Modernize lua read (part 1): C++ templating insurance (#7394)

* Modernize lua read (part 1): C++ templating assurance

Implement the float reader

src/script/lua_api/l_base.cpp

@@ -90,3 +90,15 @@ bool ModApiBase::isNaN(lua_State *L, int idx)
 {
 	return lua_type(L, idx) == LUA_TNUMBER && std::isnan(lua_tonumber(L, idx));
 }
+
+/*
+ * Read template functions
+ */
+template<>
+float ModApiBase::readParam(lua_State *L, int index)
+{
+	if (isNaN(L, index))
+		throw LuaError("NaN value is not allowed.");
+
+	return (float) luaL_checknumber(L, index);
+}

src/script/lua_api/l_base.h

@@ -71,4 +71,15 @@ public:
 			int top);
 
 	static bool isNaN(lua_State *L, int idx);
+
+	/**
+	 * Read a value using a template type T from Lua State L and index
+	 *
+	 * @tparam T type to read from Lua
+	 * @param L Lua state
+	 * @param index Lua Index to read
+	 * @return read value from Lua
+	 */
+	template<typename T>
+	static T readParam(lua_State *L, int index);
 };

src/script/lua_api/l_env.cpp

@@ -666,7 +666,7 @@ int ModApiEnvMod::l_get_objects_inside_radius(lua_State *L)
 
 	// Do it
 	v3f pos = checkFloatPos(L, 1);
-	float radius = luaL_checknumber(L, 2) * BS;
+	float radius = readParam<float>(L, 2) * BS;
 	std::vector<u16> ids;
 	env->getObjectsInsideRadius(ids, pos, radius);
 	ScriptApiBase *script = getScriptApiBase(L);
@@ -690,7 +690,7 @@ int ModApiEnvMod::l_set_timeofday(lua_State *L)
 	GET_ENV_PTR;
 
 	// Do it
-	float timeofday_f = luaL_checknumber(L, 1);
+	float timeofday_f = readParam<float>(L, 1);
 	sanity_check(timeofday_f >= 0.0 && timeofday_f <= 1.0);
 	int timeofday_mh = (int)(timeofday_f * 24000.0);
 	// This should be set directly in the environment but currently
@@ -925,8 +925,8 @@ int ModApiEnvMod::l_get_perlin(lua_State *L)
 	} else {
 		params.seed    = luaL_checkint(L, 1);
 		params.octaves = luaL_checkint(L, 2);
-		params.persist = luaL_checknumber(L, 3);
-		params.spread  = v3f(1, 1, 1) * luaL_checknumber(L, 4);
+		params.persist = readParam<float>(L, 3);
+		params.spread  = v3f(1, 1, 1) * readParam<float>(L, 4);
 	}
 
 	params.seed += (int)env->getServerMap().getSeed();

src/script/lua_api/l_metadata.cpp

@@ -190,7 +190,7 @@ int MetaDataRef::l_set_float(lua_State *L)
 
 	MetaDataRef *ref = checkobject(L, 1);
 	std::string name = luaL_checkstring(L, 2);
-	float a = luaL_checknumber(L, 3);
+	float a = readParam<float>(L, 3);
 	std::string str = ftos(a);
 
 	Metadata *meta = ref->getmeta(true);

src/script/lua_api/l_nodetimer.cpp

@@ -43,8 +43,8 @@ int NodeTimerRef::l_set(lua_State *L)
 	NodeTimerRef *o = checkobject(L, 1);
 	ServerEnvironment *env = o->m_env;
 	if(env == NULL) return 0;
-	f32 t = luaL_checknumber(L,2);
-	f32 e = luaL_checknumber(L,3);
+	f32 t = readParam<float>(L,2);
+	f32 e = readParam<float>(L,3);
 	env->getMap().setNodeTimer(NodeTimer(t, e, o->m_p));
 	return 0;
 }
@@ -55,7 +55,7 @@ int NodeTimerRef::l_start(lua_State *L)
 	NodeTimerRef *o = checkobject(L, 1);
 	ServerEnvironment *env = o->m_env;
 	if(env == NULL) return 0;
-	f32 t = luaL_checknumber(L,2);
+	f32 t = readParam<float>(L,2);
 	env->getMap().setNodeTimer(NodeTimer(t, 0, o->m_p));
 	return 0;
 }

src/script/lua_api/l_noise.cpp

@@ -69,8 +69,8 @@ int LuaPerlinNoise::create_object(lua_State *L)
 	} else {
 		params.seed    = luaL_checkint(L, 1);
 		params.octaves = luaL_checkint(L, 2);
-		params.persist = luaL_checknumber(L, 3);
-		params.spread  = v3f(1, 1, 1) * luaL_checknumber(L, 4);
+		params.persist = readParam<float>(L, 3);
+		params.spread  = v3f(1, 1, 1) * readParam<float>(L, 4);
 	}
 
