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Fast path for self-triggered IC thinks #1379

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eecf956
Fast path for self-triggered IC thinks
RasmusKD Aug 16, 2026
27e9b1b
Drop the chunk-loaded memoisation
RasmusKD Aug 19, 2026
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25 changes: 5 additions & 20 deletions src/main/java/com/sk89q/craftbook/core/st/SelfTriggeringManager.java
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Original file line number Diff line number Diff line change
Expand Up @@ -91,31 +91,16 @@ public Collection<Location> getSelfTriggeringMechanics() {
private Location[] registeredLocations;
private boolean hasChanged = false;

private boolean areAdjacentChunksLoaded(Location loc) {
private static boolean areAdjacentChunksLoaded(Location loc) {
World world = loc.getWorld();

final int CX = loc.getBlockX() >> 4;
final int CZ = loc.getBlockZ() >> 4;

for (int x = -1; x <= 1; ++x) {
for (int z = -1; z <= 1; ++z) {
// Check only cardinal directions
if (x != 0 && z != 0) {
continue;
}

// Don't test the current chunk
if (x == 0 && z == 0) {
continue;
}

if (!world.isChunkLoaded(CX + x, CZ + z)) {
return false;
}
}
}

return true;
return world.isChunkLoaded(CX - 1, CZ)
&& world.isChunkLoaded(CX + 1, CZ)
&& world.isChunkLoaded(CX, CZ - 1)
&& world.isChunkLoaded(CX, CZ + 1);
}

/**
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33 changes: 33 additions & 0 deletions src/main/java/com/sk89q/craftbook/mechanics/ic/ICMechanic.java
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@
import com.sk89q.worldedit.bukkit.BukkitAdapter;
import org.apache.commons.lang.StringUtils;
import org.bukkit.Bukkit;
import org.bukkit.Location;
import org.bukkit.block.Block;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
Expand All @@ -45,8 +46,10 @@
import org.bukkit.event.block.SignChangeEvent;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.regex.Matcher;

/**
Expand Down Expand Up @@ -303,10 +306,35 @@ public void onThink(SelfTriggerThinkEvent event) {

if(!EventUtil.passesFilter(event)) return;

// Fast path: a cached self-triggered IC thinks without re-snapshotting and
// re-parsing its sign (getState + component serialization + regex, per IC
// per tick - the dominant framework cost with many STs). The full setupIC
// verification still reruns once a second per IC, and the entry is only
// honoured while the IC remains in ICManager's cache, so break/unload
// invalidation is unchanged.
Location loc = event.getBlock().getLocation();
long now = System.currentTimeMillis();
Object[] fast = thinkFastCache.get(loc);
if (fast != null && now < (Long) fast[1] && ICManager.isCachedIC(loc)) {
IC cachedIC = ICManager.getCachedIC(loc);
if (cachedIC instanceof SelfTriggeredIC selfTriggeredIC) {
event.setHandled(true);
ChipState chipState = ((ICFamily) fast[0]).detectSelfTriggered(BukkitAdapter.adapt(loc), cachedIC.getSign());
selfTriggeredIC.think(chipState);
try {
cachedIC.getSign().update(false);
} catch (Throwable ignored) {}
return;
}
}

final Object[] icData = setupIC(event.getBlock(), true);

if(icData != null && icData[2] instanceof SelfTriggeredIC ic) {
event.setHandled(true);
if (thinkFastCache.size() > MAX_THINK_FAST_ENTRIES)
thinkFastCache.clear();
thinkFastCache.put(loc, new Object[] { icData[1], now + THINK_REVERIFY_MILLIS });
ChipState chipState = ((ICFamily) icData[1]).detectSelfTriggered(BukkitAdapter.adapt(event.getBlock().getLocation()), ((IC) icData[2]).getSign());
ic.think(chipState);
try {
Expand All @@ -315,6 +343,11 @@ public void onThink(SelfTriggerThinkEvent event) {
}
}

/** Location -> {ICFamily, reverify-deadline millis} for the think fast path. */
private final Map<Location, Object[]> thinkFastCache = new HashMap<>();
private static final long THINK_REVERIFY_MILLIS = 1000L;
private static final int MAX_THINK_FAST_ENTRIES = 4096;

@EventHandler(priority = EventPriority.HIGH)
public void onBlockBreak(BlockBreakEvent event) {

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