Improve performance of various commands/actions

- Add chunk preloading to RegionVisitor if supplied with a suitable Extent
 - Where extents are used in masks, set EditSession as the extent as they are otherwise initialised with WorldWrapper that is very slow
 - Fixes #1073

worldedit-core/src/main/java/com/sk89q/worldedit/EditSession.java

@@ -1242,7 +1242,7 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
                 }
             }
             return true;
-        });
+        }, this);
         Operations.completeBlindly(visitor);
         return this.changes;
     }
@@ -2783,7 +2783,7 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
             } catch (EvaluationException e) {
                 throw new RuntimeException(e);
             }
-        });
+        }, this);
         Operations.completeBlindly(visitor);
         changes += visitor.getAffected();
         return changes;

worldedit-core/src/main/java/com/sk89q/worldedit/command/BiomeCommands.java

@@ -177,7 +177,9 @@ public class BiomeCommands {
         if (mask != null) {
             replace = new RegionMaskingFilter(editSession, mask, replace);
         }
-        RegionVisitor visitor = new RegionVisitor(region, replace);
+        //FAWE start > add extent to RegionVisitor to allow chunk preloading
+        RegionVisitor visitor = new RegionVisitor(region, replace, editSession);
+        //FAWE end
         Operations.completeLegacy(visitor);
 
         player.print(Caption.of(

worldedit-core/src/main/java/com/sk89q/worldedit/command/GenerationCommands.java

@@ -35,6 +35,7 @@ import com.sk89q.worldedit.command.util.annotation.Confirm;
 import com.sk89q.worldedit.entity.Player;
 import com.sk89q.worldedit.extension.platform.Actor;
 import com.fastasyncworldedit.core.function.generator.CavesGen;
+import com.sk89q.worldedit.function.mask.AbstractExtentMask;
 import com.sk89q.worldedit.function.mask.Mask;
 import com.sk89q.worldedit.function.operation.Operations;
 import com.sk89q.worldedit.function.pattern.Pattern;
@@ -467,6 +468,9 @@ public class GenerationCommands {
     @Logging(PLACEMENT)
     @Confirm(Confirm.Processor.REGION)
     public void ores(Actor actor, LocalSession session, EditSession editSession, @Selection Region region, @Arg(desc = "Mask") Mask mask) throws WorldEditException {
+        if (mask instanceof AbstractExtentMask) {
+            ((AbstractExtentMask) mask).setExtent(editSession);
+        }
         editSession.addOres(region, mask);
         actor.print(Caption.of("fawe.worldedit.visitor.visitor.block", editSession.getBlockChangeCount()));
     }
@@ -516,7 +520,7 @@ public class GenerationCommands {
                 e.printStackTrace();
             }
             return false;
-        });
+        }, editSession);
         Operations.completeBlindly(visitor);
         actor.print(Caption.of("fawe.worldedit.visitor.visitor.block", editSession.getBlockChangeCount()));
     }
@@ -536,6 +540,9 @@ public class GenerationCommands {
                     @Arg(desc = "Ore vein rarity (% chance each attempt is placed)", def = "100") @Range(from = 0, to = 100) int rarity,
                     @Arg(desc = "Ore vein min y", def = "0") @Range(from = 0, to = 255) int minY,
                     @Arg(desc = "Ore vein max y", def = "63") @Range(from = 0, to = 255) int maxY) throws WorldEditException {
+        if (mask instanceof AbstractExtentMask) {
+            ((AbstractExtentMask) mask).setExtent(editSession);
+        }
         editSession.addOre(region, mask, material, size, freq, rarity, minY, maxY);
         actor.print(Caption.of("fawe.worldedit.visitor.visitor.block", editSession.getBlockChangeCount()));
     }

