Use existing isPlayerPlaced value to track who placed a block

eco-api/src/main/java/com/willfp/eco/util/BlockUtils.java

@@ -3,6 +3,7 @@
 import org.bukkit.Chunk;
 import org.bukkit.Location;
 import org.bukkit.Material;
+import org.bukkit.OfflinePlayer;
 import org.bukkit.World;
 import org.bukkit.block.Block;
 import org.bukkit.block.BlockFace;
@@ -97,6 +98,34 @@ public static boolean isPlayerPlaced(@NotNull final Block block) {
                 PersistentDataType.INTEGER
         );
     }
+    /**
+     * Get who placed the block (as an internal ID).
+     *
+     * @param block The block.
+     * @return Internal ID of placing player, or 0 if not placed by a player.
+     */
+    public static int placedByID(@NotNull final Block block) {
+        Chunk chunk = block.getChunk();
+
+        return chunk.getPersistentDataContainer().getOrDefault(
+            NamespacedKeyUtils.createEcoKey(Integer.toString(block.getLocation().hashCode(), 16)),
+            PersistentDataType.INTEGER,
+            0
+        );
+    }
+
+    /**
+     * Get whether a specific player placed the block.
+     *
+     * @param block The block.
+     * @param player The player to check.
+     * @return If placed by that specific player.
+     */
+    public static boolean isPlacedBy(@NotNull final Block block, @NotNull final OfflinePlayer player) {
+        int placed_by = placedByID(block);
+        int local_id = PlayerUtils.getLocalID(player);
+        return placed_by == local_id;        
+    }
 
     private BlockUtils() {
         throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");

eco-api/src/main/java/com/willfp/eco/util/PlayerUtils.java

@@ -33,6 +33,16 @@ public final class PlayerUtils {
             PersistentDataKeyType.STRING,
             "Unknown Player"
     );
+    /**
+     * The data key for saved player local IDs.
+     * The default value of 1 means no local ID has been assigned; this is to allow the
+     * gradual migration of BlockUtils isPlayerPlaced values.
+     */
+    private static final PersistentDataKey<Integer> PLAYER_LOCAL_ID = new PersistentDataKey<>(
+            NamespacedKeyUtils.createEcoKey("player_local_id"),
+            PersistentDataKeyType.INT,
+            1
+    );
 
     /**
      * Get the audience from a player.
@@ -106,6 +116,29 @@ public static String getSavedDisplayName(@NotNull final OfflinePlayer player) {
         return saved;
     }
 
+    /**
+     * Get local ID for a player.  
+     * Local IDs are more compact than UUIDs, but are local to our storage backing. 
+     * They're useful in scenarios where we want to store a player identifier per-block,
+     * like in BlockUtils.isPlacedBy
+     * 
+     * @param player The player.
+     * @return The player local ID.
+     */
+    public static Integer getLocalID(@NotNull final OfflinePlayer player) {
+        PlayerProfile profile = PlayerProfile.load(player);
+        Integer local_id = profile.read(PLAYER_LOCAL_ID);
+
+        // If we haven't gotten a player local ID, generate one here.
+        if (local_id.equals(PLAYER_LOCAL_ID.getDefaultValue())) {
+            Integer generatedID = ServerUtils.generateLocalID();
+            profile.write(PLAYER_LOCAL_ID, generatedID);
+            return generatedID;
+        }
+
+        return local_id;
+    }
+
     /**
      * Update the saved display name for a player.
      *

eco-api/src/main/java/com/willfp/eco/util/ServerUtils.java

@@ -1,11 +1,24 @@
 package com.willfp.eco.util;
 
 import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.data.ServerProfile;
+import com.willfp.eco.core.data.keys.PersistentDataKey;
+import com.willfp.eco.core.data.keys.PersistentDataKeyType;
 
 /**
  * Utilities / API methods for the server.
  */
 public final class ServerUtils {
+    /**
+     * The data key on the server profile which holds the top player local id.
+     * The default value is 1 to allow gradual migration of BlockUtils isPlayerPlaced values.
+     */
+    private static final PersistentDataKey<Integer> TOP_LOCAL_ID = new PersistentDataKey<>(
+            NamespacedKeyUtils.createEcoKey("top_player_local_id"),
+            PersistentDataKeyType.INT,
+            1
+    );
+
     /**
      * Get the current server TPS.
      *
@@ -21,6 +34,21 @@ public static double getTps() {
         }
     }
 
