Code modernization: subfolders (#6283)

* Code modernization: subfolders

Modernize various code on subfolders client, network, script, threading, unittests, util

* empty function
* default constructor/destructor
* for range-based loops
* use emplace_back instead of push_back
* C++ STL header style
* Make connection.cpp readable in a pointed place + typo

25 files changed, 72 insertions, 114 deletions

diff --git a/src/script/lua_api/l_camera.h b/src/script/lua_api/l_camera.h
index a7103c9b0..f3021bc49 100644
--- a/src/script/lua_api/l_camera.h
+++ b/src/script/lua_api/l_camera.h
@@ -48,7 +48,7 @@ private:
 
 public:
 	LuaCamera(Camera *m);
-	~LuaCamera() {}
+	~LuaCamera() = default;
 
 	static void create(lua_State *L, Camera *m);
 
diff --git a/src/script/lua_api/l_client.cpp b/src/script/lua_api/l_client.cpp
index 81dfdb1e9..6a87b20e9 100644
--- a/src/script/lua_api/l_client.cpp
+++ b/src/script/lua_api/l_client.cpp
@@ -34,7 +34,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/string.h"
 #include "nodedef.h"
 
-extern MainGameCallback *g_gamecallback;
 
 int ModApiClient::l_get_current_modname(lua_State *L)
 {
diff --git a/src/script/lua_api/l_craft.cpp b/src/script/lua_api/l_craft.cpp
index 315391856..7bf1d314b 100644
--- a/src/script/lua_api/l_craft.cpp
+++ b/src/script/lua_api/l_craft.cpp
@@ -57,7 +57,7 @@ bool ModApiCraft::readCraftRecipeShaped(lua_State *L, int index,
 			// key at index -2 and value at index -1
 			if(!lua_isstring(L, -1))
 				return false;
-			recipe.push_back(lua_tostring(L, -1));
+			recipe.emplace_back(lua_tostring(L, -1));
 			// removes value, keeps key for next iteration
 			lua_pop(L, 1);
 			colcount++;
@@ -90,7 +90,7 @@ bool ModApiCraft::readCraftRecipeShapeless(lua_State *L, int index,
 		// key at index -2 and value at index -1
 		if(!lua_isstring(L, -1))
 			return false;
-		recipe.push_back(lua_tostring(L, -1));
+		recipe.emplace_back(lua_tostring(L, -1));
 		// removes value, keeps key for next iteration
 		lua_pop(L, 1);
 	}
@@ -122,8 +122,7 @@ bool ModApiCraft::readCraftReplacements(lua_State *L, int index,
 			return false;
 		std::string replace_to = lua_tostring(L, -1);
 		lua_pop(L, 1);
-		replacements.pairs.push_back(
-				std::make_pair(replace_from, replace_to));
+		replacements.pairs.emplace_back(replace_from, replace_to);
 		// removes value, keeps key for next iteration
 		lua_pop(L, 1);
 	}
@@ -148,7 +147,7 @@ int ModApiCraft::l_register_craft(lua_State *L)
 	*/
 	if(type == "shaped"){
 		std::string output = getstringfield_default(L, table, "output", "");
-		if(output == "")
+		if (output.empty())
 			throw LuaError("Crafting definition is missing an output");
 
 		int width = 0;
@@ -179,7 +178,7 @@ int ModApiCraft::l_register_craft(lua_State *L)
 	*/
 	else if(type == "shapeless"){
 		std::string output = getstringfield_default(L, table, "output", "");
-		if(output == "")
+		if (output.empty())
 			throw LuaError("Crafting definition (shapeless)"
 					" is missing an output");
 
