Replace setPosition with trySetPosition (#1403)

Allows cancellation information to be fed back into the ascend/descend
algorithms.

(cherry picked from commit 71e104bcb187a5313e88dda5df79059c8ffbc1fe)

worldedit-bukkit/src/main/java/com/sk89q/worldedit/bukkit/BukkitPlayer.java

@@ -194,7 +194,7 @@ public class BukkitPlayer extends AbstractPlayerActor {
     }
 
     @Override
-    public void setPosition(Vector3 pos, float pitch, float yaw) {
+    public void trySetPosition(Vector3 pos, float pitch, float yaw) {
         org.bukkit.World world = player.getWorld();
         if (pos instanceof com.sk89q.worldedit.util.Location) {
             com.sk89q.worldedit.util.Location loc = (com.sk89q.worldedit.util.Location) pos;

worldedit-core/src/main/java/com/sk89q/worldedit/entity/Player.java

@@ -36,6 +36,8 @@ import com.sk89q.worldedit.extension.platform.Actor;
 import com.sk89q.worldedit.extent.clipboard.Clipboard;
 import com.sk89q.worldedit.extent.inventory.BlockBag;
 import com.sk89q.worldedit.function.mask.Mask;
+import com.sk89q.worldedit.internal.util.DeprecationUtil;
+import com.sk89q.worldedit.internal.util.NonAbstractForCompatibility;
 import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.math.Vector3;
 import com.sk89q.worldedit.regions.Region;
@@ -301,8 +303,40 @@ public interface Player extends Entity, Actor {
      * @param pos where to move them
      * @param pitch the pitch (up/down) of the player's view in degrees
      * @param yaw the yaw (left/right) of the player's view in degrees
+     * @deprecated This method may fail without indication. Use
+     * {@link #trySetPosition(Vector3, float, float)} instead
      */
-    void setPosition(Vector3 pos, float pitch, float yaw);
+    @Deprecated
+    default void setPosition(Vector3 pos, float pitch, float yaw) {
+        trySetPosition(pos, pitch, yaw);
+    }
+
+    /**
+     * Attempt to move the player.
+     *
+     * <p>
+     * This action may fail, due to other mods cancelling the move.
+     * If so, this method will return {@code false}.
+     * </p>
+     *
+     * @param pos where to move them
+     * @param pitch the pitch (up/down) of the player's view in degrees
+     * @param yaw the yaw (left/right) of the player's view in degrees
+     * @return if the move was able to occur
+     * @apiNote This must be overridden by new subclasses. See {@link NonAbstractForCompatibility}
+     *          for details
+     */
+    @NonAbstractForCompatibility(
+        delegateName = "setPosition",
+        delegateParams = { Vector3.class, float.class, float.class }
+    )
+    default boolean trySetPosition(Vector3 pos, float pitch, float yaw) {
+        DeprecationUtil.checkDelegatingOverride(getClass());
+
+        setPosition(pos, pitch, yaw);
+
+        return true;
+    }
 
     /**
      * Sends a fake block to the client.

worldedit-core/src/main/java/com/sk89q/worldedit/extension/platform/AbstractPlayerActor.java

@@ -65,11 +65,14 @@ import com.sk89q.worldedit.world.gamemode.GameModes;
 import com.sk89q.worldedit.world.item.ItemType;
 import com.sk89q.worldedit.world.item.ItemTypes;
 import com.sk89q.worldedit.world.registry.BlockMaterial;
+
 import java.io.File;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import javax.annotation.Nullable;
+
 /**
  * An abstract implementation of both a {@link Actor} and a {@link Player}
  * that is intended for implementations of WorldEdit to use to wrap
@@ -179,8 +182,13 @@ public abstract class AbstractPlayerActor implements Actor, Player, Cloneable {
             }
 
             if (free == 2) {
+                boolean worked = true;
+
                 if (y - 1 != origY) {
-                    setPosition(Vector3.at(x + 0.5, y - 2 + 1, z + 0.5));
+                    worked = trySetPosition(Vector3.at(x + 0.5, y - 2 + 1, z + 0.5));
+                }
+
+                if (worked) {
                     return;
                 }
             }
@@ -199,8 +207,8 @@ public abstract class AbstractPlayerActor implements Actor, Player, Cloneable {
         while (y >= 0) {
             final BlockVector3 pos = BlockVector3.at(x, y, z);
             final BlockState id = world.getBlock(pos);
-            if (id.getBlockType().getMaterial().isMovementBlocker()) {
-                setPosition(Vector3.at(x + 0.5, y + +BlockTypeUtil.centralTopLimit(id), z + 0.5));
+            if (id.getBlockType().getMaterial().isMovementBlocker()
+                && trySetPosition(Vector3.at(x + 0.5, y + +BlockTypeUtil.centralTopLimit(id), z + 0.5))) {
                 return;
             }
 
@@ -213,6 +221,26 @@ public abstract class AbstractPlayerActor implements Actor, Player, Cloneable {
         findFreePosition(getBlockLocation());
     }
 
