Improve splicing table media refill logic (fix #40, fix #41, fix #44, fix #45)

Author: object-Object

CHANGELOG.md

@@ -10,10 +10,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/)
 
 - Added keyboard shortcuts to the Splicing Table, configurable in HexDebug's client config menu.
 - The Splicing Table now works with Media Purification from [Hexpose](https://miyucomics.github.io/hexpose) (requires at least build [2e90cf5b](https://github.com/miyucomics/hexpose/commit/2e90cf5babb7677a26ca211bd66ac2777e5518cd), or any version after 1.0.0).
+- Added a tag (`hexdebug:splicing_table/media_blacklist`) to prevent an item from being used to refill the Splicing Table's media buffer.  
 
 ### Fixed
 
 - Fixed an issue where newly placed splicing tables would default to having the first iota selected.
+- Fixed several bugs/exploits related to the Splicing Table's media buffer ([#40](https://github.com/object-Object/HexDebug/pull/40), [#41](https://github.com/object-Object/HexDebug/pull/41), [#44](https://github.com/object-Object/HexDebug/pull/44), [#45](https://github.com/object-Object/HexDebug/pull/45)).
 
 ## `0.4.0+1.20.1` - 2025-09-21
 

Common/src/main/java/gay/object/hexdebug/api/HexDebugTags.java

@@ -0,0 +1,17 @@
+package gay.object.hexdebug.api;
+
+import gay.object.hexdebug.HexDebug;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.tags.TagKey;
+import net.minecraft.world.item.Item;
+
+@SuppressWarnings("SameParameterValue")
+public final class HexDebugTags {
+    public static final class Items {
+        public static final TagKey<Item> SPLICING_TABLE_MEDIA_BLACKLIST = create("splicing_table/media_blacklist");
+
+        private static TagKey<Item> create(String name) {
+            return TagKey.create(Registries.ITEM, HexDebug.id(name));
+        }
+    }
+}

Common/src/main/kotlin/gay/object/hexdebug/blocks/splicing/SplicingTableBlockEntity.kt

@@ -18,6 +18,7 @@ import at.petrak.hexcasting.api.utils.extractMedia
 import at.petrak.hexcasting.api.utils.getInt
 import at.petrak.hexcasting.api.utils.getList
 import at.petrak.hexcasting.xplat.IXplatAbstractions
+import gay.`object`.hexdebug.api.HexDebugTags
 import gay.`object`.hexdebug.blocks.base.BaseContainer
 import gay.`object`.hexdebug.blocks.base.ContainerDataDelegate
 import gay.`object`.hexdebug.blocks.base.ContainerDataLongDelegate
@@ -58,12 +59,16 @@ class SplicingTableBlockEntity(pos: BlockPos, state: BlockState) :
 
     var listStack by SplicingTableItemSlot.LIST.delegate
     var clipboardStack by SplicingTableItemSlot.CLIPBOARD.delegate
-    var mediaStack by SplicingTableItemSlot.MEDIA.delegate
-        private set
+    private var mediaStack by SplicingTableItemSlot.MEDIA.delegate
     private var staffStack by SplicingTableItemSlot.STAFF.delegate
 
     private val listHolder get() = IXplatAbstractions.INSTANCE.findDataHolder(listStack)
     val clipboardHolder get() = IXplatAbstractions.INSTANCE.findDataHolder(clipboardStack)
+    val mediaHolder get() =
+        mediaStack
+            .takeIf { !it.`is`(HexDebugTags.Items.SPLICING_TABLE_MEDIA_BLACKLIST) }
+            ?.let { HexAPI.instance().findMediaHolder(it) }
+            ?.takeIf { it.canProvide() }
 
     private val containerData = SimpleContainerData(SplicingTableDataSlot.size)
 
@@ -89,6 +94,7 @@ class SplicingTableBlockEntity(pos: BlockPos, state: BlockState) :
         private set
 
     private var castingCooldown = 0
+    private var isCurrentlyCasting = false
 
     val analogOutputSignal get() = if (!listStack.isEmpty) 15 else 0
 
@@ -346,7 +352,16 @@ class SplicingTableBlockEntity(pos: BlockPos, state: BlockState) :
         val env = SplicingTableCastEnv(player, this)
         val vm = CastingVM.empty(env)
 