@@ -222,12 +221,12 @@ int ModApiCraft::l_register_craft(lua_State *L)
 	*/
 	else if(type == "cooking"){
 		std::string output = getstringfield_default(L, table, "output", "");
-		if(output == "")
+		if (output.empty())
 			throw LuaError("Crafting definition (cooking)"
 					" is missing an output");
 
 		std::string recipe = getstringfield_default(L, table, "recipe", "");
-		if(recipe == "")
+		if (recipe.empty())
 			throw LuaError("Crafting definition (cooking)"
 					" is missing a recipe"
 					" (output=\"" + output + "\")");
@@ -252,7 +251,7 @@ int ModApiCraft::l_register_craft(lua_State *L)
 	*/
 	else if(type == "fuel"){
 		std::string recipe = getstringfield_default(L, table, "recipe", "");
-		if(recipe == "")
+		if (recipe.empty())
 			throw LuaError("Crafting definition (fuel)"
 					" is missing a recipe");
 
@@ -294,12 +293,12 @@ int ModApiCraft::l_clear_craft(lua_State *L)
 	std::string output = getstringfield_default(L, table, "output", "");
 	std::string type = getstringfield_default(L, table, "type", "shaped");
 	CraftOutput c_output(output, 0);
-	if (output != "") {
+	if (!output.empty()) {
 		if (craftdef->clearCraftRecipesByOutput(c_output, getServer(L)))
 			return 0;
-		else
-			throw LuaError("No craft recipe known for output"
-					" (output=\"" + output + "\")");
+
+		throw LuaError("No craft recipe known for output"
+				" (output=\"" + output + "\")");
 	}
 	std::vector<std::string> recipe;
 	int width = 0;
@@ -330,7 +329,7 @@ int ModApiCraft::l_clear_craft(lua_State *L)
 	else if (type == "cooking") {
 		method = CRAFT_METHOD_COOKING;
 		std::string rec = getstringfield_default(L, table, "recipe", "");
-		if (rec == "")
+		if (rec.empty())
 			throw LuaError("Crafting definition (cooking)"
 					" is missing a recipe");
 		recipe.push_back(rec);
@@ -341,7 +340,7 @@ int ModApiCraft::l_clear_craft(lua_State *L)
 	else if (type == "fuel") {
 		method = CRAFT_METHOD_FUEL;
 		std::string rec = getstringfield_default(L, table, "recipe", "");
-		if (rec == "")
+		if (rec.empty())
 			throw LuaError("Crafting definition (fuel)"
 					" is missing a recipe");
 		recipe.push_back(rec);
diff --git a/src/script/lua_api/l_env.cpp b/src/script/lua_api/l_env.cpp
index 1b1f96389..94edf201e 100644
--- a/src/script/lua_api/l_env.cpp
+++ b/src/script/lua_api/l_env.cpp
@@ -743,9 +743,8 @@ int ModApiEnvMod::l_find_node_near(lua_State *L)
 
 	for (int d = start_radius; d <= radius; d++) {
 		std::vector<v3s16> list = FacePositionCache::getFacePositions(d);
-		for (std::vector<v3s16>::iterator i = list.begin();
-				i != list.end(); ++i) {
-			v3s16 p = pos + (*i);
+		for (v3s16 i : list) {
+			v3s16 p = pos + i;
 			content_t c = env->getMap().getNodeNoEx(p).getContent();
 			if (filter.count(c) != 0) {
 				push_v3s16(L, p);
@@ -809,10 +808,9 @@ int ModApiEnvMod::l_find_nodes_in_area(lua_State *L)
 		}
 	}
 	lua_newtable(L);
-	for (std::set<content_t>::const_iterator it = filter.begin();
-			it != filter.end(); ++it) {
-		lua_pushnumber(L, individual_count[*it]);
-		lua_setfield(L, -2, ndef->get(*it).name.c_str());
+	for (content_t it : filter) {
+		lua_pushnumber(L, individual_count[it]);
+		lua_setfield(L, -2, ndef->get(it).name.c_str());
 	}
 	return 2;
 }
@@ -1004,12 +1002,11 @@ int ModApiEnvMod::l_fix_light(lua_State *L)
 	for (blockpos.Z = blockpos1.Z; blockpos.Z <= blockpos2.Z; blockpos.Z++) {
 		success = success & map.repairBlockLight(blockpos, &modified_blocks);
 	}
-	if (modified_blocks.size() > 0) {
+	if (!modified_blocks.empty()) {
 		MapEditEvent event;
 		event.type = MEET_OTHER;
-		for (std::map<v3s16, MapBlock *>::iterator it = modified_blocks.begin();
-				it != modified_blocks.end(); ++it)
-			event.modified_blocks.insert(it->first);
+		for (auto &modified_block : modified_blocks)
+			event.modified_blocks.insert(modified_block.first);
 
