From 7014c9ad5ae7db1ea03e09c19094eacd80ee2950 Mon Sep 17 00:00:00 2001
From: Dirk Sohler <dirk@0x7be.de>
Date: Sat, 22 Jun 2019 12:28:21 +0200
Subject: [PATCH] add node sounds checking function

Some nodes do not provide sounds. With implementation of this function
and saubsequent checks no sounds are played if not available.

Fixes https://gitlab.com/4w/uniham/issues/2
---
 system/crush_nodes.lua | 47 +++++++++++++++++++++++++++++++-----------
 1 file changed, 35 insertions(+), 12 deletions(-)

diff --git a/system/crush_nodes.lua b/system/crush_nodes.lua
index f92caad..b890b56 100644
--- a/system/crush_nodes.lua
+++ b/system/crush_nodes.lua
@@ -13,6 +13,25 @@ local replacements = {
     ['default:silver_sandstone']  =  'default:silver_sand',
 }
 
+-- Get a node sound
+--
+-- This helper function returns a sound table or nil depending on wheter the
+-- requested sound type exists in the provided node definition or not.
+--
+-- Common sound types are `dug`, footstep`, or `place`. For example: When
+-- requesting the `dug` sounds of a node definition the function checks if
+-- the table node_definition.sounds.dug exists and if so it returns that
+-- table. If the table does not exist `nil` is returned.
+--
+-- @param node_definition The desired node’s definition
+-- @param sound_type Name of a sound
+local get_sound = function (node_definition, sound_type)
+    if not node_definition then return end
+    if not node_definition.sounds then return end
+    if not node_definition.sounds[sound_type] then return end
+    return node_definition.sounds[sound_type]
+end
+
 
 -- Hammer use function
 --
@@ -29,26 +48,30 @@ uniham.crush_nodes = function (itemstack, player, pointed_thing)
     if pointed_thing.type ~= 'node' then return end
     local node_pos = minetest.get_pointed_thing_position(pointed_thing)
     local node_name = minetest.get_node(node_pos).name
-    local node_sounds = minetest.registered_nodes[node_name].sounds
+    local node_sound = get_sound(minetest.registered_nodes[node_name], 'dug')
 
     if not replacements[node_name] then
-        minetest.sound_play(node_sounds.dug.name, {
-            pos = node_pos,
-            max_hear_distance = 8,
-            gain = node_sounds.dug.gain,
-        })
+        if node_sound then
+            minetest.sound_play(node_sound.name, {
+                pos = node_pos,
+                max_hear_distance = 8,
+                gain = node_sound.gain,
+            })
+        end
         return
     end
 
     local replacement = replacements[node_name]
-    local replacement_sounds = minetest.registered_nodes[replacement].sounds
+    local rep_sound = get_sound(minetest.registered_nodes[replacement], 'dug')
     local uses = minetest.registered_tools[itemstack:get_name()]._uniham.uses
 
-    minetest.sound_play(replacement_sounds.dug.name, {
-        pos = node_pos,
-        max_hear_distance = 8,
-        gain = replacement_sounds.dug.gain,
-    })
+    if rep_sound then
+        minetest.sound_play(rep_sound.name, {
+            pos = node_pos,
+            max_hear_distance = 8,
+            gain = rep_sound.gain,
+        })
+    end
 
     minetest.set_node(node_pos, { name = replacement })
     minetest.check_for_falling(node_pos)