+
+    /**
+     * Generates a local ID for a player by incrementing the top value.
+     * Local IDs are more compact than UUIDs, but are local to our storage backing. 
+     * 
+     * @return The player local ID.
+     */
+    public static Integer generateLocalID() {
+        ServerProfile profile = ServerProfile.load();
+        Integer local_id = profile.read(TOP_LOCAL_ID);
+        local_id += 1;
+        profile.write(TOP_LOCAL_ID, local_id);
+        return local_id;
+    }
+
     private ServerUtils() {
         throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
     }

eco-api/src/main/kotlin/com/willfp/eco/util/BlockUtils.kt

@@ -3,7 +3,12 @@
 package com.willfp.eco.util
 
 import org.bukkit.block.Block
+import org.bukkit.OfflinePlayer;
 
 /** @see ArrowUtils.getBow */
 val Block.isPlayerPlaced: Boolean
     get() = BlockUtils.isPlayerPlaced(this)
+
+/** @see BlockUtils.IsPlacedBy */
+fun Block.isPlacedBy(player: OfflinePlayer) =
+    BlockUtils.isPlacedBy(this,player)

eco-api/src/main/kotlin/com/willfp/eco/util/PlayerUtils.kt

@@ -12,6 +12,10 @@ import org.bukkit.entity.Player
 val OfflinePlayer.savedDisplayName: String
     get() = PlayerUtils.getSavedDisplayName(this)
 
+/** @see PlayerUtils.getLocalID */
+val OfflinePlayer.localID: Int
+    get() = PlayerUtils.getLocalID(this)
+
 /** @see PlayerUtils.getAudience */
 fun Player.asAudience(): Audience =
     PlayerUtils.getAudience(this)

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/PlayerBlockListener.kt

@@ -2,6 +2,7 @@ package com.willfp.eco.internal.spigot.data
 
 import com.willfp.eco.core.EcoPlugin
 import com.willfp.eco.util.BlockUtils
+import com.willfp.eco.util.PlayerUtils
 import org.bukkit.Location
 import org.bukkit.block.Block
 import org.bukkit.event.EventHandler
@@ -21,15 +22,17 @@ class PlayerBlockListener(
     @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
     fun onPlace(event: BlockPlaceEvent) {
         val block = event.blockPlaced
+        val player = event.player
 
-        writeKey(block)
+        writeKey(block, PlayerUtils.getLocalID(player))
     }
 
     @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
     fun onPlace(event: BlockMultiPlaceEvent) {
         val block = event.blockPlaced
+        val player = event.player
 
-        writeKey(block)
+        writeKey(block, PlayerUtils.getLocalID(player))
     }
 
     @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
@@ -53,11 +56,14 @@ class PlayerBlockListener(
     @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
     fun onExtend(event: BlockPistonExtendEvent) {
         val locs = mutableListOf<Location>()
+        val placers = mutableListOf<Int>()
         val toRemove = mutableListOf<Location>()
 
         for (block in event.blocks) {
-            if (BlockUtils.isPlayerPlaced(block)) {
+            val placedBy = BlockUtils.placedByID(block)
+            if (placedBy != 0) {
                 locs.add(block.getRelative(event.direction).location)
+                placers.add(placedBy)
                 toRemove.add(block.location)
             }
         }
@@ -67,20 +73,23 @@ class PlayerBlockListener(
                 removeKey(loc)
             }
 
-            for (loc in locs) {
-                writeKey(loc)
+            for (idx in locs.indices) {
+                writeKey(locs[idx], placers[idx])
             }
         }
     }
 
     @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
     fun onRetract(event: BlockPistonRetractEvent) {
         val locs = mutableListOf<Location>()
+        val placers = mutableListOf<Int>()
         val toRemove = mutableListOf<Location>()
 
         for (block in event.blocks) {
-            if (BlockUtils.isPlayerPlaced(block)) {
+            val placedBy = BlockUtils.placedByID(block)
+            if (placedBy != 0) {
                 locs.add(block.getRelative(event.direction).location)
+                placers.add(placedBy)
                 toRemove.add(block.location)
             }
         }
@@ -90,22 +99,22 @@ class PlayerBlockListener(
                 removeKey(loc)
             }
 
-            for (loc in locs) {
-                writeKey(loc)
+            for (idx in locs.indices) {
+                writeKey(locs[idx], placers[idx])
             }
         }
     }
 
-    private fun writeKey(block: Block) {
-        writeKey(block.location)
+    private fun writeKey(block: Block, placerID: Int) {
+        writeKey(block.location, placerID)
     }
 
-    private fun writeKey(location: Location) {
+    private fun writeKey(location: Location, placerID: Int) {
         val loc = location.hashCode().toString(16)
         location.chunk.persistentDataContainer.set(
             plugin.createNamespacedKey(loc.lowercase()),
             PersistentDataType.INTEGER,
-            1
+            placerID
         )
     }