 		map.dispatchEvent(&event);
 	}
@@ -1126,14 +1123,13 @@ int ModApiEnvMod::l_find_path(lua_State *L)
 	std::vector<v3s16> path = get_path(env, pos1, pos2,
 		searchdistance, max_jump, max_drop, algo);
 
-	if (path.size() > 0)
-	{
+	if (!path.empty()) {
 		lua_newtable(L);
 		int top = lua_gettop(L);
 		unsigned int index = 1;
-		for (std::vector<v3s16>::iterator i = path.begin(); i != path.end(); ++i) {
+		for (v3s16 i : path) {
 			lua_pushnumber(L,index);
-			push_v3s16(L, *i);
+			push_v3s16(L, i);
 			lua_settable(L, top);
 			index++;
 		}
@@ -1167,8 +1163,7 @@ int ModApiEnvMod::l_spawn_tree(lua_State *L)
 		tree_def.leavesnode=ndef->getId(leaves);
 		tree_def.leaves2_chance=0;
 		getstringfield(L, 2, "leaves2", leaves);
-		if (leaves !="")
-		{
+		if (!leaves.empty()) {
 			tree_def.leaves2node=ndef->getId(leaves);
 			getintfield(L, 2, "leaves2_chance", tree_def.leaves2_chance);
 		}
@@ -1180,8 +1175,7 @@ int ModApiEnvMod::l_spawn_tree(lua_State *L)
 		getboolfield(L, 2, "thin_branches", tree_def.thin_branches);
 		tree_def.fruit_chance=0;
 		getstringfield(L, 2, "fruit", fruit);
-		if (fruit != "")
-		{
+		if (!fruit.empty()) {
 			tree_def.fruitnode=ndef->getId(fruit);
 			getintfield(L, 2, "fruit_chance",tree_def.fruit_chance);
 		}
diff --git a/src/script/lua_api/l_http.cpp b/src/script/lua_api/l_http.cpp
index 8bd39b6ed..641f4194a 100644
--- a/src/script/lua_api/l_http.cpp
+++ b/src/script/lua_api/l_http.cpp
@@ -69,7 +69,7 @@ void ModApiHttp::read_http_fetch_request(lua_State *L, HTTPFetchRequest &req)
 		while (lua_next(L, 2) != 0)
 		{
 			const char *header = luaL_checkstring(L, -1);
-			req.extra_headers.push_back(header);
+			req.extra_headers.emplace_back(header);
 			lua_pop(L, 1);
 		}
 	}
diff --git a/src/script/lua_api/l_inventory.cpp b/src/script/lua_api/l_inventory.cpp
index aac5eed8e..b0d43090c 100644
--- a/src/script/lua_api/l_inventory.cpp
+++ b/src/script/lua_api/l_inventory.cpp
@@ -409,10 +409,6 @@ InvRef::InvRef(const InventoryLocation &loc):
 {
 }
 
-InvRef::~InvRef()
-{
-}
-
 // Creates an InvRef and leaves it on top of stack
 // Not callable from Lua; all references are created on the C side.
 void InvRef::create(lua_State *L, const InventoryLocation &loc)
diff --git a/src/script/lua_api/l_inventory.h b/src/script/lua_api/l_inventory.h
index f12377ece..2b7910ac3 100644
--- a/src/script/lua_api/l_inventory.h
+++ b/src/script/lua_api/l_inventory.h
@@ -106,7 +106,7 @@ private:
 public:
 	InvRef(const InventoryLocation &loc);
 
