Add some more __internal__ <-> air logi

Fixes #831

worldedit-core/src/main/java/com/boydti/fawe/object/mask/AirMask.java

@@ -16,4 +16,9 @@ public class AirMask extends BlockMask {
         return new AirMask(getExtent());
     }
 
+    @Override
+    public boolean replacesAir() {
+        return true;
+    }
+
 }

worldedit-core/src/main/java/com/boydti/fawe/object/mask/IdDataMask.java

@@ -37,4 +37,9 @@ public class IdDataMask extends AbstractExtentMask implements ResettableMask {
         return new IdDataMask(getExtent());
     }
 
+    @Override
+    public boolean replacesAir() {
+        return true;
+    }
+
 }

worldedit-core/src/main/java/com/boydti/fawe/object/mask/IdMask.java

@@ -38,4 +38,9 @@ public class IdMask extends AbstractExtentMask implements ResettableMask {
         return new IdMask(getExtent());
     }
 
+    @Override
+    public boolean replacesAir() {
+        return true;
+    }
+
 }

worldedit-core/src/main/java/com/sk89q/worldedit/function/mask/BlockCategoryMask.java

@@ -22,6 +22,7 @@ package com.sk89q.worldedit.function.mask;
 import com.sk89q.worldedit.extent.Extent;
 import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.world.block.BlockCategory;
+import com.sk89q.worldedit.world.block.BlockTypes;
 
 import javax.annotation.Nullable;
 
@@ -61,4 +62,9 @@ public class BlockCategoryMask extends AbstractExtentMask {
     public Mask copy() {
         return new BlockCategoryMask(getExtent(), category);
     }
+
+    @Override
+    public boolean replacesAir() {
+        return category.contains(BlockTypes.AIR);
+    }
 }

worldedit-core/src/main/java/com/sk89q/worldedit/function/mask/BlockMask.java

@@ -29,12 +29,12 @@ import com.sk89q.worldedit.world.block.BlockTypes;
 import com.sk89q.worldedit.world.block.BlockTypesCache;
 import com.sk89q.worldedit.world.block.ImmutableBaseBlock;
 
+import javax.annotation.Nullable;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.function.Predicate;
-import javax.annotation.Nullable;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
@@ -185,7 +185,7 @@ public class BlockMask extends ABlockMask {
 
     @Override
     public boolean test(BlockState state) {
-        return ordinals[state.getOrdinal()] || replacesAir() && state.getOrdinal() <= 3;
+        return ordinals[state.getOrdinal()] || replacesAir() && state.getOrdinal() == 0;
     }
 
     @Override
@@ -259,19 +259,16 @@ public class BlockMask extends ABlockMask {
 
         int setTypes = 0;
         BlockType setType = null;
-        BlockType unsetType = null;
         int totalTypes = 0;
 
         for (BlockType type : BlockTypesCache.values) {
             if (type != null) {
                 totalTypes++;
                 boolean hasAll = true;
-                boolean hasAny = false;
                 List<BlockState> all = type.getAllStates();
                 for (BlockState state : all) {
                     totalStates++;
                     hasAll &= test(state);
-                    hasAny = true;
                 }
                 if (hasAll) {
                     setTypes++;
@@ -326,6 +323,7 @@ public class BlockMask extends ABlockMask {
             cloned[BlockTypes.AIR.getDefaultState().getOrdinal()] = false;
             cloned[BlockTypes.CAVE_AIR.getDefaultState().getOrdinal()] = false;
             cloned[BlockTypes.VOID_AIR.getDefaultState().getOrdinal()] = false;
+            cloned[0] = false;
         }
         return new BlockMask(getExtent(), cloned);
     }

worldedit-core/src/main/java/com/sk89q/worldedit/function/mask/InverseMask.java

@@ -36,4 +36,9 @@ public class InverseMask extends AbstractMask {
     public Mask copy() {
         return new InverseMask(mask.copy());
     }
+
+    @Override
+    public boolean replacesAir() {
+        return mask.replacesAir();
+    }
 }

worldedit-core/src/main/java/com/sk89q/worldedit/function/mask/InverseSingleBlockTypeMask.java

@@ -8,10 +8,12 @@ import com.sk89q.worldedit.world.block.BlockTypesCache;
 
 public class InverseSingleBlockTypeMask extends ABlockMask {
     private final int internalId;
+    private final boolean replacesAir;
 
     public InverseSingleBlockTypeMask(Extent extent, BlockType type) {
         super(extent);
         this.internalId = type.getInternalId();
+        this.replacesAir = type.getMaterial().isAir();
     }
 
     @Override
@@ -33,4 +35,9 @@ public class InverseSingleBlockTypeMask extends ABlockMask {
         // The mask is not mutable. There is no need to clone it.
         return this;
     }
+
+    @Override
+    public boolean replacesAir() {
+        return replacesAir;
+    }
 }

worldedit-core/src/main/java/com/sk89q/worldedit/function/mask/MaskIntersection.java

@@ -275,4 +275,14 @@ public class MaskIntersection extends AbstractMask {
         return new MaskIntersection(masks);
     }
 
+    @Override
+    public boolean replacesAir() {
+        for (Mask mask : masksArray) {
+            if (mask.replacesAir()) {
+                return true;
+            }
+        }
+        return false;
+    }
+
 }

worldedit-core/src/main/java/com/sk89q/worldedit/function/mask/MaskUnion.java

@@ -118,4 +118,14 @@ public class MaskUnion extends MaskIntersection {
         Set<Mask> masksCopy = masks.stream().map(Mask::copy).collect(Collectors.toSet());
         return new MaskUnion(masksCopy);
     }
+
+    @Override
+    public boolean replacesAir() {
+        for (Mask mask : getMasksArray()) {
+            if (mask.replacesAir()) {
+                return true;
+            }
+        }
+        return false;
+    }
 }