Fix block entity memory leak (API 9) (#3813)

* Fix block entity memory leak * Update src/mixins/java/org/spongepowered/common/mixin/core/server/level/ServerLevelMixin.java
SpongePowered · Jan 13, 2023 · 02d449c · 02d449c
1 parent 687a135
commit 02d449c
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diff --git a/src/mixins/java/org/spongepowered/common/mixin/core/server/level/ServerLevelMixin.java b/src/mixins/java/org/spongepowered/common/mixin/core/server/level/ServerLevelMixin.java
@@ -47,6 +47,7 @@
 import net.minecraft.world.level.block.Block;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.entity.JukeboxBlockEntity;
+import net.minecraft.world.level.block.entity.TickingBlockEntity;
 import net.minecraft.world.level.chunk.ChunkGenerator;
 import net.minecraft.world.level.dimension.DimensionType;
 import net.minecraft.world.level.gameevent.GameEvent;
@@ -57,6 +58,7 @@
 import net.minecraft.world.level.storage.ServerLevelData;
 import net.minecraft.world.level.storage.WorldData;
 import net.minecraft.world.ticks.LevelTicks;
+import org.objectweb.asm.Opcodes;
 import org.spongepowered.api.ResourceKey;
 import org.spongepowered.api.Sponge;
 import org.spongepowered.api.block.BlockSnapshot;
@@ -520,6 +522,29 @@ public void save(@Nullable final ProgressListener progress, final boolean flush,
         manager.add(pos, type);
     }
 
+    @Inject(
+        method = "tick",
+        at = @At(
+            value = "FIELD",
+            target = "Lnet/minecraft/server/level/ServerLevel;emptyTime:I",
+            opcode = Opcodes.PUTFIELD,
+            shift = At.Shift.AFTER
+        )
+    )
+    private void impl$unloadBlockEntities(final BooleanSupplier param0, final CallbackInfo ci) {
+        /*
+         * This code fixes block entity memory leak when the level hasn't online players
+         * and forced chunks. For the first 300 ticks the level can still clean up removed
+         * block entities on its own (ticks are performed for block entities). After it
+         * this mixin code is responsible for the subsequent unloading of block entities.
+         * Such a memory leak occurs when a plugin writes a lot of blocks, but the level
+         * is without players.
+         */
+        if (this.emptyTime >= 300 && !this.blockEntityTickers.isEmpty()) {
+            this.blockEntityTickers.removeIf(TickingBlockEntity::isRemoved);
+        }
+    }
+
     @Override
     public String toString() {
         final Optional<ResourceKey> worldTypeKey = RegistryTypes.WORLD_TYPE.get().findValueKey((WorldType) this.shadow$dimensionType());

diff --git a/src/mixins/java/org/spongepowered/common/mixin/core/world/level/LevelMixin.java b/src/mixins/java/org/spongepowered/common/mixin/core/world/level/LevelMixin.java
@@ -40,6 +40,7 @@
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.LevelAccessor;
 import net.minecraft.world.level.block.Blocks;
+import net.minecraft.world.level.block.entity.TickingBlockEntity;
 import net.minecraft.world.level.border.WorldBorder;
 import net.minecraft.world.level.chunk.LevelChunk;
 import net.minecraft.world.level.dimension.DimensionType;
@@ -67,6 +68,7 @@
 import org.spongepowered.common.util.DataUtil;
 import org.spongepowered.math.vector.Vector3d;
 
+import java.util.List;
 import java.util.function.Predicate;
 
 @Mixin(net.minecraft.world.level.Level.class)
@@ -78,6 +80,7 @@ public abstract class LevelMixin implements LevelBridge, LevelAccessor {
     @Shadow protected float rainLevel;
     @Shadow protected float oThunderLevel;
     @Shadow protected float thunderLevel;
+    @Shadow @Final protected List<TickingBlockEntity> blockEntityTickers;
 
     @Shadow public abstract LevelData shadow$getLevelData();
     @Shadow public abstract void shadow$updateSkyBrightness();