-	~InvRef();
+	~InvRef() = default;
 
 	// Creates an InvRef and leaves it on top of stack
 	// Not callable from Lua; all references are created on the C side.
diff --git a/src/script/lua_api/l_item.cpp b/src/script/lua_api/l_item.cpp
index 0e4fc4ef0..207a04c6c 100644
--- a/src/script/lua_api/l_item.cpp
+++ b/src/script/lua_api/l_item.cpp
@@ -67,7 +67,7 @@ int LuaItemStack::l_set_name(lua_State *L)
 
 	bool status = true;
 	item.name = luaL_checkstring(L, 2);
-	if (item.name == "" || item.empty()) {
+	if (item.name.empty() || item.empty()) {
 		item.clear();
 		status = false;
 	}
@@ -231,12 +231,11 @@ int LuaItemStack::l_to_table(lua_State *L)
 
 		lua_newtable(L);
 		const StringMap &fields = item.metadata.getStrings();
-		for (StringMap::const_iterator it = fields.begin();
-				it != fields.end(); ++it) {
-			const std::string &name = it->first;
+		for (const auto &field : fields) {
+			const std::string &name = field.first;
 			if (name.empty())
 				continue;
-			const std::string &value = it->second;
+			const std::string &value = field.second;
 			lua_pushlstring(L, name.c_str(), name.size());
 			lua_pushlstring(L, value.c_str(), value.size());
 			lua_settable(L, -3);
@@ -391,10 +390,6 @@ LuaItemStack::LuaItemStack(const ItemStack &item):
 {
 }
 
-LuaItemStack::~LuaItemStack()
-{
-}
-
 const ItemStack& LuaItemStack::getItem() const
 {
 	return m_stack;
diff --git a/src/script/lua_api/l_item.h b/src/script/lua_api/l_item.h
index 6aa62808b..5ff715b2a 100644
--- a/src/script/lua_api/l_item.h
+++ b/src/script/lua_api/l_item.h
@@ -121,7 +121,7 @@ private:
 
 public:
 	LuaItemStack(const ItemStack &item);
-	~LuaItemStack();
+	~LuaItemStack() = default;
 
 	const ItemStack& getItem() const;
 	ItemStack& getItem();
diff --git a/src/script/lua_api/l_itemstackmeta.h b/src/script/lua_api/l_itemstackmeta.h
index cfaece794..241f04c4c 100644
--- a/src/script/lua_api/l_itemstackmeta.h
+++ b/src/script/lua_api/l_itemstackmeta.h
@@ -46,7 +46,7 @@ private:
 	static int gc_object(lua_State *L);
 public:
 	ItemStackMetaRef(ItemStack *istack): istack(istack) {}
-	~ItemStackMetaRef() {}
+	~ItemStackMetaRef() = default;
 
 	// Creates an ItemStackMetaRef and leaves it on top of stack
 	// Not callable from Lua; all references are created on the C side.
diff --git a/src/script/lua_api/l_localplayer.h b/src/script/lua_api/l_localplayer.h
index dcb5c878c..d30fe1d64 100644
--- a/src/script/lua_api/l_localplayer.h
+++ b/src/script/lua_api/l_localplayer.h
@@ -70,7 +70,7 @@ private:
 
 public:
 	LuaLocalPlayer(LocalPlayer *m);
-	~LuaLocalPlayer() {}
+	~LuaLocalPlayer() = default;
 
 	static void create(lua_State *L, LocalPlayer *m);
 
diff --git a/src/script/lua_api/l_minimap.h b/src/script/lua_api/l_minimap.h
index 2d0e6ae9f..cc859ad0d 100644
--- a/src/script/lua_api/l_minimap.h
+++ b/src/script/lua_api/l_minimap.h
@@ -51,7 +51,7 @@ private:
 
 public:
 	LuaMinimap(Minimap *m);
-	~LuaMinimap() {}
+	~LuaMinimap() = default;
 
 	static void create(lua_State *L, Minimap *object);
 
diff --git a/src/script/lua_api/l_nodemeta.cpp b/src/script/lua_api/l_nodemeta.cpp
index d1f314079..3d7adf27d 100644
--- a/src/script/lua_api/l_nodemeta.cpp
+++ b/src/script/lua_api/l_nodemeta.cpp
@@ -182,10 +182,6 @@ NodeMetaRef::NodeMetaRef(Metadata *meta):
 {
 }
 
