Add after_destruct and cache the existence of on_construct, on_destruct and after_destruct for quick skipping when a node does not have them

doc/lua_api.txt

@@ -1150,15 +1150,18 @@ Node definition (register_node)
     on_destruct = func(pos),
     ^ Node destructor; always called before removing node
     ^ default: nil
+    after_destruct = func(pos, oldnode),
+    ^ Node destructor; always called after removing node
+    ^ default: nil
 
     after_place_node = func(pos, placer),
     ^ Called after constructing node when node was placed using
-      minetest.item_place_node
+      minetest.item_place_node / minetest.env:place_node
     ^ default: nil
     after_dig_node = func(pos, oldnode, oldmetadata, digger),
     ^ oldmetadata is in table format
     ^ Called after destructing node when node was dug using
-      minetest.node_dig
+      minetest.node_dig / minetest.env:dig_node
     ^ default: nil
     can_dig = function(pos,player)
     ^ returns true if node can be dug, or false if not

games/minimal/mods/experimental/init.lua

@@ -468,6 +468,10 @@ minetest.register_node("experimental:tester_node_1", {
 		experimental.print_to_everything("experimental:tester_node_1:on_destruct("..minetest.pos_to_string(pos)..")")
 	end,
  
+	after_destruct = function(pos)
+		experimental.print_to_everything("experimental:tester_node_1:after_destruct("..minetest.pos_to_string(pos)..")")
+	end,
+ 
 	after_dig_node = function(pos, oldnode, oldmetadata, digger)
 		experimental.print_to_everything("experimental:tester_node_1:after_dig_node("..minetest.pos_to_string(pos)..")")
 	end,

src/nodedef.cpp

@@ -117,6 +117,9 @@ void ContentFeatures::reset()
 	visual_solidness = 0;
 	backface_culling = true;
 #endif
+	has_on_construct = false;
+	has_on_destruct = false;
+	has_after_destruct = false;
 	/*
 		Actual data
 		

src/nodedef.h

@@ -144,6 +144,11 @@ struct ContentFeatures
 	bool backface_culling;
 #endif
 
+	// Server-side cached callback existence for fast skipping
+	bool has_on_construct;
+	bool has_on_destruct;
+	bool has_after_destruct;
+
 	/*
 		Actual data
 	*/

src/scriptapi.cpp

@@ -994,6 +994,18 @@ static ContentFeatures read_content_features(lua_State *L, int index)
 		index = lua_gettop(L) + 1 + index;
 
 	ContentFeatures f;
+	
+	/* Cache existence of some callbacks */
+	lua_getfield(L, index, "on_construct");
+	if(!lua_isnil(L, -1)) f.has_on_construct = true;
+	lua_pop(L, 1);
+	lua_getfield(L, index, "on_destruct");
+	if(!lua_isnil(L, -1)) f.has_on_destruct = true;
+	lua_pop(L, 1);
+	lua_getfield(L, index, "after_destruct");
+	if(!lua_isnil(L, -1)) f.has_after_destruct = true;
+	lua_pop(L, 1);
+
 	/* Name */
 	getstringfield(L, index, "name", f.name);
 
@@ -3024,20 +3036,26 @@ private:
 		EnvRef *o = checkobject(L, 1);
 		ServerEnvironment *env = o->m_env;
 		if(env == NULL) return 0;
-		// pos
+		INodeDefManager *ndef = env->getGameDef()->ndef();
+		// parameters
 		v3s16 pos = read_v3s16(L, 2);
-		// content
+		MapNode n = readnode(L, 3, ndef);
-		MapNode n = readnode(L, 3, env->getGameDef()->ndef());
 		// Do it
-		// Call destructor
 		MapNode n_old = env->getMap().getNodeNoEx(pos);
-		scriptapi_node_on_destruct(L, pos, n_old);
+		// Call destructor
+		if(ndef->get(n_old).has_on_destruct)
+			scriptapi_node_on_destruct(L, pos, n_old);
 		// Replace node
 		bool succeeded = env->getMap().addNodeWithEvent(pos, n);
+		if(succeeded){
+			// Call post-destructor
+			if(ndef->get(n_old).has_after_destruct)
+				scriptapi_node_after_destruct(L, pos, n_old);
+			// Call constructor
+			if(ndef->get(n).has_on_construct)
+				scriptapi_node_on_construct(L, pos, n);
+		}
 		lua_pushboolean(L, succeeded);
-		// Call constructor
-		if(succeeded)
-			scriptapi_node_on_construct(L, pos, n);
 		return 1;
 	}
 
@@ -3053,14 +3071,22 @@ private:
 		EnvRef *o = checkobject(L, 1);
 		ServerEnvironment *env = o->m_env;
 		if(env == NULL) return 0;
+		INodeDefManager *ndef = env->getGameDef()->ndef();
+		// parameters
 		v3s16 pos = read_v3s16(L, 2);
 		// Do it
+		MapNode n_old = env->getMap().getNodeNoEx(pos);
 		// Call destructor
-		MapNode n = env->getMap().getNodeNoEx(pos);
+		if(ndef->get(n_old).has_on_destruct)
-		scriptapi_node_on_destruct(L, pos, n);
+			scriptapi_node_on_destruct(L, pos, n_old);
 		// Replace with air
 		// This is slightly optimized compared to addNodeWithEvent(air)
 		bool succeeded = env->getMap().removeNodeWithEvent(pos);
+		if(succeeded){
+			// Call post-destructor
+			if(ndef->get(n_old).has_after_destruct)
+				scriptapi_node_after_destruct(L, pos, n_old);
+		}
 		lua_pushboolean(L, succeeded);
 		// Air doesn't require constructor
 		return 1;
@@ -5143,6 +5169,25 @@ void scriptapi_node_on_destruct(lua_State *L, v3s16 p, MapNode node)
 		script_error(L, "error: %s", lua_tostring(L, -1));
 }
 
+void scriptapi_node_after_destruct(lua_State *L, v3s16 p, MapNode node)
+{
+	realitycheck(L);
+	assert(lua_checkstack(L, 20));
+	StackUnroller stack_unroller(L);
+
+	INodeDefManager *ndef = get_server(L)->ndef();
+
+	// Push callback function on stack
+	if(!get_item_callback(L, ndef->get(node).name.c_str(), "after_destruct"))
+		return;
+
+	// Call function
+	push_v3s16(L, p);
+	pushnode(L, node, ndef);
+	if(lua_pcall(L, 2, 0, 0))
+		script_error(L, "error: %s", lua_tostring(L, -1));
+}
+
 void scriptapi_node_on_receive_fields(lua_State *L, v3s16 p,
 		const std::string &formname,
 		const std::map<std::string, std::string> &fields,

src/scriptapi.h

@@ -86,6 +86,8 @@ bool scriptapi_node_on_dig(lua_State *L, v3s16 p, MapNode node,
 void scriptapi_node_on_construct(lua_State *L, v3s16 p, MapNode node);
 // Node destructor
 void scriptapi_node_on_destruct(lua_State *L, v3s16 p, MapNode node);
+// Node post-destructor
+void scriptapi_node_after_destruct(lua_State *L, v3s16 p, MapNode node);
 // Called when a metadata form returns values
 void scriptapi_node_on_receive_fields(lua_State *L, v3s16 p,
 		const std::string &formname,