worldedit-core/src/main/java/com/sk89q/worldedit/command/RegionCommands.java

@@ -299,6 +299,10 @@ public class RegionCommands {
                            Pattern to) throws WorldEditException {
         if (from == null) {
             from = new ExistingBlockMask(editSession);
+        //FAWE start > the mask will have been initialised with a WorldWrapper extent (very bad/slow
+        } else if (from instanceof AbstractExtentMask) {
+            ((AbstractExtentMask) from).setExtent(editSession);
+        //FAWE end
         }
         if (from instanceof AbstractExtentMask) {
             ((AbstractExtentMask) from).setExtent(editSession);
@@ -422,6 +426,11 @@ public class RegionCommands {
                           Mask mask,
                       @Switch(name = 's', desc = "The flag makes it only consider snow")
                           boolean snow) throws WorldEditException {
+        //FAWE start > the mask will have been initialised with a WorldWrapper extent (very bad/slow)
+        if (mask instanceof AbstractExtentMask) {
+            ((AbstractExtentMask) mask).setExtent(editSession);
+        }
+        //FAWE end
         BlockVector3 min = region.getMinimumPoint();
         BlockVector3 max = region.getMaximumPoint();
         long volume = (((long) max.getX() - (long) min.getX() + 1) * ((long) max.getY() - (long) min.getY() + 1) * ((long) max.getZ() - (long) min.getZ() + 1));
@@ -502,7 +511,11 @@ public class RegionCommands {
                     @ArgFlag(name = 'm', desc = "Set the include mask, non-matching blocks become air")
                         Mask mask) throws WorldEditException {
         checkCommandArgument(count >= 1, "Count must be >= 1");
-
+        //FAWE start > the mask will have been initialised with a WorldWrapper extent (very bad/slow)
+        if (mask instanceof AbstractExtentMask) {
+            ((AbstractExtentMask) mask).setExtent(editSession);
+        }
+        //FAWE end
         Mask combinedMask;
         if (ignoreAirBlocks) {
             if (mask == null) {
@@ -573,7 +586,11 @@ public class RegionCommands {
                          boolean copyBiomes,
                      @ArgFlag(name = 'm', desc = "Set the include mask, non-matching blocks become air")
                          Mask mask) throws WorldEditException {
-
+        //FAWE start > the mask will have been initialised with a WorldWrapper extent (very bad/slow)
+        if (mask instanceof AbstractExtentMask) {
+            ((AbstractExtentMask) mask).setExtent(editSession);
+        }
+        //FAWE end
         Mask combinedMask;
         if (ignoreAirBlocks) {
             if (mask == null) {
@@ -731,7 +748,18 @@ public class RegionCommands {
                       @ArgFlag(name = 'm', desc = "Mask to hollow with")
                           Mask mask) throws WorldEditException {
         checkCommandArgument(thickness >= 0, "Thickness must be >= 0");
-        Mask finalMask = mask == null ? new SolidBlockMask(editSession) : mask;
+
+        //FAWE start > the mask will have been initialised with a WorldWrapper extent (very bad/slow)
+        Mask finalMask;
+        if (mask != null) {
+            if (mask instanceof AbstractExtentMask) {
+                ((AbstractExtentMask) mask).setExtent(editSession);
+            }
+            finalMask = mask;
+        } else {
+            finalMask = new SolidBlockMask(editSession);
+        }
+        //FAWE end
 
         int affected = editSession.hollowOutRegion(region, thickness, pattern, finalMask);
         actor.print(Caption.of("worldedit.hollow.changed", TextComponent.of(affected)));

worldedit-core/src/main/java/com/sk89q/worldedit/command/SelectionCommands.java

@@ -42,6 +42,7 @@ import com.sk89q.worldedit.extension.platform.Locatable;
 import com.sk89q.worldedit.extension.platform.permission.ActorSelectorLimits;
 import com.sk89q.worldedit.extent.clipboard.Clipboard;
 import com.sk89q.worldedit.function.block.BlockDistributionCounter;
+import com.sk89q.worldedit.function.mask.AbstractExtentMask;
 import com.sk89q.worldedit.function.mask.Mask;
 import com.sk89q.worldedit.function.operation.Operations;
 import com.sk89q.worldedit.function.visitor.RegionVisitor;
@@ -534,6 +535,11 @@ public class SelectionCommands {
     public int count(Actor actor, World world, LocalSession session, EditSession editSession,
                       @Arg(desc = "The mask of blocks to match")
                           Mask mask) throws WorldEditException {
+        //FAWE start > the mask will have been initialised with a WorldWrapper extent (very bad/slow)
+        if (mask instanceof AbstractExtentMask) {
+            ((AbstractExtentMask) mask).setExtent(editSession);
+        }
+        //FAWE end
         int count = editSession.countBlocks(session.getSelection(world), mask);
         actor.print(Caption.of("worldedit.count.counted", TextComponent.of(count)));
         return count;
@@ -545,6 +551,9 @@ public class SelectionCommands {
     )
     @CommandPermissions("worldedit.analysis.distr")
     public void distr(Actor actor, World world, LocalSession session,
+        //FAWE start > add extent to RegionVisitor to allow chunk preloading
+        EditSession editSession,
+        //FAWE end
                       @Switch(name = 'c', desc = "Get the distribution of the clipboard instead")
                           boolean clipboardDistr,
                       @Switch(name = 'd', desc = "Separate blocks by state")
@@ -557,14 +566,14 @@ public class SelectionCommands {
             if (clipboardDistr) {
                 Clipboard clipboard = session.getClipboard().getClipboard(); // throws if missing
                 BlockDistributionCounter count = new BlockDistributionCounter(clipboard, separateStates);
-                RegionVisitor visitor = new RegionVisitor(clipboard.getRegion(), count);
+                //FAWE start > add extent to RegionVisitor to allow chunk preloading
+                RegionVisitor visitor = new RegionVisitor(clipboard.getRegion(), count, editSession);
+                //FAWE end
                 Operations.completeBlindly(visitor);
                 distribution = count.getDistribution();
             } else {
-                try (EditSession editSession = session.createEditSession(actor)) {
                     distribution = editSession.getBlockDistribution(session.getSelection(world), separateStates);
             }
-            }
             session.setLastDistribution(distribution);
             page = 1;
         } else {