-NodeMetaRef::~NodeMetaRef()
-{
-}
-
 // Creates an NodeMetaRef and leaves it on top of stack
 // Not callable from Lua; all references are created on the C side.
 void NodeMetaRef::create(lua_State *L, v3s16 p, ServerEnvironment *env)
diff --git a/src/script/lua_api/l_nodemeta.h b/src/script/lua_api/l_nodemeta.h
index 683f79932..b0b4a9623 100644
--- a/src/script/lua_api/l_nodemeta.h
+++ b/src/script/lua_api/l_nodemeta.h
@@ -80,7 +80,7 @@ public:
 	NodeMetaRef(v3s16 p, ServerEnvironment *env);
 	NodeMetaRef(Metadata *meta);
 
-	~NodeMetaRef();
+	~NodeMetaRef() = default;
 
 	// Creates an NodeMetaRef and leaves it on top of stack
 	// Not callable from Lua; all references are created on the C side.
diff --git a/src/script/lua_api/l_nodetimer.cpp b/src/script/lua_api/l_nodetimer.cpp
index 17b275c46..55d3aec70 100644
--- a/src/script/lua_api/l_nodetimer.cpp
+++ b/src/script/lua_api/l_nodetimer.cpp
@@ -113,10 +113,6 @@ NodeTimerRef::NodeTimerRef(v3s16 p, ServerEnvironment *env):
 {
 }
 
-NodeTimerRef::~NodeTimerRef()
-{
-}
-
 // Creates an NodeTimerRef and leaves it on top of stack
 // Not callable from Lua; all references are created on the C side.
 void NodeTimerRef::create(lua_State *L, v3s16 p, ServerEnvironment *env)
diff --git a/src/script/lua_api/l_nodetimer.h b/src/script/lua_api/l_nodetimer.h
index c7cc76244..b894c5c8c 100644
--- a/src/script/lua_api/l_nodetimer.h
+++ b/src/script/lua_api/l_nodetimer.h
@@ -51,7 +51,7 @@ private:
 
 public:
 	NodeTimerRef(v3s16 p, ServerEnvironment *env);
-	~NodeTimerRef();
+	~NodeTimerRef() = default;
 
 	// Creates an NodeTimerRef and leaves it on top of stack
 	// Not callable from Lua; all references are created on the C side.
diff --git a/src/script/lua_api/l_noise.cpp b/src/script/lua_api/l_noise.cpp
index e3e76191f..35d3bbb6e 100644
--- a/src/script/lua_api/l_noise.cpp
+++ b/src/script/lua_api/l_noise.cpp
@@ -36,11 +36,6 @@ LuaPerlinNoise::LuaPerlinNoise(NoiseParams *params) :
 }
 
 
-LuaPerlinNoise::~LuaPerlinNoise()
-{
-}
-
-
 int LuaPerlinNoise::l_get2d(lua_State *L)
 {
 	NO_MAP_LOCK_REQUIRED;
diff --git a/src/script/lua_api/l_noise.h b/src/script/lua_api/l_noise.h
index 8af4fbd12..552d67db9 100644
--- a/src/script/lua_api/l_noise.h
+++ b/src/script/lua_api/l_noise.h
@@ -43,7 +43,7 @@ private:
 
 public:
 	LuaPerlinNoise(NoiseParams *params);
-	~LuaPerlinNoise();
+	~LuaPerlinNoise() = default;
 
