new: preDowngrade hook

Author: ishland

FlowSched

@@ -50,7 +50,7 @@ public Completable upgradeToThis(ChunkLoadingContext context, Cancellable cancel
             }
 
             @Override
-            public Completable downgradeFromThis(ChunkLoadingContext context, Cancellable cancellable) {
+            public Completable downgradeFromThis(ChunkLoadingContext context) {
                 throw new UnsupportedOperationException();
             }
 

c2me-rewrites-chunk-system/src/main/java/com/ishland/c2me/rewrites/chunksystem/common/NewChunkStatus.java

@@ -6,8 +6,6 @@
 import io.reactivex.rxjava3.core.Completable;
 import net.minecraft.world.chunk.ChunkStatus;
 
-import java.util.concurrent.CompletableFuture;
-
 public class Deferred extends NewChunkStatus {
 
     public Deferred(int ordinal) {
@@ -20,7 +18,7 @@ public Completable upgradeToThis(ChunkLoadingContext context, Cancellable cancel
     }
 
     @Override
-    public Completable downgradeFromThis(ChunkLoadingContext context, Cancellable cancellable) {
+    public Completable downgradeFromThis(ChunkLoadingContext context) {
         return Completable.complete();
     }
 

c2me-rewrites-chunk-system/src/main/java/com/ishland/c2me/rewrites/chunksystem/common/statuses/Deferred.java

@@ -26,6 +26,7 @@
 import com.ishland.flowsched.util.Assertions;
 import io.reactivex.rxjava3.annotations.NonNull;
 import io.reactivex.rxjava3.core.Completable;
+import io.reactivex.rxjava3.core.CompletableObserver;
 import io.reactivex.rxjava3.core.Single;
 import io.reactivex.rxjava3.schedulers.Schedulers;
 import net.minecraft.nbt.NbtCompound;
@@ -46,10 +47,8 @@
 
 import java.util.Optional;
 import java.util.concurrent.CancellationException;
-import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionStage;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.function.Function;
 
 public class ReadFromDisk extends NewChunkStatus {
 
@@ -155,18 +154,26 @@ public Completable upgradeToThis(ChunkLoadingContext context, Cancellable cancel
     }
 
     @Override
-    public Completable downgradeFromThis(ChunkLoadingContext context, Cancellable cancellable) {
-        final AtomicBoolean loadedToWorld = new AtomicBoolean(false);
+    public Completable preDowngradeFromThis(ChunkLoadingContext context, Cancellable cancellable) {
         return Completable.defer(() -> Completable.fromCompletionStage(syncWithLightEngine(context)))
                 .observeOn(Schedulers.from(((IThreadedAnvilChunkStorage) context.tacs()).getMainThreadExecutor()))
-                .andThen(Completable.defer(() -> {
+                .andThen((CompletableObserver observer) -> {
+                    if (context.holder().getTargetStatus().ordinal() > this.ordinal()) { // saving cancelled
+                        cancellable.cancel();
+                        observer.onError(new CancellationException());
+                    } else {
+                        observer.onComplete();
+                    }
+                });
+    }
+
+    @Override
+    public Completable downgradeFromThis(ChunkLoadingContext context) {
+        final AtomicBoolean loadedToWorld = new AtomicBoolean(false);
+        return Completable.defer(() -> {
                     Assertions.assertTrue(((IThreadedAnvilChunkStorage) context.tacs()).getMainThreadExecutor().isOnThread());
 
                     try (var ignored = ThreadInstrumentation.getCurrent().begin(new ChunkTaskWork(context, this, false))) {
-                        if (context.holder().getTargetStatus().ordinal() > this.ordinal()) { // saving cancelled
-                            cancellable.cancel();
-                            return Completable.error(new CancellationException());
-                        }
                         final ChunkState chunkState = context.holder().getItem().get();
                         Chunk chunk = chunkState.chunk();
                         if (chunk instanceof WrapperProtoChunk protoChunk) chunk = protoChunk.getWrappedChunk();
@@ -206,7 +213,7 @@ public Completable downgradeFromThis(ChunkLoadingContext context, Cancellable ca
 