worldedit-core/src/main/java/com/sk89q/worldedit/command/UtilityCommands.java

@@ -49,6 +49,7 @@ import com.sk89q.worldedit.extension.platform.Actor;
 import com.sk89q.worldedit.extent.clipboard.io.ClipboardFormat;
 import com.sk89q.worldedit.extent.clipboard.io.ClipboardFormats;
 import com.sk89q.worldedit.function.EntityFunction;
+import com.sk89q.worldedit.function.mask.AbstractExtentMask;
 import com.sk89q.worldedit.function.mask.BlockTypeMask;
 import com.sk89q.worldedit.function.mask.ExistingBlockMask;
 import com.sk89q.worldedit.function.mask.Mask;
@@ -424,6 +425,11 @@ public class UtilityCommands {
                               Mask mask,
                           @Arg(desc = "The radius of the square to remove from", def = "50")
                               int radius) throws WorldEditException {
+        //FAWE start > the mask will have been initialised with a WorldWrapper extent (very bad/slow)
+        if (mask instanceof AbstractExtentMask) {
+            ((AbstractExtentMask) mask).setExtent(editSession);
+        }
+        //FAWE end
         radius = Math.max(1, radius);
         we.checkMaxRadius(radius);
 
@@ -446,6 +452,11 @@ public class UtilityCommands {
                                Mask from,
                            @Arg(desc = "The pattern of blocks to replace with")
                                Pattern to) throws WorldEditException {
+        //FAWE start > the mask will have been initialised with a WorldWrapper extent (very bad/slow)
+        if (from instanceof AbstractExtentMask) {
+            ((AbstractExtentMask) from).setExtent(editSession);
+        }
+        //FAWE end
         radius = Math.max(1, radius);
         we.checkMaxRadius(radius);
 

worldedit-core/src/main/java/com/sk89q/worldedit/extent/Extent.java

@@ -549,7 +549,9 @@ public interface Extent extends InputExtent, OutputExtent {
      * @return the number of blocks that matched the mask
      */
     default int countBlocks(Region region, Mask searchMask) {
-        RegionVisitor visitor = new RegionVisitor(region, searchMask::test);
+        //FAWE start > use slightly more performant RegionVisitor
+        RegionVisitor visitor = new RegionVisitor(region, searchMask::test, this);
+        //FAWE end
         Operations.completeBlindly(visitor);
         return visitor.getAffected();
     }
@@ -648,7 +650,9 @@ public interface Extent extends InputExtent, OutputExtent {
 
         BlockReplace replace = new BlockReplace(this, pattern);
         RegionMaskingFilter filter = new RegionMaskingFilter(this, mask, replace);
-        RegionVisitor visitor = new RegionVisitor(region, filter);
+        //FAWE start > add extent to RegionVisitor to allow chunk preloading
+        RegionVisitor visitor = new RegionVisitor(region, filter, this);
+        //FAWE end
         Operations.completeLegacy(visitor);
         return visitor.getAffected();
     }

worldedit-core/src/main/java/com/sk89q/worldedit/function/factory/Apply.java

@@ -55,7 +55,9 @@ public class Apply implements Contextual<Operation> {
 
     @Override
     public Operation createFromContext(EditContext context) {
-        return new RegionVisitor(firstNonNull(context.getRegion(), region), function.createFromContext(context));
+        //FAWE start > add extent to RegionVisitor to allow chunk preloading
+        return new RegionVisitor(firstNonNull(context.getRegion(), region), function.createFromContext(context), context.getDestination());
+        //FAWE end
     }
 