 	// LuaPerlinNoise(seed, octaves, persistence, scale)
 	// Creates an LuaPerlinNoise and leaves it on top of stack
diff --git a/src/script/lua_api/l_object.cpp b/src/script/lua_api/l_object.cpp
index 9ddbc3e41..bad5ec8af 100644
--- a/src/script/lua_api/l_object.cpp
+++ b/src/script/lua_api/l_object.cpp
@@ -551,8 +551,8 @@ int ObjectRef::l_get_local_animation(lua_State *L)
 	float frame_speed;
 	player->getLocalAnimations(frames, &frame_speed);
 
-	for (int i = 0; i < 4; i++) {
-		push_v2s32(L, frames[i]);
+	for (v2s32 frame : frames) {
+		push_v2s32(L, frame);
 	}
 
 	lua_pushnumber(L, frame_speed);
@@ -611,7 +611,7 @@ int ObjectRef::l_set_bone_position(lua_State *L)
 	ServerActiveObject *co = getobject(ref);
 	if (co == NULL) return 0;
 	// Do it
-	std::string bone = "";
+	std::string bone;
 	if (!lua_isnil(L, 2))
 		bone = lua_tostring(L, 2);
 	v3f position = v3f(0, 0, 0);
@@ -633,7 +633,7 @@ int ObjectRef::l_get_bone_position(lua_State *L)
 	if (co == NULL)
 		return 0;
 	// Do it
-	std::string bone = "";
+	std::string bone;
 	if (!lua_isnil(L, 2))
 		bone = lua_tostring(L, 2);
 
@@ -661,7 +661,7 @@ int ObjectRef::l_set_attach(lua_State *L)
 		return 0;
 	// Do it
 	int parent_id = 0;
-	std::string bone = "";
+	std::string bone;
 	v3f position = v3f(0, 0, 0);
 	v3f rotation = v3f(0, 0, 0);
 	co->getAttachment(&parent_id, &bone, &position, &rotation);
@@ -696,7 +696,7 @@ int ObjectRef::l_get_attach(lua_State *L)
 
 	// Do it
 	int parent_id = 0;
-	std::string bone = "";
+	std::string bone;
 	v3f position = v3f(0, 0, 0);
 	v3f rotation = v3f(0, 0, 0);
 	co->getAttachment(&parent_id, &bone, &position, &rotation);
@@ -722,7 +722,7 @@ int ObjectRef::l_set_detach(lua_State *L)
 		return 0;
 
 	int parent_id = 0;
-	std::string bone = "";
+	std::string bone;
 	v3f position;
 	v3f rotation;
 	co->getAttachment(&parent_id, &bone, &position, &rotation);
@@ -1223,7 +1223,7 @@ int ObjectRef::l_get_attribute(lua_State *L)
 
 	std::string attr = luaL_checkstring(L, 2);
 
-	std::string value = "";
+	std::string value;
 	if (co->getExtendedAttribute(attr, &value)) {
 		lua_pushstring(L, value.c_str());
 		return 1;
@@ -1684,9 +1684,9 @@ int ObjectRef::l_set_sky(lua_State *L)
 		while (lua_next(L, 4) != 0) {
 			// key at index -2 and value at index -1
 			if (lua_isstring(L, -1))
-				params.push_back(lua_tostring(L, -1));
+				params.emplace_back(lua_tostring(L, -1));
 			else
-				params.push_back("");
+				params.emplace_back("");
 			// removes value, keeps key for next iteration
 			lua_pop(L, 1);
 		}
@@ -1720,15 +1720,14 @@ int ObjectRef::l_get_sky(lua_State *L)
 	bool clouds;
 
 	player->getSky(&bgcolor, &type, &params, &clouds);
-	type = type == "" ? "regular" : type;
+	type = type.empty() ? "regular" : type;
 
