lua_race.cpp

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/*
   Copyright (C) 2014 - 2018 by Chris Beck <render787@gmail.com>
   Part of the Battle for Wesnoth Project https://www.wesnoth.org/

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY.

   See the COPYING file for more details.
*/

#include "scripting/lua_race.hpp"

#include "units/race.hpp"
#include "scripting/lua_common.hpp"
#include "scripting/push_check.hpp"
#include "units/types.hpp"

#include <string>
#include <cstring>

#include "lua/lua.h"
#include "lua/lauxlib.h"

/**
 * Implementation for a lua reference to a race,
 * used by the wesnoth in-game races table.
 */

// Registry key
static const char * Race = "race";
static const char * Gen = "name generator";

/**
 * Gets some data on a race (__index metamethod).
 * - Arg 1: table containing an "id" field.
 * - Arg 2: string containing the name of the property.
 * - Ret 1: something containing the attribute.
 */
static int impl_race_get(lua_State* L)
{
    const unit_race& race = luaW_checkrace(L, 1);
    char const* m = luaL_checkstring(L, 2);

    return_tstring_attrib("description", race.description());
    return_tstring_attrib("name", race.name());
    return_int_attrib("num_traits", race.num_traits());
    return_tstring_attrib("plural_name", race.plural_name());
    return_bool_attrib("ignore_global_traits", !race.uses_global_traits());
    return_string_attrib("undead_variation", race.undead_variation());
    return_cfgref_attrib("__cfg", race.get_cfg());
    if (strcmp(m, "traits") == 0) {
        lua_newtable(L);
        if (race.uses_global_traits()) {
            for (const config& trait : unit_types.traits()) {
                const std::string& id = trait["id"];
                lua_pushlstring(L, id.c_str(), id.length());
                luaW_pushconfig(L, trait);
                lua_rawset(L, -3);
            }
        }
        for (const config& trait : race.additional_traits()) {
            const std::string& id = trait["id"];
            lua_pushlstring(L, id.c_str(), id.length());
            luaW_pushconfig(L, trait);
            lua_rawset(L, -3);
        }
        return 1;
    }
    if (strcmp(m, "male_name_gen") == 0) {
        new(L) proxy_name_generator(race.generator(unit_race::MALE));
        luaL_getmetatable(L, Gen);
        lua_setmetatable(L, -2);
        return 1;
    }
    if (strcmp(m, "female_name_gen") == 0) {
        new(L) proxy_name_generator(race.generator(unit_race::FEMALE));
        luaL_getmetatable(L, Gen);
        lua_setmetatable(L, -2);
        return 1;
    }

    return 0;
}

/**
 * Turns a lua proxy race to string. (__tostring metamethod)
 */
static int impl_race_tostring(lua_State* L)
{
    const unit_race& race = luaW_checkrace(L, 1);
    std::ostringstream str;
    str << "race: <" << race.id() << '>';
    lua_push(L, str.str());
    return 1;
}

namespace lua_race {

    std::string register_metatable(lua_State * L)
    {
        luaL_newmetatable(L, Race);

        static luaL_Reg const callbacks[] {
            { "__index",        &impl_race_get},
            { "__tostring",     &impl_race_tostring},
            { nullptr, nullptr }
        };
        luaL_setfuncs(L, callbacks, 0);

        lua_pushstring(L, "race");
        lua_setfield(L, -2, "__metatable");

        return "Adding getrace metatable...\n";
    }
}

void luaW_pushrace(lua_State *L, const unit_race & race)
{
    lua_createtable(L, 0, 1);
    lua_pushstring(L, race.id().c_str());
    lua_setfield(L, -2, "id");
    luaL_setmetatable(L, Race);
}

void luaW_pushracetable(lua_State *L)
{
    const race_map& races = unit_types.races();
    lua_createtable(L, 0, races.size());

    for (const race_map::value_type &race : races)
    {
        assert(race.first == race.second.id());
        luaW_pushrace(L, race.second);
        lua_setfield(L, -2, race.first.c_str());
    }
}

const unit_race& luaW_checkrace(lua_State* L, int idx)
{
    lua_pushstring(L, "id");
    lua_rawget(L, idx);
    const unit_race* raceptr = unit_types.find_race(lua_tostring(L, -1));
    if(!raceptr) {
        luaL_argerror(L, idx, "unknown race");
        throw "UNREACHABLE";
    }
    return *raceptr;
}