+    private boolean isBadSpaceForStanding(BlockVector3 location) {
+        BlockType type = getWorld().getBlock(location).getBlockType();
+        return type.getMaterial().isMovementBlocker() || type == BlockTypes.LAVA;
+    }
+
+    /**
+     * @param location where the player would be placed (not Y offset)
+     * @return if the player can stand at the location
+     */
+    private boolean isLocationGoodForStanding(BlockVector3 location) {
+        if (isBadSpaceForStanding(location.add(0, 1, 0))) {
+            return false;
+        }
+        if (isBadSpaceForStanding(location)) {
+            return false;
+        }
+        return getWorld().getBlock(location.add(0, -1, 0)).getBlockType().getMaterial()
+            .isMovementBlocker();
+    }
+
     @Override
     public boolean ascendLevel() {
         final Location pos = getBlockLocation();
@@ -254,9 +282,9 @@ public abstract class AbstractPlayerActor implements Actor, Player, Cloneable {
                     double bottomLimit = BlockTypeUtil.centralBottomLimit(state);
                     double space = level + bottomLimit - freeStart;
                     if (space >= height) {
-                        setPosition(Vector3.at(x + 0.5, freeStart, z + 0.5));
-                    return true;
-                }
+                        trySetPosition(Vector3.at(x + 0.5, freeStart, z + 0.5));
+                return true;
+            }
                     // Not enough room, reset the free position
                     if (bottomLimit != 1) {
                         freeStart = -1;
@@ -312,9 +340,9 @@ public abstract class AbstractPlayerActor implements Actor, Player, Cloneable {
                     double freeStart = level + topLimit;
                     double space = freeEnd - freeStart;
                     if (space >= height) {
-                        setPosition(Vector3.at(x + 0.5, freeStart, z + 0.5));
-                        return true;
-                    }
+                        trySetPosition(Vector3.at(x + 0.5, freeStart, z + 0.5));
+                return true;
+            }
                     // Not enough room, reset the free position
                     if (topLimit != 0) {
                         freeEnd = -1;
@@ -577,9 +605,9 @@ public abstract class AbstractPlayerActor implements Actor, Player, Cloneable {
     }
 
     @Override
-    public void setPosition(Vector3 pos) {
+    public boolean trySetPosition(Vector3 pos) {
         final Location location = getLocation();
-        setPosition(pos, location.getPitch(), location.getYaw());
+        return trySetPosition(pos, location.getPitch(), location.getYaw());
     }
 
     @Override

worldedit-core/src/main/java/com/sk89q/worldedit/extension/platform/Locatable.java

@@ -54,9 +54,27 @@ public interface Locatable {
      * Sets the position of this actor.
      *
      * @param pos where to move them
+     * @deprecated This method may fail without indication. Use {@link #trySetPosition(Vector3)}
+     * instead
      */
+    @Deprecated
     default void setPosition(Vector3 pos) {
-        setLocation(new Location(getExtent(), pos));
+        trySetPosition(pos);
+    }
+
+    /**
+     * Attempts to set the position of this actor.
+     *
+     * <p>
+     * This action may fail, due to other mods cancelling the move.
+     * If so, this method will return {@code false}.
+     * </p>
+     *
+     * @param pos the position to set
+     * @return if the position was able to be set
+     */
+    default boolean trySetPosition(Vector3 pos) {
+        return setLocation(new Location(getExtent(), pos));
     }
 
     /**

worldedit-core/src/main/java/com/sk89q/worldedit/extension/platform/PlayerProxy.java

@@ -131,8 +131,8 @@ public class PlayerProxy extends AbstractPlayerActor {
     }
 
     @Override
-    public void setPosition(Vector3 pos, float pitch, float yaw) {
-        basePlayer.setPosition(pos, pitch, yaw);
+    public boolean trySetPosition(Vector3 pos, float pitch, float yaw) {
+        return basePlayer.trySetPosition(pos, pitch, yaw);
     }
 
     @Override

worldedit-fabric/src/main/java/com/sk89q/worldedit/fabric/FabricPlayer.java

@@ -172,8 +172,9 @@ public class FabricPlayer extends AbstractPlayerActor {
     }
 
     @Override
-    public void setPosition(Vector3 pos, float pitch, float yaw) {
+    public boolean trySetPosition(Vector3 pos, float pitch, float yaw) {
         this.player.networkHandler.requestTeleport(pos.getX(), pos.getY(), pos.getZ(), yaw, pitch);
+        return true;
     }
 
     @Override

worldedit-forge/src/main/java/com/sk89q/worldedit/forge/ForgePlayer.java

@@ -168,8 +168,9 @@ public class ForgePlayer extends AbstractPlayerActor {
     }
 
     @Override
-    public void setPosition(Vector3 pos, float pitch, float yaw) {
+    public boolean trySetPosition(Vector3 pos, float pitch, float yaw) {
         this.player.connection.setPlayerLocation(pos.getX(), pos.getY(), pos.getZ(), yaw, pitch);
+        return true;
     }
 
     @Override

worldedit-sponge/src/main/java/com/sk89q/worldedit/sponge/SpongePlayer.java

@@ -165,12 +165,12 @@ public class SpongePlayer extends AbstractPlayerActor {
     }
 
     @Override
-    public void setPosition(Vector3 pos, float pitch, float yaw) {
+    public boolean trySetPosition(Vector3 pos, float pitch, float yaw) {
         org.spongepowered.api.world.Location<World> loc = new org.spongepowered.api.world.Location<>(
-                this.player.getWorld(), pos.getX(), pos.getY(), pos.getZ()
+            this.player.getWorld(), pos.getX(), pos.getY(), pos.getZ()
         );
 
-        this.player.setLocationAndRotation(loc, new Vector3d(pitch, yaw, 0));
+        return this.player.setLocationAndRotation(loc, new Vector3d(pitch, yaw, 0));
     }
 
     @Override