 	LuaPerlinNoise *o = new LuaPerlinNoise(&params);

src/script/lua_api/l_object.cpp

@@ -898,7 +898,7 @@ int ObjectRef::l_set_yaw(lua_State *L)
 	if (isNaN(L, 2))
 		throw LuaError("ObjectRef::set_yaw: NaN value is not allowed.");
 
-	float yaw = luaL_checknumber(L, 2) * core::RADTODEG;
+	float yaw = readParam<float>(L, 2) * core::RADTODEG;
 	// Do it
 	co->setYaw(yaw);
 	return 0;
@@ -1118,7 +1118,7 @@ int ObjectRef::l_set_look_vertical(lua_State *L)
 	ObjectRef *ref = checkobject(L, 1);
 	PlayerSAO* co = getplayersao(ref);
 	if (co == NULL) return 0;
-	float pitch = luaL_checknumber(L, 2) * core::RADTODEG;
+	float pitch = readParam<float>(L, 2) * core::RADTODEG;
 	// Do it
 	co->setPitchAndSend(pitch);
 	return 1;
@@ -1131,7 +1131,7 @@ int ObjectRef::l_set_look_horizontal(lua_State *L)
 	ObjectRef *ref = checkobject(L, 1);
 	PlayerSAO* co = getplayersao(ref);
 	if (co == NULL) return 0;
-	float yaw = luaL_checknumber(L, 2) * core::RADTODEG;
+	float yaw = readParam<float>(L, 2) * core::RADTODEG;
 	// Do it
 	co->setYawAndSend(yaw);
 	return 1;
@@ -1149,7 +1149,7 @@ int ObjectRef::l_set_look_pitch(lua_State *L)
 	ObjectRef *ref = checkobject(L, 1);
 	PlayerSAO* co = getplayersao(ref);
 	if (co == NULL) return 0;
-	float pitch = luaL_checknumber(L, 2) * core::RADTODEG;
+	float pitch = readParam<float>(L, 2) * core::RADTODEG;
 	// Do it
 	co->setPitchAndSend(pitch);
 	return 1;
@@ -1167,7 +1167,7 @@ int ObjectRef::l_set_look_yaw(lua_State *L)
 	ObjectRef *ref = checkobject(L, 1);
 	PlayerSAO* co = getplayersao(ref);
 	if (co == NULL) return 0;
-	float yaw = luaL_checknumber(L, 2) * core::RADTODEG;
+	float yaw = readParam<float>(L, 2) * core::RADTODEG;
 	// Do it
 	co->setYawAndSend(yaw);
 	return 1;
@@ -1739,7 +1739,7 @@ int ObjectRef::l_override_day_night_ratio(lua_State *L)
 	float ratio = 0.0f;
 	if (!lua_isnil(L, 2)) {
 		do_override = true;
-		ratio = luaL_checknumber(L, 2);
+		ratio = readParam<float>(L, 2);
 	}
 
 	if (!getServer(L)->overrideDayNightRatio(player, do_override, ratio))

src/script/lua_api/l_server.cpp

@@ -455,8 +455,8 @@ int ModApiServer::l_sound_fade(lua_State *L)
 {
 	NO_MAP_LOCK_REQUIRED;
 	s32 handle = luaL_checkinteger(L, 1);
-	float step = luaL_checknumber(L, 2);
-	float gain = luaL_checknumber(L, 3);
+	float step = readParam<float>(L, 2);
+	float gain = readParam<float>(L, 3);
 	getServer(L)->fadeSound(handle, step, gain);
 	return 0;
 }

src/script/lua_api/l_util.cpp

@@ -179,8 +179,7 @@ int ModApiUtil::l_get_hit_params(lua_State *L)
 	if(lua_isnoneornil(L, 3))
 		push_hit_params(L, getHitParams(groups, &tp));
 	else
-		push_hit_params(L, getHitParams(groups, &tp,
-					luaL_checknumber(L, 3)));
+		push_hit_params(L, getHitParams(groups, &tp, readParam<float>(L, 3)));
 	return 1;
 }
 
@@ -270,7 +269,7 @@ int ModApiUtil::l_compress(lua_State *L)
 
 	int level = -1;
 	if (!lua_isnone(L, 3) && !lua_isnil(L, 3))
-		level = luaL_checknumber(L, 3);
+		level = readParam<float>(L, 3);
 
 	std::ostringstream os;
 	compressZlib(std::string(data, size), os, level);