 	push_ARGB8(L, bgcolor);
 	lua_pushlstring(L, type.c_str(), type.size());
 	lua_newtable(L);
 	s16 i = 1;
-	for (std::vector<std::string>::iterator it = params.begin();
-			it != params.end(); ++it) {
-		lua_pushlstring(L, it->c_str(), it->size());
+	for (const std::string &param : params) {
+		lua_pushlstring(L, param.c_str(), param.size());
 		lua_rawseti(L, -2, i);
 		i++;
 	}
@@ -1865,15 +1864,6 @@ ObjectRef::ObjectRef(ServerActiveObject *object):
 	//infostream<<"ObjectRef created for id="<<m_object->getId()<<std::endl;
 }
 
-ObjectRef::~ObjectRef()
-{
-	/*if (m_object)
-		infostream<<"ObjectRef destructing for id="
-				<<m_object->getId()<<std::endl;
-	else
-		infostream<<"ObjectRef destructing for id=unknown"<<std::endl;*/
-}
-
 // Creates an ObjectRef and leaves it on top of stack
 // Not callable from Lua; all references are created on the C side.
 void ObjectRef::create(lua_State *L, ServerActiveObject *object)
diff --git a/src/script/lua_api/l_object.h b/src/script/lua_api/l_object.h
index a2438e434..19cc890c7 100644
--- a/src/script/lua_api/l_object.h
+++ b/src/script/lua_api/l_object.h
@@ -35,7 +35,7 @@ class ObjectRef : public ModApiBase {
 public:
 	ObjectRef(ServerActiveObject *object);
 
-	~ObjectRef();
+	~ObjectRef() = default;
 
 	// Creates an ObjectRef and leaves it on top of stack
 	// Not callable from Lua; all references are created on the C side.
diff --git a/src/script/lua_api/l_particles.cpp b/src/script/lua_api/l_particles.cpp
index 2f3e9a58d..8a7de8b4f 100644
--- a/src/script/lua_api/l_particles.cpp
+++ b/src/script/lua_api/l_particles.cpp
@@ -53,8 +53,8 @@ int ModApiParticles::l_add_particle(lua_State *L)
 	struct TileAnimationParams animation;
 	animation.type = TAT_NONE;
 
-	std::string texture = "";
-	std::string playername = "";
+	std::string texture;
+	std::string playername;
 
 	u8 glow = 0;
 
@@ -158,8 +158,8 @@ int ModApiParticles::l_add_particlespawner(lua_State *L)
 	struct TileAnimationParams animation;
 	animation.type = TAT_NONE;
 	ServerActiveObject *attached = NULL;
-	std::string texture = "";
-	std::string playername = "";
+	std::string texture;
+	std::string playername;
 	u8 glow = 0;
 
 	if (lua_gettop(L) > 1) //deprecated
@@ -262,7 +262,7 @@ int ModApiParticles::l_delete_particlespawner(lua_State *L)
 
 	// Get parameters
 	u32 id = luaL_checknumber(L, 1);
-	std::string playername = "";
+	std::string playername;
 	if (lua_gettop(L) == 2) {
 		playername = luaL_checkstring(L, 2);
 	}
diff --git a/src/script/lua_api/l_settings.cpp b/src/script/lua_api/l_settings.cpp
index 3dc5c9574..2d6769ea1 100644
--- a/src/script/lua_api/l_settings.cpp
+++ b/src/script/lua_api/l_settings.cpp
@@ -198,10 +198,9 @@ int LuaSettings::l_to_table(lua_State* L)
 	std::vector<std::string> keys = o->m_settings->getNames();
 
 	lua_newtable(L);
-	for (unsigned int i=0; i < keys.size(); i++)
-	{
-		lua_pushstring(L, o->m_settings->get(keys[i]).c_str());
-		lua_setfield(L, -2, keys[i].c_str());
+	for (const std::string &key : keys) {
+		lua_pushstring(L, o->m_settings->get(key).c_str());
+		lua_setfield(L, -2, key.c_str());
 	}
 