                         return asyncSaveFuture;
                     }
-                }));
+        });
     }
 
     private Completable asyncSave(ChunkLoadingContext context, Chunk chunk) {

c2me-rewrites-chunk-system/src/main/java/com/ishland/c2me/rewrites/chunksystem/common/statuses/ReadFromDisk.java

@@ -96,7 +96,7 @@ private static WorldChunk toFullChunk(ProtoChunk protoChunk, ServerWorld serverW
     }
 
     @Override
-    public Completable downgradeFromThis(ChunkLoadingContext context, Cancellable cancellable) {
+    public Completable downgradeFromThis(ChunkLoadingContext context) {
         ChunkState state = context.holder().getItem().get();
         final Chunk chunk = state.chunk();
         Preconditions.checkState(chunk instanceof WorldChunk, "Chunk must be a full chunk");

c2me-rewrites-chunk-system/src/main/java/com/ishland/c2me/rewrites/chunksystem/common/statuses/ServerAccessible.java

@@ -10,8 +10,6 @@
 import net.minecraft.util.math.ChunkPos;
 import net.minecraft.world.chunk.ChunkStatus;
 
-import java.util.concurrent.CompletableFuture;
-
 public class ServerAccessibleChunkSending extends NewChunkStatus {
 
     private static final KeyStatusPair<ChunkPos, ChunkState, ChunkLoadingContext>[] deps;
@@ -30,7 +28,7 @@ public Completable upgradeToThis(ChunkLoadingContext context, Cancellable cancel
     }
 
     @Override
-    public Completable downgradeFromThis(ChunkLoadingContext context, Cancellable cancellable) {
+    public Completable downgradeFromThis(ChunkLoadingContext context) {
         return Completable.complete();
     }
 

c2me-rewrites-chunk-system/src/main/java/com/ishland/c2me/rewrites/chunksystem/common/statuses/ServerAccessibleChunkSending.java

@@ -129,7 +129,7 @@ private static void sendChunkToPlayer(ChunkLoadingContext context) {
     }
 
     @Override
-    public Completable downgradeFromThis(ChunkLoadingContext context, Cancellable cancellable) {
+    public Completable downgradeFromThis(ChunkLoadingContext context) {
         ServerWorld serverWorld = ((IThreadedAnvilChunkStorage) context.tacs()).getWorld();
         final WorldChunk chunk = (WorldChunk) context.holder().getItem().get().chunk();
         ((WorldChunkExtension) chunk).c2me$setBlockTicking(false);

c2me-rewrites-chunk-system/src/main/java/com/ishland/c2me/rewrites/chunksystem/common/statuses/ServerBlockTicking.java

@@ -20,8 +20,6 @@
 import net.minecraft.world.chunk.ChunkStatus;
 import net.minecraft.world.chunk.WorldChunk;
 
-import java.util.concurrent.CompletableFuture;
-
 public class ServerEntityTicking extends NewChunkStatus {
 
     private static final KeyStatusPair<ChunkPos, ChunkState, ChunkLoadingContext>[] deps;
@@ -61,7 +59,7 @@ public Completable upgradeToThis(ChunkLoadingContext context, Cancellable cancel
     }
 
     @Override
-    public Completable downgradeFromThis(ChunkLoadingContext context, Cancellable cancellable) {
+    public Completable downgradeFromThis(ChunkLoadingContext context) {
         if (ModStatuses.fabric_lifecycle_events_v1 && LifecycleEventInvoker.needsInvokeChunkLevelTypeChange()) {
             return Completable
                     .fromRunnable(() -> {

c2me-rewrites-chunk-system/src/main/java/com/ishland/c2me/rewrites/chunksystem/common/statuses/ServerEntityTicking.java

@@ -149,7 +149,7 @@ public Completable upgradeToThis(ChunkLoadingContext context, Cancellable cancel
     }
 
     @Override
-    public Completable downgradeFromThis(ChunkLoadingContext context, Cancellable cancellable) {
+    public Completable downgradeFromThis(ChunkLoadingContext context) {
         return Completable.complete();
     }