TNT: Track TNT owner in metadata for protection mods

It is useful for protection mods to know who owns an exploding
TNT block. This allows the blocks destroyed by the TNT to be
limited to the same ones the owner could destroy without using
TNT.

TNT placed within a protected area by the area owner, and later
ignited by another player will destroy within the protected area
nodes the igniter may not otherwise be able to interact with. Any
player could significantly increase the size of an explosion by
placing more TNT in an adjacent unprotected area if the original
TNT block was placed withing 1 node of such a boundary. This
feature sounds dangerous, but we are talking about TNT. Players
should use it carefully.

mods/tnt/init.lua

@@ -86,8 +86,8 @@ end
 local basic_flame_on_construct -- cached value
 local function destroy(drops, npos, cid, c_air, c_fire,
 		on_blast_queue, on_construct_queue,
-		ignore_protection, ignore_on_blast)
+		ignore_protection, ignore_on_blast, owner)
-	if not ignore_protection and minetest.is_protected(npos, "") then
+	if not ignore_protection and minetest.is_protected(npos, owner) then
 		return cid
 	end
 
@@ -266,13 +266,13 @@ function tnt.burn(pos, nodename)
 	elseif def.on_ignite then
 		def.on_ignite(pos)
 	elseif minetest.get_item_group(name, "tnt") > 0 then
+		minetest.swap_node(pos, {name = name .. "_burning"})
 		minetest.sound_play("tnt_ignite", {pos = pos})
-		minetest.set_node(pos, {name = name .. "_burning"})
 		minetest.get_node_timer(pos):start(1)
 	end
 end
 
-local function tnt_explode(pos, radius, ignore_protection, ignore_on_blast)
+local function tnt_explode(pos, radius, ignore_protection, ignore_on_blast, owner)
 	pos = vector.round(pos)
 	-- scan for adjacent TNT nodes first, and enlarge the explosion
 	local vm1 = VoxelManip()
@@ -333,7 +333,7 @@ local function tnt_explode(pos, radius, ignore_protection, ignore_on_blast)
 			if cid ~= c_air then
 				data[vi] = destroy(drops, p, cid, c_air, c_fire,
 					on_blast_queue, on_construct_queue,
-					ignore_protection, ignore_on_blast)
+					ignore_protection, ignore_on_blast, owner)
 			end
 		end
 		vi = vi + 1
@@ -375,14 +375,19 @@ local function tnt_explode(pos, radius, ignore_protection, ignore_on_blast)
 		queued_data.fn(queued_data.pos)
 	end
 
+	minetest.log("action", "TNT owned by " .. owner .. " detonated at " ..
+		minetest.pos_to_string(pos) .. " with radius " .. radius)
+
 	return drops, radius
 end
 
 function tnt.boom(pos, def)
+	local meta = minetest.get_meta(pos)
+	local owner = meta:get_string("owner")
 	minetest.sound_play("tnt_explode", {pos = pos, gain = 1.5, max_hear_distance = 2*64})
 	minetest.set_node(pos, {name = "tnt:boom"})
 	local drops, radius = tnt_explode(pos, def.radius, def.ignore_protection,
-			def.ignore_on_blast)
+			def.ignore_on_blast, owner)
 	-- append entity drops
 	local damage_radius = (radius / def.radius) * def.damage_radius
 	entity_physics(pos, damage_radius, drops)
@@ -579,9 +584,16 @@ function tnt.register_tnt(def)
 			is_ground_content = false,
 			groups = {dig_immediate = 2, mesecon = 2, tnt = 1, flammable = 5},
 			sounds = default.node_sound_wood_defaults(),
+			after_place_node = function(pos, placer)
+				if placer:is_player() then
+					local meta = minetest.get_meta(pos)
+					meta:set_string("owner", placer:get_player_name())
+				end
+			end,
 			on_punch = function(pos, node, puncher)
 				if puncher:get_wielded_item():get_name() == "default:torch" then
-					minetest.set_node(pos, {name = name .. "_burning"})
+					minetest.swap_node(pos, {name = name .. "_burning"})
+					minetest.registered_nodes[name .. "_burning"].on_construct(pos)
 					minetest.log("action", puncher:get_player_name() ..
 						" ignites " .. node.name .. " at " ..
 						minetest.pos_to_string(pos))
@@ -600,10 +612,12 @@ function tnt.register_tnt(def)
 				}
 			},
 			on_burn = function(pos)
-				minetest.set_node(pos, {name = name .. "_burning"})
+				minetest.swap_node(pos, {name = name .. "_burning"})
+				minetest.registered_nodes[name .. "_burning"].on_construct(pos)
 			end,
 			on_ignite = function(pos, igniter)
-				minetest.set_node(pos, {name = name .. "_burning"})
+				minetest.swap_node(pos, {name = name .. "_burning"})
+				minetest.registered_nodes[name .. "_burning"].on_construct(pos)
 			end,
 		})
 	end