 	return 1;
diff --git a/src/script/lua_api/l_storage.h b/src/script/lua_api/l_storage.h
index 4e808c393..f8d102d04 100644
--- a/src/script/lua_api/l_storage.h
+++ b/src/script/lua_api/l_storage.h
@@ -50,7 +50,7 @@ private:
 
 public:
 	StorageRef(ModMetadata *object);
-	~StorageRef() {}
+	~StorageRef() = default;
 
 	static void Register(lua_State *L);
 	static void create(lua_State *L, ModMetadata *object);
diff --git a/src/script/lua_api/l_util.cpp b/src/script/lua_api/l_util.cpp
index c68f64a64..dffbc66d1 100644
--- a/src/script/lua_api/l_util.cpp
+++ b/src/script/lua_api/l_util.cpp
@@ -344,9 +344,9 @@ int ModApiUtil::l_get_dir_list(lua_State *L)
 	int index = 0;
 	lua_newtable(L);
 
-	for (size_t i = 0; i < list.size(); i++) {
-		if (list_all || list_dirs == list[i].dir) {
-			lua_pushstring(L, list[i].name.c_str());
+	for (const fs::DirListNode &dln : list) {
+		if (list_all || list_dirs == dln.dir) {
+			lua_pushstring(L, dln.name.c_str());
 			lua_rawseti(L, -2, ++index);
 		}
 	}
@@ -414,7 +414,7 @@ int ModApiUtil::l_get_version(lua_State *L)
 	lua_pushstring(L, g_version_string);
 	lua_setfield(L, table, "string");
 
-	if (strcmp(g_version_string, g_version_hash)) {
+	if (strcmp(g_version_string, g_version_hash) != 0) {
 		lua_pushstring(L, g_version_hash);
 		lua_setfield(L, table, "hash");
 	}
diff --git a/src/script/lua_api/l_vmanip.cpp b/src/script/lua_api/l_vmanip.cpp
index 1e973703c..a84ecfc0f 100644
--- a/src/script/lua_api/l_vmanip.cpp
+++ b/src/script/lua_api/l_vmanip.cpp
@@ -111,7 +111,7 @@ int LuaVoxelManip::l_write_to_map(lua_State *L)
 	MAP_LOCK_REQUIRED;
 
 	LuaVoxelManip *o = checkobject(L, 1);
-	bool update_light = lua_isboolean(L, 2) ? lua_toboolean(L, 2) : true;
+	bool update_light = !lua_isboolean(L, 2) || lua_toboolean(L, 2);
 	GET_ENV_PTR;
 	ServerMap *map = &(env->getServerMap());
 	if (o->is_mapgen_vm || !update_light) {
@@ -123,9 +123,8 @@ int LuaVoxelManip::l_write_to_map(lua_State *L)
 
 	MapEditEvent event;
 	event.type = MEET_OTHER;
-	for (std::map<v3s16, MapBlock *>::iterator it = o->modified_blocks.begin();
-			it != o->modified_blocks.end(); ++it)
-		event.modified_blocks.insert(it->first);
+	for (const auto &modified_block : o->modified_blocks)
+		event.modified_blocks.insert(modified_block.first);
 
 	map->dispatchEvent(&event);
 
@@ -198,7 +197,7 @@ int LuaVoxelManip::l_calc_lighting(lua_State *L)
 	v3s16 fpmax  = vm->m_area.MaxEdge;
 	v3s16 pmin   = lua_istable(L, 2) ? check_v3s16(L, 2) : fpmin + yblock;
 	v3s16 pmax   = lua_istable(L, 3) ? check_v3s16(L, 3) : fpmax - yblock;
-	bool propagate_shadow = lua_isboolean(L, 4) ? lua_toboolean(L, 4) : true;
+	bool propagate_shadow = !lua_isboolean(L, 4) || lua_toboolean(L, 4);
 
 	sortBoxVerticies(pmin, pmax);
 	if (!vm->m_area.contains(VoxelArea(pmin, pmax)))