-    }
-    luaL_traceback(lua_state, lua_state, msg, 1); // append a standard traceback
-    return 1;                                     // return the traceback
-}
-
-int output_flex_t::do_pcall(int narg, int nres)
-{
-    int const base = lua_gettop(lua_state()) - narg; // function index
-    lua_pushcfunction(lua_state(), msghandler);      // push message handler
-    lua_insert(lua_state(), base);                   // put it under function and args
-    int status = lua_pcall(lua_state(), narg, nres, base);
-    lua_remove(lua_state(), base);                   // remove message handler from the stack
-    return status;
-}
-
 void output_flex_t::call_process_function(int index,
                                           osmium::OSMObject const &object)
 {
@@ -1025,7 +996,7 @@ void output_flex_t::call_process_function(int index,
         get_options()->extra_attributes); // the single argument
 
     luaX_set_context(lua_state(), this);
-    if (do_pcall(1, 0)) {
+    if (luaX_pcall(lua_state(), 1, 0)) {
         throw std::runtime_error{"Failed to execute lua processing function:"
                                  " {}"_format(lua_tostring(lua_state(), -1))};
     }

src/output-flex.hpp

@@ -100,7 +100,6 @@ class output_flex_t : public output_t
     void init_clone();
 
     void call_process_function(int index, osmium::OSMObject const &object);
-    int do_pcall(int narg, int nres);
 
     void init_lua(std::string const &filename);