     @Override

worldedit-core/src/main/java/com/sk89q/worldedit/function/factory/ApplyRegion.java

@@ -48,7 +48,9 @@ public class ApplyRegion implements Contextual<Operation> {
 
     @Override
     public Operation createFromContext(EditContext context) {
-        return new RegionVisitor(firstNonNull(context.getRegion(), region), function.createFromContext(context));
+        //FAWE start > add extent to RegionVisitor to allow chunk preloading
+        return new RegionVisitor(firstNonNull(context.getRegion(), region), function.createFromContext(context), context.getDestination());
+        //FAWE end
     }
 
     @Override

worldedit-core/src/main/java/com/sk89q/worldedit/function/visitor/RegionVisitor.java

@@ -19,9 +19,19 @@
 
 package com.sk89q.worldedit.function.visitor;
 
+import com.fastasyncworldedit.core.Fawe;
 import com.fastasyncworldedit.core.configuration.Caption;
+import com.fastasyncworldedit.core.configuration.Settings;
+import com.fastasyncworldedit.core.internal.exception.FaweException;
+import com.fastasyncworldedit.core.queue.implementation.ParallelQueueExtent;
+import com.fastasyncworldedit.core.queue.implementation.SingleThreadQueueExtent;
+import com.fastasyncworldedit.core.queue.implementation.chunk.ChunkHolder;
+import com.fastasyncworldedit.core.util.ExtentTraverser;
+import com.fastasyncworldedit.core.util.MemUtil;
+import com.fastasyncworldedit.core.util.TaskManager;
 import com.google.common.collect.ImmutableList;
 import com.sk89q.worldedit.WorldEditException;
+import com.sk89q.worldedit.extent.Extent;
 import com.sk89q.worldedit.function.RegionFunction;
 import com.sk89q.worldedit.function.operation.Operation;
 import com.sk89q.worldedit.function.operation.RunContext;
@@ -29,25 +39,45 @@ import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.regions.Region;
 import com.sk89q.worldedit.util.formatting.text.Component;
 import com.sk89q.worldedit.util.formatting.text.TextComponent;
+import java.util.Iterator;
 
 /**
  * Utility class to apply region functions to {@link com.sk89q.worldedit.regions.Region}.
+ *
  * @deprecated - FAWE deprecation: Let the queue iterate, not the region function which lacks any kind of optimizations / parallelism
  */
-@Deprecated
+@Deprecated public class RegionVisitor implements Operation {
-public class RegionVisitor implements Operation {
 
+    public final Iterable<? extends BlockVector3> iterable;
     private final Region region;
     private final RegionFunction function;
     private int affected = 0;
+    private SingleThreadQueueExtent singleQueue;
 
     /**
      * @deprecated Use other constructors which will preload chunks during iteration
      */
-    @Deprecated
+    @Deprecated public RegionVisitor(Region region, RegionFunction function) {
-    public RegionVisitor(Region region, RegionFunction function) {
+        this(region, function, null);
-        this.region = region;
+    }
+
+    /**
+     * Allows for preloading chunks, and non-specific "regions" to be visited.
+     *
+     * @param iterable Can be supplied as a region, or a raw iterator
+     * @param function The function to be applied to each BlockVector3 iterated over
+     * @param extent   Supplied editsession/extent to attempt to extract {@link SingleThreadQueueExtent} from
+     */
+    public RegionVisitor(Iterable<BlockVector3> iterable, RegionFunction function, Extent extent) {
+        region = iterable instanceof Region ? (Region) iterable : null;
+        this.iterable = iterable;
         this.function = function;
+        if (extent != null) {
+            ExtentTraverser<ParallelQueueExtent> queueTraverser = new ExtentTraverser<>(extent).find(ParallelQueueExtent.class);
+            this.singleQueue = queueTraverser != null ? (SingleThreadQueueExtent) queueTraverser.get().getExtent() : null;
+        } else {
+            this.singleQueue = null;
+        }
     }
 