-        val clientView = vm.queueExecuteAndWrapIotas(instrs, level)
+        // prevent refilling while casting
+        isCurrentlyCasting = true
+        val clientView = try {
+            vm.queueExecuteAndWrapIotas(instrs, level)
+        } finally {
+            isCurrentlyCasting = false
+        }
+
+        refillMedia()
+        sync()
 
         if (clientView.resolutionType.success) {
             ParticleSpray(blockPos.center, Vec3(0.0, 1.5, 0.0), 0.4, Math.PI / 3, 30)
@@ -413,17 +428,29 @@ class SplicingTableBlockEntity(pos: BlockPos, state: BlockState) :
         refillMedia()
     }
 
-    fun refillMedia() {
-        val mediaHolder = HexAPI.instance().findMediaHolder(mediaStack) ?: return
-        while (media < maxMedia) {
-            val cost = maxMedia - media
+    private fun refillMedia() {
+        if (isCurrentlyCasting) return
+        val mediaHolder = mediaHolder ?: return
+
+        // for static media items (eg. dust), extract media from one item at a time
+        // this is necessary to avoid wasting media while still getting as much as possible out of the stack
+        val unitCost = HexAPI.instance()
+            .findMediaHolder(mediaStack.copyWithCount(1))
+            ?.withdrawMedia(-1, true)
+            ?: media
+
+        // extract media at most once for each item in the stack
+        // prevents big looping in case someone thinks they're funny
+        for (i in 0 until mediaStack.count) {
+            val cost = min(maxMedia - media, unitCost)
+            if (cost <= 0) return
 
             // avoid wasting media if the item is too large
-            if (extractMedia(mediaStack, cost = cost, simulate = true) !in 1..cost) return
+            if (extractMedia(mediaHolder, cost = cost, simulate = true) !in 1..cost) return
 
-            // avoid an infinite loop - stop looping as soon as we stop adding media
+            // stop looping as soon as we stop adding media
             val extracted = extractMedia(mediaHolder, cost = cost)
-            if (extracted < 1) return
+            if (extracted <= 1) return // the Inexhaustible Phial thinks it's funny.
 
             media += extracted
         }

Common/src/main/kotlin/gay/object/hexdebug/casting/eval/SplicingTableCastEnv.kt

@@ -35,7 +35,6 @@ class SplicingTableCastEnv(
 
     override fun postCast(image: CastingImage) {
         super.postCast(image)
-        table.sync() // TODO: is this necessary?
         sound.sound?.let {
             world.playSound(null, blockPos, it, SoundSource.PLAYERS, 1f, 1f)
         }
@@ -57,15 +56,11 @@ class SplicingTableCastEnv(
 
         // then, pull straight from the item in the media slot
         if (costLeft > 0) {
-            HexAPI.instance().findMediaHolder(table.mediaStack)?.let {
+            table.mediaHolder?.let {
                 costLeft -= extractMedia(it, cost = costLeft, simulate = simulate)
             }
         }
 
-        if (!simulate) {
-            table.refillMedia()
-        }
-
         return costLeft
     }
 

Common/src/main/kotlin/gay/object/hexdebug/gui/splicing/SplicingTableMenu.kt

@@ -2,6 +2,7 @@ package gay.`object`.hexdebug.gui.splicing
 
 import at.petrak.hexcasting.api.mod.HexTags
 import at.petrak.hexcasting.api.utils.isMediaItem
+import gay.`object`.hexdebug.api.HexDebugTags
 import gay.`object`.hexdebug.blocks.base.ContainerDataDelegate
 import gay.`object`.hexdebug.blocks.base.ContainerDataLongDelegate
 import gay.`object`.hexdebug.blocks.base.ContainerDataSelectionDelegate
@@ -80,7 +81,7 @@ class SplicingTableMenu(
             mayPlace = ::isIotaHolder
         }
         mediaSlot = addTableSlot(SplicingTableItemSlot.MEDIA, 205, 169) {
-            mayPlace = ::isMediaItem
+            mayPlace = { isMediaItem(it) && !it.`is`(HexDebugTags.Items.SPLICING_TABLE_MEDIA_BLACKLIST) }
         }
         staffSlot = addTableSlot(SplicingTableItemSlot.STAFF, -20, 169) {
             maxStackSize = 1