     /**
@@ -59,27 +89,132 @@ public class RegionVisitor implements Operation {
         return affected;
     }
 
-    @Override
+    @Override public Operation resume(RunContext run) throws WorldEditException {
-    public Operation resume(RunContext run) throws WorldEditException {
+        //FAWE start > allow chunk preloading
+        if (singleQueue != null && Settings.IMP.QUEUE.PRELOAD_CHUNKS > 1) {
+            /*
+             * The following is done to reduce iteration cost
+             *  - Preload chunks just in time
+             *  - Only check every 16th block for potential chunk loads
+             *  - Stop iteration on exception instead of hasNext
+             *  - Do not calculate the stacktrace as it is expensive
+             */
+            Iterator<? extends BlockVector3> trailIter = iterable.iterator();
+            Iterator<? extends BlockVector3> leadIter = iterable.iterator();
+            int lastTrailChunkX = Integer.MIN_VALUE;
+            int lastTrailChunkZ = Integer.MIN_VALUE;
+            int lastLeadChunkX = Integer.MIN_VALUE;
+            int lastLeadChunkZ = Integer.MIN_VALUE;
+            int loadingTarget = Settings.IMP.QUEUE.PRELOAD_CHUNKS;
+            try {
+                for (; ; ) {
+                    BlockVector3 pt = trailIter.next();
+                    apply(pt);
+                    int cx = pt.getBlockX() >> 4;
+                    int cz = pt.getBlockZ() >> 4;
+                    if (cx != lastTrailChunkX || cz != lastTrailChunkZ) {
+                        lastTrailChunkX = cx;
+                        lastTrailChunkZ = cz;
+                        int amount;
+                        if (lastLeadChunkX == Integer.MIN_VALUE) {
+                            lastLeadChunkX = cx;
+                            lastLeadChunkZ = cz;
+                            amount = loadingTarget;
+                        } else {
+                            amount = 1;
+                        }
+                        for (int count = 0; count < amount; ) {
+                            BlockVector3 v = leadIter.next();
+                            int vcx = v.getBlockX() >> 4;
+                            int vcz = v.getBlockZ() >> 4;
+                            if (vcx != lastLeadChunkX || vcz != lastLeadChunkZ) {
+                                lastLeadChunkX = vcx;
+                                lastLeadChunkZ = vcz;
+                                queueChunkLoad(vcx, vcz);
+                                count++;
+                            }
+                            // Skip the next 15 blocks
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                            leadIter.next();
+                        }
+                    }
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                }
+            } catch (FaweException e) {
+                throw new RuntimeException(e);
+            } catch (Throwable ignore) {
+            }
+            try {
+                for (; ; ) {
+                    apply(trailIter.next());
+                    apply(trailIter.next());
+                }
+            } catch (FaweException e) {
+                throw new RuntimeException(e);
+            } catch (Throwable ignore) {
+            }
+        } else {
             for (BlockVector3 pt : region) {
+                apply(pt);
+            }
+        }
+        //FAWE end
+
+        return null;
+    }
+
+    //FAWE start > extract methods for slightly clean resume method
+    private void apply(BlockVector3 pt) throws WorldEditException {
         if (function.apply(pt)) {
             affected++;
         }
     }
 
+    private void queueChunkLoad(int cx, int cz) {
+        TaskManager.IMP.sync(() -> {
+            boolean lowMem = MemUtil.isMemoryLimited();
+            if (!singleQueue.isQueueEnabled() || (!(lowMem && singleQueue.size() > Settings.IMP.QUEUE.PARALLEL_THREADS + 8)
+                && singleQueue.size() < Settings.IMP.QUEUE.TARGET_SIZE && Fawe.get().getQueueHandler().isUnderutilized())) {
+                //The GET chunk is what will take longest.
+                ((ChunkHolder)singleQueue.getOrCreateChunk(cx, cz)).getOrCreateGet();
+            }
             return null;
+        });
+    }
+    //FAWE end
+
+    @Override public void cancel() {
     }
 
-    @Override
+    @Override public Iterable<Component> getStatusMessages() {
-    public void cancel() {
+        return ImmutableList.of(Caption.of("worldedit.operation.affected.block", TextComponent.of(getAffected())));
-    }
-
-    @Override
-    public Iterable<Component> getStatusMessages() {
-        return ImmutableList.of(Caption.of(
-                "worldedit.operation.affected.block",
-                TextComponent.of(getAffected())
-        ));
     }
 
 }